Scientific amcvican ^cricsi 
 
 Home Mechanics 
 
 For Amateurs 
 
 BY 
 
 GEORGE M. HOPKINS 
 
 Author of ^'^ Experimental Science'' 
 
 3" J J 
 
 MuNN & Co., Publishers 
 
 SCIENTIFIC AMERICAN OFFICE 
 
 NEW YORK, 1903 
 
H 
 
 Two CoPi<ie Bfc.QKiweaL> 
 
 mrr 'it \pm 
 
 GLASS ft YXn- Mo. 
 COPY B, 
 
 Copyright, 190?, by Munn & Co. 
 All rights reserved. 
 
 Entered at Stationers' Hall, London, England, 
 
 
 Press of Andrew H. Kellogg 
 New Yokk, U. S. A. 
 
^/r 
 
 PREFACE 
 
 SPECIAL INTEREST ahvays attaches to a post- 
 humous work. It is not always, however, that 
 a work of this character possesses equal merit 
 with one entirel}^ completed before the death of the 
 author. As a rule such works have not had the ad- 
 vantage of the final perusal and correction by the 
 author. Such has not, however, been the case in the 
 present instance, for the following work by the late 
 George M. Hopkins, was completed before his death. 
 Tl ere is no doubt, however, that this volume will come 
 as a surprise to thousands Avho have closely followed 
 Mr. Hopkins' Avork, and who have enjoyed making 
 the many experiments described by him. The present 
 volume contains much matter which has never before 
 appeared in print, and some articles Avhich have al- 
 ready been published in the Scientific American. The 
 object of the work is to furnish food for thought to the 
 amateur, and to give him suggestions Avhereby he may 
 pass many pleasant hours in his Avork-shop. 3Ir. Hop- 
 kins Avas an expert mechanic. One of his chief pleas- 
 ures Avas to make experiments at his home in his Avell- 
 equipped Avork-shop and laboratory, and the Avork 
 described in the present volume is nearly all the result 
 of experiments made by him during such ^Mdle" hours. 
 It has been the intent of the author to make the present 
 
PEEFACE. 
 
 work as suggestive as possible. No complicated ap- 
 paratus is required iu carrying out the experiuieuts 
 described. Any one with ordinary mechanical inge- 
 nuity and having a lathe and a few tools can make most 
 of the experiments described in these pages. 
 
 A few articles by other authors have been included 
 as they are germane to the scope of the book. It is 
 hoped that ''Home ^Mechanics for Amateurs" will prove 
 helpful to as. many thousands as has ''Experimental 
 Science." 
 
Table of Contents 
 
 PART I. 
 
 Wood- WoR K I n g 
 
 An Inexpensive Turning Lathe. Turning. Wood-Working on a 
 Lathe. Work Bench and Tools for Woodwork. Whittling. 
 Different Shapes of Saw Teeth and the Way they Cut. A 
 Wrinkle in Sawing. Wood Carving 1 
 
 PART n. 
 
 How TO Make Household Orxamexts 
 
 Home-made Grilles and Gratings. Wall Ornaments. Pseudo- 
 Ceramics. Imitation of Majolica. Stained Glass and Ob- 
 jects of Wire Cloth. Japanese Portiere or Curtain. 
 Repousse. An Easy Method of Producing Bas-reliefs. 
 Ornamental Iron Work for Amateurs. Some Things in 
 Wire. Some Things in Burnished Brass. Forming Plaster 
 Objects 31 
 
 PART III. 
 
 Metal-Workixg 
 
 Sawing Metals. Soldering. Grinding and Polishing. Silver 
 Work. Metal Foot Lathe. Drills and Drilling. Centering 
 and Steadying. Chucking. Metal Turning. Chasing and 
 Knurling. Rotary Cutters. Easily made Slide Rest. In- 
 dex Plates for Gear Cutting. Gear Cutting Apparatus. 
 Hints on Model Making. Metal Spinning 89 
 
TABLE OF CONTENTS 
 
 PART IV. 
 
 Model Engines and Boilers 
 
 A Home-made Steam Engine. A Safe Way of Running a Small 
 Engine. A Miniature Caloric Engine. An Inexpensive 
 Water Motor 169 
 
 PART V. 
 
 Meteorology 
 
 Self-Recording Instruments. What may be learned by the Use 
 of the Meteorological Instruments. A Weather Vane. 
 Wind Pressure Gauge. Rain Gauge. A Metallic Ther- 
 mometer. A Simple Hygroscope. A Mercurial Barometer. 187 
 
 PART VI. 
 
 Telescopes and Microscopes 
 
 How to make a Telescope. The Microscope 207 
 
 PART VII. 
 
 Electricity 
 
 Practical Primary Battery. Electric Lighting for Amateurs. 
 The Electric Chime. Home-made Electric Night Lamp. 
 An Electrical Cabinet. Simple Electric Motor. Small 
 Electric Motor for Amateurs. How to make a Sewing 
 Machine Motor without Castings. A Design for an Electric 
 Launch Motor. How to make an Edison Dynamo and 
 Motor. The Utilization of 110 Volt Electric Circuits for 
 Small Furnace Work. Recording Telegraph for Amateurs. 
 How to make a Telephone 227 
 
PART I. 
 
 WOOD-WORKIISTG 
 
 AN INEXPENSIVE TURNING LATHE 
 
 THE BOY who has a turning lathe can readily 
 make many things which he might not feel 
 disposed to buy ; for example, he can make tops, 
 ninepins, and ornamental and useful objects 
 without much trouble and with very little expense. 
 The ancient lathe consisted of two conical points, sup- 
 ported in position by suitable standards, and the work 
 to be done was whirled on these points b}^ means of a 
 strong cord wrapi)ed once around the stick to be turned, 
 with the upper end attached to a spring pole and 
 the lower end secured to a treadle. The lathe we are 
 about to describe is one remove from this primitive 
 lathe of the olden time. It has the two standards with 
 points or dead centers, as thej would be called by ma- 
 chinists, but one of the points projects far enough from 
 the standard to receive a hard wood pulley, having 
 inserted in its side, at diametrically opposite points, 
 two spurs, which enter the end of the piece of wood 
 to be turned, so that when the pulley is revolved by 
 a belt, the wood will be turned on the centers. 
 
 This lathe is made almost entirely from strips of 
 hard Avood, 1 inch thick and 2^ inches wide. These 
 strips can be easily furnished by any carpenter, cabinet 
 maker or wagon maker, and an old table may be used 
 for the frame. 
 
 The bed-piece is made of two such strips, 2 feet long, 
 and a block of the same material, 1 inch square and 2 
 
 [IJ 
 
2 HOME MECIIAXICS FOR AMATEURS 
 
 inches long, at one end is placed between the strips 
 and held in place bv wood screws. A piece of thick 
 j)aper is placed between the block and one of the strips, 
 
 Fig. 1. An Easily Constructed Wood Lathe. 
 
 to make the space between the strips a little wider than 
 the thickness of the block. 
 
 To each end of the bed is secured a foot, consisting 
 of a piece of the same strip, 6 inches long. These are 
 secured by wood screws passing upward through holes 
 
HOME MECHAmCS FOR AMATEUES 3 
 
 in the lower edoe of the foot, the holes being deeply 
 countersunk to let in the heads of the screws. 
 
 The head stock and tail stock are nearly alike, in 
 so far as the wood work is concerned. Each is formed 
 of three pieces of the strip from Avhich the bed is 
 made. To opposite sides of a central piece, 74 inches 
 long, are secured side pieces 4 inches long, by means 
 of screws. These side pieces must of course be square 
 on the end so that they will set squarely on the bed 
 when the projecting end of the central piece is inserted 
 
 Fig. 2. Work in the Lathe. 
 
 in the slot of the bed. The loAver end of the center piece 
 is mortised to receive a Avooden key or wedge, which 
 clamps the tail stock to the bed. In the tail stock. -J 
 inch from the top, is bored a hole in which is inserted 
 a large wood screw, the point of which is filed conically, 
 as shown. In the head stock is also bored a hole 
 corresponding with that of the tail stock, to receiA^e a 
 large wood scrcAv, i or 5-16 inch in diameter. The head 
 of this screw is cut off, and the head (^nd is filed off 
 conically. This point should project about an inch 
 from the head stock, and to the plain, smooth pro- 
 
4 HOME MECHANICS FOE AMATEUES 
 
 jeeting part of the screw is fitted a small grooved 
 pulley about 1^ inches in diameter at the bottom of 
 the groove. The pulley should be of Babbitt metal 
 or type metal. In the side of the pulley, about J 
 inch from the hole, are inserted two small screws, about 
 f inch long, which are allowed to project ; these screws 
 are filed to form chisel-edged spurs for driving the 
 work in the lathe. The points should project as far 
 as the point of the conical end of the large screw. 
 
 The lower end of the head stock — which is about 2^ 
 inches long — is inserted between the strips forming 
 the bed, and fastened with screws; a piece of paper 
 being inserted to increase the space between the strips, 
 so that the tail stock can be moved easily. 
 
 The wood to be turned has a small hole^ — say, ^ inch 
 — bored in the center at each end, and is placed be- 
 tween the centers; the tail stock having been clamped 
 in the proper position, the tail screw is turned with 
 a screw driver until it is forced a short distance into 
 the end of the stick. Then the stick is driven for- 
 ward on to the center, and spurs of the head stock, and 
 the screw in the tail stock is turned so as to hold the 
 stick, but not enough to create friction. A drop of oil 
 should be put on each center, and the pulley should 
 be oiled. 
 
 The rest on which the gouge or chisel is placed while 
 the turning is being done consists of a piece of the 
 wooden strip with a slot in it to allow a 5-inch car- 
 riage bolt to pass through. This bolt extends through 
 the slot of the bed, and through a block or washer be- 
 low. A wing nut is placed on the bolt so that the rest 
 may be clamped in any desired iDosition. To the end of 
 the slotted piece is secured a short piece of the wooden 
 
HOME MECHAmCS FOR AMATEURS 5 
 
 strip by two screws passing through the slotted piece 
 and into the wood. The wooden rest should be beveled 
 as shown. 
 
 Jt must be frankly admitted this lathe is not an 
 elegant machine to look at, but it is capable of turning 
 out quite reputable small work. 
 
 Having made the lathe, it will be necessary to pro- 
 vide some means to drive it. In almost every city and 
 town may be found old sewing machine tables, which 
 have been taken in trade as old iron. One of these can 
 be bought cheaply, and when the treadle is turned 
 around and a round leather belt applied to the lathe 
 pulley and the sewing machine wheel, the arrangement 
 is complete. 
 
 Some one may be found good enough to loan a sew- 
 ing table for the purpose. In this case, an assistant 
 will be obliged to work the treadle while the turning 
 is being done. 
 
 As the flywheel should be heavy, not less than 20 
 pounds, and as it should be about 20 inches in diameter 
 to secure the desired speed, it is perhaps better to fit 
 up the lathe with a wheel and table better adapted 
 to it than a sewing machine wheel and table would be. 
 
 The lathe shown in the illustration is mounted on a 
 common kitchen table of the smallest size. In this 
 case, an old wheel is selected at the junk shop; one 
 with a groove in the edge is to be preferred, but a flat 
 rim will answer. The one here shown has a flat face 
 and is provided with a shaft, a crank and standards. 
 The standards are inverted and fastened with screws 
 to the under side of the table top. 
 
 A strip of board extending lengthwise of the table 
 is attached to the rear legs with screws, and the piece 
 
6 
 
 HOME MECHANICS FOR AMATEURS 
 
 of board forming the treadle is hinged to it in position 
 to receive the screw Avhich passes through the lower 
 end of the pitman rod or connecting rod, the npper 
 end being apertnred to receiA e the crank pin. A ronnd 
 leather belt is used in this case. 
 
 The tools for turning are not very expensive; with 
 two gouges and one or two flat chisels a great variety 
 of work mav be done. 
 
 TURNING 
 
 There is no secret in turning. It requires a great 
 deal of practice to become an expert, but beyond acquir- 
 ing the first principles nothing further than practice 
 is required. When reducing a piece of wood to the 
 
 Fig. 3. Lathe Turning Tools. 
 
 desired approximate size, the gouge is held on the 
 rest with its handle-end inclined downward at an angle 
 of about 60° with the horizontal, the rest being near 
 the work, and the gouge is moved back and forth on the 
 
HOME MECHANICS FOR AMATEURS 7 
 
 rest, takiiiij; off a slii»lit sliaviug each lime it is moved. 
 The handle is held in the right hand, while the blade 
 of the gouge is held in the left hand, with the thumb 
 pressing on the coneave side. If a plain cylinder is 
 required it may be made by using the flat chisel, lay- 
 ing the beveled edge on the work in such a manner as 
 to produce a drawing cut as the wood passes the edge. 
 If the work is to be cut into at right angles or at any 
 other angle, the chisel is placed on its edge on the rest 
 and held firmly while moving it forward. 
 
 In cutting concave forms the gouge is made to make 
 a drawing cut by placing it partly on its edge on the 
 rest. It will be found necessary in either of these 
 cases to hold the tool very firmly on the rest to pre- 
 vent the edge from drawing itself forward on the wood 
 and spoiling the work. By practice the art of wood- 
 turning can be readily acquired even by the use of 
 the ^'Simple Lathe." 
 
 For hard wood and ivory a different class of tools 
 is required. The chisels are all flat, not oblique; some 
 of them have edges that are square across; some have 
 V-shaped points and others are round-nosed. For 
 under-cuts and odd work, special tools are bent at 
 different angles. Flat work, such as rosettes, etc., is 
 chucked upon the face plate, or attached with screws 
 to a board fixed to the face plate. 
 
 In finishing work the use of fine sandpaper is admis- 
 sible, but it never should be used to correct poor turn- 
 ing. Wood work, when smoothed a little with fine 
 sandpaper, may be finished by applying to it with a 
 cloth a mixture of shellac varnish and linseed oil, in 
 proportion of about one part of oil to two of shellac. 
 Only a little is applied to the cloth at one time, the pol- 
 
8 HOME MECHANICS FOR AMATEURS 
 
 ish being well shaken before it is applied. The work in 
 the lathe is rapidly revolved until it is brightly polished 
 and the shellac varnish is hard. If desired, the work 
 may be stained before it is polished. The stains are 
 readily obtainable, and are described in the "Scientific 
 American Cyclopedia of Receipts, Notes and Queries." 
 
 WOOD-WORKING ON A LATHE 
 
 It is not the intention of the writer to enter largely 
 into the subject of wood-working, but simply to sug- 
 gest a few handy attachments to the foot lathe which 
 will greatly facilitate the operations of the amateur 
 
 
 Fig. 4. Saw Table 
 
 IH^^^^^^^^^ " 
 
 wood worker, and will be found very useful by almost 
 any one working in wood. It is not an easy matter 
 to split even thin lumber into strips of uniform width 
 by means of a handsaw, but by using the circular saw 
 attachment, shown in Fig. 4, the operation becomes 
 rapid and easy, and the stuff may be sawed or slit at 
 any desired angle or bevel. The attachment consists 
 of a saw mandrel of the usual form, and a wooden table 
 supported by a right angled piece. A, of round iron 
 
HOME MECHAOTCS FOR AMATEURS 9 
 
 fitted to tlie toolpost aud clamped by a woodeu cleat, 
 B, which is secured to the under side of the table, 
 split from the aperture to one end, and provided with 
 a thumbscrew for drawing the parts together. By 
 means of this arrangement the table may be inclined 
 to a limited angle in either direction, the slot through 
 which the saw projects being enlarged below to admit 
 of this adjustment. 
 
 The back of the table is steadied by a screw which 
 rests upon the back end of the tool rest support, and 
 enters a block attached to the under side of the table. 
 The gauge at the top of the table is used in slitting and 
 for other purposes which will be presently mentioned, 
 and it is adjusted by aid of lines made across the table 
 parallel witli the saw. 
 
 Fig. 5. 
 Saw between beveled Washers. 
 
 Fig. 6. Fig. 7. 
 
 Moulding Knives. 
 
 For the purpose of cross-cutting or cutting on a 
 bevel a thin sliding table is fitted to slide upon the 
 main table, and is provided with a gauge which is 
 capable of being adjusted at any desired angle. For 
 cutting slots for panels, etc., thick saws may be used, 
 or the saw may be made to wabble by placing it be- 
 tween two beveled washers, as shown in Fig. 5. 
 
 The saw table has an inserted portion, C, held in 
 place by two screws which may be removed when it 
 is desired to use the saw mandrel for carrying a sticker 
 head for planing small strips of moulding or reeding. 
 
10 
 
 HOME MECHANICS FOR AMATEURS 
 
 (Figs. G and T.j Tlu' head for lioldiiig the moulding 
 knives is best made of good tough brass or steam metaL 
 The knives can be made of good saw steel about ^ inch 
 thick. They may be filed into shape and afterward 
 tempered. They are slotted and held to their places 
 on the head by means of i-inch machine screws. It is 
 not absolutely necessary to use two knives, but when 
 only one is employed a counterbalance should be fas- 
 tened to the head in place of the other. All kinds of 
 moulding, beading, tonguing and grooving may be done 
 w^ith this attachment, the gauge being used to guide the 
 
 Turning Fluted Work. 
 
 edge of the stuff. If the boards are too thin to sup- 
 port themselves against the action of the knives they 
 must be backed up by a thick strip of wood planed 
 true. The speed for this cutter head should be as great 
 as possible. 
 
 Fig. 8 shows an attachment to be used in connection 
 with the cutter head and saw table for cutting straight, 
 spiral or irregular flutes on turned work. It consists 
 of a bar, D, carrying a central fixed arm, and at either 
 end an adjustable arm, the purpose of the latter being 
 to adapt the device to work of different lengths. The 
 arm projecting from the center of the bar, D, sup- 
 
IIO]\rE MECHANICS FOE AMATEUES 
 
 11 
 
 ports an arbor Iia\'inj;al one end a socket foi* rccciviii^ii^ 
 the twisted iron bar, E, and at the other end a center 
 and a short finder or pin. A metal disk havini;- three 
 spurs, a central aperture and a series of holes equally 
 distant from the center and from each other, is at- 
 tached by its spurs to the end of the cylinder to be 
 fluted, and the center of the arbor in the arm, D, enters 
 the central hole in the disk while its finger enters 
 
 Fig. 9. 
 Moulding Irregular Work. 
 
 Fig. 10. 
 
 one of the other holes. The opposite end of the cylin- 
 der is supported by a center screw. A fork attached 
 to the back of the table embraces the twisted iron, E, 
 so that as the wooden cylinder is moved diagonally 
 over the cutter it is slowly rotated, making a spiral 
 cut. After the first cut is made the finger of the arbor 
 is removed from the disk and placed in an adjoining 
 hole, when the second cut is made, and so on. 
 
12 
 
 HOME MECHANICS FOE AMATEUES 
 
 Figs. 9 and 10 show a convenient and easily made 
 attachment for moulding the edges of irregular work, 
 such as brackets, frames, parts of patterns, etc. It 
 consists of a brass frame, F, supporting a small man- 
 drel turning at the top in a conical bearing in the 
 frame, and at the bottom upon a conical screw. A very 
 small grooved pulley is fastened to the mandrel and 
 surrounded by a rubber ring which bears against the 
 face plate of the lathe, as shown in the engraving. The 
 frame, F, is let into a wooden table supported by an 
 
 Fig. 11. Scroll Saw. 
 
 iron rod which is received by the tool rest holder of 
 the lathe. The cutter, G, is made by turning upon a 
 piece of steel the reverse of the required moulding, and 
 slotting it transversely to form cutting edges. The 
 shank of the cutter is fitted to a hole in the mandrel and 
 secured in place by a small set screw. The edge of the 
 work is permitted to bear against the shank of the cut- 
 ter. Should the face plate of the lathe be too small to 
 give the required speed, a wooden disk may be attached 
 to it by means of screws and turned off. 
 
HOME MECHANICS FOR AMATEURS 
 
 13 
 
 Fig-s. 11, 12, aud 13 represent a cheaply and easily 
 made scroll saw attachment for the foot lathe. It is 
 made entirely of wood and is practically noiseless. The 
 board, H, supports two uprights, I, between which is 
 pivoted the arm, J, whose under side is parallel with 
 the edge of the board. A block is placed between the 
 uprights, I, to limit the downward movement of the 
 arm, and the arm is clamped by a bolt which passes 
 through it and through the two uprights and is pro- 
 vided with a wing nut. 
 
 A wooden table, secured to the upper edge of the 
 board, H, is perforated to allow the saw to pass 
 
 Fig. 12. 
 Details of Saw. 
 
 Fig. 13. 
 
 through, and is provided with an inserted hard- 
 wood strip which supports the back of the saw, 
 and which may be moved forward from time to 
 time and cut off as it becomes worn. The upper 
 guide of the saw consists of a round piece of 
 hard wood inserted in a hole bored in the end 
 of the arm, J. The upper end of the saw is secured in a 
 small steel clamp pivoted in a slot in the end of a 
 wooden spring secured to the top of the arm, J, and the 
 lower end of the saw is secured in a similar clamp 
 pivoted to the end of tlie wooden spring, K. Fig. 13 
 is an enlarged view showing the construction of clamp. 
 The relation of the spring, K, to the board, H, and to 
 
14 HOME MECHANICS FOPt z\MATEUES 
 
 the other part is showu iu Fig. 12. It is attached to the 
 side of the board and is pressed upward by au adjust- 
 ing screw near its fixed end. 
 
 The saw is driven by a wooden eccentric phiced on the 
 saw mandrel shown in Figs. 4 and 5, and the spring, K, 
 always pressed upward against the eccentric by its own 
 ehisticity, and it is also drawn in an upward direction 
 by the upper spring. This arrangement insures a con- 
 tinuous contact between the spring, K, and the eccen- 
 tric, and consequently avoids noise. The friction sur- 
 faces of the eccentric and spring may be lubricated 
 with tallow and plumbago. The eccentric may, with 
 advantage, be made of metal. 
 
 The tension of the uppc^r spring may be varied by 
 putting under it blocks of ditferent heights, or the 
 screw which holds the back end may be used for this 
 purpose. 
 
 The saw is attached to the lathe by means of an iron 
 bent twice at right angles, attached to the board, H, and 
 fitted to the tool rest support. The rear end of the saw- 
 ing apparatus may be supported by a brace running to 
 the lower part of the lathe or to the floor. 
 
 The simple attachments above described will enable 
 the possessor to make man^^ small articles of furniture 
 which he would not undertake without them, and for 
 making models of small patterns they are almost in- 
 valuable. 
 
 WOEK BENCH AND TOOLS FOE WOODWORK 
 
 The first thing rexpiirc^d by the amateur workman is 
 a bench with a few tools for wood working. The bench 
 need not necessarily be a long and heavy structure like 
 
HOME MECHAmCS FOE AMATEUES 15 
 
 a carpenter's bench, as the work to be done by the ama- 
 teur is mostly small, requiring but little material and 
 small room. A table like that shown in connection 
 with the simple lathe will answer, or the rear portion 
 of the lathe table may be used as a bench. A small 
 wooden vise is secured to the side of the table near the 
 left hand end, and in the top of the table is inserted a 
 common flat headed wood screw, which may be screwed 
 down even with the top of the table, or raised i or :i 
 inch, as the work ma^^ require. This screw takes the 
 place of the usual bench dog, and holds the end of a 
 piece of wood while it is being planed. Two planes are 
 required to begin with, a jack plane and a smooth plane. 
 A good fine cross-cut saw will probably answer for 
 all ordinary sawing, and it may be used as a rip saw 
 when only a little of this kind of work is required. Two 
 chisels, one f inch, the other ^ inch, and two gouges of 
 about the same width, will be needed. A hammer and 
 a screwdriver, together with a brad awl and a foot rule 
 complete an outfit that will enable the owner to do a 
 great deal of work. 
 
 Of course a good oil stone should be at hand for 
 sharpening the tools, and they should be kept shai'p. 
 
 Chisels and plane irons must be held at an angle of 
 about 60° to the surface of the stone and moved back 
 and forth on the stone until an edge is produced. The 
 straight side of the tool must be kept from the oil stone. 
 
 While the tool is being sharpened the oil stone must 
 be lubricated with a few drops of sewing machine oil or 
 bicycle oil. When the tools need grinding it is advis- 
 able to have the Avork done by a competent workman. 
 
 The plane irons are set so that the edge is seen all the 
 A\'av across the Avood of the plane and secured by driv- 
 
16 HOME MECHANICS FOR AMATEURS 
 
 ing in the wedge. If the tool projects so as to make a 
 thick shaving, the wedge is loosened slightly and tlie 
 iron is made to rise slightly by tapping with a hammer 
 on the top of the plane. The iron may be adjusted lat- 
 erally by tapping the iron on one edge or the other near 
 the top, and it may be forced downward by a few light 
 taps on the upper end. 
 
 After some observation — ever}^ boy has opportunities 
 for observation — and after practice, the amateur will 
 be able to do an ordinary job of carpentry, and he will 
 seek after a few more tools, such for example as a try- 
 square, a bit-stock and a few bits, a few clamps and a 
 glue pot. He can then enter into the work heartily, and 
 not only make needed repairs, but construct many plain 
 little articles such as boxes Avith hinged covers, cabi- 
 nets, screen frames, etc. The main requirements are to 
 construct each part as carefully as possible, to assem- 
 ble the parts with equal care, and to never use plugs or 
 putty, or in other ways patch up for bad workmanship. 
 If a mistake is made, it is generally better to throw the 
 part away and begin again rather than to patch. 
 
 WHITTLING 
 
 The boy who is a good whittler will make a good me- 
 chanic, or will at least understand mechanics well 
 enough to know a good job from a poor one, and will 
 be able to help himself in many an emergency. Real 
 proficiency with a jack-knife implies a knowledge of 
 mechanics and exhibits an ai^titude for mechanical 
 work which only needs opportunity and encouragement 
 to reach a useful stage of development. 
 
 A jack-knife is a very simple tool, but without doubt 
 
HOME MECHAXICS FOR AMATEUKS 17 
 
 it is more generally useful tliau au}^ other. For whit- 
 tling, an ordinary two or four-bladed knife should be 
 selected. It should have a good-sized handle and its 
 blades should be fine and well tempered. With the 
 knife should be purchased a fine, sharp oil stone, and 
 the knife should be kept sharp, as it is impossible even 
 
 
 
 \, 
 
 
 
 ^ 
 
 
 'K 
 
 
 
 ^-J 
 
 
 ^E,^ ^'^^^S 
 
 
 ""^ 
 
 ^^^^Tz 
 
 T~IZ^^ 
 
 ^^g 
 
 
 1 
 
 
 ^1 
 
 i 
 
 1 
 
 Fig. 14. Knives adapted for Whittling. 
 
 for an expert workman to do good work with a dull 
 knife. 
 
 In sharpening the knife, the blade should be kept at 
 an angle of about 20° with the face of the 
 stone and rubbed back and forth the full length of the 
 stone about an equal number of times for opposite sides 
 of the blade, until it appears to be sharp, the stone 
 meantime being lubricated with water or oil ; then it 
 may be stropped like a razor on a strip of leather until 
 it is literally as sharp as a razor. 
 
 In whittling curious and ornamental objects, sea- 
 soned straight-grained white pine should be selected. 
 
18 HOME MECHANICS FOR AMATEUES 
 
 The piece should be a little larger than the finished 
 work, and the design should be laid out in pencil on one 
 side of the block, when it can be sawed out with a scroll 
 saw. If the form can be traced on the edge of the work 
 much whittling may be avoided by doing more sawing. 
 The knife work may now proceed. It is well to begin 
 with the heavier portions and finish with the lighter 
 portions. 
 
 As much should be done as possible without the use 
 of sand paper. If it can all be done without sand paper 
 so much the better. It will sometimes be found nec- 
 essary to put on the finishing touches with a piece of 
 very fine sand paper. Blades of different forms are 
 found useful, and in some kinds of work a penknife 
 blade which has been broken off rather short will prove 
 exceedingly useful when the blade has been repointed. 
 
 The saw used for shaping the work may be like the 
 one on pages 12 and 13, or one of the small scroll saw- 
 ing machines so much in use at one time would be still 
 better. 
 
 A very pretty example of whittling is the chain whose 
 links are formed from a single bar of wood of 0-shaped 
 cross section. To make a good job the bar should be 
 evenly spaced, and the links drawn on the sides of the 
 bar. Then holes are bored diagonally through the bar. 
 At the angle the cutting proceeds slowly and cautious- 
 ly, finishing the link as far as possible before it is cut 
 loose. If any sandpapering is to be done it should be 
 done as far as possible before the link is cut loose. In 
 the example shown, only a iDortion of the wooden bar 
 has been formed with links, the remainder being left 
 to give an idea of the method. 
 
 It is more difficult to whittle a pair of pliers from a 
 
HOME ]\[ECHAXICS FOR AMATEUES 19 
 
 single piece of wood, so that the jaws work freely, and 
 at the same time the joints are neat. 
 
 Fig. 15. Examples of Whittled Work. 
 
 The blank for the pliers is sawed from ^-inch pine. 
 The sides of the pliers where the joint is to be formed 
 are finished and the joint is carefnlly laid out in fine 
 
20 HOME MECHANICS FOR AMATEURS 
 
 lines. Then with a very thin knife blade inserted from 
 each side the central portion of the joint is cut through ; 
 thin incisions are made in the sides to intersect the 
 other cuts. The jaws of the pliers are carefully sep- 
 arated by cutting from either side, and the cuts which 
 separate the inside piece are then made with great care. 
 The outside of the jaws and the handles are now fin- 
 ished. In cutting the joint the wood is somewhat com- 
 pressed by the insertion of the knife, and the joint ap- 
 pears badly made. By soaking the wood in water for 
 a half-hour or so the wood resumes its normal condi- 
 tion, and the joint becomes tight. When the wood is 
 dry the finishing may be done with a knife and with 
 fine sand paper. 
 
 The tower containing the balls and the revolving 
 spindle is cut from a single bar of wood, with the balls 
 and spheroid formed with a knife in the places they 
 now occupy. The design is carefully drawn on the bar, 
 and the work begins by making a diagonal cut across 
 each corner for the corner posts, not cutting through 
 the floors of the different stories. Then the inner 
 postern is cut roughly in the form of a cylinder. The 
 cross cuts are then made and the pieces are shaped into 
 balls. The spindle in the lower story is formed in the 
 same w^ay, but it is cut loose by running the point of 
 the knife into the apexes of the cones formed above 
 and below^ the spheroid, thus at one operation forming 
 the points of the spindle and the bearings for them. 
 The posts at the corners are left as large as possible 
 and finished finally by taking off only enough w^ood to 
 make them straight and square. 
 
 An anchor with its cross bar and ring is made of a 
 single piece of wood a little thicker than the width of 
 
HOME MECHANICS FOR AMATEUKS 21 
 
 the flukes. The cross bar is whittled out parallel with 
 the shank of the anchor, and the curved end is cut 
 across the "rain. The hole in the shank is formed at 
 the same time the curved end is cut loose. The shoulder 
 on the bar is thus formed and the bar is pushed through 
 the hole in the shank. A small mortise is made in the 
 bar to receive the key which keeps it in place. The ring 
 at the top of the anchor is made in the same manner as 
 the first link of the chain. The anchor looks very sim- 
 ple, but it is in reality quite difficult. 
 
 In all these examples the wood should not be cut 
 away more than is necessary, except to finish. 
 
 The puzzle shown assembled and separated cannot 
 readily be described. The pieces are notched so that 
 they will go together and form the symmetrical whole, 
 as shown in the engraving. 
 
 DIFFERENT SHAPES OF SAW TEETH AND THE 
 WAY THEY CUT* 
 
 The accompanying sketches show the different shapes 
 of saw teeth and the way that they cut the timber. Fig. 
 16 shows the dress of a shingle saw tooth. By examin- 
 
 \\\W -/////////////A -wwwwVwVWW ' 
 
 Pig. 16. The " Dress " of a Shingle Saw Tooth. 
 
 ing it, it will be seen that it is a ^'sprung tooth," and 
 the teeth cut on alternate sides of kerf, taking two teeth 
 to clear out the kerf on both sides. The bevel of the 
 teeth gives it a shear cut on the timber. The Avood will 
 slip on the edge of the teeth, wearing them on the inside 
 and leaving the outer corner full and sharp, and a cor- 
 * From the Saw Mill Gazette. 
 
22 
 
 HOME MECHANICS FOR AMATEFRS 
 
 ner to clear up the side of the kerf, thus making smootli 
 lumber. 
 
 Fig. IT shows a square dressed tooth. The wood 
 
 Fig. 17. A Square 
 Dressed Tooth. 
 
 Fig. 18. 
 A Vertical Saw with Square Teeth. 
 
 wears off the corners, leaving them dull, and they will 
 fly from timber to the other side if the wood is not 
 equal in hardness, and lead the saw to that side of the 
 log. This trouble is found in wood with a hard and 
 soft grain or in knots, but with the beveled teeth the 
 sharp corner will lead the saw straight. 
 
 Fig. 18 shows a vertical saw with square teeth, a very 
 common dress. The wood wears the out corner off, 
 leaving it round or blunt, and as there is nothing to sup- 
 port the inside of the teeth, they will fly from the wood. 
 
 Fig. 19. A Swaged Tooth of the Same Kind as Fig. 18. 
 
 and in the up stroke of the saw wear against the side of 
 the kerf until w^orn in the shape shown in cut. 
 
 Fig. 19 is a swaged tooth of the same kind of saw and 
 is a ver}^ good dress for sash, muley, gang, and other 
 
HOME MECHAXICS FOR AMATEURS 
 
 23 
 
 saws nsiii<j; li.i>ht fet'd, but for heavy feed it is better to 
 swage the teeth out on both sides and joint off for set. 
 By referring to Fig. 20 it is seen that all teeth of this 
 shape cut with a scrape cut, not with edge cutting, like 
 
 a chisel, but with the edge set at right angle with the 
 line of cut. For soft w^ood, such as white pine, ham- 
 mer the top of the teeth, turning the edge down enough 
 to give a cutting edge downward. Figs. 21 and 22 are 
 circular log saws. 
 
 Fig. 21 shows a side view of a tooth. It is seen that 
 the back of the tooth lies close to the wood, and the 
 
 Fig. 21. Side View of Circular Saw Tooth. 
 
 tooth may be filed thin without danger of breaking. 
 This dress of saws cut Avith a chisel cut, will carry more 
 feed than any other, and at the same time do the best of 
 work. 
 
u 
 
 HOME MECHANICS FOE AMATEURS 
 
 Fig. 22 shows the shape of the edge of the same tooth. 
 It being hollow on the edge, with the corners sharp, 
 the wood will fiv or slip from the corners, not wearing 
 them as much as a square tooth, leaving a good corner 
 
 "iiiiii ^ 
 
 Fig. 22. 
 Edge of Circular Saw Tooth. 
 
 Fig. 23. 
 A Square Dressed Tooth. 
 
 to clear the sides of the kerf. It will be seen by refer- 
 ring to Fig. 22 that it takes two teeth, one on each 
 side of the saw, to cut both sides of kerf, but in this 
 dress each tooth cuts both sides, and again, if a beveled 
 sprung tooth is forced to do more than a medium 
 amount of duty, it will fly into the wood and be in dan- 
 ger of tearing off the teeth. 
 
 In Fig. 23 is seen a square dressed tooth. All teeth 
 swaged with a square dress leave the corners rather 
 weak and not much to joint off the side in setting. 
 This shows one such tooth cutting through cross 
 grained or twisted timber, a sharp corner but nothing 
 to clear the side of the kerf, the cross grain filling so 
 much of the kerf as to rub on the plate of the saw and 
 heat it. 
 
HOME MECHANICS FOR AMATEUKS 25 
 
 Fig. 24 refers to a dress for hand and other saws that 
 
 Fig. 24. Dress for Hand and other Saws, 
 
 is nsed for cross-cutting soft wood that is to be cut very 
 smooth. 
 
 A WRINKLE IN SAWING 
 
 A try-square is not always at hand when it is desired 
 to saw a sticlc, and when it is handy some mechanics 
 prefer to work by ^^guess" than otherwise. When a 
 bright straight saw is placed upon a stick or on the edge 
 
 Fig. 25. Reflection Substituted for the Try Square. 
 
 of a board, the reflection of the stick or board in the 
 saw is sufficiently well defined to permit of placing the 
 saw so that the reflected image coincides with the object 
 reflected, forming a continuous straight line. If the 
 sawing is done while the image and the stick are in line, 
 the stick Avill be cut at right angles. 
 
 It is obvious that a line may be drawn at right angles 
 to the stick by arranging the saw as shown in Fig. 26. 
 If, after forming this line, the saw be placed across the 
 stick so that the line and its reflected image and the 
 
26 HOME MECHANICS FOE AMATEUES 
 
 stick and its reflected image form a square, with the 
 reflected image and the stick lying in the same plane, 
 
 Fig. 26. Laying out Work by Reflection. 
 
 Fig. 27. Forty-five Degree Angle by Reflection. 
 
 as shown in Fig. 27, the stick ma}^ be sawed at an angle 
 of forty-five degrees, provided the saw is held in the 
 same position relative to the stick. 
 
 WOOD CARVING 
 
 To one having an idea of form and proportion, wood 
 carving is not very diflflcult, even though a practical 
 knowledge of drawing and modeling be wanting. Cre^d- 
 
Tro:\rE imechaxtcs for A]\rATETTES 2: 
 
 i table specimeus of carving have heeii |)r()(lneed bv 
 means of the pocket knife alone, by persons having 
 dextrous hands and good eyes; but it takes a good 
 workman to produce a fine job with poor tools, or none 
 at all, therefore the average wood carver will be obliged 
 to rely somewhat upon tools and appliances. In fact, 
 the more complete the set of tools and the more perfect 
 the accessories, the more readily can the work be done 
 and the more satisfactory the result. 
 
 Fig. 28. Violet Panel. 
 
 The principal tools are gouges, chisels, parting tools, 
 curA'ed and straight, a heavy mallet, a light mallet, a 
 solid bench, and some clamps. As to materials: For 
 the beginner soft woods are best, such as pine. Avhite 
 wood, or cedar. After a little experience, pear, black 
 Avalnut, and oak may be tried. Nine-tenths of the dif- 
 ficulty in carving is in working one's self up to the 
 
28 
 
 HOME MECHANICS FOR AMATEUES 
 
 point of setting out in the work. The chances are that 
 in the beginning the tyro wiU not succeed in producing 
 the exact forms desired; but progress will be made with 
 every successive trial. 
 
 It is, indeed, difficult to give any explicit directions 
 for carving. We might almost say, here are the ma- 
 terials, the tools, and the design. The whole of carving 
 is to take these tools and cut this design from this piece 
 of material, using your own judgment, at the same 
 time "making haste slowly." 
 
 Fig. 29. Carvirxg Tools. 
 
 
 Fig. 30. 
 
 Edge View 
 
 of Tools. 
 
 The tools required are shown in Fig. 29, 1 being a 
 firmer, 2 a straight gouge, 3 a curved gouge, 4 a bent 
 chisel, 5 a front-bent gouge, 6 a back-bent gouge, 7 a 
 parting tool, 8 a curved parting tool, and 9 a macaroni 
 tool. These tools can be purchased either separately 
 or in sets. There are other forms and many different 
 
HOME MECHAXICS FOE AMATEURS 29 
 
 sizes. It is well to begin with a half dozen medinin 
 sized tools, and then learn by experience what further 
 tools are required. A flat and curved chisel and a flat 
 and curved gouge, each one-half inch wide, a narrow 
 deep gouge, and a parting tool are sufficient for the 
 first effort. 
 
 The design is marked upon the wood to be carved, 
 and the outline is shaped by means of a scroll saw, if 
 the design is to be in high relief, and the most promi- 
 nent is isolated from the rest. Avoid cutting too 
 deeply, or raising slivers that run into the wood and 
 spoil the work. Where the carving is done on a flat 
 surface in low relief, gouges having little curvature 
 are required. 
 
 The tools should be kept as sharp as possible, to se- 
 cure smooth work and to economize labor. Carving 
 tools are usually sharpened from both sides by means 
 of suitable oil stone slips and by leather strops charged 
 with crocus. 
 
 The wood while being carved is held in place on the 
 bench by means of screw clamjjs, or by pointed screws 
 passing upward through the bench into the back of 
 the work. 
 
 In Fig. 28 is shown a panel of violets, which may be 
 copied after some experience is gained. It is easier, 
 however, to copy other carvings than to produce the 
 work from engravings. 
 
 Simple subjects should be chosen, and no work 
 should be passed until it has been made as perfect as 
 the tools, materials, and ability of the carver will per- 
 mit. A final finish imparted with tine sandpaper is ad- 
 missible ; but neither sandpaper nor putty should be de- 
 pended upon as material aids in this kind of work. 
 
PART II. 
 
 hoay to make household 
 or^^ame:n^ts 
 
 home made grilles and gratings 
 
 A DWELLING HOUSE without ornamentation 
 of the class mentioned above indicates one of 
 three things — either the owner or occupant 
 does not appreciate the value of this kind of 
 home decoration or he does not possess the skill to 
 make or the power to purchase it. It is true, the 
 beautiful metal and wood work now manufactured for 
 this purpose is very expensive; but it is also true that 
 something equally as beautiful may be had without 
 much trouble or expense. 
 
 The grilles shown in Figs. 31, 32, and 33 are made of 
 rope, sized, bent into shape, dried, glued in a wooden 
 frame and finally painted an appropriate color or 
 gilded or bronzed. These ornaments when placed in a 
 doorway or w indow or across a hall from the stairway 
 to the wall, or in some corner in the library, add won- 
 derfully to the appearance of the room. 
 
 The materials required are some iV inch sash cord, 
 glue, round sticks or doweling t\ inch in diameter, 
 paraffine (a paraffine candle will do), some strips of 
 wood, and paint or varnish. 
 
 There are in the present case only two fundamental 
 forms for the spindles or bars, but these are combined 
 in several different ways, as shown in Fig 36. The spin- 
 
 [31] 
 
'62 
 
 HOME MECHANICS FOR AMATEURS 
 
 die most used is sliOAvn in Fig. 34. It is formed by 
 winding- the sash cord — which has been previously 
 steeped in the glue size — upon the wooden rod. The 
 rod is coated with melted paraffine before use, to pre- 
 vent the size from adhering, and equidistant marks are 
 made upon the rod as guides for the winding. These 
 marks are 1^ inches apart. The winding can be easily 
 done by placing one end of the wooden rod in a vise, 
 driving a tack through the end of the rope into the rod. 
 If every turn of the rope around the rod is made to co- 
 incide Avith one of the marks, the spindle will be true 
 enough for all purposes. A tack should be driven 
 
 Fig. 31. Grille for Double Doors. 
 
 through the end of the finished spiral into the rod to 
 prevent the rope from unwinding. A number of rods 
 will be required. Part of the spindles should be wound 
 in a right-handed direction and the remainder in a 
 left-handed direction. The rope should be allowed 
 to stand for a day or so to dry. It is well, espe- 
 cially in warm weather, to add to the size some oil of 
 cloves or carbolic acid to prevent it from souring while 
 drying. 
 
 The other form of spindle is shown in Fig. 35. This 
 is made by bending the sized rope around pins driven 
 into a board in two rows, the pins of one row alternat- 
 
HOME MECHANICS FOE AMATEURS 33 
 
 Fig. 32. Rope Grille for Window, Door, or Hall. 
 
 ing* in position with those of the other row. The board 
 
 and pins are covered with paraffine, as in the other case. 
 
 The spiral spindles may be combined with each 
 
 other, as shown at a^ h, c, d, and e in Fig. 36, and with 
 
 Fig. 33. Grille for Window. 
 
34 
 
 HOME MECHANICS FOR AMATEURS 
 
 a straight rod, as shown at /. At g they are shown in 
 combination with the zigzag rope. At // the zigzag rope 
 is shoAvn in combination with straight rods. 
 
 The circles and segments of circles shown in Figs. 32 
 and 33 are made by winding the sized rope around a tin 
 pail, a can, or some other cylindrical body and allowing 
 it to dry. To form a complete ring, one turn of the rope 
 is cut off, its ends are cut off diagonally and fastened 
 together with strong glue. 
 
 The spindles are cut by means of a sharp knife. The 
 various parts of the work are fastened together and at- 
 tached to a light wooden frame, and, as a rule, no fas- 
 tening other than glue w^ill be required. If, however, a 
 stronger fastening is necessary at some points, small 
 brads or wire nails, or even screws, may be used. 
 
 In Fig. 33, the rosette, d^ is formed of a circular ring 
 filled with segments of a similar ring in the manner 
 shown. Each pair of spirals, a, consists of one right- 
 
 PiG. 35. Zigzag Bar, 
 
 handed one and one left-handed. The spindles, h, c, 
 are spirals. 
 
 Grilles made in this way may be finished in the same 
 
HOME MECHANICS FOE AMATEUKS 
 
 35 
 
 manner as wood. They may be stained or painted to 
 matcli the work into which tliey are fitted, or they may 
 l)e painted white and relieved by a little gilt on the pro- 
 jecting part. 
 
 It is obvions that a large nnmber of patterns may be 
 Avorked ont by the aid of these suggestions. Different 
 
 Oy Jf e^ d. e J *9 y^- 
 
 Fig. 36. Forms of Spindles and Bars. 
 
 kinds and sizes of rope may be used alone or in combi- 
 nation. 
 
 Tliese grilles may be placed in windows, doorways, 
 across halls, above mantels, across niches, between win- 
 dows, and in many other places which will suggest 
 themselves. Like many other household ornaments, if 
 well and carefully made, they will repay the labor and 
 trouble of makinj?. 
 
 WALL ORNAMENTS 
 
 There is a great deal of satisfaction in the possession 
 of home made ornamental objects, because they are the 
 work of one's own hand, and, besides this, they are not 
 obtained by the expenditure of money that might per- 
 haps, be needed for other purposes. 
 
 Ornaments belonging to the wall go a long way in 
 furnishing and beautifying the house. Pictures, care- 
 
36 
 
 HOME MECHAXICS FOR AMATEURS 
 
 fully selected, are liiglih^ effective. ^lauy of the mod- 
 ern photographs, photo-graviires, and photo-engravings 
 which are really meritorious can be obtained for fifty 
 cents or a dollar each. Some fairly good etchings and 
 imitations of water colors are also sold at reasonable 
 prices. The great item in connection with a low-priced 
 picture is the frame ; but any one Avith such tools as are 
 commonly found about the house and Avith a small 
 quantity of material can readily make a variety of 
 frames worthy of any place in the house. 
 
 The simplest frame to make is that shown in Fig 37. 
 This is made from a narrow flat board of chestnut, 
 
 
 Fig. 37. Wooden Frame. 
 
 butternut, or even ash or oak, having its inner edge 
 rabbeted to receive the glass, mat, and backing. This 
 strip is stained and finished before it is mitered. The 
 staining is done by brushing the strip evenly with a 
 thin coating of asphaltum, or with a thin stain of log- 
 
HOME MECHANICS FOR AMATEURS 3*? 
 
 Avood, or witli a stain foniuMl of (^ither of the following 
 dry pigments, bnrnt nniber, bnrnt or raw sienna, mixed 
 witli turpentine and a very small proportion of boiled 
 linseed oil. Chemical ink or writing fluid, reduced 
 with water so as to produce a greenish gray tint, 
 answers a good purpose. 
 
 After the stain is dry, the tint is lightened along the 
 inner or outer edge of the strip, as taste may dictate, 
 l)y scraping the wood by means of an ordinary wood 
 scraper, or by rubbing the surface down by means of 
 fine sandpaper. It is obvious that the stain may be 
 applied to the wood in such a way as to graduate the 
 tint without the necessity of scraping or sandpapering, 
 but this requires practice. 
 
 The tint should be so graduated as to be very light, 
 or nearly the natural color of the Avood at one edge of 
 the strip, Avhile the other edge should be quite dark. 
 The strip may be finished by flowing over it three thin 
 coats of shellac a arnish, allowing each coat to dry thor- 
 oughly before applying the next. The first tAVO coats 
 should be rubbed doAvn with very fine emery paper 
 after they become thoroughly dry and hard. The last 
 coat ma}^ be left bright, or its luster may be toned 
 down by means of the fine emery paper. The mould- 
 ing or strip thus prepared is mitered in the usual Avay 
 by the aid of a miter box, and nailed and glued to- 
 gether at the corners. 
 
 The mat in this case consists of a piece of thick paste- 
 board in Avhicli is cut an opening of the desired form. 
 The edges of the pasteboard are beveled around the 
 opening, and cauA^as, crash tOAveling, or AAiiite or tinted 
 cotton velvet is secured to the pasteboard by means 
 of bookbinder's paste (flour paste \Aath glue added). 
 
38 
 
 HO]\[E MP:CHAXICS foe AMATErRS 
 
 Afttir the paste bcccjiues dry, if desired, a design may 
 be painted on the mat with water colors. 
 
 The frame shoAvn in Fig. 38 is made on a different 
 plan. In this case the wooden moulding is half round 
 on its face. A saw kerf is made at the inner side of the 
 rabbet. The edge of a strip of white or ^^ivory'' zylon- 
 ite is inserted in the saw kerf, and held there by a thin 
 
 Fig. 38. Zylonite Frame. 
 
 strip of wood glued in. A small percentage of glycer- 
 ine or even common molasses should be added to the 
 glue used for this purpose. The zylonite is wrapped 
 around the moulding and fastened by means of a thin 
 strip of wood laid over it and secured by small nails or 
 brads. The corners of this frame are formed by means 
 of rectangular blocks of wood painted white on their 
 sides and furnished on the front with a square of zylon- 
 ite held in place by an ornamental brass nail. 
 
 If a larger frame is required, that can be made with 
 
HO:\lE MECHANICS FOR AMATEURS 
 
 39 
 
 a single strip of zylonite, the joint may be covered by 
 means of a curved half round strip of brass well pol- 
 ished and lacquered, and applied as shown in the en- 
 graving. 
 
 This frame may have a gilt lining as well as the mat. 
 It has a very chaste appearance, looking much like a 
 frame of ivory, and it is withal durable. 
 
 Fig. 39. Feather Ornament. 
 
 A very pretty and easily made Avail ornament is 
 shown in Fig. 39. It consists of a number of peacock 
 feathers arranged radially or in the form of a fan with 
 the quills attached to an elliptical piece of pasteboard 
 by means of sealing wax. The pasteboard is fitted to 
 an iridescent shell and fastened in with sealing wax. 
 A wire loop inserted in the pasteboard serves for hang- 
 ing the ornament. It may be placed between windows, 
 
40 
 
 HOME MECHANICS EOE AMATEUES 
 
 above or below pictures, and in man^^ other places with 
 good effect. 
 
 In Fig. 40 is shown a wall cabinet, which is not only 
 highly ornamental, but very useful. The body of the 
 cabinet is of pine or other soft wood. The doors are 
 
 Fig. 40. A Wall Cabinet. 
 
 arranged to receive the beautiful zylonite bas-reliefs 
 sold by the manufacturers of this superb material. In 
 openings in the back of the cabinet are inserted orna- 
 ments of the same character. They resemble ivory 
 and are very serviceable. 
 
 The bod}^ of the cabinet is neatly covered with can- 
 
HO]\rE MECHANICS FOR AMATEURS 
 
 41 
 
 vas, toweliiii»", or lii;litlv tinted cotton velvet, on wliicli 
 are painted designs in water or oil colors. The edges 
 of the shelves are preferably covered with sheet zylon- 
 ite, although they may with good effect be covered with 
 the material used on the other parts of the cabinet. Or- 
 namental brass hinges and trimmings should be applied 
 to the doors, as shown in the engraving. 
 
 PSEUDO-CERAMICS 
 
 The ceramic art is generally practiced under condi- 
 tions which render it exceedingly difficult for an ama- 
 
 
 fpi^i . ■ 
 
 ■■'^^WM 
 
 Fig. 41, Square Vase. 
 
 teur to make progress in it, even so far as to produce 
 work of the most modest and unassuming character. 
 
42 HOME MECHANICS FOE AMATEURS 
 
 lu the first plac(^ it is difficult to obtain the proper 
 quaHty of clay, unless one is in the yicinitj of a pottery 
 or clay bed ; in the second place, even though one has 
 the skill and practice which will enable him to shape 
 the clay into the desired forms, still it is difficult, if not 
 impossible to bake the work after it is done in other 
 respects, and it can scarcely be expected that a potter 
 will bake these odd articles. These and other difflcul- 
 
 M 
 
 
 
 j^ ~^^ 
 
 
 Fig. 42. Triangular Vase. 
 
 ties prevent the would-be amateur potter from attempt- 
 ing what, under more favorable circumstances, might 
 be productive of works creditable to both the art and 
 the artisan. 
 
 Eecently some exceedingly plain articles of pottery, 
 with extremely simple ornamentation, consisting 
 merely of a little paint and a little glaze, have become 
 very fashionable, and have been accepted as works of 
 
HOME MECHAA1C8 FOK AMATEUKS 
 
 43 
 
 art. Some of tliese articles are handsome, others are 
 not. Inasmuch as these articles have no practical 
 utility, they do not require to be made of materials 
 either fireproof or waterproof. The requisites are 
 simply shape, strength, and a resemblance to pottery. 
 The materials required for making imitation pottery 
 are junk-board — a strong, thick board having a smooth 
 surface — glue, and small wire nails. The ornamenta- 
 tion may consist of such floral or landscape decorations 
 as the maker is able to produce if he or she be artist 
 
 "^"T 
 
 ^::^; 
 
 §0: m^smiM 
 
 Fig. 43. Cylindrical Vase. 
 
 enough to paint in oil colors. Without this ability the 
 aid of chromos must be invoked. This will certainly 
 afford very satisfactory results, and the expense will b(* 
 slight, as very passable German chromos may be ob- 
 tained for twenty-five cents each. The engravings show 
 several examples of pseudo-ceramics Avhich are de- 
 signed with reference to the material to be employed, 
 and compare favorably with the high-priced articles to 
 be found in the shops. 
 
44 HO^rE MECHAXICS FOE AMATEUES 
 
 Tlie body of tlic vase shown in Fii*. 41 consists of 
 rectangular pieces of jnnk-board nailed and glned to- 
 gether at the corners, after the fashion of an ordinary 
 wooden box. The nails used are the small wire nails 
 used in bracket-work. They are about three-eighths 
 of an inch long, and about the size of an ordinary pin. 
 
 Fig. 44. Vase with Latticed Base. 
 
 In the absence of such nails common pins may be cut off 
 and used to good advantage. Holes for these nails 
 must be made with a fine-pointed awl. The bottom of 
 the vase consists of a single piece of junk-board, with 
 V-shaped notches cut from the corners to give it the 
 bevel. 
 
 The concave sides of the top consist of sections of 
 
HOME MECHAXICS FOll AMATEUES 
 
 45 
 
 paper tube such as is employed for inailin.u pictures. 
 The bead around the top is of Avood. Any imperfec- 
 tions in tlie joints may be filled with a mixture of glue 
 size and whiting formed into a putty. 
 
 Fig. 42 sho\ys a yase which can readily be made after 
 the aboAX^ hints. It is triangular in form, and has three 
 Ayooden balls for legs. The band around the top is 
 merely a narrow strip of pasteboard glued on. 
 
 Fig. 43 shows a cylindrical yase made of a strip of 
 junk-board scarfed or beyehMl on the edges and lapped 
 
 Fig. 45. Elliptical Vase. 
 and glued. To facilitate bending the junk-board, the 
 side which is to be outermost in the yase is wet. The 
 bottom is glued and nailed in, and the corners are 
 rounded with a moderately coarse file and sandpaper. 
 A band of pasteboard finishes the top, and three or four 
 wooden balls form the legs. The inner corner of this 
 yase at the bottom may be filled in slightly Avitli glue 
 and Ayhiting to strenii'then it. 
 
46 
 
 HOME MECHANICS FOR AMATEUES 
 
 The vase shown in Fig. 44 is made in the same way 
 as that last described. The bottom is placed above the 
 lattice work. The latter is formed by cutting out the 
 holes Avith a chisel. The ring and its fixture are made 
 of wood. 
 
 Figs. 45, 46, and 47 are examples of "pilgrim" vases 
 of different shapes. That shown in Fig. 47 is circular, 
 and has convex sides or heads. The hoop is bent in the 
 manner already described, i. c, after first wetting the 
 
 Fig. 46. " Pilgrim " Vase. 
 
 outer side. The heads are made convex by wetting the 
 junk-board and hammering it in the middle, in the same 
 Avay that a shoemaker hammers a shoe sole, or tap, to 
 nmke it convex, that is, it is placed upon an ordinary 
 fiat-iron or sad-iron, and hammered with a round-faced 
 hammer until it acquires the desired convexity. The 
 sides are nailed and glued to the hoop, and a thin paste- 
 board circle is glued to each of the convex surfaces of 
 the vase to form a border. The mouth of the vase is 
 
HOME MECHANICS FOR A.MATEURS 
 
 47 
 
 made of four pieces of junk-board, glued and nailed to- 
 o-etber and secured to tbe vase bv olue. Tbe legs of tbis 
 vase consist of two pieces of paper tube closed at tbe 
 ends witb turned pieces of wood. Tbe corners of tbe 
 vase may be filed and sandpapered to make it ready for 
 furtber operations. 
 
 After wbat bas already been said tbe construction of 
 tbe vases sbown in Figs. 45 and 46 will need no descrip- 
 
 o ?■" " , ' 
 
 ij 
 
 Fig. 47. Circular Vase 
 
 tion, except tbat tbe vase sbown in Fig. 46 bas wooden 
 legs and wooden strips at tbe sides of tbe moutb. 
 
 Tbe body of tbe vase sbown in Fig. 48 can be con- 
 structed witbout special description. Tbe ornamenta- 
 tion consists of ordinary artificial flowers and vines, se- 
 cured to tbe body of tbe vase witb common glue. Tbey 
 are stiffened by spraying or spattering sbellac var- 
 nisb on tbem from an old tootb or nail brusb. Tbey 
 
48 
 
 HOME MECHANICS FOR AMATEURS 
 
 should be sprayed several times to give tlieiii a good 
 heavy coating of varnish. When this becomes dry the 
 leaves and tiowers may be painted in the same manner 
 as the other parts of the vase. These vases should be 
 smoothly finished and thoroughly dried before any at- 
 tempt at finishing is made. The first operation in the 
 way of finishing is to give the vase two coats of shellac 
 
 , -- _ -^--. varnish inside and out, 
 
 allowing one coat to be- 
 come dry before the 
 other is applied. When 
 both coats of varnish are 
 dry and hard, which will 
 require about two days, 
 the painting may be 
 done. 
 
 It is not the design of 
 this section to enter into 
 all of the details of 
 painting necessary to 
 enable the tjvo to paint 
 landscapes or flowers, 
 but a suggestion or two 
 in regard to the paint- 
 ing will not be out of 
 place. The best results 
 will be obtained by giv- 
 ing the vase two coats of white paint before attempting 
 to lay on the color. The sides and border of the vase 
 should be of a neutral tint, slightly mottled. An olive 
 green or a gray looks well and gives relief to any de- 
 sign that may be chosen. 
 
 No attempt should be made to apply the colors 
 
 Fig. 48. Vase with Leaves 
 and Flowers in Relief. 
 
HOME MECHAXICS FOE AMATEUliS 49 
 
 sniootlily. The whole sliould be done in a bold, dashini^ 
 
 If paintin<>- is out of the (]uestion, some of the chro- 
 nios before mentioned may be nsed with i;ood effect. 
 The edges of the ehromos may be concealed beneath the 
 pasteboard border. In either case after the paint on 
 the article has become thoronghly dry and hard, which 
 will probably reipiire fonr or six weeks, it may receive 
 a coat of pottery varnish, to be obtained at any of the 
 color stores. 
 
 In the case of the applied artiticial flowers, they 
 shonld be hea\dly painted with, sa}^ four or five coats of 
 white paint before applying the color. 
 
 Ornamental articles of this kind cost little save the 
 labor, and will well repay the trouble of making. 
 
 IMITATION OF MAJOLICA 
 
 Cements and sealing wax are nsefnl for giving to 
 paper and wooden articles a hard glaze, resembling that 
 of majolica ware. The cylindrical vase shown in the 
 following engraving consists of a paper mailing tube 
 3 inches in diameter, and 6 inches long, furnished 
 with a pasteboard bottom, which is glued in. The 
 inside and bottom of the vase are provided with two or 
 three coats of asphaltum or shellac varnish to render 
 it waterproof. The outside is covered with jeweler's 
 cement of different colors, or with sealing wax, or 
 both. The bar of cement or wax is melted at the end, 
 and applied to the paper cylinder in the same manner 
 as it is applied in sealing packages. No particular care 
 is required in applying the wax. It is, however, neces- 
 sary that the edges of adjoining patches of wax be 
 
50 
 
 HOME MECHANICS FOR AMATEUKS 
 
 broiiglit into contact with each other to insure the com- 
 plete covering of the paper. In the example shoAvn in 
 the engraAing, olive green jeweler's cement forms the 
 covering of the lower part of the vase. This is blended 
 into cement colored with Venetian red or Indian red, 
 and the cement at the top is flecked with yellow. 
 
 The mass of cement is laid on in spiral lines, and 
 when the covering is complete, the vase is held over a 
 
 smokeless flame, such as 
 that of a Bunsen burner 
 or alcohol lamp, or it 
 mav be held over a coal 
 fire until the cement 
 fuses. The vase should 
 be turned in such a way 
 as to cause the variously 
 colored cements to run 
 into each other. The 
 vase is held by means of 
 a paper tube or a stick 
 inserted in its open end. 
 Ornamentation may be 
 applied by cutting 
 leaves, stems, petals, 
 etc., from pieces of thick 
 paper, dipping them in 
 melted cement of appro- 
 priate color, allowing 
 them to cool, afterward 
 arranging them upon the vase; finally softening the 
 cement of the vase and the ornament by holding a flame 
 or a hot iron over them until the cement softens, and 
 the ornaments are attached. Care is required at this 
 
 Fig. 49. Imitation of Majolica. 
 
HOME MECHxVXICS FOR AMATEUES 51 
 
 point to avoid the complete fusing of the cement, as 
 this Avonld spoil the job. Care is also required to 
 avoid igniting tlie cement or wax, as it is nearly impos- 
 sible to extinguish it. 
 
 STAINED GLASS AND OBJECTS OF WIRE 
 CLOTH 
 
 A little stained glass work judiciously distributed 
 imparts a bright and cheerful air to the house by intro- 
 ducing a few brilliant colors in a legitimate way, where 
 they would be entirel}^ out of place if introduced in 
 draperies, carpets, or furniture. 
 
 It is an easy matter to make stained glass work after 
 the more simple designs. It only requires a knowledge 
 of the use of the glazier's diamond, or the very effi'-ient 
 
 ^ It -^ 
 
 L 
 Fig. 50. Details of the Lead Work. 
 
 substitute for the same known as the roller glass cut- 
 ter, and some proficiency in the use of the soldering 
 iron. 
 
 The colored glass can be procured from almost any 
 dealer, and for the grooved lead strips in which the 
 glass is set, the amateur will have to depend on the 
 stained glass Avorks. Some manufacturers are willing 
 
52 HOME MECHAXICS FOE AMATEURS 
 
 to furnish it in small quantities, while others are reluc- 
 tant. It is to be regretted that there is no simple way 
 of making these strips. Every stained glass manufac- 
 turer is provided with a machine by means of which he 
 rolls them from larger strips of about the same form, 
 made at the lead works, and known as cames. 
 
 Fig. 51. Stained Glass Work " Crazy " Pattern. 
 
 Two kinds of lead strips are generally used in this 
 kind of work, one of Avhich is shown at r/, in Fig. 50. 
 This is narrow and convex, and well adapted for small 
 curves, circles, etc. The other, shown at h, in the same 
 figure, is wider and thinner and better adapted for 
 straight Avork. At c, in the same figure, is shoAvn the 
 method of attaching copper Avires to the lead for twist- 
 ing around the rods which support the work, as shown 
 at^. 
 
 A drawing of the pattern is made upon stout paper, 
 
HOME :\rECHAXICS FOE AMATEUES 53 
 
 iuid the work is bei^uii hv enttim>- tlie olass accordiuir 
 to tlie pattern, fittiiio- the lead strips and soldering* 
 them at their jnnction. After all of the glass pieces 
 have b(Mm fitted and secnred, the work is tnrned over 
 and soldered upon the other side. The wii'( s are then 
 attached by first tinning them and then secnring them 
 by means of soldia'. These wires are twisted around 
 
 Fi(i. 52. A Leaded Glass Butterfly. 
 
 iron rods, which are so arranged as to support the work. 
 Small pieces Avill not require the iron rods, but larger 
 ones are liable to sag and buckle of their own weight. 
 They are also apt to b(^ blown out of shape by a heavy 
 wind. The easiest pattern to produce on stained glass 
 is that shoAvn in Fig. 51. It is hardly worthy of classi- 
 
 * P'or the soldering, an ordinary soldering iron is employed, and 
 common tinner's solder is used in fastening the joints. Tallow is 
 used as flux. A tallow candle is commonly employed for this pur- 
 pose. The joint to be soldered is rubbed with the end of the 
 candle, and the solder is applied. Of course the iron must be well 
 tinned and hot, and the touch of the iron upon the work must be 
 very quickly and dexterously done. 
 
54 HOME MEC'HAXICS FOK AMATEUES 
 
 fication among patterns, bUt it is pleasing if properiy 
 (lone. Some care is necessary to secure harmony of 
 color, but there is little chance of failure in this kind of 
 Ayork. 
 
 It is a common practice to gild oyer the lead strips 
 after the work is done, by means of gold paint, but it is 
 a question whether it is any improyement oyer the nat- 
 ural color of the lead, especially in work exposed to the 
 action of the elements. For some indoor work, such 
 as fire screens, sash screens, lanterns, lamp shades, etc. 
 the gilding is not objectionable. 
 
 The screen shown in Fig. 52 is not difficult. All of 
 the glass pieces are of such form as to be easily cut, and 
 the work of joining the lead str-ips is quite simple. As 
 to colors, it would be well to follow the example of na- 
 ture, or in any case to select such as will harmonize. It 
 is hardly possible to produce more gorgeous coloring 
 than is found among the butterflies. Green, blue, 
 greenish-blue, red, yellow, brown, black and white 
 (opalescent^ are colors from which to select for this 
 object. 
 
 The wire frame which supports the glass is carried 
 along the lead strips and secured by solder. The an- 
 tennae are of wire. The base is of wood, neatly stained 
 and polished. 
 
 A class of ornamental objects may be made from wire 
 cloth which riyal in beauty any kind of stained glass 
 work. Figs. 53 and 54 are examples of this kind of 
 work. 
 
 The wire cloth for this puri3ose should be made of 
 fine wire, the mesh should be coarse, say 10 to the inch, 
 and, moreoyer, the cloth should be painted and allowed 
 to dry before the ornamental work is applied. The 
 
IIO.AIE MECHANICS FOli AMATEURS 
 
 55 
 
 wire cloth is supported a short distance from a design 
 drawn on paper and the different colors are introduced 
 into the meshes by means of an ordinary writing pen. 
 A gelatine solution is used for this purpose. It should 
 not be very thick, and it must be kept warm. Ordi- 
 nary, transparent gelatine may be colored for this pur- 
 pose by adding aniline. Colored lacquers answer ad- 
 
 FiG. 53. Lamp Shade. 
 
 Fig, 54. Hanging Lantern 
 of Wire Cloth. 
 
 mirably for filling the squares. Common white glue 
 answers very well for filling the body of the design. 
 The beauty of this kind of work and the simplicity of 
 the method by which it is produced recommend it for 
 many purposes. 
 
 The construction of the frames for the lamp shade 
 and hanging lantern requires some mechanical skill. 
 
56 
 
 HOME :\rECHANlCS FOR A:\rATEUES 
 
 Trobablv the aid of the tinsiiiitli will have to be in- 
 voked in these cases. It will pay, however, as the arti- 
 cles will well repay the trouble and expense. 
 
 The hanging lantern, h'ig. 54, is designed for a hall. 
 It may contain a kerosene lamp, or the device known 
 as the ''fairy lamp,'- in which a large candle is em- 
 ployed as a source of light. 
 
 The colored checks in the wire cloth appear like gems 
 when illuminated. 
 
 An experiment showing a phase of capillarity is illus- 
 trated b}^ the annexed engravings, which give patterns. 
 
 -- 
 
 S 
 
 
 ^Hil 
 
 
 X A V 
 
 
 
 
 
 
 
 1' \ 
 
 llT-=t 
 
 nil H^ 1 
 
 \\ 
 
 
 ' ' \ 
 
 X iu 
 
 
 :::l 
 
 -i^-i 
 
 
 
 r-%=== 
 
 -j-l- J 
 
 
 11 
 
 *-i'- 
 
 
 -■^--1 
 
 ■-}, 
 
 
 ; i 
 
 ■ 
 
 fcL-. 
 
 ■gj-^p^it- 
 
 ~™"l| 1 
 
 ■L 
 
 
 
 — - 
 
 
 
 
 i.:'- 
 
 ii':-fc 
 
 T- - 1 
 
 :- 
 
 ii:: 
 
 E::^." 
 
 p 1 
 
 I 
 
 ■F ■?-:::_ 
 
 i--|l 
 
 f::: = :!Bffin"F 
 
 -■---| 
 
 t 
 
 
 
 "'' 1 
 
 
 
 ^^ 
 
 
 |t:::T[:;:: 
 
 r - : : : 1 it j^ 
 
 1 
 
 
 -:S'--ll' "; 
 
 
 Kl 
 
 lfe 
 
 
 Fig. 55. Method of producing Designs on Wire Cloth. 
 
 This experiment was originally intended for illus- 
 trating tapestry and other designs formed of small 
 squares, in colors, upon the screen ; but it has another 
 practical application, which is capable of considerable 
 expansion. For projection, a piece of brass wire cloth, 
 of any desired mesh, say from 12 to 20 to the inch, 
 is mounted in a metallic frame to adapt it to the slide 
 holder of the lantern, and the wire cloth is coated 
 lightly Avith lacquer and allowed to dry. 
 
 The slide thus j)repared is placed in the lantern and 
 focused. The required design may now be traced by 
 
IT():\rE MECHAXTCS FOE A:\rATKrEi^ 57 
 
 nieaus of a small caiiicrs hair bnisli, colored inks or 
 aqueous solutions of auiliue dyes Ijeinii- used. The 
 snuill squares of the wire cloth are filled with the col- 
 ored liquid, and show as colored S(]uares upon the 
 screen. Different colors may be placed in juxtaposi- 
 tion without liability to mixing-, and a design traced 
 without special care will appear regular as the rec- 
 tangular apertures of the wire cloth control the differ- 
 ent parts of the design. 
 
 The colored liquid squares are retained in the meshes 
 of the wire cloth by capillarity. A damp sponge will 
 remove the color, so that the experiment may be re- 
 peated as often as desired. In this experiment the 
 colored squares have the appearance of gems. 
 
 These designs nuiy be made permanent by employ- 
 ing solutions of colored gelatine; but in this case the 
 squares are so small that they are not very effective 
 without magnification. Really elegant designs may be 
 produced in this way for lamp shades, window and fire 
 screens, siuns, etc., as described above. 
 
 JAPANESE PORTIERE OR CURTAIX 
 
 There is a certain delicacy in a curtain macte of 
 long lashes formed of straw or bamboo and beads 
 which is not found in a fabric of any kind. Cur- 
 tains of this sort have been largely introduced into 
 this country of late, some of them being simple, plain 
 and cheap, while others are really very elaborate and, 
 of course, correspondingly expensive. It is a very 
 simple matter to make a curtain of this class, pro- 
 vided the materials are at hand ; but where neither 
 bamboo nor straw nor beads are available, it becomes 
 
58 
 
 HOME MECHANICS FOR AMATEURS 
 
 more difficult. But a very presentable curtain may 
 be made from paper, Avhich is obtainable everywhere. 
 The large engraving sIioavs a very simple pattern 
 made of straws of different length, and glass beads 
 of different colors, strung on strong thread or fine 
 strong twine. 
 
 The first thing to be done toward making the cur- 
 tain is to draw a design roughly on a sheet of paper, 
 then tie a thread in a bead Avhich is to form the fin- 
 ish of the lower end of the lash. Then the bead is 
 
 Fig. 56. Method for making Paper Rolls. 
 
 fastened in its place on the pattern by driving an 
 ordinary pin through it into the board or table be- 
 neath. The stringing of the straws and beads is thus 
 proceeded with according to the requirements of the 
 pattern. 
 
 When one lash is finished, its upper end is fastened 
 on the design by an ordinar^^ jun driven through a 
 knot tied in the thread. The next lash in order is pro- 
 ceeded with in the same manner, and so on until the 
 entire series of lashes is done. A stout string is 
 
BCniK ^rKdlAXTCS FOIJ A:\rATFJ^T7S 50 
 
 stretched along the series of pins by which ilie upper 
 ends of the laslies are secured. Eacli thread is tlien 
 tied around the transvere string. If desired, the threads 
 may be spaced by beads arranged on tlie string be- 
 tween the lashes. As all the knots are necessarily 
 trimmed close, it is well to touch each knot with muci- 
 lage. When this is dry, the curtain is finished. 
 
 A very handsome curtain may be made from beads 
 alone, or from beads and plain uncolored straws, or 
 the straws may be dyed different colors by means 
 of aniline dyes, or by dipping them into thin colored 
 lacquers. 
 
 A curtain or portiere of bamboo and beads is made 
 in the same way, but on a larger scale. 
 
 It is easy to make a good imitation of these curtains 
 with paper tubes and beads, or the tubes alone. The 
 manner of making these tubes is shown in Fig. 56. The 
 ])aper from Avliich the tubes are made should not be 
 thicker than common writing paper. It may be either 
 colored or white. The best results will be secured by 
 using common white writing paper and coloring the 
 tubes after they are formed and dry, by means of thin 
 brown or white shellac varnish, colored Avith pigments 
 or the anilines. 
 
 The pieces of paper from which the tubes are made 
 are preferably cut in trapezoidal shape, as shown at 
 1 and 2, so that when the tube is finished it will have 
 conical ends, as shown at 5, G, and 7. The wire shown 
 at 3 is used as a mandrel upon which to roll the paper. 
 The larger end of the piece of paper is applied to the 
 A^'ire when the paper is rolled up in the manner illus- 
 trated at 4. The narrower end of the paper is gummed 
 and pressed down closely, when the ware is removed 
 
60 HOME MECHANICS FOE AMATEUES 
 
 Fig. 57. Curtain formed of Straw, Bamboo, or Paper, and Beads. 
 
HOME MECIIAXICS FOIl A:yrATEUES 01 
 
 ;ui(I tlie opc^ration is repeated. It is not advautaueous 
 to i»uiii the entire surface of the paper. Fastening at 
 the end is sultieient. The wire nsed as a mandrel should 
 not be more than one-sixteenth inch in diameter, as 
 too large a hole through the rolls allows them to ar- 
 range themselves irregularly. At 7 is shown a part of 
 a lash formed of a long tube, a bead, and a short tube. 
 
 In stringing both the straws and the paper tubes a 
 long slim needle will be required. If this is not ob- 
 tainable, a. ver}^ good substitute for it may be made by 
 forming an eye or loop on the end of a thin wire of 
 suitable length. 
 
 There is scarcely any limit to the amount of labor 
 that may be expended upon an article of this kind; 
 but very pleasing results will be secured by the adop- 
 tion of simple designs, which may be easily carried 
 out. 
 
 in]pousi8E 
 
 This art, as practiced by the silversmith and the art- 
 ist, is almost entirely dependent upon the manual dex- 
 terity of the operator. A kind of repousse is here sug- 
 gested which depends more upon appliances than skill. 
 It is not, however, assumed that any set of devices can 
 be made to serve in lieu of taste and judgment. 
 
 To carry out this method, a piece of heavy cotton 
 lace, or heavy open work fabric, or a piece of a basket 
 may be glued to a block of hard Avood to serve as a sort 
 of die for producing the impression in the metal. The 
 fabric or basket work is not only attached to the 
 block by means of glue, but its finer interstices are 
 filled with glue so as to present a surface resembling 
 the original fabric only in the most general way. 
 
62 
 
 HOME MECHANICS FOli AMATEUKS 
 
 When the glue is perfectly dry and hard, the die is 
 laid upon a solid foundation, and a piece of very 
 thin, soft copper or brass is secured to the block so 
 
 Fig. 58. Embossing Thin Metal. 
 
 Fig. 59. Basket Pattern. 
 
 as to cover the lace as shown in Fig. 58. A piece of 
 cork, about i inch thick, and about three inches wide 
 and B or 8 inches long, is laid over the metal and 
 
HOME MECHANICS FOR AMATEURS 
 
 63 
 
 struck with a mallet, as shown. The cork yields suf- 
 ficiently to push the metal clown upon the die, and 
 cause it to take the pattern of the lace or whatever 
 is used in formin<>' the die. A piece of rather hard 
 rubber packing- will answer tliis purpose equally as 
 well as the cork. 
 
 Fig. 60. Die formed of Pasteboard. 
 
 Designs may be cut from strong* paper or pasteboard, 
 and glued to the block. Fig. 60 shows a design which 
 may be reproduced in this manner. 
 
 In Fig. 61 is represented a stencil design to be sawed 
 
64 
 
 BOUE MECHANICS FOE AMATEIIES 
 
 
 Fig. 61. Stencil Pattern. 
 
 from hard wood. The Hues and scrolls are discon- 
 tinued in places so as to cause the wood to hold to- 
 gether. If it is desired to render the lines continuous 
 at these points, they may l)e run through with a V- 
 tool. The dots are picked out with a small gouge or 
 
 '2:^x:^^22:^22sa;X 
 
 ^MlUiiLillA^^ 
 
 Fig. 62. Rope Pattern. 
 
HOME MECHANICS FOE AMATEUES 65 
 
 tlie point of a revolving drill. In all these cases the 
 metal is attached to tlie block and treated as shown 
 in Fig. 58. 
 
 In Fig. 62 is represented in side elevation and in 
 section a die formed of a small rope, glued in a semi- 
 circular groove in a bar of hard wood. The embossing 
 is done in the manner before described. In this case 
 a thick piece of soft rubber is preferable to cork for 
 forcing the metal into the depression of the die. 
 
 Fig. 63. Vase formed of Embossed Plates. 
 
 Either panels or continuous strips may be embossed 
 in the manner described, and these are to be used in 
 making frames, vases, and various ornamental objects. 
 If the metal is too thin for a certain case, it may be 
 strengthened by flowing soft solder over the back of the 
 plate by means of a soldering iron. 
 
 The vase shown in Fig. G3 is formed of four embossed 
 
66 HOME MECHAXICS FOR AMATEITES 
 
 plates of copper, fastened to the back of four vertical 
 brass strips b}^ solder, the whole being' secured to the 
 bottom piece in the same manner. The bottom consists 
 of a disk of copper soldered in. The base is formed of a 
 brass stove-pipe collar soldered to the lower part of the 
 body of the vase. The rim around the top consists of a 
 strip embossed on the rope die. 
 
 Fig. 64. A Bas-relief in Lead. Copper, or Brass. 
 
 As to finish, any of the usual methods of brass finish- 
 ing should be employed. This vase is esjiecially 
 adapted for containing a palm or other large foliage 
 plant. The earth and roots may be placed directly 
 in the vase or they may be contained by a pot which is 
 enclosed by the vase. 
 
HOME MECHANICS FOE AMATEURS 
 
 67 
 
 It is obvious that vases of other forms and other em- 
 bossed designs may be made on this plan. 
 
 Bas-reliefs may easily be made by a method which 
 is a modification of the one described. Fig. 64 shows 
 such a relief, and Figs. 65 and 66 illustrate the tools 
 required for making it. 
 
 To the wooden frame, A, is fitted a board, B, upon 
 
 Pig. 65. Frame and Form for making the Bas-reliefs. 
 
 which is drawn in outline the design which is to be 
 produced in relief. The board may be of pine or any 
 close-grained soft wood for lead work ; but for brass or 
 copper, the wood should be hard. To the frame, A, is 
 attached the plate of metal by means of screws. 
 
 The board, B, is removed from the frame, and the 
 
68 
 
 HOME MECHANICS FOE AMATEURS 
 
 portion of the design which is to form the most promi- 
 nent feature of the relief is sawed out of the board, 
 when the latter is replaced in the frame, and the metal 
 is forced into the opening of the board by pressing upon 
 the surface of the lead opposite the hole in the board, or 
 by pounding it by means of the mallet, C, shown in Fig. 
 66. As soon as this feature is complete, the next in 
 order is sawed out of the board, and the operation is 
 
 J) 
 
 Fig. 66. Tools for Repousse. 
 
 repeated until all of the general features are developed. 
 The progress of tlie work can be observed at any time 
 by removing the board, B. 
 
 The features may be corrected or modified by work- 
 ing from either side of the plate by means of the con- 
 vex mallet and the wooden punches and chisels, D 
 (Fig. 66). If a support is desired for any part while 
 the work is progressing, a stout bag filled with sand 
 may be placed under the part. A few very small bags, 
 
HOME MECHANICS FOR AMATEURS 
 
 69 
 
 say 1 inch or 1^ inches in diameter, will be found con- 
 venient. If desired, the drapery or the background 
 may be chased by means of hard wood or metal punches, 
 bearing on their faces tlie desired figures. 
 
 The relief, if of lead, looks well with an antique fin- 
 ish. 
 
 AN EASY METHOD OF PRODUCINCx BAS- 
 EELIEFS 
 
 The production of patterns from which to cast orna- 
 mental articles is confined to a class of artisans who, 
 by long experience in carving and modeling, have at- 
 tained great excellence in workmanship. An amateur, 
 while he may not hope to attain such excellence, and 
 
 Fig. 67. 
 
 Bas-reliefs in Wax. 
 
 cannot expect to produce, by the usual processes and 
 with limited practice, such exquisite articles as may be 
 seen in many of the city shop-windows, may, if he pos- 
 sesses even a modicum of artistic taste and skill, do 
 
 something in that direction. 
 
70 
 
 HOME MECHAmCS FOR AMATEURS 
 
 The articles required to carry out the process are 
 some thin sheets of semi-transparent wax, a Ivuife hav- 
 ing a narrow, dull blade, and the printed or drawn 
 design of the form to be produced. The backing, or sur- 
 face on which the relief is made, may be of any of the 
 materials of which patterns are commonly made. 
 
 Fig. 69. A Scroll Design. 
 
 Having given the backing the required form and 
 located thereon the position of the relief, a sheet of wax 
 is laid over the design and the extreme outline of the 
 figure is traced on the surface of the wax with a dull 
 point. The wax is now laid upon a smooth board and 
 cut upon the line just made with the knife, the blade 
 being slightly warm. The wax thus cut is now placed 
 
HOME MECHAXICS FOR AMATEUES ^1 
 
 on the foundation or backino, and fastened by heating 
 the knife bhide quite hot and touching the wax at sev- 
 eral points, so as to cause it to melt and adhere to the 
 
 
 
 Fig. 
 
 70. 
 
 
 
 ^^Ma 
 
 li^^ 
 
 ^^s^ 
 
 p^^ 
 
 
 
 hW 
 
 Ml 
 
 rA^ 
 
 -^ 
 
 
 
 ^m 
 
 ^^ 
 
 ^1^ 
 
 K^ 
 
 
 
 ^^ 
 
 ^m 
 
 ^^j\ 
 
 -« 
 
 
 
 ^m 
 
 ^S 
 
 J^d 
 
 ^ 
 
 
 
 m^j 
 
 i^a 
 
 w^ 
 
 ■^mmiji 
 
 
 
 L^m 
 
 ^^s 
 
 J^p 
 
 ISliO 
 
 
 
 Fig. 71. 
 
 Fig. 72. 
 Patterns for Bas-reliefs. 
 
72 HOME MECHANICS FOR AMATEURS 
 
 backing. Supposing this piece of wax to have the 
 thickness required in the thinnest portion of the relief, 
 another sheet is laid upon the design and traced within, 
 and a small distance from, the outline of the design. It 
 is cut and laid upon the first piece and made to adhere 
 by pressing it down slightly. 
 
 Another sheet of Avax is traced within the outline of 
 the second, and cut and placed upon the two already 
 secured to the backing, and so on until the design is 
 produced in Avhat might be termed the rough. This 
 stage is illustrated in Figs. 67 and 68, which are re- 
 spectively front and edge views, which give the idea of 
 the arrangement of the several sheets. 
 
 After the sheets are placed upon one another in the 
 manner first observed, the edges may be burnished 
 doAvn by the rounded back of the knife, or by any 
 smooth, rounded implement, which must be slightly 
 warmed. 
 
 Superfluous wax may be removed by scraping when 
 cold, and indentations and interstices may be filled by 
 adding a little wax. A scroll design is shown in Fig. 69. 
 
 When the model is to be reproduced in metal cast in 
 sand moulds, the wax should be slightly varnished with 
 pattern varnish ; but when the design is to be produced 
 in plaster, a mould of plaster may be taken from the 
 model after it has been oiled. 
 
 A bas-relief may be made in this way from a profile 
 photograph or from an engraving. 
 
 The process may be emplo^^ed to advantage in orna- 
 menting patterns for the coarser and heavier kinds of 
 work. 
 
 Figs. 70, 71, and 72 represent surfaces ornamented in 
 this manner. 
 
HOME MECHANICS FOR AMATEURS 
 
 73 
 
 ORNAMENTAL IRON WORK FOR, AMATEURS 
 
 Although artistic wrought iron work dates from very 
 early times, it was never more popular than it is at 
 present. This remark applies especially to movable 
 
 Fig. 73. Fig. 74. 
 
 Iron Lamp Supports. 
 
 articles such as tables, stands, racks of various kinds, 
 fuel baskets, lamp supports, etc. Many of these arti- 
 cles of recent manufacture are copies of antique ob- 
 jects, while others are of modern design. As works of 
 
74 HOME MECHANICS FOR AMATEURS 
 
 art they are fully equal, if not superior, to the speci- 
 mens of earlier work. 
 
 Now, while no imitation can ever equal the original 
 article, it must be admitted that imitations often prove 
 very satisfactory to those who can neither make nor 
 purchase the real article. 
 
 The examples of iron work here illustrated are styled 
 imitations, as they are made without forging, i. e., the 
 iron is bent either cold or hot, without the use of a 
 hammer, while the iron bars or rods maintain their 
 original cross section. Any one used to the hammer 
 and anvil can, in addition to the curves, apply forged 
 portions, or twist and forge the bars used in the scrolls. 
 
 Fig. 75. Jaw for Bending. 
 
 The only special tool used in making articles of this 
 class is the steel jaw shown in Fig. 75. Its slot re- 
 ceives the bar to be bent, and its flattened shank is 
 designed to be held in an iron vise. A scroll is formed 
 by placing the end of a bar in the jaw, and winding the 
 bar around the jaw and upon itself, afterward unwind- 
 ing the bar to open the spiral as much as may be re- 
 quired. After the scroll is complete, the inner straight 
 end of the bar is cut off by means of a hack saw. The 
 sharp angles may also be bent by the use of the jaw. It 
 will facilitate the operation if the bar is heated red hot 
 at the point of bending. A hammer may prove useful 
 in this part of the operation. 
 
HOME MECHANICS FOR AMATEUES 75 
 
 The standard of the lamp support consists of a piece 
 of gas pipe. The feet are attached by means of screws, 
 and the different parts of the iron work are fastened 
 together by means of small screws or bolts. 
 
 A rod is fitted to the gas pipe and has at its upper 
 end a frame or cup for receiving the lamp. A clamp- 
 ing screw passing through the gas pipe holds the rod at 
 the desired height. 
 
 An easy and satisfactory way of blacking the work 
 after it is finished is to coat it with a thin varnish 
 of stick or seed lac cut in alcohol, with refined lamp- 
 black stirred in to give it the required color. The var- 
 nish should be made quite thin to avoid any gloSvS, and 
 should be strained through cheesecloth or similar 
 material. 
 
 It is obvious that grilles, gates, screens, doors, and 
 other objects may be made from iron in this way with 
 little trouble or expense. 
 
 SOME THINGS IN WIRE 
 
 There is scarcely a limit to the number of useful and 
 ornamental things that can be made from wire. Two 
 examples are shown in the engravings. Figs. 76 and 77, 
 representing respectively front and edge views of a 
 newspaper and magazine holder formed of a wooden 
 back and wire scrolls; Fig. 78 showing a small wire 
 stand or card receiver having a zylonite top. 
 
 The scrolls of the newspaper holder are formed of 
 three-sixteenths inch square brass wire; the several 
 pieces being bent in the form shown and held in place 
 by clips of the same material soft-soldered by means of 
 a blowpipe. The overlapping portions of the scrolls 
 
76 
 
 HOME MECHANICS FOR AMATEUES 
 
 are also soft soldered. The lower part of each main 
 scroll is held by a strong staple passing over the wire 
 of the scroll and through the cleat and backboard and 
 clinched on the back of the board. The three wires at 
 the center of each scroll are prolonged below the cleat, 
 as shown, to form a stop for limiting the swing of the 
 scroll. 
 
 Fig. 76. Newspaper Holder. 
 
 Fig. 77. Edge View of 
 Newspaper Holder. 
 
 If care is taken in soldering the clips, the brasswork 
 will require little preparation for lacquering. A stiff 
 brush charged with finely powdered pumice wet with 
 water and applied vigorously to the work will quickly 
 remove all stains, and will give the work a uniform ap- 
 
HOME MECHANICS FOR AMATEURS 
 
 77 
 
 pearance. The backboard, which may be of walnut, 
 mahogany, cherry, oak, ash, or maple, should be var- 
 nished and well rubbed down before the cleats are 
 applied. 
 
 A holder of this kind will receive a large number of 
 periodicals. 
 
 The wire stand or card receiver, shown in Fig. 78, is 
 
 Fig. 78. Wire Stand or Card Receiver. 
 
 made of one-quarter inch or three-eighths inch round 
 brass wire. It may be made of brass tubing three- 
 eighths inch or one-half inch outside diameter and 
 rather thick. In this case the tubes are annealed and 
 filled with lead before bending. The lead is melted out 
 
78 HOME MECHx\NICS FOE AMATEURS 
 
 of the tubes after bending. The spirals are formed 
 separately by wrapping the tube or wire around a 
 cylindrical bar of wood or iron in a close helical coil, 
 then stretching out the coils, placing them together, 
 as shown. They are then clamped on a smaller cylin- 
 drical bar and their upper ends are twisted together. 
 Two rings surround the loAver part of the spiral and 
 to these rings are secured the legs by means of solder 
 or screws. 
 
 The small rings surrounding the legs may be pur- 
 chased and secured in place by solder. 
 
 The top of the stand consists of a disk of wood, con- 
 caved at the top and furnished with an embossed disk 
 of zylonite. 
 
 The under surface of the stand top is provided with 
 a perforated block, which fits over the closely twisted 
 end on the standard. This receiver may be made so 
 small as to stand upon a table, or it may be made of 
 the usual table height. 
 
 SOME THINGS IN BURNISHED BRASS 
 
 The old and commendable fashion of making orna- 
 mental objects from solid hand-wrought metal is being 
 revived to a wonderful extent. Steel, iron, brass, and 
 copper are wrought into a thousand beautiful and use- 
 ful forms, and the gilded and tinsel objects of recent 
 days are now set aside for substantial and elegant solid 
 cast and hand- wrought ornaments. It will require only 
 a suggestion to set the amateur mechanic at work at 
 this sort of thing, when his dwelling will soon be 
 adorned with articles that will be the more valuable 
 for having been produced at home. 
 
HOME MECHANICS FOE AMATEURS 79 
 
 Fig. 79. A Brass Easel. 
 
80 
 
 HOME MECHANICS FOR AMATEUKS 
 
 Brass tubing and rods of round, hexagonal and oc- 
 tagonal section, plain and perforated strips of different 
 widths and thicknesses, half round and semi-hexagonal 
 strips, and brass buttons, knobs, and nails of various 
 shapes, may be purchased so that the amateur will 
 
 Fig. 80. A Brass Frame. 
 
 readily find available materials for the kind of work 
 suggested. Half-inch square tubes, strips of brass half 
 an inch by one-sixth of an inch, a few brass buttons, 
 and a few knobs, are required for the easel shown in 
 
HOME MECHANICS FOR AMATEURS 
 
 81 
 
 Fig. 79. The tubes may be draw-filed, then finished 
 with the different grades of emery paper with oil, or 
 they may be polished on an emery wheel, and the final 
 finish may be imparted by using the finest French 
 emery paper with oil. 
 
 When two tubes cross each other they may be halved 
 
 Fig. 81. A Nautilus Card Receiver. 
 
 together precisely as in wood work, and may be fas- 
 tened by soldering wdth soft solder. 
 
 When the end of a tube abuts against the side of an- 
 other tube it may be fastened solid enough for all 
 practical purposes by soft soldering by means of a 
 blowpipe. Of course the joint may be brazed or sol- 
 
82 
 
 HOME MECHANICS FOE AMATEURS 
 
 dered with silver solder, but as great strength is not 
 required, it is unnecessary to take that amount of 
 trouble. 
 
 A very good way of fastening is to solder a plug in 
 the end of the tube that abuts against the side of 
 another tube, and to put a screw laterally through one 
 into the plug in the other. In this case it is well to leave 
 a slight feather on opposite sides of the abutting tube 
 
 Fig. 82. A Brass Clock. 
 
 to engage the corners of the tube to which it is at- 
 tached. 
 
 The scrolls should be attached by means of small 
 screws. The panels consist of thin pieces of board cov- 
 ered Avith velvet or plush of any suitable color. They 
 are inserted from the back, and are provided with a 
 number of large convex nails. The support for the pic- 
 ture is movable up and down on the side pieces of the 
 
HOME MECHANICS FOE AMATEUES 83 
 
 easel, and may be secured at any desired point by the 
 milled screws. 
 
 The frame shown in Fig. 80 will require no special 
 description. The main portion of it is made of square 
 brass tubing. The side bars are made of round brass 
 
 Fig. 83. A Brass Table. 
 
 rods with turned end pieces, as shown. The mat of 
 thin wood is covered with velvet or plush. The picture 
 and glass are placed behind the mat ; the latter is pro- 
 vided with small brass ears wdiich are fastened to the 
 back of the frame by screws. The knobs at the top, 
 
84 
 
 HOME MECHANICS FOE AMATEUES 
 
 bottom, and sides of the frame and easel are turned and 
 attached with solder. 
 
 Fig. 81 shows a tripod stand for a nautilus shell, with 
 an ornamental shell placed below it in the center of the 
 plate, forming the triangular base. Fig. 82 shows a 
 clock case, consisting of an ordinary box of suitable 
 size covered with plush or velvet, and inclosed in a 
 frame of brass. 
 
 The frame is built up in the manner already de- 
 scribed from square brass tubing split lengthwise 
 through diagonally opposite corners. The lower por- 
 
 FiG. 84. Examples of Paneling. 
 
 tion of the frame consists of a wide band of brass, hav- 
 ing a light bead soldered to its upper edge and a heavy 
 bead soldered to its loAver edge. A number of the brass 
 nails are placed at regular intervals and soldered at 
 the back of the brass base. The rail at the top is made 
 of hexagonal brass tubing, and the small balusters are 
 turned from brass rods. The palette and brushes are 
 sawed from a plate of brass and attached by tacks 
 soldered to the back. The patches of color are pro- 
 duced by different colors of sealing wax. Four brass 
 nails are inserted around the dial to relieve the blank 
 
HOME MECHANICS IQE AMATEUKS 85 
 
 spaces on the plush. The dock and its plush-covered 
 case may be removed from the brass frame when it is 
 desired to clean the latter. 
 
 The table shown in Fig. 83 is of the same general 
 character as the other articles, and will not, therefore, 
 need particular description. The central portion is of 
 three-quarters inch round brass tubing. The legs are 
 of five-eighths square brass tubing. The top is of 
 wood, plush-covered and fringed, and provided with a 
 border of perforated brass. 
 
 Fig. 84 shows different kinds of panels. The balus- 
 ters in the upper one are turned ; in the two lower ones 
 they are cut from sheet metal. 
 
 All of these articles may be lacquered, but they pre- 
 sent a more elegant appearance if the metal is left un- 
 protected and cleaned occasionally with rottenstone 
 and oil. 
 
 There is hardly any limit to the number of pretty 
 and useful articles that may be made of such materials, 
 with the expenditure of little thought and labor. 
 
 FORMING PLASTER OBJECTS 
 
 It is sometimes convenient to form objects of cir- 
 cular section from plaster of Paris. This is a very sim- 
 ple operation, requiring only very simple tools and 
 apparatus. An iron rod, bent at one end to form a 
 crank, and carrying a conical wooden roller, two 
 notched bars of wood for supporting the iron rod, and 
 a pattern made from a thin piece of hard wood, com- 
 prise the outfit for making these articles. The rod is 
 held in its bearings in the bars by pins inserted 
 obliquely in holes in the wood, so as to project over 
 
86 
 
 HOME MECHANICS FOR AMATEURS 
 
 the rod. The pattern is cut so that its edge is a profile 
 of one side of the article to be made. The wood should 
 be made thin on the working edge. The patterns may 
 be made to advantage of metal backed by wood. 
 
 The conical wooden roller should be flattened on 
 three or four sides to prevent the plaster from turning 
 around on it. The roller is oiled or smeared over with 
 grease, and a batter of plaster of Paris is prepared by 
 mixing the dry plaster with water to the consistency of 
 cream. As soon as the plaster begins to set it is applied 
 plenteously to the roller, and while the rod is turned 
 
 Fig. 85. Forming Plaster Objects. 
 
 by means of the crank the pattern is moved forward 
 toward the rod, and the surplus plaster is removed by 
 the pattern which acts as a scraper. Any deficiencies 
 are supplied by a new application of the batter. 
 
 When the object is of the right size and form, the 
 pattern is removed and cleaned, and again applied to 
 the object, the latter having been brushed over freely 
 with water. This gives the finishing touch. 
 
 After the plaster becomes perfectly dry and hard, 
 the roller is knocked out, and the object is subjected to 
 
HOME MECHANICS FOR AMATEUES 87 
 
 a dry heat at a temperature of about 212 degrees Falir. 
 for an hour or so. It is then brushed over with thin 
 glue size until it has absorbed as much as possible, 
 when it is allowed to dry for several days. The latter 
 treatment renders the plaster hard and strong. 
 
 The final operation consists in painting, lacquering 
 or bronzing the object, as taste may dictate. 
 
PART III. 
 
 METAL WORKING 
 
 SAWING METALS 
 
 A GREAT DEAL of hard labor in working 
 metals may be avoided by the use of hack 
 saws and jeweler's saws. The large hack 
 saw has a malleable iron frame and a handle 
 and tail piece which will revolve so as to adjust 
 the saw to any desired angle. The tail piece has an 
 adjusting screw by which the tension of the saw may 
 be regulated. Several kinds of saws can be used in 
 this frame, /. c, saws with coarse and tine teeth, which 
 are set more or less according to the kind of metal on 
 which they are used. These saws all have very hard 
 teeth, but the main portion is soft, so that the saw 
 does not readily break. These saws are cheap, and 
 when one becomes dull or is broken it is replaced by 
 another. They are so hard they cannot be tiled. 
 
 The next saw in size has a heavy wire frame. Slits 
 are cut in opposite ends of the frame to secure the saw, 
 and small pins extending through holes in the ends of 
 the saw rest in notches cut in the frame. The spring 
 of the frame holds the saw under tension. To put in a 
 new saw, the ends of the frame are sprung inwardly 
 with considerable pressure. The saws for this frame 
 are also hardened on the toothed edge, the remainder 
 being soft. They are much thinner than the large saws. 
 The smaller saw frame is adjustable as to length and 
 is designed to receive very small saws made from mate- 
 rial like watch springs. 
 
 [89] 
 
GO HOME MECHANICS FOR AMATEUES 
 
 This saw is for more delicate work than the others. 
 No attempt is made to sharpen them with a file. A dull 
 one is thrown away and replaced by a new one. 
 
 There are many kinds of work in which a great deal 
 of time and labor may be saved by the use of these 
 saws ; for example, cutting off iron, steel and brass bars 
 and tubes, cutting various straps out of thick sheet 
 brass; cutting slots in work when required. They 
 may also be used in place of files in places where a file 
 cannot be introduced. 
 
 SOLDERING 
 Nothing is more useful for the amateur than a knowl- 
 edge of the art of soldering. It is a very simple one, 
 
 x^ 
 
 \ 
 
 
 "'^.. .«.- 
 
 '^ jBter 
 
 1 i*^ ^S?^,iii • 
 
 fn^' ' -^j^sifcfc-- - 
 
 
 mB 
 
 Fig. 86. Articles used in Soldering. 
 
 the tools required are inexpensive, and there is real 
 satisfaction in doing it rather than being delayed to 
 employ a regular tinsmith or other mechanic. 
 
 The soldering iron consists of a small oblong block 
 of copper, pointed at one end and having a large wire 
 screwed into the other end, the wire being provided 
 with a wooden handle. Some soft solder will be re- 
 quired, say a quarter or half pound. It is better to buy 
 
HOME MECHAXICS FOE AMATEUES 91 
 
 this in the form of solder wire, l)ut it can be readily 
 made by melting together equal parts of pure tin and 
 pure lead. 
 
 To carry on the work a small box of pulyerized rosin 
 and a bottle of soldering fluid will be required. 
 
 The soldering fluid can be purchased. It is readily 
 made by filling a small bottle half full of hydrochloric 
 acid. (This acid must be handled with care as it is 
 poisonous and yery corrosiye.) Into the acid drop lit- 
 tle strips of zinc, a few at a time, until it will dissolye 
 no more. This operation must be done in the open air, 
 as the fumes are sutfocating and injurious, ^lien the 
 boiling of the acid ceases the bottle should be filled up 
 with water and closed with a rubber stopper. In addi- 
 tion to these things already mentioned a small tin 
 box containing a wet cloth will be required. 
 
 Before soldering can be done the copper must be 
 heated so that it will melt the solder readily. Then 
 the pointed end must be cleaned with a file and a piece 
 of the solder wire is dipped in the soldering fluid. 
 When the end of the wire wet with the fluid is placed in 
 contact with the side of the hot soldering iron it will 
 melt and the soldering fluid will cause the solder to ad- 
 here to the copper. This may be repeated until the four 
 sides of the pointed end are coyered with solder, or 
 ^'tinned" as the smiths haye it. 
 
 To solder, the joint to be made is scraped clean ; then 
 a yery small amount of the soldering fluid is applied 
 if the work to be soldered is iron or copper, or brass, 
 but if it is bright tin a little of the rosin \sill answer 
 rather better than the acid. The iron is to be heated, 
 not too hot, howeyer. then quickly wiped on the damp 
 cloth and applied to the solder, to take up a drop, then 
 
92 HOME MECHANICS FOE AMATEUES 
 
 placed on the joint and moved slowly alon^, allowing 
 the solder to follow. If the tinning is burned off the 
 soldering iron, it must of course be retinned. The 
 secret of success in soldering is to have the iron just hot 
 enough, and to have the surface to which the solder is 
 applied very clean. 
 
 GRINDING AND POLISHING 
 
 Removing surplus metal by grinding, sharpening 
 tools, and smoothing and finishing work are most readi- 
 ly accomplished by the amateur by means of emery 
 wheels of various degrees of fineness, or corundum or 
 carborundum wheels used in the lathe. If a fine lathe 
 is available, the wheels may be carried by suitable steel 
 mandrels mounted between the lathe centers, or by a 
 single mandrel held by a chuck ; but when these things 
 are not available, the wheels may be mounted on a hard 
 wood mandrel. The mandrel has a shoulder against 
 which the wheel is clamped by a wooden collar, and a 
 pin or key passing through a hole in the mandrel. 
 Washers of leather or pasteboard may be used to adapt 
 the mandrel to emery wheels of different thicknesses. 
 In selecting an emery wheel, one should be chosen 
 which will cut freely without glazing. Such wheels 
 revolved in a lathe cut rapidly and serve well for re- 
 moving surplus metal and for sharpening tools. A 
 rather fine wheel is preferable to a coarse one for the 
 latter purpose. 
 
 For polishing, a wheel may be made of a disk of wood 
 turned in the lathe and covered on its periphery or side 
 or both w^ith leather. Sole leather Avhich contains no 
 oil or grease is the best for the purpose. If the leather- 
 
HOME MECHANICS FOR AMATEURS 93 
 
 covered wheel is not true it may be turned off in the 
 lathe and smoothed with fine sandpaper. The leather 
 on the edge of the wheel should be scarfed and lapped 
 so as to make a smooth joint. 
 
 After the leatlier is properly finished it should be 
 coated witn emery of the degree of fineness required. 
 This is done by warming the wheel, coating it with 
 strong glue and rolling it i'U the powdered emery. To 
 insure a good job, the emery itself should be warm. 
 Probably the best way to secure good results is to 
 spread the emery out on a flat metal plate which has 
 been heated. The leather-covered wheels are very use- 
 ful. They may even be used in place of the solid emery 
 wheel in many kinds of work. If they are used care- 
 fulW they will last a long time After one is partly 
 worn it is even more useful than it is when new. For 
 polishing steel a leather-covered wheel of the kind de- 
 scribed charged with crocus instead of emery will be 
 required, also another charged with fine rouge or putty 
 powder for a very fine finish. For buffing silver and 
 other soft metals a wheel of chamois skin or buck- 
 skin drawn over a padding of soft felt and tacked at 
 the sides of the wheel will be found valuable. The skin 
 will have to be lapped on the periphery of the wheel, 
 but it cannot be glued. Fine rouge is the best to apply 
 to this wheel. For polishing irregular surfaces bristle 
 brushes must be used, a coarse brush charged with 
 powdered pumice stone for doing the rougher work; 
 this to be followed by a finer brush charged with tripoli 
 or whiting and water. 
 
 The brushes, which have wooden hubs, are carried by 
 tapering screws held in the lathe chuck or inserted in 
 the mandrel in place of one of the centers. 
 
94 HOME MECHAXICS FOR AMATEURS 
 
 SILVER WORK 
 
 Silver is not a very expensive material for the manu- 
 facture of small objects, and it is easily worked and 
 finished. The objects when finished have an intrinsic 
 value, and if the effort to produce a fine article results 
 in failure, the material is not lost ; it can be sold as old 
 silver, with little loss. 
 
 The engraving shows articles which an amateur can 
 make. The bonbon dish and spoon shown in the illus- 
 tration were quickly made by an amateur silversmith. 
 
 
 .-^s. 
 
 ^ /f 
 
 
 |^:^|^ 
 
 
 < 
 
 
 Fig. 87. Examples of Silver Work. 
 
 It is first folded in the center, then opened and folded 
 at right angles to the first fold ; then opened and folded 
 again parallel with the first fold, and so on until the 
 entire surface is crossed with folds about three-fourths 
 of an inch apart. The edges are turned up all around 
 for about f of an inch, and the corners are 
 crimped a little, and small folds are made. The whole 
 W'Ork up to this point can be done with the fingers 
 alone. The folds at the corners are hammered down 
 
HOME MECHAXICS FOR AMATEURS 95 
 
 with a wooden mallet while the sheet rests at the corner 
 on a round support. From time to time the silver 
 should be annealed, i. c, heated to a low red heat, and 
 plunged into cool water. This will permit of bending 
 the silver without breaking it. 
 
 Little folds should be made in the sides at the upper 
 edges if necessary, to allow the sides to be straightened ; 
 then the upper edge should be trimmed off with shears, 
 so that the dish is the same height all around. Then a 
 piece of hollow silver wire which has not been soldered 
 is opened slightly at the seam by drawing a knife 
 through the seam. A piece of this wire long enough 
 to reach around the upper edge of the dish is slipped 
 over the upper edge of the dish and soldered at differ- 
 ent points, with silver solder. If this is not within the 
 power of the amateur, he may attach it at frequent in- 
 tervals by means of very snmll pieces of soft solder 
 melted after the application of a very minute quantity 
 of soldering fluid, b}^ holding the edge of the dish with 
 a pair of pliers over a gas flame two or three inches 
 above the top of the flame. If this is carefully done, the 
 small particles of solder Avill soak into the joint and 
 become invisible. Across the corner of the dish is se- 
 cured a tree limb made of silver, and on this are secured 
 the birds. The silver limb is made by hammering a 
 stout silver wire into a half-round notch in the end of a 
 piece of steel, grooves being formed in the notch to give 
 the flattened wire the appearance of having bark on it. 
 The birds are of special make, used for other purposes. 
 If the amateur silversmith desires to use the birds he 
 will be obliged to purchase them, as they cannot readily 
 be made by one having no experience in this line. They 
 are of bronze and are colored. 
 
96 HOME MECHANICS FOR AMATEUES 
 
 This particular dish was oxidized before the birds 
 were applied. The dish was oxidized by immersing it 
 for a few minutes in a solution of bisulphuret of soda. 
 It was then washed and dried and the oxide was re- 
 moved from the projecting portions by means of a 
 chamois skin charged with rouge. This dish may read- 
 ily be made round, elliptical, or triangular, as taste 
 may indicate. It is well in a case like this to try the 
 experiment of making the dish in copper or soft brass 
 before trying silver. 
 
 METAL FOOT LATHE 
 
 The amateur after using the simple wooden lathe will 
 no doubt ask for something more pretentious, a lathe 
 that can be used for working metals in various ways, 
 and drilling and turning hard wood, horn, ivory, rub- 
 ber, etc. Lathes vary in price from ?15 to |50 and up- 
 ward. In fact, almost any amount of money may be 
 invested in a foot lathe and the accessories which can 
 be used in connection with it to great advantage. 
 
 The better way to proceed is to purchase a lathe 
 complete, with fly-wheel, treadle, belt, chucks for turn- 
 ing wood, centers for turning metals, a face plate, one 
 or two lathe dogs, a drill chuck, three or four hand 
 tools for turning brass and other metals, and three or 
 four tools for turning wood. 
 
 Not a great deal can be said in regard to the various 
 kinds of work to be done on a foot lathe of this kind. 
 More can be learned in a half hour by the observation 
 of a skilled workman than can be acquired by a day's 
 practice, or by a ^tudy of books. However, any one 
 having a mechanical turn of mind can take the various 
 
HOME MECHANICS FOR AMATEURS 97 
 
 tools, and with the aid of a little common sense can 
 soon master the art of hand turning. 
 
 After practice with the lathe the amateur soon finds 
 that other tools are required, and he will either make 
 them or hiij them, and thus gradually add to his outfit 
 until he is able to undertake any work that may come 
 along. 
 
 To turn longer pieces of metal than can be held ad- 
 vantageously in the chuck, the pieces are centered, 
 drilled, and then countersunk to fit the centers of the 
 lathe, one of which is in the mandrel, the other in the 
 tail-stock spindle. A lathe dog is placed on one end 
 of the i)iece of metal and inserted in the slot in the 
 face plate of the lathe, while the lathe center is inserted 
 in the countersunk drill-hole in the end of the bar to be 
 turned. The center carried by the tail-stock is brought 
 forward and inserted. The tail-stock is then made fast 
 to the lathe bed, and the center is adjusted by turning 
 the tail-stock screw ; the work should turn easily with- 
 out chattering and the center should be oiled. 
 
 It is a good plan to finish the work without filing, 
 but the file and emery paper may be used ; they should 
 be used with care, however, as they are liable to injure 
 the angles and finer features of the work. A tool will 
 give a fine finish on steel work if it is sharpened on a 
 fine oil stone and the work is wet with oil or some 
 other liquid ; even saliva is often made use of with good 
 effect. Brass and other materials softer than steel are 
 readily turned in any form desired, and of course hard 
 rubber and hard and soft woods are still more easily 
 worked. 
 
 Turning brass. Babbitt metal, or type metal is not 
 materially different from turning hard wood. The tools 
 
98 HOME MECHANICS FOE AMATEURS 
 
 are practically the same, and the methods are the same, 
 but the metal turning is done at a somewhat slower 
 speed. In the case of metals, the finishing of the sharp- 
 ening of the turning tools is done on an oil stone to 
 insure the smoothness of the work. The work should 
 be so smoothly done that no final finishing will be 
 required. If, however, brass work is to be finished it 
 may be done by means of very fine emery paper or 
 cloth. This may be applied by the hand or strips of it 
 may be glued on flat or convex strips of wood which are 
 used in the same manner as a file. 
 
 The amateur cannot expect to cut screw threads with 
 chasers as readily as a skilled mechanic, but he can 
 make some headway with practice on brass and hard 
 wood. Chasers may be purchased for cutting inside 
 and outside threads. The chaser is moved along the 
 lathe rest at what is judged to be the speed the thread 
 would carry it along if already cut in the brass or 
 wood. The chaser is at the same time pressed firmly 
 on the rest and brought into engagement with the ma- 
 terial revolving in the lathe. 
 
 Make-shifts are not to be generally approved, but 
 the writer will relate a circumstance which came to his 
 knowledge some years ago that may be helpful to some 
 one caught in a similar predicament. 
 
 A lathe was available but no screw-cutting tools of 
 any kind were at hand. It was necessary to make one 
 or two fittings for a half-inch gas pipe. Tw^o old files 
 were found and annealed, and in the end of one were 
 filed with an ordinary triangular file the teeth to fit the 
 threads of the gas pipe. In the side of the other file 
 were filed teeth to fit the teeth of the first chaser. 
 These teeth were filed at a slight inclination to cor- 
 
HOME MECHANICS FOR AMATEURS 99 
 
 respond roughly with the pitch of the screw thread. 
 These chasers were hardened and tempered and used to 
 good advantage in finishing work which would other- 
 wise have been delayed at considerable inconvenience. 
 
 METAL-WORKIKG ON A LATHE 
 
 INSTRUCTIONS ABOUT DRILLS AND 
 DRILLING 
 
 An ordinary flat drill for most purposes will answer 
 nearly, if not quite, as well as a twist drill. It is not 
 a difficult matter to make them, since we have such 
 reliable material as Stubs' steel wire of every size. The 
 best form of flat drill for general purposes is shown in 
 Figs. 88, 89, and 90. It is made by milling or flling the 
 opposite sides of the wire, so as to form a bit or blade 
 having a thickness equal to about one-fourth of the 
 diameter of the wire. The angle of the point should be 
 90 degrees, and the angle of its cutting edge about 45 
 degrees for most uses. For a drill for very hard sub- 
 stances these angles may be more obtuse. 
 
 Having formed the drill, it should be hardened by 
 heating it to a low red and plunging it straight down 
 into cool (not cold) water. In case of a very small 
 drill, it may be held in the flame of a gas burner or 
 lamp in a pair of spring nippers over a vessel of water. 
 ^yhen it attains the required degree of heat it may be 
 dropped into the water. 
 
 To temper for most cases, the drill, after being 
 brightened on an emery wheel or piece of emery paper, 
 is heated ; if it is a small one, in an alcohol or gas flame, 
 until its color at the point runs down to a brownish 
 
 L.ofC. 
 
100 HOME MECHANICS FOR zVMATETJRS 
 
 yellow verging^ on a purple. If the drill is very large 
 it may be heated over a forge fire, or over a heavy piece 
 of red-hot iron. If the drill is a very small one, it may 
 be hardened and tempered at one operation by heating 
 to a low red heat and plunging it immediately into a 
 piece of beeswax. 
 
 and 89. Tempering. 
 
 If it is desired to have the point of the drill very hard, 
 without being liable to breakage, its temper may be 
 drawn by holding its point in pliers, as shown in Fig. 
 88, while the main portion is held over a gas flame. 
 The cool jaws of the pliers prevent the point from be- 
 coming heated. 
 
 Another method, applicable to larger drills, is to em- 
 ploy a notched block of lead, as shown in Fig. 89. The 
 drill in this case is driven a short distance into the 
 lead before it is hardened ; then, as it is tempered, it is 
 replaced in the lead to preserve the hardness of the 
 cutting edges while the temper is drawn in the other 
 portions. 
 
HOME MECHANICS FOK AMATEUES 101 
 
 When a drill is liardciied by immersing its point in 
 mercury instead of water, it acquires a diamond-like 
 hardness. The point of the drill jnst described is 
 shown in perspective and in section at D in Fig. 90. 
 The drill F is similar to the drill D, the point of dif- 
 ference being a half-round groove along each face ad- 
 jacent to the cutting edge. This device gives the cut- 
 ting edge a more acute angle, which is desirable for 
 some kinds of work. G is a .straight drill having con- 
 cave or fluted sides, and E is the well known twist 
 drill. The drills, G E, are shown in cross section in 
 the central figure. Twist drills of recent manufacture 
 have a central longitudinal line, which locates the point 
 in grinding. 
 
 The best rule for grinding twist drills is to preserve 
 as nearly as possible the original form. The ordinary 
 pin drill, H, is used for counterboring, a hole being 
 first drilled to receive the pin. The drill I is employed 
 to give an ornamental appearance to plates in which 
 pivots or small shafts are journaled, as in clock work. 
 The bottoming drill, J, has three cutting edges, one 
 upon each side, and a central transverse one connecting 
 the other two. This drill, as its name indicates, is de- 
 signed to make a flat bottom in a drill hole. 
 
 The pin drill, K, which is shown in side and end 
 views in Fig. 93 is first carefully turned and afterward 
 milled with the rose bit, L, producing the cutting points 
 or lips, which are afterward beveled with a file. This 
 drill is used for boring large holes in sheet metal, a 
 small hole being drilled first to receive the pin. M is 
 an expansion drill for the same purpose; its construc- 
 tion will be readily understood from the engraving. 
 The spindle is mortised to receive the tool carrying 
 
102 HOME MECHANICS FOE AMATEURS 
 
 arm, which is secured in the mortise by a key. The 
 lower end of the spindle is bored to receive the drill, 
 which also forms the pin for guiding the cutter. 
 
 While universal chucks are recommended for holding 
 drills, another form of chuck, shown in Fig. 91, may 
 be used with equal advantage. It consists of a main 
 
 Fig. 90. Forms of Drills. 
 
 portion. A, which screws on the lathe spindle, and has 
 a tapering threaded end for receiving the milled nut, B. 
 The threaded end is split to admit of its contraction as 
 the nut, B, is screwed on. The part. A, is bored longi- 
 tudinally to receive sections, C, of iron or steel rod. To 
 prepare this chuck for holding drills, the pieces, C, 
 
HOME MECHANICS FOR AMATEURS 103 
 
 are inserted in the chuck, centered with a pointed tool, 
 and are drilled with the drill with which they are 
 intended to be used. They are then split longitudinally 
 with a saw for about three-fourths their length. The 
 pieces, C, when once prepared, Avill always answer for 
 the same sized drill; they may also be used with an 
 ordinary chuck having a set screw. 
 
 Fig. 91. Drill Chuck. 
 
 The fluted countersink, O, may be classed among the 
 drills; its special application is to form the centers of 
 articles to be turned. It has the same form as the lathe 
 centers, and makes a truly circular conical hole, provid- 
 ing the number of flukes or cutting edges is odd. 
 
 Every lathe should be provided with a plate, or drill 
 rest, P, fitted to the tail spindle, for supporting plain 
 work while drilling it. The lathe should also have a 
 
104 
 
 HOME MECHANICS FOE AMATEURS 
 
HOME MECHAmCS FOR AMATEUES 
 
 105 
 
 hinged or pivoted rest, Q, which may be clamped at any 
 desired angle for drilling irregular work. This plate 
 should have several perforations for receiving pins, 
 for preventing the work from slipping. For supporting- 
 cylindrical objects to be drilled transversely, a fork, 
 R, is inserted in the tail spindle. 
 
 Fig. 93. Drills and a Rose Bit. 
 
 As to the matter of drilling, little need be said, as 
 nearh^ everything must be learned by experience; how- 
 ever, a few points may be mentioned. The work should 
 be carried forward with a regular and not too heavy 
 pressure. The speed of the drill will vary with the ma- 
 terial being worked. For steel, wrought iron, and cop- 
 per, the speed should be slow ; for brass and cast iron, it 
 may be quite rapid. In drilling steel or wrought iron, 
 oil is the best lubricant for the drills; in drilling glass, 
 the drill should be wet with turpentine. 
 
106 HOME MECHANICS FOR AMATEURS 
 
 HINTS CONCERNING CENTERING AND 
 STEADYING 
 
 To center a cylindrical piece of metal readily and 
 accurately is a very simple matter when the workman 
 is provided with tools especially designed for the pur- 
 pose, and it is not difficult when an engine lathe or even 
 an engine rest is available; but to do it easily and prop- 
 erly in an ordinary plain foot lathe may puzzle some of 
 
 Jiiliiii"!il|l;!jiill' 
 Fig. 94. Centering with a Forked Tool. 
 
 the amateur mechanicians. Although some of these 
 methods are well known, they will nevertheless be de- 
 scribed for the benefit of some Avho may require the in- 
 formation. The method of centering shown in Fig. 94 
 is one of the most common where the lathe is provided 
 with an engine rest. A forked tool, A, is clamped in 
 the tool post in such a position that a line drawn from 
 the point of the tail center will bisect the 
 
HOME MECHANICS FOE AMATEURS 107 
 
 angle of the fork. A square pointed center, 
 G, is inserted in the tail spindle and moved 
 against the end of the rod being centered with 
 
 Fig. 95. Centering. 
 
 a slight pressure, the tool, A, being at the same 
 time moved forward by the screw of the engine rest un- 
 til the rod turns smoothly in the fork and the square 
 
 Fig. 96. Centering with a Hand Tool. 
 
 pointed center lias found the center of the rod ; the tail 
 spindle is then moved forward until the cavity is suffi- 
 ciently deej) to permit of starting the center drill. The 
 
108 HOME MECHAlSriCS FOR AMATEUES 
 
 angle of square center, G, for very hard material, 
 should be a little more obtuse than that shown in Pig. 
 97. In any case, it should be of good material and well 
 tempered. 
 
 In Fig. 95 is shown a centering tool which is designed 
 to take the place of the engine rest and fork in Fig. 94. 
 The part B is fitted in place of the ordinary tool rest. 
 
 Pig. 97. 
 
 Fig. 98. 
 
 Fig. 100. 
 
 and the jaw, C, which has in it a V-shaped notch, is 
 hinged to the part B at D. A screw, E, passes through 
 the upper end of the part B, and bears against the jaw, 
 C. After what has already been said in connection 
 with the engine rest, the manner of using this con- 
 trivance will be readily understood. 
 
 In Fig. 96 the hand tool, F, is employed for steadying 
 
HOME MECHxiNICS FOR AMATEUES 
 
 109 
 
 the shaft and bringing it to a center. This tool is bent 
 to form a right-angled notch for receiving the shaft, 
 and when in use it is supported b}^ the tool rest after 
 the manner of an ordinary hand turning tool. 
 
 Work that is too large to be readily centered in this 
 manner is often centered approximately by means of 
 the universal square, as shown in Fig. 98. A diamet- 
 
 FiG. 103. 
 Steadying Devices. 
 
 rical line is draAvn along the tongue of the square, 
 the work is then turned through a quarter of a revolu- 
 tion, and another line is drawn. The intersection of 
 these lines will be the center, at least approximately. 
 
no HOME MECHANICS FOR AMATEURS 
 
HOME MECHANICS FOR AMATEUES 111 
 
 This point may now be marked with a center punch, 
 and the work may be tested in a lathe. If it is found to 
 revolve truly on the centers it may be drilled, otherwise 
 the center must be corrected with the center punch, and 
 the work again tested in the lathe. 
 
 After centering by any of these methods, the center 
 must be drilled and countersunk with a suitable tool, 
 so that it will fit the lathe center, as shown in Fig. 99. 
 The angle of the lathe centers should be sixty degrees. 
 To insure uniformity in everything pertaining to the 
 centers, the center gauge, shown in Fig. 100, should be 
 used for getting the required angle on the lathe centers 
 and on the drills used in centering. 
 
 The matter of steadying the long, slender rods while 
 being turned in the lathe is often perplexing. 
 
 In some cases it may be done tolerably well in the 
 manner illustrated in Fig. 101. The fork, H, is sup- 
 ported by the standard, I, which is inserted in the 
 socket of the rest support, J. The device shown in Fig. 
 95 may be used in a similar way. 
 
 Fig. 102 represents a steady rest, the construction of 
 Avhich will hardly need explanation. For light work it 
 may be made of wood ; the upright being secured to the 
 cross piece, L, which rests upon the lathe bed. The 
 slotted pieces, M, are adjustable lengthwise to accom- 
 modate the size and position of the shaft. When it is 
 required to support a bar which is not round, the sleeve, 
 N, shown in Fig. 103, is employed. It slips over the 
 shaft and revolves in the steady rest. The bar is cen- 
 tered by the screws, O. 
 
 The device shown in Fig. 101 is used where a hollow 
 mandrel lathe is not at hand. A piece of gas pipe, Q, 
 is held by the chuck, P, and is secured by a set screw in 
 
112 HOME MECHANICS FOR AMATEURS 
 
 the sleeve, B, which is journaled in the standard, S, 
 and carries the chuck, T. This arrangement may also 
 be employed for turning the ends of long rods where it 
 is not desirable to put them regularly on the centers of 
 the lathe. 
 
 CHUCKING 
 
 In spite of all possible appliances to be used in a 
 general way for chucking work in the lathe, a degree of 
 inventive skill is often required to accomplish it quickly 
 
 Fig. 105. Chucking a Metallic Disk. 
 
 and securely. The accompanying cuts are designed to 
 aid the amateur in chucking, but after all is said, there 
 is a world of knowledge that can be gained by experi- 
 ence only. 
 
HOME MECHANICS FOK AMATEURS 
 
 113 
 
 The arrangement of a metal disk in the lathe so that 
 it can be turned on its face, and upon its edge, cannot 
 well be accomplished by means of chucks ; for this pur- 
 pose recourse is frequently had to cement. A good 
 
 Fig. 106. Chucking a Spindle. 
 
 cement for this purpose consists of Burgundy pitch, 2 
 pounds; resin, 2 pounds; yellow wax, 2 ounces; dried 
 whiting, 2 pounds; melt together the pitch, resin, and 
 wax, and stir in the whiting. 
 
 Fig. 107. Chucking Work on Face Plate. 
 
 To chuck work with this cement, apply a small por- 
 tion of it to a face plate devoted especially to this pur- 
 pose; heat the plate so that the cement will cover the 
 
114 HOME MECHANICS FOE AMATEUKS 
 
 greater portion of its surface. The plate may be al- 
 lowed to cool. Whenever it is desirable to chuck a 
 metallic disk, it is heated and placed against the cement 
 on the face plate, and allowed, to remain until the 
 cement begins to stiffen, when a tool having a right- 
 angled notch is applied to the edge of the disk, as shown 
 in the cut, the lathe being rotated until, by the com- 
 pound action of the tool pressure and the rotary mo- 
 tion, the disk becomes perfectly true. 
 
 To chuck a spindle or any similar object a cement 
 chuck like that shown in section in Fig. 106 is some- 
 times used. The larger portion is screwed on the lathe 
 mandrel, and the inner end of the hole in the outer por- 
 tion terminates conically. The hole is filled with 
 cement, and the article to be chucked is warmed and 
 introduced. It may sometimes be necessary to heat the 
 chuck with an alcohol or gas flame. The lathe is 
 rotated, and the spindle is held lightly until it becomes 
 true and the cement begins to harden. 
 
 To remove the work from a cement chuck, it must be 
 warmed by means of a lamp or otherwise. Most of the 
 cement adhering to the work may be wiped off after 
 heating it; whatever remains may be removed with a 
 little turpentine. 
 
 A common method of chucking work on the face plate 
 is shown in Fig. 107 ; the Avheel is temporarily retained 
 in place by a pointed rod. A, Avhich is forced against the 
 wheel by the tail spindle. A little rapping one w ay or 
 the other readily centers the wheel. A piece of crayon 
 held in a crayon holder supported by the tool rest may 
 be used to discover which side of the wheel is "out." 
 After the wheel is trued, it is fastened by the short bars, 
 B, whose outer ends rest upon any convenient blocking 
 
HOME MECHANICS FOR AMATEURS 115 
 
 while they are drawn by the bolts, so as to clamp the 
 wheel firmly to the face plate. 
 
 It is sometimes preferable to use the yoke shown in 
 Fig. 108 instead of the bars shown in Fig. 107 ; it is 
 placed diametrically across the wheel and secured by 
 two bolts. 
 
 Fig. 108. Yoke. 
 
 Fig. 109 represents a chuck consisting of a wooden 
 disk, c, bored to receive the wooden hoop, d, which may 
 be forced inward by the common wood screws, e, which 
 bear upon it. This chuck is useful where a consider- 
 able number of similar pieces are to be turned or bored. 
 
 Fig. 109. Wood Chuck for Duplicate Work. 
 
 Fig. 110 represents a simple and well known chuck. 
 It is simply a block of wood secured to a face plate by 
 a screw center and turned out to fit the work. 
 
116 HOME MECHANICS FOE AMATEUES 
 
 Fig. Ill represents an easily made chuck, which is 
 useful for holding plugs of wood to be turned or bored. 
 It consists of a piece of hard wood fitted to the mandrel, 
 turned, bored, and split longitudinally, as shown in the 
 
 Fig. 110. 
 
 Fig. 111. 
 
 Fig. 112. 
 
 Fig. 113. 
 Chucking Devices. 
 
 engraving. Its outer end is tapered, and to it is fitted a 
 metallic ring that serves to contract the chuck when it 
 is forced on. 
 
 Fig. 112 represents a tapered and split mandrel. 
 
HOME MECHANICS FOR AMATEUES 
 
 11? 
 
 which ma^^ be either of metal or wood according to the 
 purpose to Avhich it is to be applied. The part F is 
 bored conically at the smaller end before splitting, and 
 to this hole is fitted the conical plug, G, which being 
 forced in expands the mandrel. 
 
 In Fig. 113 the mandrel, C, has permanently attached 
 to it the cone, D, and upon it is placed the movable 
 
 Fig. 114. 
 Chucking on Angle Plate. 
 
 Fig. 115. 
 Face Plate Jaw. 
 
 cone, E, which is forced against the work held between 
 the two cones by a nut which turns on the threaded end 
 of the mandrel. 
 
 In Fig. 114 the manner of chucking work on the 
 angle plate, H, is shown so clearly as to require no 
 explanation. It may be well, however, to state that 
 when the work is rotated rapidly a counterbalance 
 
118 
 
 HOME MECHANICS FOR AMATEURS 
 
 should be attached to the face phite on the side dia- 
 metrically opposite the angle plate. 
 
 Fig. 115 shows a jaw for attachm^^nt to the face plate, 
 which consists of a right-angled piece, I, a jaw, J, which 
 has two guide pins, entering holes in the piece, I, and 
 the screw, K, which passes through a tapped hole in 
 the piece, I, and bears against the jaw, J. The piece, I, 
 has a dowel, a, that keeps it from turning, and a screw, 
 h^ by which it is secured to the face plate. 
 
 Fig. 116. 
 
 Fig. 117. 
 
 In Figs. 116 and 117 the pin, L, is fitted to the face 
 plate, and has formed on its projecting end an eccen- 
 tric which fits the jaw, M. It has also a hexagonal head 
 for receiving the wrench by which it is turned. Three 
 pins, L, are fitted to the face plate, which is quite thick. 
 Two of the pins need not be turned after being adjusted 
 for a certain kind of work; the third is loosened and 
 turned when work is put in and taken out of the lathe. 
 
HOME MECHAXICS FOE AMATEURS 119 
 
 After the work is damped tightly by turning the eccen- 
 tric the nut on the back of the face plate is tightened. 
 In Fig. 118 is shown a type of the most convenient 
 and most universally useful chuck in existence. Its 
 
 Fig. 118. Scroll Chuck. 
 
 construction and use are so well known as to need no 
 description. The jaws are simultaneously moved to 
 or from the piece of metal which is being machined by 
 the aid of a kev. Such chucks hold drills admirably. 
 
 METAL TURNING 
 
 In selecting a lathe an amateur may exercise more or 
 less taste, and he may be governed somewhat by the 
 length of his purse; the same is true in the matter of 
 chucks ; but when he comes to the selection or making 
 of turning tools he must conform to fundamental prin- 
 ciples ; he must profit as far as possible by the experi- 
 ence of others, and will, after all, find enough to be 
 learned by practice. 
 
 Tools of almost every description may be purchased 
 at reasonable prices, but the practice of making one's 
 
120 
 
 HOME MECHANICS FOR AMATEUES 
 
 own tools cannot be too strongly recommended. It 
 affords a way out of many an emergency, and where 
 time is not too valuable, a saving will be realized. A 
 few bars of fine tool steel, a hammer, and a small anvil, 
 are all that are required, aside from fire and water. 
 The steel should be heated to a low red, and shaped 
 with as little hammering as possible ; it may then be al- 
 lowed to cool slowly, when it may be filed or ground to 
 
 Fig. 119. 
 
 Metal Lathe Tools. 
 
 give it the required form. It may now be hardened by 
 heating it to a cherry red and plunging it straight down 
 into clean cool (not too cold) water. It should then be 
 polished on two of its sides, when the temper may be 
 drawn in the flame of an alcohol lamp or Bunsen gas 
 burner; or, if these are not convenient, a heated bar of 
 iron ma}^ be used instead, the tool being placed in con- 
 
HOME MECHANICS FOR AMATEURS 
 
 121 
 
 tact with it until the required color appears. This for 
 tools to be used in turning steel, iron, and brass may be 
 a straw color. For turning wood it may be softer. The 
 main point to be observed in tempering a tool is to have 
 it as hard as possible without danger of its being 
 broken while in use. By a little experiment the ama- 
 teur will be able to suit the temper of his tools to the 
 work in hand. 
 
 Pig. 122. Fig. 123. 
 
 Metal Lathe Tools. 
 
 In the engravings accompanying the present section 
 a number of hand turning tools are shown, also a few 
 tools for the slide rest. These tools are familiar to ma- 
 chinists and may be w^ell known to many amateurs ; but 
 we give them for the benefit of those who are unac- 
 quainted with them and for the sake of completeness in 
 this volume. 
 
122 
 
 HOME MECHAmCS FOE AMATEUES 
 
 No. 1, Fig. 119, is the ordinary diamond tool, 
 made from a square bar of steel ground diag- 
 onally so as to give it two similar cutting edges. 
 This tool is perhaps more geuerallj' useful than 
 any of the others. The manner of using it is 
 
 shown in Fig. 127; it is placed on the tool rest 
 and dexterously moved on the rest as a pivot, caus- 
 ing the point to travel in a circular path along the 
 metal in the lathe. Of course only a small distance is 
 traveled over before the tool is moved alonsr on the 
 
 ■■■1^^ 
 
 Fig. 125. Drill and Holder. 
 
 rest. After a little experience it will be found that by 
 exercising care a good job in plain turning may be 
 done with the tool. 
 
 No. 2, Fig. 120, shows a sharp Y-shaped tool which 
 will be found useful for many purposes. No. 3 is a 
 V-shaped tool for finishing screw threads. Nos. 4 and 
 
HOME MECHANICS FOR AMATEUES 123 
 
 5 are round-nosed tools for concave surfaces. No. 6 
 a square tool for turning convex and plane surfaces. 
 The tool shown in No. 7 should be made right and left; 
 it is useful in turning brass, ivory, hard wood, etc. No. 
 8 is a separating tool. No. 9 is an inside tool, which 
 should be made both right and left, and its point may 
 be either round, V shaped or square. 
 
 Fig. 128 shows the manner of holding an inside tool. 
 No. 10 is a tool for making curved undercuts. No. 11 
 
 Fig. 126. Boring with a Drill. 
 
 is a representative of a large class of tools for duplicat- 
 ing a given form. 
 
 These figures represent a series of tools which may be 
 varied infinitely to adapt them to different purposes. 
 The user, if he is wide awake, is not long in discovering 
 what angle to give the cutting edge, what shape to give 
 the point, and what position to give the tool in relation 
 to the work to be done. 
 
124 HOME MECHANICS FOR AMATEURS 
 
 Having had experience with hand tools it requires 
 only a little practice and observation to apply the same 
 principles to slide rest tools. 
 
 A few examples of this class of tools are given. No. 
 12 is the ordinary diamond pointed tool, which shonld 
 be made right and left. The cutting edge may have 
 a more or less acute angle, according to the work to be 
 
 Fig. 127. Using the Diamond Tool. 
 
 done, and the inclined or front end of the tool may be 
 slightly squared or rounded, according to the work. 
 Fig. 13 is a separating tool, which is a little wider at 
 the cutting edge than anywhere else, so that it will 
 clear itself as it is forced into the work. 
 
 For brass this tool should be beveled downward 
 slightly. By giving the point the form shown in No. 
 3 it Avill be adapted to screw cutting. 
 
HOME MECHANICS FOR AMATEUES 
 
 125 
 
 No. 14 shows an inside tool for the slide rest; its 
 point may be modified according to the work to be 
 done. No. 15 is a side tool for squaring the ends of 
 shafts ; Nos. 16, 17, 18 and 19 represent tools for brass ; 
 No. 10 is a round-nosed tool for brass, No. IT a V-shaped 
 tool, No. 18 a screw thread tool, and No. 19 a side tool. 
 In boring, whether the object is cored or not, it is de- 
 sirable, where the hole is not too large, to take out the 
 first cut with a drill. The drill and the drill holder 
 
 Fig. 128. Method of Holding an Inside Tool. 
 
 for the purpose is shown in Fig. 125, and the manner 
 of using in Fig. 126. The drill holder, B, is held by 
 a mortised post placed in the rest support. The slot of 
 the drill holder is placed exactly opposite the tail cen- 
 ter and made secure. The drill, which is fiat, is drilled 
 to receive the tail center, and it is kept from turning 
 by the holder, and is kept from lateral movement and 
 chattering by a wrench, C, which is turned so as to 
 bind the drill in the slot of the holder. 
 
 The relative position of the tool and work is shown 
 
126 HOME MECHANICS FOR AMATEURS 
 
 in Fig. 129. The upper cut shows the position for brass ; 
 the next for iron and steel ; the third, the relative posi- 
 tion of the engine rest tool and its work, and the fourth 
 the position of the tool for soft metal and wood. 
 
 In all of these cases the point of the tool is above 
 
 Fig. 129. Position of Cutting Tools. 
 
 the center of the work. In the matter of the adjustment 
 of the tool, as well as in all other operations referred 
 to, experiment is recommended as the best means of 
 gaining valuable knowledge in the matter of turning 
 metals. 
 
 CHASING AND KNURLING 
 
 Among the multitude of operations possible with a 
 foot lathe perhaps none is more vexatious to the ama- 
 teur than that of cutting a good screw thread, and no 
 acquirement is more valuable than to be able to chase 
 a screw thread easily and accurately. 
 
 The ordinary chaser, No. 1, Fig. 130, is a simple 
 tool which is easily made when one has the hubs for 
 the dilferent sizes; but wanting these, we recommend 
 the purchase of chasers. A blank for an outside chaser 
 is shown in No. 2, and the hub used in cutting the 
 teeth is represented in Fig. 131. The latter consists 
 
HOME MECHANICS FOE AMATEUES 
 
 127 
 
 of a piece of good steel having a thread of the desired 
 pitch, which is traversed by spiral grooves to form 
 cutting edges. This tool must have about the same 
 temper as that of a tap. When used it is placed be- 
 tween the lathe centers and revolved at a slow speed, 
 
 No. 1. 
 
 No. 2. 
 
 Fig. 130. Chaser and Blank. 
 
 Fig. 131. Hub. 
 
 Fig. 132. Inside Chaser. 
 
 Fig. 133. Blank for Chaser. 
 
 while the end of the chaser blank is held against it, 
 being at the same time supported by the tool rest. The 
 hub should be oiled during the cutting process. After 
 cutting, the tool is hardened and tempered, and ground 
 on the elevated portion, which is the face, and smoothed 
 on the back which slides upon the tool rest. 
 
128 
 
 HOME MECHANICS FOR AMATEURS 
 
 An inside chaser is shown in Fig. 132, the blank 
 from Avhich it is made in Fig. 133. For convenience 
 in cutting the teeth, the blank is bent at right angles; 
 after cutting and before hardening it is straightened. 
 
 Fig. 134. Starting a Thread. 
 
 The manner of starting a thread for chasing is shown 
 in Fig. 134, the tool used being shown. The rest is 
 placed a short distance from the work, the tool is held 
 
 Fig. 135. 
 
 firmly upon it, and while the work revolves with a 
 uniform speed the tool is moved dexterously so as to 
 make a spiral line on the work, w^hich is nearly, if 
 not exactly, of the same pitch as the thread to be cut. 
 
HOME MECHANICS FOR AMATEUES 
 
 129 
 
 If the operator is fortunate in the attempt, it will be 
 a simple matter to start the chaser and move it along 
 as indicated in Fig. 130. After a little practice it will 
 in most cases be found an easy matter to chase threads 
 Avithout first starting them with a pointed tool. It is 
 much easier to chase an inside thread than an outside 
 one. A chaser seldom goes wrong when w^orking on 
 the inside. 
 
 Fig. 136. Chasing a Thread. 
 
 A method of chasing thimbles is shoAvn in Fig. 137. 
 The threaded thimble which forms the guide screw is 
 driven on the larger end of the tapering mandrel ; the 
 thimble on which the thread is to be cut is placed on 
 the smaller end of the mandrel. One arm of the forked 
 tool has a vertical chisel edge, which engages the guide 
 
 point which cuts 
 
 screw; the other arm has a chasin 
 
130 HOME MECHANICS FOR AMATEURS 
 
 the thread. The chisel edge is first brought into eu- 
 gagement with the guide screw, the point is then 
 quickly brought against the work with more or less 
 pressure. After the thread is well started it may be 
 finished with an ordinary chaser or with a pointed 
 tool. 
 
 Fig. 137. Chasing Thimbles. 
 
 Fig. 138 shows a method of starting an inside thread. 
 The chaser has a tracing edge that follows the guide 
 screw projecting from the center of the chuck, and a 
 cutting point that forms the thread. Fig. 139 shows 
 the tool in detail. 
 
 Threads cut by a chaser without some kind of a 
 guide to start them are often more or less crooked or 
 drunken. To correct such threads and in cutting large 
 threads, the doctor, shown in Fig. 140, is sometimes 
 
HOME MECHANICS FOK AMATEUKS 
 
 131 
 
 employed. The follower opposite the chaser is moved 
 lip by the thumbscrew as the thread deepens. 
 
 The most expensive, and at the same time the most 
 desirable, contrivance for chasing screw threads is 
 shown in Fig. 141. A casting fitted to the lathe bed 
 has two ears, wiiich are bored to receive the round 
 
 Fig. 138. 
 
 Fig. 139. Chasing Inside Threads, 
 
 sliding rod carrying the tool holder and tracer. The 
 tool holder is placed on the sliding rod between the two 
 ears, and it carries a well-fitted screw, which bears 
 against the horizontal bar supported by two square 
 posts, which form a part of the main casting. This 
 bar forms a guide wliicli may be adjusted within nar- 
 row limits by the screw seen in the right hand post. 
 
132 
 
 HOME MECHANICS YOU AMATEUES 
 
 The lathe is provided with a face i^late having a long 
 boss arranged to receive thimbles having leading- 
 threads of different pitches cut on them. The tracing 
 arm carries a thin tracing which engages the threaded 
 thimbleSj and is capable of yielding to admit of mov- 
 ing the cutting tool forward against the object being 
 threaded ; but being well fitted to the mortise in the 
 arm it cannot move laterally without carrying the 
 sliding rod and all attached to it. The tracing tool is 
 slotted to receive a pin which passes transversely 
 
 Fig. 140. A Doctor for Cutting Large Threads. 
 
 through the head of the tracing arm, and in the slot is 
 placed a spiral spring which tends to throw the tracer 
 forward. 
 
 The operation of this device needs no special ex- 
 planation. The arm that carries the cutting tool is 
 moved forward until its adjusting screw strikes the 
 horizontal guide bar; the tracing tool at the same 
 time engages the leading screw and carries all forward. 
 When the- tool has traveled as far as desirable it is 
 drawn back and returned to its original position. With 
 this tool threads may be cut on either cylindrical or 
 tapering work. 
 
ILO^IK I^IECHANTCS YOU A]\rATEUES 133 
 
134 HOME MECHANICS FOR AMATEURS 
 
 It is sometimes desirable to form spiral grooves in 
 the face of a disk ; this may be accomplished in exactly 
 the same manner as in the case of the cylindrical work. 
 The method of doing it is illustrated by Fig. 142. 
 
 Knurls of various patterns are shown in Fig. 143. 
 These are employed in ^'beadingy' "milling," or knurl- 
 ing the heads of screws, the handles of small tools, etc. 
 The manner of using this tool is shown in Fig. 145. 
 
 Fig. 142. Cutting Spiral Grooves. 
 
 The knurl is placed between the forks of a holder and 
 upon a pin that passes through the fork, and is held 
 with considerable pressure against the work as it re- 
 volves. 
 
 The knurls shown in Fig. 144 are easily made. 
 All that is required is a hub something like that 
 shown in Fig. 131. This is placed between the centers 
 of the lathe, and the knurl blank is brought in contact 
 with it and allowed to revolve in a holder supported 
 
HOME MECHANICS FOR AMATEUES 
 
 135 
 
 by the tool rest. The straight blank is moved up and 
 down until every part of the surface is cut in the same 
 wav. The concave blanks cannot be moved, but the 
 
 Fig. 143. Knurls. 
 
 Fig. 144. Examples of Knurling. 
 
 Fig. 145. Knurling. 
 
 hub should fit the hollow of the face of the blank. The 
 fancy knurl shown in Fig. 143 must be made by a die 
 sinker. Fig. 144 represents examples of knurling 
 done with knurls shown in the preceding figure. 
 
136 HOME MECHAXICS FOE xVMATEURS 
 
 EOTAKiY CUTTEK8 
 
 Tlie saving of files, time, materials and patience, by 
 the employment of such rotary cutters as may be 
 profitably used in connection Avith a foot lathe, can 
 hardly be appreciated by one who has never attempted 
 to use this class of tools. It is astonishing how much 
 very hard labor may be saved by means of a small 
 
 Fig. 146. Metal Circular Saw. 
 
 circular saw like that shown in Fig. 146. This tool, 
 like many of the others described in this section, 
 can, in most instances, be purchased cheaper than it 
 can be made, and the chances are in favor of its being 
 a more perfect article. However, it is not so difficult 
 to make as one might suppose. A piece of sheet steel 
 may be chucked upon the face plate, or on a wooden 
 block attached to the face plate, where it may be bored 
 to fit the saw mandrel, and cut in circular form by 
 means of a suitable hand tool. It may then be placed 
 upon the mandrel and turned true, and it is well 
 enough to make it a little thinner in the middle than 
 at the periphery. 
 
 There are several methods of forming the teeth on 
 a circular saw. It nmy be spaced and filed, or it may 
 
HOME ]^IECHAXICS FOE AMATEUES 
 
 137 
 
 be knurled, as shown in Fi^-. 147^ and tlien filed, leaving 
 every third or fourth tooth formed h\ tlie knurl; or 
 it may, for some purposes, be knurled and not filed 
 
 Fig. 14 
 
 at all. Another wav of forming the teeth is to employ 
 a hub, something like that used in making chasers, as 
 shown in Fig. 148. The difference between this hub 
 and the other one referred to, is that the thread has 
 one straight side corresponding with the radial side of 
 
 Fig. 148. Hub for Saw Making. 
 
138 
 
 HOME MECHANICS FOE AMATEUES 
 
 the tooth. The blank from wliich the saw is made is 
 placed on a stud projecting from a handle made spe- 
 cially for the purpose, and having* a rounded end which 
 supports the edge of the blank, as the teeth are formed 
 by the cutters on the hub. 
 
 Fig. 149. Small Saw. 
 
 The saw, after the teeth are formed, may be hardened 
 and tempered by heating it slowly until it attains a 
 cherry red, and plunging it straight down edgewise into 
 cool, clean water. On removing it from the water 
 it should be dried and cleaned with a piece of emery 
 paper, and its temper drawn to a purple over a Bun- 
 sen gas flame, over the flame of an alcohol lamp or 
 over a hot plate of iron. The small saw shown in Fig. 
 149 is easily made from a rod of fine steel. It is very 
 useful for slitting sheet brass and tubes, slotting small 
 shafts, nicking screws, etc. Being quite small it has 
 
 Fig. 150. Mandrel. 
 
 Fig. 151. Cutter. 
 
 the advantage of having few teeth to keep in order, and 
 it may be made harder than those of larger diameter. 
 A series of them, varying in diameter from one-eighth 
 to three-eighths of an inch, and varying considerably 
 in thickness, will be found very convenient. 
 
HOME MECHAXICS FOR AMATEUKS 139 
 
 Tliese cutlers or saws, witli tlie excci)tioii of the 
 smaller one, may be used to the best advantage in con- 
 nection with a saw table, like that shown in Fig. 153. 
 This is a plane iron table having a longitudinal groove 
 in its face to receive the guiding rib of the carriage, 
 shown in Fig. 154, and a transverse groove running 
 half way across, to receive a slitting gauge, as shown 
 in Fig. 153. The table is supported by a standard or 
 shank, which fits into the tool-rest socket. The saw 
 
 Fig. 152. Making a Cutter. 
 
 mandrel is supported between the centers of the lathe, 
 and the saw projects more or less through a slot formed 
 in the table. The gauge serves to guide the work to 
 be slotted, and other kinds of work may be placed 
 on or against the carriage, shown in Fig. 154. 
 
 It is a very simple matter to arrange guiding pieces 
 for cutting at any angle, and the saw table may be 
 used for either metal or wood. The saws for wood 
 differ from those used for metal; the latter are filed 
 straight, the former diagonally or fleaming. Among 
 
140 HOME MECHAXICS YOV, AMATEUKS 
 
 the many uses to wliicli metal saws may be applied we 
 mention the slitting of sheet metals, splitting wires and 
 rods, slotting and grooving, nicking screws, etc. Fig. 
 155 shows a holder for receiving screws to be nicked. 
 It is used in connection with the saw table, and is 
 moved over the saw against the gange. 
 
 To facilitate the removal of the screws the holder 
 may be split longitudinally and hinged together. An- 
 other method of nicking screws is illustrated b}^ Fig. 
 
 Fig. 153. Saw Table. 
 
 156. A simple lever, fulcrumed on a bar held by the 
 tool post, is drilled and tapped in the end to receive 
 the screw. After adjusting the tool all that is required 
 is to insert the screw and press down the handle so 
 as to bring the screw head into contact with the saw. 
 Where a lathe is provided Avith an engine rest, the 
 cutter shown in Fig. 151, mounted on the mandrel 
 shown in Fig. 150, is very useful ; it is used by clamp- 
 ing the work to the slide rest and moving it under the 
 cutter bv working the slide rest screw. 
 
HOME MECHA^^CS FOPi AMATEURS 141 
 
 To make a cutter of this kiud is more difficult than 
 to make a saw, and to do it readily a milling machine 
 would he recpiired. It may be done, however, on a 
 plain foot lathe, by employing a V-shaped cutter and 
 
 Fig. 154. Saw Carriage. 
 
 using a holder (Fig. 152) haying an angular groove 
 for receiving the cylinder on which the cutting edges 
 are formed. The blank can be spaced with sufficient ac- 
 curacy, by means of a fine pair of dividers, and after 
 the first groove is cut there will be no difficulty in 
 getting the rest sufficiently accurate, as a nib inserted 
 in the side of the guide enters the first groove and all 
 of the others in succession and regulates the spacing. 
 
 One of the best applications of this tool is shown 
 in the small engraving. In this case a table similar 
 to the saw table before described is supported in a 
 vertical position, and arranged at right angles with 
 
 Fig. 155. Holder for Screws. 
 
 the cutter mandrel. The mandrel is of tlie same diam- 
 eter as the cutter, and serves as a guide to the pattern 
 which carries the work to be operated upon. The prin- 
 cipal use of this contrivance is to shape the edges of 
 
142 
 
 HOME MECHANICS FOE AMATEURS 
 
 curved or irregular metal work. The castiug to be 
 finished is fastened — by cement if small, and by clamps, 
 if large — to a pattern having exactly the shape required 
 in the finished work. 
 
 Fig. 156. Nicking Screws. 
 
 By moving the pattern in contact with the table and 
 the mandrel, while the latter revolves, the edges of 
 the work will be shaped and finished at the same time. 
 By substituting a conical cutter for a cylindrical one, 
 the work may be beveled; by using both, the edge may 
 be made smooth and square, while the corner is beveled. 
 
 The tool shown in Fig. 157 might properly be called 
 a barrel saw. It is made by drilling in the end of a 
 
 Fig. 157. Barrel Saw. 
 
 steel rod and forming the teeth with a file. To avoid 
 cracking in tempering a small hole should be drilled 
 through the side near the bottom of the larger hole. 
 To insure the free working of the tool it should be 
 turned so that its cutting edge will be rather thicker 
 than the portion b(^hin(l it. This tool should be made 
 in various sizes. 
 
HOME MECHANICS FOR AMATEUES 
 
 143 
 
 EASILY MADE SLIDE REST 
 
 While the most of the Avork to be done on the foot 
 lathe may be accomplished as expeditiously and quite 
 as well without a slide rest as with it, yet there are 
 some operations that are greatly facilitated by means 
 of this tool. Boring, for example — a very difficult thing 
 to do with hand tools — may be done quickly and ac- 
 curately by using a slide rest. In gear cutting — de- 
 scribed in another part of this section — a slide rest is 
 essential. 
 
 Fig. 158. The Complete Slide Rest. 
 
 In the case of tliis tool, as well as others previously 
 described, the purchase of a well-made article is recom- 
 mended. Yet, if one has time and feels so inclined, lie 
 may make a really efficient slide rest with no other 
 tools than his lathe and ordinarj^ turning tools. Figs. 
 158 to 160 inclusive represent a slide rest that may be 
 made in this way, Fig. 158 being a jDerspective view, 
 and Figs. 159 and 1(>0 respectively longitudinal and 
 transverse sections of the tool carriage. 
 
144 
 
 HOME MECHAXICS FOK AMATEURS 
 
 The T-shaped casting, A, has a h)ngitudinal slot, 
 which is made T-shaped in cross section to receive the 
 head of the bolt that confines it in position upon the 
 plate fitted to the lathe bed. The vertical ears at op- 
 posite ends of the casting are bored to receive the ends 
 of the rods, B, upon which the tool carriage, C, slides. 
 
 The first operation in making the slide rest is to 
 make one side of the casting, C, perfectly plane. It is 
 
 Fig. 159. Longitudinal Section of Slide Rest. 
 
 Fig. 160. Transverse Section of Slide Rest. 
 
 then chucked in the lathe with the plane side next 
 the face plate. Three holes are bored through it, two 
 for the rods, B, and a smaller one for the screw, G. 
 It is then chucked on an angle plate, so that the holes 
 for the rods, B, are equally distant from the center line 
 of the lathe, and the hole for the rod D, is bored very 
 carefully to insure the i)arallelism of its sides. The 
 casting. A, is now placed upon a plane surface, and the 
 
HOME MECHANICS FOR A.AIATEURS 145 
 
 castin<>-, C, is clamped to the ear at one of its ends, and 
 adjusted so that a line drawn through the center of 
 the holes is exactly parallel with the bottom of the 
 casting. The casting, C, is used in this manner as a 
 template for drilling both of the ears for the reception 
 of the rods B. It will be necessary to exercise great 
 care in drilling these holes, as it is of vital importance 
 to have the rods, B, perfectly parallel. 
 
 The casting, C, may now be tapped to receive the 
 scrcAV, G, and the tool-carrying bar, D, may be fitted 
 to its place, and turned down and threaded to receive 
 the internally threaded boss of the wheel, E. This 
 boss is fitted to the base of the casting, C, and is grooved 
 circumferentially to receive a split ring, F, the latter 
 being drilled to receive the ends of three screws that 
 project through the casting into it and prevent the 
 boss of the wheel, E, from moving lengthwise of the 
 hole, while the arrangement permits of the free rotation 
 of the wheel. The bar, D, has a head which is drilled 
 vertically to receive the tool post, and is provided 
 with a heavy feather at the top, which is received by 
 the slot formed by sawing into the upper portion of the 
 casting, C. To render the bearing of the bar, D, some- 
 what adjustable, two screws pass through the casting- 
 above the feather. The tool post is of the usual de- 
 scription, having a loose collar above the head of the 
 bar, D, and a nut below it. The mortise for receiving 
 the tool extends a little below the loose collar, so that 
 when the tool is clamped the post and ring will also 
 be clamped. A slot is cut through the bottom of the 
 casting, C, into each of the guide rod holes, to permit 
 of adjustment in case of wear by means of the screws 
 which pass transversely through the slot. The ends of 
 
14G HOME MECHANICS FOR AMATEUES 
 
 the rods, B, are fastened by a similar device. The screw, 
 G, is prevented from end motion by a shoulder on the 
 outside of the ear at the crank end, and a collar on 
 the inside. The rods, B and D, may be made of steel 
 or of cold rolled iron; the latter Avill be true enough 
 without turning. The casting may be either of brass 
 or iron ; a good quality of iron will perhaps prove the 
 most satisfactorv. The slots may be cut with the 
 
 Fig. 161. Boring Attachment. 
 
 saws described in a former article. The tools to be 
 used with the slide rest have also been previously 
 described. 
 
 In Fig. 161 is represented a boring device which will 
 be readily understood without special description. The 
 casting, A, is fitted to the tool rest socket and provided 
 with a sliding bar, B, which is like the bar, D, in the 
 slide rest above described, excepting that its back end 
 
HOME MECHANICS FOR AMATEURS 147 
 
 is rounded and provided with a pin which slides in the 
 slotted arm attached to the tail spindle of the lathe by 
 which it is moved^ instead of havin^^' a moving device of 
 its own. Witli this tool, boring and some kinds of out- 
 side turning may be done. It is less expensive than 
 the slide rest and ansAvers a good purpose. It is prob- 
 able that in making both these tools the services of a 
 mechanic provided with a planer or shaper will be re- 
 quired. 
 
 INDEX PLATES FOR GEAR CUTTING 
 
 There are many amateurs who would make their 
 own gear wheels were it not for the expense of pur- 
 chasing or the trouble of dividing and drilling the 
 index plate, which is the principal item in the ap- 
 paratus required in cutting small gears. 
 
 Of course an index plate may be purchased, but the 
 money thus laid out would go a long way toward pay- 
 ing for cutting all the gears that would ever be re- 
 quired by most amateurs. 
 
 It is admitted that it is difficult to obtain absolute 
 accuracy by ordinary methods, but the plans here sug- 
 gested will probably give as nearly perfect results as 
 can be obtained without copying another index plate 
 or using a dividing engine. 
 
 The index plate, before being divided, should be 
 nicely turned and fitted to the place it Avill occupy on 
 the lathe. This Avill generally l)e on the larger side of 
 the cone pulley. 
 
 Two methods of graduating an index plate are il- 
 lustrated by the accompanying engravings. One con- 
 
148 HOME MECHAXICS FOll AMATEURS 
 
 sists iu locating the holes by using paper scales whieli 
 are printed from engine divided plates, and are, there- 
 fore, very nearh^ accurate. The other consists in divid- 
 ing the plate b^' aid of a large paper disk graduated by 
 hand. 
 
 For the most of purposes four rows of holes will 
 answer. The best nund^n' of holes for the different 
 rows is as folloAvs: 240, 200, 144, 132. 240 can be 
 divided as follows: 120, 60, 48, 40, 30, 20, 15, 12, 6. 
 With 200 divisions: 100, 50, 40, 25, 20, 10 and 5 may 
 be made. 144 divides into 72, 48, 30, 24, 18, 16, 12, 
 9, 8, 6. 132 into 66, 44, 33, 22, 11. 
 
 The best method of dividing an index plate of which 
 the T^^iter has any knowledge, aside from duplicating 
 another, or using a dividing engine, is shown on the 
 next page. A wooden block. A, is attached to the face 
 plate of the lathe by means of screws, and turned down 
 truly on the face and upon the edge. A portion of the 
 edge is turned to a suitable diameter for receiving a 
 certain length of ])aper scale, C. The other portion of 
 the edge is pressed by a brake shoe, F, which is kept 
 up by a screw in the standard, D. An index, E, is 
 slotted and secured to the top of the standard, D, by 
 a screw. To the face of the block. A, is secured the 
 index plate, B, and in front of the plate there is a drill 
 support which takes the place (^f the ordinary tool rest. 
 The drill is capable of longitudinal as well as rotary 
 motion in its support; it is driven by a belt from the 
 drive wheel of the lathe, and is pushed forward a lim- 
 ited distance by tin* handle swiveled to the end of the 
 drill spindle, Tlie size of the drill will be gov(^rned 
 altogether l)y tlie si/.e (jf thi^ plale; l)ut in any case 
 it should be as large as possibles always bearing in 
 
HOME MECHAXICS FOli AMATEUES 
 
 149 
 
 iiiiud tlial the space between tlie holes slionid be of suf- 
 ficient width to insure tlie rcMinired stren<;tli. 
 
 That portion of the wooden bloclv, A, which receives 
 tlie paper scale, C, is carefully turned so as to permit 
 the ends of the scale to abut; the scale being very care- 
 fullv cnt so that its ends will join accurately and render 
 
 Fig. 162. Method of Graduating Index Plates. 
 
 the graduations of the scale uniform throughout. The 
 scale is best attached to the block by means of paper 
 tacks or small screws. For the greatest number of 
 graduations given above, a two foot paper scale, or 
 two pieces of shorter scales, will be required. The 
 inches should be divided into tenths. The block should 
 be 7.64 inches in diameter where it is surrounded by 
 
150 HOME MECHANICS FOR AMATEUES 
 
 the scale. The diameter of that part engaged by the 
 brake shoe is not limited to any particular size. 
 
 It is obvious that for drilling 240 holes every mark 
 on the scale must be brouglit opposite the index, E, 
 and stopped by means of the brake, F, while a hole is 
 drilled. After drilling tliis row of holes, the row con- 
 taining 144 holes should be drilled, leaving a space 
 between it and the 240 row^ for the 200 row. For the 
 144 row the operation is the same as that already 
 described, except that a scale divided into twelfths is 
 used, and alternate graduations only are noticed. The 
 intermediate ones should be crossed out, so that the 
 scale will really be a scale of inches divided into sixths. 
 For the 132 row the block is turned down to 7 inches 
 diameter, and the scale last used is shortened to 22 
 inches and again applied to the block and used as 
 before. 
 
 After completing these rows of holes the drill is 
 moved to the space between the first and second row^s, 
 the block is turned down to 6.36 inches, and 20 inches 
 of the paper scale first used (inches divided into 
 tenths) is employed. Every graduation on the paper 
 scale is used in this case as in the first instance. This 
 gives 200 divisions. 
 
 The paper scales recommended for this purpose are 
 those used by engineers and draughtsmen. They may 
 be obtained for a few cents from any dealer in mathe- 
 matical instruments. 
 
 In Fig. 163 the larger circle represents a disk of 
 paper which is carefully divided into large spaces by 
 means of ordinary dividers, and the large spaces are 
 subdivided in the same way. 
 
 In the center of the paper disk is placed the plate to 
 
HOME MECHAI^ICS FOR AMATEtTES 
 
 151 
 
 be divided, and from the center of the plate rises a 
 stud, to which is accurately fitted the sleeve attached 
 to the end of the radius bar. The radius bar extends 
 beyond the outer circle on the paper disk, and carries 
 an adjustable sleeve, to which is accurately fitted a 
 
 Fig. 163. Index Plates for Gear Cutting. 
 
 drill which may be rotated by means of a small drill 
 stock. The slecA^e that forms the bearing of the radius 
 bar is shown in detail in the lower left hand corner of 
 the engraving, and the sleeve that receives the drill is 
 shown in the opjiosite corner. 
 
 While drilling, the radius bar is held in place by a 
 
152 HOME MECHAXICS YOR A]\rATEUES 
 
 wcjolit or by means of a clamp. After drilling each liole 
 the bar is moved forward one space and secnred by the 
 weight or clamp. When one row of holes is completed, 
 the sleeve which gnides the drill is moved toward the 
 center of the disk, and the operation of drilling is car- 
 ried on as before. By this method whatever errors may 
 exist in the gradnations on the paper disk are greatly 
 reduced in the index plate, and the plate produced will 
 l)e accurate enough for most purposes if the work on 
 the paper disk has been carefully done. The smallest 
 plate should be at least three-sixteenths of an inch 
 thick, and the lioles should not be drilled quite through. 
 Either iron or brass may be used for the disk. The lat- 
 ter works the easiest and will answer every purpose. 
 
 GEAR CUTTING APPARATUS 
 
 The index plate, A, is attached to the larger of the 
 pulleys on the mandrel of the lathe by means of three 
 or four screws, and the stop, C, provided with a point 
 well fitted to the holes in the plate, is held in position 
 on the bed plate, B, by a screw iDassing through a slot in 
 the foot into the bed piece. The stop, C, is capable of 
 springing sufficiently to admit of withdrawing the pin 
 from the hole in the plate, and it is strong enough to 
 hold the plate without vibration. Two standards, G, 
 mounted on the plate, B, support pulleys over which 
 the driving belt runs. The gear cutter head consists of 
 a casting, D, fitted to the tool post of the slide rest, 
 and the mandrel, E, provided Avith a pulley and 
 mounted on carefully fitted centers in the casting. The 
 casting, D, has upon opposite sides, near the upper end, 
 ears (as shown in Fig. 165) for receiving the pulleys. 
 
HOME MECHAXICS FOR AMATEL'IJS 153 
 
 o 
 
154: HOME MECHAXICS FOR AMATEURS 
 
 (/ h, which ,i»nide the driviug belt, so that the cutter 
 may be removed across the face of the wheel being cut 
 Avithout chauging the tension of the belt. The ex- 
 treme end of the loop formed by the belt is supported 
 
 Fig. 165. Detail of Gear Cutter. 
 
 by the pulley, H, mounted on a standard rising from 
 the lathe bed. The standard may be placed far enough 
 from the slide rest to admit of putting the tail stock 
 between it and the slide rest in case it should be neces- 
 sary to use the tail stock for supporting the work. 
 
 Detail of Pulleys. 
 
 JF 
 
 Fig. 166. 
 
 P 
 I 
 
 Cutters. 
 
HOME MECHANICS FOR AMATEURS 155 
 
 The mandrel, E, is provided with a eolhir and a nut 
 for damping the cutter, F. It will be noticed that the 
 cutter comes exactly opposite the line of the lathe cen- 
 ters, and that it occupies about the same position, in 
 relation to the tool post, that the point of an ordinary 
 turning tool does. The cutter, F, is sho^yn in Fig. !()(>, 
 enlarged. The upper yicAy represents the side, the 
 loAyer view the edge of the cutter. It has but a single 
 tooth and is adapted to brass and similar alloys only. 
 It may be sharpened by grinding. When iron or steel 
 is to be cut the cutter should haye several cutting edges, 
 and the mandrel, E, should have a larger pulley, as 
 more power will be required and the speed must be 
 slower. By setting the slide rest at an angle bevel 
 gears may be cut. 
 
 HINTS ON MODEL MAKING 
 
 It is a simple matter for an experienced instrument 
 maker or machinist to produce a fine model with turned 
 shafts, cut gearing, true pulleys, and smooth working 
 cams, but it is quite another thing for an inventor, 
 without tools or materials, to embody his ideas in a 
 working model even though he may have a mechanical 
 taste. 
 
 It is fair to suppose that every mechanical inventor 
 in these days of cheap machinery possesses some sort 
 of a lathe, as these indispensable machines are now 
 made for prices within the reach of almost any one. 
 
 It is quite evident, from an inspection of the models 
 of the Patent Office, that most inventors who under- 
 take to make their own models expend a great deal of 
 labor without corresponding results. In the matter of 
 
156 
 
 HOME MECHAXTCS FOT^ AMATEUES 
 
 ^iicai-ini;, for instance, one w'\]\ y\]\\t{]v liis ^^■luH*ls iu 
 wood, another will borrow liis <»earini> from some de- 
 funct clock, while still another will purchase ready- 
 made wheels from one of our well known firms makin^i,' 
 a business of furnishing parts of models. 
 
 Of the three methods of obtaining the gearing the 
 latter is undoubtedly the best, as all that is necessary 
 to l)e done, in case of the cast gear wheels, is to bore 
 them and file up the teeth, and as the cut gear wheels 
 
 Fig. 167. Friction Gearing 
 
 are generally bored, the shaft may be fitted without 
 further work on the wheels. It is, however, seldom 
 absolutely necessary to use toothed gearing, as rotary 
 motion may be readily transferred by suitable friction 
 wheels or by grooved or sprocket wheels and a round 
 belt. 
 
 Fig. 167 shows a form of friction gearing which is 
 both simple and effective. The larger wheel is simply 
 a disk of sheet brass having rounded edges, and boss 
 
HOME MECHANICS FOll AMATEUl^S 
 
 157 
 
 spim or soldered on, and a smaller wheel consists of two 
 swaged disks of steel having their convex faces sepa- 
 rated by a metal washer a little thinner than the large 
 wheel. These three members are secured to a common 
 l)oss by spinning the end of the boss partly over one of 
 the disks, as shown in the sectional view, No. 2. This 
 form of friction gearing is noiseless and runs strong 
 enough for the requirements of almost an}^ model. 
 
 Figs. 168 and 169 show a form of sprocket wheel 
 
 Fig. 168. 
 
 Fig. 169. 
 
 Sprocket Wheels. 
 
 which is readily made and is almost as positive in its 
 action as gearing. In this case the two wheels are 
 alike; they consist of disks of sheet metal nicked to a 
 uniform depth from the edge, and the arms thus formed 
 are bent alternately in opposite directions, forming a 
 groove for receiving the round belt used in transferring 
 motion from one wheel to the other. It is evident that 
 a belt cannot slip on a wheel of this construction. 
 
 Fig. 170 shows a form of friction gearing for trans- 
 ferring motion at right angles, and for imparting a 
 variable speed to a shaft from another shaft running at 
 
158 HOME MECHANICS FOli AMATEUES 
 
 a uniform rate. The large wheel in this instance is 
 merely a plane disk of metal mounted in the manner 
 already described. The smaller wheel is a grooved 
 metal pulley surrounded by an elastic rubber ring. 
 This is pressed with more or less force against the me- 
 tallic disk, and its speed may be varied by moving it 
 toward or away from the axis of the disk. 
 
 As to the matter of irregular motion usually im- 
 parted by cams, it is difficult to make a cam in the ordi- 
 
 FiG. 170. Transferring Motion at Right Angles. 
 
 nary way with the milling machine, and there appears 
 no very simple way of cutting them from solid castings. 
 There is, however, a simple way of building them up 
 from readily obtained materials. 
 
 Fig. 171 shows a cam consisting of a cylinder of brass 
 or a short section of brass tubing provided with two 
 heads and mounted on a shaft. The cam groove is laid 
 out on this surface, and two parallel pieces of square 
 brass wire are soldered to the surface of the cylinder, 
 or fastened by means of screws. They are placed uni- 
 forndy distant tliroughout tlie entire circumference of 
 the cylinder. 
 
HOME MECHANICS FOR AMATEURS 
 
 159 
 
 Fig. 172 shows a cam built up iu tlie same way on the 
 face of a dislv. 
 
 As to shafts, the model maker may save himself much 
 labor and expense by nsing l^tnl)bs' steel for small 
 shafts, and cold rolled iron for larger ones. Either 
 the steel or iron may be bought in one and three foot 
 lengths. 
 
 Almost anything in the way of parts of models may 
 be purchased ready for use, so that all the inventor need 
 do is to combine them and mount them on a suitable 
 
 Fig. 171. Drum Cam. 
 
 Fig. 172. Disk Cam. 
 
 frame ; but even so simple a matter as a Avooden frame 
 for a model sometime proves troublesome. 
 
 The small tenons and mortises are difficult to make, 
 and the frame to be strong enough to bear handling 
 must be made so heavy as to be entirely out of propor- 
 tion. A simple and easy method of securing the joints 
 of small frames is to clamp the parts in the position 
 they are to occupy in relation to each other, and then 
 drill, with a sharp twist drill, two holes through one 
 piece from side to side and into the end of the abutting 
 piece, then inserting two hard wood pins, having previ- 
 ously coated them with glue. This makes a joint far 
 stronger than the xuortise and tenon, and it is very 
 quickly done. 
 
160 
 
 IIO.AIE MECHANICS FOE. AMATEURS 
 
 METAL SPINNING 
 
 The operation of spinnin.i>' metals, irltliougli exceed- 
 iii<ilv simple and capable of beino- practiced to advan- 
 tage in almost every shop, and also by the amateur me- 
 chanic upon the foot lathe, is not generally understood. 
 One reason for this is that the artisans who follow this 
 
 Fig. 173. Metal Spinning. 
 
 branch of mechanics as a business usually conduct it 
 under locked doors, and it is with considerable diffi- 
 culty that the amateur in search of information on this 
 and kindred subjects can obtain (mtrance to one of 
 these establishments. The reason of this secrecy is 
 plain enough, as the ^'kink'' or ''wrinkle/' or, in plain 
 
HOME MECHANICS FOR AMATEURS 101 
 
 English, the knowledge required to do the mechanical 
 part of spinning is so slight that secrecy is the only 
 protection. 
 
 The tools required are few. They consist of a lathe ; 
 a form or mould on which to shape the article; a tool 
 rest with a series of holes for receiving a pin to keep the 
 
 Fig. 174. 
 
 Fig. it; 
 
 Spinning Tools. 
 
 tool from slipping, and a few spinning tools or burnish- 
 ers of different sizes and shapes. 
 
 The lathe the amateur is supposed to possess; the 
 tool rest he may easily make ; and the only other addi- 
 tion to the lathe will be a back center of the form shown 
 in Fig. 174. This form of center answers as a step to 
 the work holder, and will bear considerable pressure 
 without undue friction. 
 
 The tools required are shown in Fig. 175. These are 
 
162 HOME MECHANICS EOK AMATEUliS 
 
 simplj^ hard steel burnishers of the form shown^ and 
 varying in size with the size and kind of work to be 
 done. The size given in the engraving is about right for 
 amateur work on a foot lathe. No. 1 shows in two 
 
 Fig. 176. 
 
 Fig, 177. 
 
 The Forms in the Lathe. 
 
 Fig. 178. The Use of the Bolt 
 
 views a ball tool. No. 2 shows both side and edge views 
 of a curved tooL No. 3 shows a plain round burnisher. 
 In some instances it ma}^ be necessary to make tools of 
 different forms. The operator will be guided in the 
 selection of his tools by the particular work in hand, 
 
HOME MECHANICS FOR AMATEUES 
 
 1G3 
 
 and practice will brinji new suggestions as to the tools 
 and the manner of using them. 
 
 The materials generally used in spinning are brass, 
 copper, zinc, britannia metal and lead. All of these 
 mav be worked on the foot lathe, but perhaps the ama- 
 
 FiG. 179. Fig. 180. 
 
 The Movement of the Tool. 
 
 teur will derive the most satisfaction at first by using 
 britannia metal, as it works easily and does not require 
 annealing. Articles in this metal also present a hand- 
 some appearance when done, whether simply polished 
 
 Fig. 181. Spinning without a Form. 
 
 Fig. 182. Spinning a Ring. 
 
 or plated. Zinc must be spun quite hot. Articles of 
 brass, if of considerable depth, must be annealed when 
 partly done. 
 
164 HOME MECHANICS FOR AMATEUES 
 
 The form on which the metal is spun may be either 
 hard or soft wood or metal. A good close grained pine 
 answers as well as anything for most purposes, and i^ 
 very readily turned to the required form. It may be 
 attached to the face plate, B, and the disk to be spun 
 may he held against it at first by a hard wood or metal 
 piece, C, as shown in Figs. 176 and 177, which is forced 
 against the disk by the tail center. After the spinning 
 is a little advanced, a cup-shaped holder is applied, as 
 
 shown in dotted lines in Fig. 1 
 
 I i. 
 
 Sometimes the 
 
 Fig. 183. Concave Reflector. 
 
 Fig. 184. Cup. 
 
 holder is secured by a bolt that runs through both it 
 and the form or mould, as shown at D, Fig. 178. In 
 some cases a little rosin is applied to the form to in- 
 crease the friction, but this is rarely necessary. The 
 motion of the lathe should be quite rapid, and the disk 
 should receive a coating of grease (lard or heavy oil) 
 before applying the burnisher. A very strong solution 
 of soap may be used instead of oil. The position of the 
 Avorkman and the manner of holding the tool may be 
 seen in Fig. 173. It will be noticed that the pin in the 
 tool rest serves as a fulcrum for the tool, which must 
 be brought with considerable pressure against the sur- 
 
HOME MECHANICS FOE AMATEUES 
 
 1G5 
 
 face of the disk. Tliis pin is moved forward from lime 
 to time as the work advances. The movement of the 
 tool may be seen in Figs. 179 and 180. The shape taken 
 by the metal in front of the tool will also be seen. In 
 swinging the tool toward the form it is moved in the 
 
 Fig. 186. Ball 
 
 Fig. 185. Vase. 
 
 Fig. 187. Pitcher. 
 
 direction of the arrow as shown in Fig. 179, and it is 
 carried back as shown in Fig. 180. This last operation 
 is very essential to the proper fitting of the mould, and 
 it also thickens the metal. Too much should not be 
 attempted at a time. A succession of quick movements, 
 as indicated in Figs. 179 and 180, under a moderate 
 pressure is much better than to do a great deal of exe- 
 cution at a single stroke. Should the metal tend to 
 
160 
 
 HOME MECHxVXlCS FOR AMATEURS 
 
 vibrate or buckle, a piece of wood may be applied to the 
 back with the left hand, as shown in Fig. 178. 
 
 The method of spinning a cup or pot without a form 
 is illustrated in Fig. 181. Here the metal is supported 
 by a plain cylindrical mandrel, and is first spun into 
 
 Fig. 188. Card Receiver 
 
 Fig. 189. 
 
 the form indicated by the dotted lines, and then bring- 
 ing the burnisher on the return stroke only to the 
 shoulder Avhich forms the larger part of the ves- 
 sel. For small work on the foot lathe the handles 
 of the tools need not be as long as represented, 
 in Fig. 173. The length commonly employed for wood 
 turning tools will answer. 
 
 To spin a ring, a mandrel like that shown in Fig. 
 
HOME :\IECHAXTCS FOE AMATEURS 
 
 167 
 
 182 will he rcMiuired. A plain flat ring placed between 
 the shoulders of the mandrel is pressed upon by the 
 roller seen above the mandrel until the ring assumes 
 the desired form. Napkin rings are made in this way. 
 
 Fig. 191. Vase. 
 
 Fig. 183 shoAvs a concave reflector. Fig. 184 represents 
 a simple cup formed of two pieces. Fig. 185 represents 
 a small vase made of three pieces, the smaller end of 
 the upper or conical part and the upper portion of the 
 
168 HOME MECHANICS FOR xVMATEUES 
 
 base piece being soldered in a spherical connecting 
 piece. The two halves of the ball, Fig. 186, are made 
 upon the same form. The edges are beveled and sol- 
 dered together. The pitcher, Fig. 187, is made of five 
 spun pieces, a short cast and turned piece that unites 
 it to its base, and a handle made of square wire. The 
 card receiver. Fig. 188, has a spun top and base, and 
 a cast standard. The vase. Fig. 189, consists of four 
 spun pieces and three legs of square wire, uniting the 
 body with the base. Fig. 190 shows a base for a mag- 
 netic needle or other small apparatus. Fig. 191 repre- 
 sents a vase composed of seven spun pieces and two 
 handles of square wire. More complex examples of 
 work done by the process of spinning might be fur- 
 nished. The ones given are undoubtedly sufficient to 
 enable the amateur to get an idea of the endless variety 
 of articles that may be made by this simple and easily 
 acquired art. 
 
PART lY. 
 
 MODEL ENGINES AND BOILERS 
 
 A HOiME-MADE STEAM ENGINE 
 
 A STEAM ENGINE carefully made is a piece 
 of mechanism to be proud of, no matter 
 what its particular design may be. A 
 double-acting engine of good proportion, 
 with a bored cylinder and forged crank and crank 
 shaft, and other parts made in keeping, is, of 
 course, the better form of steam engine to make, but, 
 as we are presuming that not every amateur has the 
 facilities for building such an engine, a description of 
 a simple single-acting engine which could be made by 
 any boy handy with tools is given. It can be made with 
 an ordinary light foot lathe, as no boring is required, 
 nor is there any turning to be done that does not come 
 within the range of such a lathe. 
 
 A view of the engine and the boiler and engine is 
 given, and also a sectional view showing the construc- 
 tion of the valve and valve-operating cam, and the 
 steam passages in the base. 
 
 The cylinder consists of a piece, A^ of mandrel-drawn 
 steel tubing (which needs no boring) 2^ inches long 
 and i inch internal diameter. The thickness of the 
 metal forming the tube is tV inch. This piece of tub- 
 ing is fitted to a boss, a, about ^ inch high, formed 
 on the brass block, near one end. This block is 1^ 
 inches long and ^ inch thick, and is provided with 
 lugs for receiving screws, by which it is attached to 
 the base plate. In this block are formed the steam 
 
 [169] 
 
170 HO]\rE ]\[ECHAXICS FOR AMATEUES 
 
 passages, h c, and valve clianiber. This hole drilled 
 from the front backward and forming the passage, h, 
 receives the steam snpply pipe, B. A hole is drilled 
 from the rear end of the block forward to a point 
 about opposite the center of the cylinder, forming with 
 the hole, d, the steam duct, c d. Near the rear end of 
 the block is drilled a re inch hole, from beneath, which 
 forms the valve seat, r, just beyond the passage, h. A 
 16" inch hole is started at the valve seat, e, and con- 
 tinued to the top of the block. This smaller hole is 
 counter-bored from the top with a yV inch drill, leav- 
 ing the valve chamber. The counter-bored portion of 
 this hole receives the plug, /, which is bored longitudi- 
 nally to receive the valve stem, g, of the conical valve, 
 e'. The valve stem is about 3j inches long, and is 
 provided with the adjustable collar, //, between which 
 and the plug, /. is placed a spiral spring which tends 
 to keep the valve normally closed. The steam pas- 
 sages, h and r% are closed with screw plugs, as shown. 
 
 To the steel tube which forms the cylinder is fitted a 
 piston of cast iron. It is about IJ inches long and is 
 packed by the steam or water contained in the grooves 
 in the piston. The upper end of the piston is slotted 
 to receive the loAver end of the connecting rod, which 
 is pivoted therein upon a ^-inch pin passing through 
 the piston and lower end of the connecting rod, as 
 shown in dotted lines in the sectional view. 
 
 The brass block which supports the cylinder has 
 lugs on opposite sides receiving screws which pass 
 through them into the base plate. This plate is 4 
 inches wide, 5 inches long and ^ inch thick. At the 
 rear of the valve chamber is a post formed of a 4-inch 
 square brass rod 4f inches long, secured to the base 
 
HOME :\IECITAXICS Ton A]\rATEUTJS 
 
 171 
 
 plate l)Y ii screw passiiii;- upward iliPiMiuli i\u^ plate 
 into tlie end of the post. A similar post is placed near 
 the rear end of tlie base plate. The ends of the posts 
 are squared in the lathe. Botli posts are bored trans- 
 
 ^ 
 
 i 
 
 la ^jl'^^^liKi' m ^ ^j^^ 
 
 
 
 \ 
 
 - \ 
 
 
 m 
 
 Fig. 192. Simple Steam Engine. 
 
 verselA^ near the top to receive the shaft, which is ^ 
 inch in diameter and 5 inches long. The space be- 
 tween the posts is 2 inches, and the distance between 
 the shaft and base plate is 3J inches. On the shaft, 
 between the posts, is placed the iron flv- wheel, Avhich in 
 
172 HOME MECHAXICS FOR AMATEURS 
 
 the presenl case cousists of an olH valve wheel 4^ inches 
 in diameter, bushed to fit the shaft and fastened with 
 a set screw. 
 
 The end of the shaft which projects beyond the post 
 over the cylinder carries a ^-incli crank on which is 
 placed a connecting rod. This rod measures If inches 
 between the centers of the holes for the crank pin and 
 the pin in the piston. 
 
 In the side of the cylinder are drilled three -^j inch 
 holes in a horizontal line, and close together to form 
 the exhaust port of the engine, which is entirely un- 
 covered by the piston when it is in the position shown 
 in the engraving. The exhaust remains open for about 
 a quarter of the revolution. This port is left exposed 
 for clearness, but it may be covered by a hollow ring 
 which encircles the cylinder and receives an exhaust 
 pipe. 
 
 On the left shaft is placed a cam, in w^hose boss 
 there is a circumferential groove, and upon the upper 
 end of the valve stem is placed a fork, the upper ends 
 of which slide in the groove in the boss of the cam. A 
 stud in::Grted in the fork has upon it a roller which 
 rolls on the higher part of the cam and opens the valve 
 at the proper instant. This cam opens the valve just 
 before the piston reaches the lower limit of its stroke, 
 and allows the vah^e to close just before the exhaust is 
 opened by the piston. 
 
 The boiler of this engine consists of a copper float to 
 be found in the market, made by an electrolytic de- 
 posit of copper. Such a float forms a seamless boiler 
 capable of withstanding a great pressure, say 100 
 pounds. The boiler is mounted in a tripod made of 
 band iron and is furnished with a safety valve | inch 
 
HOME MECHANICS FOK AMATEUES 
 
 173 
 
 in diameter, the lever of which is about 2 inches lon<», 
 and graduated and weighted so that it will blow off at 
 35 pounds, thus insuring perfect safety. (The ordinary 
 copper float is not recommended.) A brass steam pipe, 
 1 inch internal diameter, is screwed into the safety 
 
 Fig. 193. Simple Steam Engine. 
 
 valve casing below the valve sat, and has at its end a 
 miniature angle valve which is connected to the engine 
 ])y th(^ inclined pipe, and by elbow and nipple which 
 extends into tlie base. As the angle valve is a trouble- 
 some piece of work, an ordinary stop cock is recom- 
 
174 
 
 HOME MECHANICS FOR AMATEURS 
 
 mended in its stead. It should be placed in the in- 
 clined pipe. 
 
 The best burner for this boiler is an Argand gas 
 Bunsen burner like that shown. Of course an alcohol 
 lamp Avill answer, but it is not as safe as the gas 
 burner. 
 
 e' c h 
 
 Fig. 194. Sectional View of Engine. 
 
 Both engine and boiler should be mounted on a 
 suitable base board. 
 
 The engine is capable of making a thousand or 
 twi^lve hundred revolutions pea* minute. It must be 
 well balanced for this speed. 
 
HOME MECHANICS FOR AMATEURS 175 
 
 • The boiler is filled when cold through the safety 
 valve opening by means of a funnel having a slim cor- 
 rugated tube. The boiler should be about two-thirds 
 full of water at the start. 
 
 It is obvious a larger engine could be made on the 
 same principle; but the front support for the shaft 
 should be made A-shaped and placed next to the 
 crank, and the cam should be placed between the sup- 
 port and the fly-wheel ; the shaft support Avould then 
 extend over the cylinder-base. 
 
 A SAFE WAY TO KUN A SMALL ENGINE 
 
 Almost every youth at some time in his life has 
 coveted a steam engine, or some other motor having 
 energy and ability to move of itself and to impart mo- 
 tion to other machines, but through fear of fire from 
 the lamp used to generate steam, or anticipating pos- 
 sible explosions, has been obliged to forego the pleasure 
 of being a boy engineer, and seek amusement in other 
 directions. Ever}^ boy can own a steam engine, since 
 one can be purchased for 50 cents, |1, |2 or more, and 
 the engine can be run with safety by means of com- 
 pressed air. Any engine that will run by steam will 
 run equally well with compressed air. 
 
 Rut how is the compressed air to be furnished and 
 stored for use? There are very few families without 
 bicycles, and every bicycle requires a pump for in- 
 flating the tire; why not use the same pump to com- 
 press air for an engine? The boiler constitutes a small 
 reservoir, and an auxiliary reservoir may be connected 
 Avith the boiler l)y means of a small rubber tube. The 
 auxiliary reservoir may consist of a piece of strong 
 
176 HOME MECHAmCS FOE AMATEURS 
 
 3-inch galvanized iron leader, with caps soldered on the 
 ends, with a small tube inserted at any convenient 
 point to receive a bicycle valve, and another small 
 tube to receive the piece of small rubber tubing which 
 forms the connection between the reservoir and the 
 engine or the boiler belonging to the engine. 
 
 This boiler and reservoir when pumped up as much 
 as possible by ordinary exertion, will run the engine 
 while driving the boat for about 15 minutes. The caps 
 to the reservoir mentioned are made conical so that 
 the reservoir may be drawn in the water after the boat, 
 the connecting rubber tube forming the hawser for tow- 
 ing the reservoir. 
 
 If it is desired to run a stationary engine with com- 
 pressed air, the reservoir may consist of a tin can. A 
 1-gallon varnish can ansAvers very well, but it can be 
 forced out of shape and even exploded unless it is en- 
 cased in a strong wooden box fitting it closely and put 
 together with screws. 
 
 A MINIATURE CALORIC ENGINE 
 
 The hot air engine is not a very recent invention. A 
 number of engines of this class, of different sizes, were 
 devised and used in the early part of the present cen- 
 tury, and in the latter part of the last century there 
 were in existence engines constructed to be operated by 
 the expansion of air. 
 
 Nothing in the way of a motor, aside from a wind- 
 mill or water wheel, can be more simple than this, and 
 it is a pity that it is not capable of more general ap- 
 plication. Motors of this kind have been used to some 
 extent for driving light macliinery, and they have been 
 largely employed in pumping water. 
 
HOME MECHANICS FOE AMATEUKS 177 
 
 Quite recently caloric enoiues have been made in the 
 form of a toy, as illustrated in the following engrav- 
 ing. In the motor here shown, the air contained in 
 the expansion cylinder is alternately heated and cooled, 
 and no fresh air is introduced. This action is so rapid 
 
 Fig. 195. Small Caloric Engine. 
 
irS HOME MECHANICS FOR AMATEURS 
 
 iu a small engine that the cranlc shaft can make 600 or 
 700 revolutions a minute. By examining the sectional 
 views (2, 3 and 4, Fig. 19(3) a good idea of the construc- 
 tion and operation of the motor may be obtained. In 
 
 5 
 
 Fig. 196. Sectional Views of Small Caloric Engine. 
 
 brief, the larger and longer of the two cylinders (the 
 expansion cylinder) contains a long, hollow piston 
 called the ''transfer piston" which fits the cylinder very 
 loosely. To this piston is attached a rod extending 
 through a close fitting sleeve in the top of the cylinder, 
 
HOME MECHANICS FOE AMATEUES 179 
 
 the piston rod being provided with a connecting rod 
 fitted to the crank at the middle of the shaft. The up- 
 per part of the expansion cylinder is furnished with a 
 wide flange forming a cap which fits over the sheet iron 
 fire box, and to the top of the expansion C3dinder are 
 secured the standards in which is journaled the crank 
 shaft. 
 
 To the flange is attached the power cylinder, which 
 is shorter and smaller in diameter than the expansion 
 cylinder. This cylinder is provided with a piston to 
 which is pivotally connected the lower end of a connect- 
 ing rod, the upper end of Avhich receivef^ a crank pin 
 projecting from one of the fly Avheels at right angles to 
 the transfer piston crank. A hole bored in the flange 
 connects the expansion cylinder and the bottom of the 
 power cylinder, as shown in No. 2, Fig. 196, and the 
 outer end of the hole is stopped by screw plug which 
 can be removed for cleaning the hole, should it become 
 stopped by oil or otherwise. 
 
 An alcohol lamp is provided for heating the expan- 
 sion cylinder, it being placed in position to heat the 
 lower end of the cylinder, as shown in the larger view. 
 The top of the lamp is provided Avith a hemispherical 
 cavity, at the bottom of Avhich is the aperture for filling. 
 The stopper consists of a marble dropped into the 
 hemispherical cavity and serving the double purpose of 
 stopper and safety valve. 
 
 The expansion and power cylinders contain a certain 
 amount of air Avhich is never changed during the op- 
 eration of the engine, except by expansion and contrac- 
 tion. Heat having been applied to the lower end of 
 the expansion cylinder, the engine is started by giving 
 the crank sliaft one or two turns in the direction indi- 
 
180 HOME MECHANICS FOR AMATEURS 
 
 cated bv the arrows on the rims of the fly wheels. The 
 air at the top of the expansion cylinder is transferred 
 to the lower end of the cylinder by the transfer piston 
 as it rises ; at the same time the power piston descends, 
 and by this time the air is heated in the lower part of 
 the expansion cylinder and begins to expand. The 
 power piston is in position to be pushed up by the air 
 pressure. As the power piston reaches the upper end 
 of its stroke, the transfer piston descends and transfers 
 the heated air to the upper end of the expansion cylin- 
 der, where it is cooled, thus reducing the pressure and 
 allowing the power piston to descend again. This op- 
 eration is repeated at every stroke. It is almost impos- 
 sible to believe that the air can be heated and cooled 
 so rapidly. 
 
 The efficiency of the motor can be increased by sur- 
 rounding the upper portion of the expansion cjdinder 
 by a Avater jacket provided with a water supply pipe 
 at the bottom and a discharge pipe at the top, as 
 shown in No. 5, Fig. 196, and keeping a continual flow 
 of cool water through the jacket. When the motor is 
 used for pumping, the water is forced through the 
 jacket. 
 
 This little motor is only a toy, but it very completely 
 illustrates the principle of one of the most successful 
 hot air engines ever devised. If the reader is mechan- 
 ically inclined, he may make a motor on this plan on a 
 much larger scale, and use it for driving machinery. 
 There can be no doubt about its successful construc- 
 tion or operation, if it is made airtight and the bear- 
 ings and friction surfaces are made to run free. The 
 proportions may be about the same as shown in the 
 cut. 
 
HOME MECHAXICS FOR AMATEURS 181 
 
 The dimensious uf the motor from wliieh the views 
 were made are as follows: 
 
 INCHES 
 
 Length of expansion cylinder 4f 
 
 Internal diameter of expansion cylinder liV 
 
 Length of transfer iDiston 2f| 
 
 Diameter of transfer piston IJ 
 
 Length of power cylinder If 
 
 Diameter of power cylinder f} 
 
 Length of cranks tV 
 
 Diameter of fly wheels . 3 
 
 Height of firebox from base 5^ 
 
 AN INEXPENSIVE WATER ^lOTOR 
 
 A simple but very effective w^ater motor can be 
 made by any one according to the plan here shown, 
 with little trouble or expense. It may be necessary to 
 have a few minutes' w^ork done by a tinsmith. The 
 maker may do this if he understands soldering. 
 
 In a pine board 7 inches square and 1 inch thick, 
 make a round hole 5 inchcfs; in diameter, by the use of 
 a scroll saw, or in any other convenient way. To the 
 sides of the board fit two thin boards ^ inch thick, 
 one on either side. In a small hole in the center of 
 each side drive a short piece of brass tube of about J 
 inch internal diameter, and to these tubes fit a straight 
 steel wire so that it will revolve freely. This wire is 
 the shaft of the motor wheel. It should be of sufficient 
 length to project an inch beyond its bearings, to receive 
 a small pulley. 
 
 To the center of the shaft is soldered a sheet brass 
 disk 3 inches in diameter, so that it will run true as 
 
182 
 
 HOME MECHANICS FOE AMATEUES 
 
 the shaft revolves, and to the disk is soldered a disk of 
 brass wire gauze 30 mesh. The edges of the brass wire 
 gauze must, as the ladies would say, be sewed over and 
 over with a fine copper wire, to prevent it from raveling 
 when the wheel revolves rapidly. If the Avorkman is 
 an adept he may solder a ring of brass wire, say No. 
 18 or No. 20, to the edge of the wire cloth. 
 
 Fig. 197. Motor Driving Sewing Machine. 
 
 The simplest way to secure a nozzle for the wheel is 
 to buy a cheap, small oil-can having a long nozzle, with 
 an opening in the smaller end of about tV inch. This 
 nozzle is inserted into the edge of the Avooden wheel- 
 case, as shown, and its smaller end is bent so that it 
 forms a small angle with the Avheel, with the point of 
 the nozzle as near ^:he wire cloth as possible without 
 touching. To cause the wheel thus made to keep a cen- 
 
HOME MECHANICS FOR AMATEUKS 
 
 183 
 
 tral position in its case, pieces of the small tube before 
 named may be slipped on the shaft each side of the 
 Avheel. 
 
 A f-inch hole may be made in the casing at the bot- 
 tom, and provided Avith a short tube for receiving a rub- 
 
 FiG. 198. Small Water Motor 
 
 ber pipe, to carry off the waste water, and there should 
 be a |-inch hole in each side near the top to admit air. 
 The casing may be secured to the wooden foot-pieces 
 with screws. It is desirable to make the casing im- 
 pervious to water. To do this, the various parts may 
 be boiled in hot paraffine for ten minutes. If it is 
 
184 HOME MECHANICS FOK AM.VTEUES 
 
 found difficult to secure paraffine in bulk, a pound of 
 paraffine candles Avill furnish enough for this purpose. 
 The inflammable nature of paraffine should be kept in 
 mind, and a cover should be provided for the vessel in 
 which it is melted, so that it may instantly be extin- 
 guished by the cover should it become ignited. The 
 metal used in the construction of this wheel should be 
 of brass, excepting the shaft. The screws with which 
 the casing is put together should be brass. The top of 
 the oil-can is cut otf to form a part of the coupling for 
 receiving the rubber pipe leading from the wash-bowl 
 faucet to the motor. 
 
 Fig. 199. Diagram Showing Position of Nozzle. 
 
 To prevent the checking of the wooden parts of the 
 motor, the parts should be arranged with the grain 
 lying in the same direction. 
 
 With sufficient water pressure, this motor will make 
 from 1,500 to 2,000 revolutions per minute. With a 
 very flexible cord belt — a leather shoestring, for ex- 
 ample — it may be made to drive a light sewing machine, 
 fan, or any other machine requiring a small amount 
 of poAver 
 
 If more power is required than can be secured by one 
 water jet, additional nozzles may be distributed around 
 the wheel, or more wheels may be j)laced on the same 
 
HOME MECHANICS FOR AMATEURS 185 
 
 shaft, but notliin<2: will be gained unless the water 
 pressure is maintained. This pressure should be from 
 25 to 40 pounds per square inch. 
 
 In a small high-speed motor of the class here de- 
 scribed, the full power is realized onl}^ when it is pro- 
 vided with a very small pulley connected by a very 
 flexible belt with a large pulley on the machine to be 
 driven. 
 
 It is obvious a non-corrosive metallic case would be 
 better than a wooden one, and the metal one is advised 
 when the builder has conveniences for making a casing 
 of that kind. 
 
PART Y. 
 
 METEOROLOGY 
 
 SELF RECORDING INSTRUMENTS 
 
 IF these instruments were constructed so that 
 each would produce a permanent record of 
 its movements, it would certainly add to 
 their usefulness as well as their convenience, 
 but it is thought best to confine the construction 
 to these simple forms of apparatus, trusting to 
 the ingenuity of the reader to apply clock mechanism 
 for keeping the records. One eight-day clock could be 
 made to do duty for all the instruments. It could be 
 geared to a drum so that it would make one revolution 
 in one day, or in one week, and each instrument could 
 be made to mark on a piece of paper carried by the 
 drum. The paper would need to be graduated so that 
 the pen carried by each instrument could be readily 
 traced. There should be divisions for days and hours. 
 
 The pen by Avhich the record is made is simply a 
 small glass tube about ^ inch in internal diameter, 
 with the end which bears upon the paper drawn out to 
 almost a capillary tube and cut off and made round and 
 smooth by heating in a gas or alcohol flame. The ink 
 used in this pen is a drop of red ink mixed with an 
 equal amount of glycerine. This ink remains in the 
 narrower end of the tube and does not evaporate. 
 
 METEOROLOGY 
 The subject of meteorology has claimed the atten- 
 tion of men to a greater or less extent doubtless since 
 
 [187] 
 
188 HOME MECHANICS FOE AMATEUES 
 
 the earth began to be iuhabited by hiiniau beiugs. The 
 phenomena of the air must have early attracted atten- 
 tion and caused the observers to reason from cause to 
 effect until there came gradually to be an under- 
 standing of earth, air and water — not always correct — 
 but in the main pointing to the present development 
 of the science, so that after the lapse of many centuries, 
 the close student of nature is able to explain various 
 phenomena and to predict with more or less certainty 
 what will happen, especially in the immediate future. 
 
 To be able to predict the weather Avith a little more 
 certainty than the ordinary 'Sveather prophet" can do, 
 the student should be in communication with the Gov- 
 ernment Weather Bureau, so as to avail himself of 
 the observations of others; but even without such 
 facilities as these many interesting observations may 
 be made with the simple apparatus hereinafter de- 
 scribed, and notes ma^^ be kept for future reference. 
 
 This kind of observation is instructive in several 
 ways. The very act of making frequent observations 
 induces a methodical habit which Avill be valuable 
 through life, and the observations are interesting and 
 instructive in themselves. Besides all this, the record 
 formed is likely to be valuable for both present and 
 future use. 
 
 WHAT MAY BE LEARNED BY THE USE OF THE 
 METEOROLOGICAL INSTRUMENTS 
 
 When we find the weather vane iDointing toward the 
 west we look for clear weather, and as a rule we are 
 not disappointed ; but when the vane indicates that the 
 wind is blowing from the east, a storm is expected. 
 
HOME MECHANICS FOR AMATEURS 189 
 
 When it blows from the north, cool weather may be 
 looked for, and when it blows from the south, it hardly 
 ever fails to bring sultry days in summer and thaws 
 in winter. 
 
 When the wind blows strong from any direction, 
 curiosity is aroused as to the pressure it is exerting. 
 This may be ascertained by observing the wind pres- 
 sure gauge ; 1^ pounds pressure shows that the wind is 
 blowing fifteen miles per hour ; 4^ pounds pressure per 
 square foot represents a velocity of thirty miles per 
 hour ; 18 pounds pressure indicates a velocity of sixty 
 miles an hour, and 50 pounds pressure is registered 
 during a tornado one hundred miles an hour. In 
 calculating the pressure as indicated by this gauge 
 it must be remembered that the board which offers 
 resistance to the wind has only a half square foot 
 area. 
 
 The velocity of the wind is shown by the anemometer. 
 Wind is hardly noticeable when it blows a mile an 
 hour. When it blows live miles an hour it is a pleas- 
 ant breeze; when it ])lows ten miles an hour it is a 
 brisk breeze; when it blows at a twenty-mile rate it is 
 a stiff breeze; at thirty miles it is a high wind, and at 
 forty miles it is a very high wind. At eighty miles it 
 is a hurricane, and at a hundred miles per hour it is 
 a tornado. 
 
 THE AVEATHER VANE 
 
 The weather vane hardly needs explanation to make 
 it understood. In the top of a stout pole is inserted 
 a i-inch rod which is bluntly pointed at its upper 
 end. On this is placed a vane consisting of a wedge- 
 shaped piece of hard wood with a hole through it, a 
 
190 HOME MECHAXICS FOE AMATEURS 
 
 piece of hoop iron beiug fastened over the hole and 
 resting on the upper end of the blnnt-pointed rod. 
 
 To opposite sides of tlie wedge are secured pieces 
 of ^-inch board 4 inches' wide and 20 inches long. 
 These pieces are let into the faces of the Avedge so 
 
 Fig. 200. Weather Vane. 
 
 as to form continuous surfaces. The boards diverge 
 so that their free ends are about 2| inches apart. 
 This construction insures steadiness. 
 
 The tliin end of the wedge has an arrow-headed arm 
 ])rojecting from it to indicate the direction of the 
 wind. In the sides of the pole, near the upper end. 
 are inserted four :[-inch rods arranged at 90 degrees 
 with each other, and in slots sawed in the ends of the 
 rods are riveted letters which indicate the points of 
 compass, N., S., E. and W. These, in connection with 
 the arrow-headed arm, enable the observer to tell which 
 Avay the wind blows. 
 
 WIND PRESSURE GAUGE 
 
 The construction of a Avind pressure gauge is as 
 simpk^ as that of the ordinary Avindmill, Avhich every 
 boy knows hoAV to make. A Avind A^ane 6 inches Avide 
 and 24 inches long is made of a J-incli board, on tlie 
 
HOME MECHANICS FOK AMATEUES 101 
 
 edge of wliicli is secured p. piece of band iron wliicli pro- 
 jects over the end of the l)oard about 1.^ inches. In the 
 end of the board are inserted two screw-eves for receiv- 
 ing tlie rod upon which the A'ane swings. The upper 
 end of the rod is pointed bluntly, so that the piece of 
 band iron which rests upon it allows the vane to swing 
 freely in any direction. 
 
 The middle portion of the board is cut away from the 
 upper edge to admit of placing a spring scale for the 
 measurement of the wind pressure. In the upper 
 edge of the board at opposite ends of the scale-notch 
 are inserted wire screw-eyes to receive the horizontal 
 Avooden rod which carries the wind-pressure board, 8 
 by 9 inches long and } inch thick. 
 
 The board is stiffened by a cleat on the back, which 
 is bored to receive the rod. A screw hook is inserted 
 in the rod, and another is inserted in the upper edge 
 
 r: 
 
 FiG. 201. Wind Pressure Gauge. 
 
 of the vane for receiving, respectively, the eye and 
 hook of the scale. The spring scale is adjusted so as 
 to hold the thin board a little more than the length 
 of the slot in the spring-scale away from the pivot 
 of the vane when the wind is light or nil. When the 
 wind blows the vane keeps the instrument headed 
 
192 HOME MECHANICS FOR AMATEURS 
 
 toward the wind, and the scale indicates the pressure 
 on a half square foot, so that the reading must be 
 multiplied by 2 to secure a correct pressure. 
 
 The rod should be inserted in a rigid post and must 
 be exactly vertical. 
 
 The amount of rain falling in a given time can 
 be ascertained approximately by placing any kind of 
 vessel having parallel sides out of doors in an open 
 place where it may receive all the rain, and then 
 measuring the depth of the water after the rain by 
 means of a small stick plunged into it; the depth 
 being registered by the wet portion of the stick. This 
 method, however, is crude and open to objections; 
 some of the water will spatter over, some Avill be lost 
 by evaporation, and some will be displaced by the 
 stick. 
 
 If the observer is really in earnest he should make, 
 or have made, a copper vessel like the one shown in 
 the illustration. It is 4 inches in diameter and 6 
 inches high, with the bottom set in 1 inch so as to 
 receive the copper tube, which is bent twice at right 
 angles, with its inner end inserted in the recessed bot- 
 tom and its outer end extended up outside the vessel, 
 and even with the bottom to receive a f-inch glass 
 tube, which is cemented therein with a cement consist- 
 ing of white lead paint and litharge formed into a soft 
 putty. 
 
 The glass tube is 7 inches long, and furnishes a 
 ready means of ascertaining the depth of water in 
 the vessel when viewed in connection with the scale 
 of inches attached to the vessel. 
 
 In the top of the vessel is inserted a funnel 3^ inches 
 long, with a cylindrical portion at the top 2 inches 
 
HOME MECHANICS FOR AMATEUES 193 
 
 deep. The upper and lower edges of the main vessel 
 are wired to give them rigidity, but the cylindrical 
 top of the funnel is not wired. 
 
 A rubber band may be stretched around the funnel 
 at the junction of the cylindrical and conical portions 
 to prevent waste by evaporation at this point. To 
 
 Fig. 202. Rain Gauge. 
 
 insure accuracy the copper pipe Avhich holds the glass 
 tube should be filled with water before the observa- 
 tion begins. 
 
 When the gauge is used in a windy place it should 
 be clamped to some fixed object by three screws en- 
 gaging the wire rim at the bottom of the vessel. 
 
194 HOME MECHANICS FOE AMATEURS 
 
 A METALLIC THERMOMETER. 
 
 A mercurial thermometer calls for manipulations 
 which are not within the scope of the amateur, but 
 require the skill and experience of the regular manu- 
 facturer. A metallic thermometer, however, is very 
 easily made, and serves the purpose fully as well as a 
 mercurial thermometer. It can be made as sensitive 
 to the variations of temperature as may be desired. 
 
 It is made by placing together a strip of steel and 
 one of brass 6 inches long, J inch wide and A inch 
 thick. The ends of the strips are tinned for about f 
 of an inch at each end of their adjacent faces, and 
 then put together and heated first at one end and then 
 at the other, so as to solder them together at the 
 ends. 
 
 The brass strip is made about i inch longer than 
 the steel strip, and is bent over and perforated to re- 
 ceive a silk thread as will be presently explained. Com- 
 monly, Avhen strips of steel and brass are used in a 
 compound bar, they are riveted at short intervals, to 
 keep them from buckling. In the present case the 
 compound bar is provided with a winding of soft wire 
 (No. 30) which keeps the strips close together. To in- 
 sure permanency the bars are drilled and riveted with 
 a single rivet at each end. 
 
 The compound bar thus made is inserted in a round 
 hole in the middle of a hard wood block 2J inches 
 long, and held there by an ordinary wood screw in- 
 serted in the end of the block and clamping the end of 
 the bar. The wooden block is secured to a base piece, 
 4 inches square and | inch thick, having attached to 
 it a back board J inch thick, 4 inches wide, and about 
 
HOME MECHANICS FOR AMATEURS 195 
 
 10 inches high. A wire nail abont tV in^h in diameter 
 and 1^ inches long is driven through the back with its 
 pointed end projecting about 1^ inches. The nail is 
 about f inch from the upper free end of the compound 
 bar. A paper roll is formed upon another nail or a 
 piece of wire a trifle larger than the one used in the 
 construction of the thermometer. The strip of writ- 
 ing paper used for this roller should be 1 inch wide 
 and about 8 inches long. Enough of the paper is wound 
 to make the roller ^ inch in diameter. The paper, 
 except the first layer, is pasted as it is rolled, so that 
 it forms a solid paper roll when it is dry. 
 
 This roll, when dry, is transferred to the nail pro- 
 jecting from the back piece, and a pointer, or index, 
 about 2^ inches long is cut from thick writing paper 
 and glued to the end of the roll. Then a silk thread 
 is tied in the eye in the free end of the compound bar, 
 and passed over the roller on the nail, and wound 
 three times around the roll, and it has attached to it a 
 small weight. In the present case this weight consists 
 of a lead bullet split half open with a knife, and 
 closed down upon the thread by pliers or by hammer- 
 ing. With every change in temperature the compound 
 bar swings, so as to cause a movement of the index by 
 the pulling or releasing of the thread and the raising 
 or lowering of the weight. 
 
 The index should be placed in a vertical position 
 Avhen the temperature is about 70° ; then the winding 
 of the silk should be separated a little, and a small 
 drop of mucilage should be placed on the middle con- 
 volution of the thread at the top of the roller, so as 
 to cement it to the roller and prevent any change of 
 adjustment. 
 
196 
 
 HOME MECHAXICS FOK AMATEURS 
 
 A semicircular piece of bristol board, about 6 inches 
 in diameter, is temporarilv supported behind the index 
 by a block glued to the back piece. The bristol board 
 is to form the thermometer scale and is fastened to 
 
 Fig. 203. A Metallic Thermometer. 
 
 the block by tacks or otherwise, so that it can be re- 
 moved and accurately replaced. A pencil mark is now 
 made on the scale at the point of the index which indi- 
 cates the temperature as shown by a mercurial ther- 
 mometer at the time. If it is 70°, the mark on the new 
 
HOME MECHANICS FOE AMATEITES 107 
 
 scale represents (liis tempeniture, and wlieuever the 
 index points to this mark the observer knows the 
 thermometer is 70°. 
 
 Now the thermometer is placed in a refrigerator 
 along with a mercurial thermometer. They are left in 
 the refrigerator for an hour, and then a pencil mark 
 is made at the point of the index. This will, perhaps, 
 be 40°. The space between these two marks is divided 
 into thirty even spaces, representing as many degrees, 
 or it may be divided into fifteen spaces, each of which 
 will represent 2°. This graduated space serves as a 
 guide for constructing the balance of the scale. If 
 2° spaces are used, twenty such spaces laid off on the 
 left-hand side of the scale will extend the scale to 
 zero. Twenty more such spaces will extend the scale 
 to 40° below zero, which is lower than any temperature 
 experienced in this climate. The space between 40° 
 and 70° is already graduated, and the space above the 
 70° mark is graduated as described for the lower end 
 of the scale. As each line represents 2°, 10° would 
 ])e represented by five lines, so that the fifth line could 
 be extended beyond the other lines for the sake of con- 
 venience in reading. Figures from 0° are placed op- 
 posite the long lines so as to read 10°, 20°, 30°, 
 40°, and so on, as in an ordinary thermometer scale. 
 
 The amateur can refine this thermometer as much as 
 he pleases. He may, if he desires, place the entire de- 
 vice in a case and cover the dial with a glass, provided 
 he furnishes several apertures to enable the air to cir- 
 culate and thus keep the temperature the same as that 
 of the external air. The free end of the compound bar 
 may have a spring riveted to it, as shown in the de- 
 tached view, and an adjusting screw may be inserted in 
 
198 HOME MECHANICS FOR AMATEURS 
 
 the compoiiud bar so as to bear against tbe spring. 
 AVith this constrnction, the silk thread may be tied in 
 a hole in the free end of the spring, and the desired 
 adjustment may be made by turning the screw one way 
 or the other. 
 
 By making the compound bar longer, or diminishing 
 the diameter of the c^dinder around which the thread 
 extends, or both, the sensitiveness of the instrument 
 may be greatly increased. 
 
 SIMPLE HYGROSCOPE 
 
 No instrument is required to indicate a superabun- 
 dance of humidity in the air. Everyone knows the dis- 
 comforts of a moist, hot day in the summer without 
 requiring a hygroscope. Still, to one scientifically 
 inclined it is some satisfaction to know the hygrometric 
 state of the air, and to compare one day with another 
 of the same year or previous years. 
 
 A very simple hygroscope which is accurate enough 
 for all practical purposes is illustrated by the engrav- 
 ing. Its construction Avas suggested by a panel made 
 of two pieces of wood glued crosswise to keep it straight 
 — the very best arrangement of the grain for causing 
 it to assume a concavo-convex form under all condi- 
 tions of the atmosphere except that in which it was 
 glued together. It has a baseboard 4 inches square 
 and I inch thick, with a back piece 4 inches wide and 
 13 inches high and ^ inch thick, attached to one edge. 
 Near the right-hand edge of the base is secured a block 
 to which is attached a hygroscopic strip made up of 
 a longitudinal piece of any elastic wood (such as white- 
 wood) 12 inches long, 1 inch wide and tV inch thick. 
 
HOME MECHANICS FOE AMATEUES 199 
 
 and a transverse piece of white wood of the same thick- 
 ness 1 inch long and 12 inches wide, carefully glued to 
 it, so that the grain of one strip is at right angles to 
 that of the other. These strips of wood should be well 
 
 Fig. 204. Hygroscope. 
 
 Fig. 205. Hygroscope Strip. 
 
 seasoned. This compound strip is secured to the small 
 block on the base of the instrument, and a piece of plain 
 cardboard is attached by two tacks to the wooden back 
 at the center of the board, 
 
 leaving the ends of the card 
 
 free. The concave side of the strip should be arranged 
 
200 HOME MECHANICS FOR AMATEURS 
 
 to face the left-hand side of the instrument, and a short 
 piece of small wire, say No. 24, or a headless pin should 
 be inserted point outward in the free end of the strip 
 to serve as an index. 
 
 The scale is constructed by first placing the instru- 
 ment under a bell glass with several pieces of wet 
 blotting paper near but not touching the strip. The 
 long, narrow strip does not change its length, but is 
 bent one way or the other by the swelling or shrink- 
 ing of the piece which is glued crosswise. The hygro- 
 scopic strip will straighten out or even curve in the 
 opposite direction when submitted to the influence of 
 moisture, and after the lapse of six or eight hours 
 the glass is removed and a pencil mark is made on the 
 card at the point of the index, which will rep- 
 resent 100 degrees, or the point of saturation. The 
 instrument is allowed to assume the normal position 
 by drying it in the open air, after which it is again 
 placed under the bell glass with a dish of calcium chlo- 
 ride and allowed to remain five or six hours. The cal- 
 cium chloride removes the moisture and causes the 
 cross-grained side to shrink and thus curve the strip 
 considerabl3\ It now indicates the maximum dryness 
 of the air, and a mark is made at the point of the index, 
 indicating zero. The spaces between zero and satura- 
 tion should now be divided into ten equal spaces, and 
 each space may be subdivided into ten spaces, each 
 representing one degree. 
 
 These lines should be neatly made with a drawing 
 pen. Every tenth graduation should be extended a 
 little and numbered; the entire scale being numbered 
 from to 100, i. c, 0, 10, 20, 30, etc. 
 
 This instrument is not intended to accurately show 
 
IIOMl^] I\rECILVNICS YOU AMATEUKS 201 
 
 the exact amount of inoistiire, as is the case with the 
 more elaborate hygrometers, but to afford a simple 
 means of showing the ever-varjing state of the air. 
 
 MERCURIAL BAROMETER 
 
 The variations of atmospheric pressure are shown 
 by the barometer. The pressure of the air in round 
 numbers is 15 pounds per square inch ; that is, a col- 
 umn of air 1 inch square, the height of the atmosphere 
 (which is not positively known), weighs 15 pounds, 
 and will balance a column of water 1 inch square and 
 31 feet high, or a column of mercury 1 square inch in 
 area and 30 inches high. 
 
 A mercurial barometer is here shown on account of 
 facility of construction and the accuracy of its opera- 
 tion. To make the simplest form of mercurial barom- 
 eter, a strong glass tube a little more than 33 inches 
 long and about tV inch internal diameter is required. 
 It must be sealed at one end, and left open and con- 
 tracted to I inch at the other. This work is readily 
 done by a glass blower. The open end is fused to 
 remove the sharp edges. A small glass bottle is pro- 
 vided, the body of which is about 1 inch internal diam- 
 eter and 1^ inches high. The neck is short and a 
 little larger internally than the outside of the tube. 
 A board | inch thick, 3 inches wide and 39 inches long 
 has a shallow half-round groove to receive the glass 
 tube, and two brass straps extend over the tube and 
 are clamped to the board by means of screws. Near 
 the bottom of the board a hole is cut for the glass 
 bottle or cistern, as it is called ; a small shelf is secured 
 by screws to the back board, even with the lower 
 
202 
 
 HOME MECHANICS FOE AMATEUES 
 
 side of the hole in the board. A small hole is made 
 in the back board near the top to receive the nail or 
 screw upon which the instrument hangs. 
 
 Fig. 206. Scale and Indicator. Pig. 207. Mercurial Barometer. 
 
 Of course all the parts will be tried in place before 
 attempting to fill the tube with mercury. 
 
 The tube must be perfectly clean, and only re-dis- 
 tilled mercury should be used. In the bottom of the 
 
JIOMF. :\[ECHAXICS FOE xViyiATEITES 203 
 
 glass bottle is placed a layer of pure beeswax tV iii<*b 
 thick. The wax is made smooth and level by melting 
 it by gently heating the glass bottle over an alcohol or 
 Runsen gas flame. When the wax is cold the filling 
 of the tube with mercury may be proceeded with. The 
 tube and the mercury are first warmed by passing 
 them over an alcohol or gas fiame; then mercury is 
 poured into the tube through a small paper funnel. 
 The tube should be filled to within ^ inch of the 
 end with mercury. Then the clean, dry forefinger is 
 held over the open end of the tube and the tube is 
 placed in a horizontal position and tilted one way and 
 then the other, to alloAv the bubble of air to gather 
 up as much as possible of the air contained in the tube. 
 The tube is then placed open end up and entirely filled 
 with mercury. It is then inverted while it is kept 
 closed b}^ the finger. The end of the tube is placed be- 
 low a body of mercury in a suitable vessel and a little 
 of the mercury is let out so as to produce a partial 
 vacuum at the top. Then the tube is closed and again 
 turned into a horizontal position and tilted in one way 
 and then the other, and at the same time turned or 
 rolled over so as to cause the bubble to gather up any 
 air that may remain. The tube is again inverted and 
 filled, until it is entirely full of mercury. The finger 
 is again applied, and a vacuum is produced hj allow- 
 ing a small amount of mercury to escape, when the 
 tube is vertical as before. It is closed and tilted, allow- 
 ing the bubble to again gather air. This operation is 
 repeated two or three times. The tube is finally in- 
 verted and filled with mercury, so as to present a 
 convex surface above the oj)en end of the tube. The 
 glass bottle containing the wax is placed over the 
 
204 HOME MECTTAXTCS FOE AI\rATErES 
 
 open end of the tube and pressed down, eausing the 
 wax to make a good eontact with the end of the tube. 
 
 The bottle is held firmly in place by the finger, and 
 the bottle and the tube may now be inverted together, 
 and after putting a little mercury in the bottle, the 
 latter may be placed on the shelf prepared for it, and 
 the tube may be raised a little, so as to clear its open 
 end from the Avax, and the tube is fastened in place 
 by clamping it with the brass strips and screws. More 
 mercury is added to that in the bottle so as to make 
 the depth about f inch above the lower end of the 
 tube. A quantity of clean cotton wool is placed in the 
 mouth of the bottle around the tube to exclude dust, 
 at the same time to admit air freely. The barometer 
 is now finished with the exception of the scale. 
 
 A scale of inches f inch Avide and 4 inches long is 
 laid out in the center of a card 2^ inches wide and 
 6^ inches long. Each inch is divided into tenths, and 
 the divisional lines for the inches and half inches are 
 extended beyond the J inch limit. The beginning of 
 tlie scale is numbered 27. The upper end of the first 
 inch is numbered 28, the second inch is numbered 29, 
 the third inch 30, and the fourth inch 31. The scale 
 is placed behind the tube and the division line corre- 
 sponding with the line at the top of the mercury in a 
 standard barometer is placed in the same position rel- 
 ative to the mercury, and fastened by small tacks. 
 
 To enable the observer to mark the height of the col- 
 umn of mercury, so that he may compare the present 
 observation with the previous one, an indicator is pro- 
 vided, which consists of a rod supported by posts at- 
 tached to the board, and a short section of spiral 
 spring placed on the rod, with the upper extremity 
 
HOME MECHAXICS FOK AMATEUES 205 
 
 straightened and extending over the barometer tnbe. 
 This end of the wire is flattened by hammering to make 
 a more delicate index. 
 
 In a general way the changes of the barometer are 
 given, bnt tliey mnst be taken with some allowance. 
 High winds and storms usually follow the sudden drop 
 of the mercury. The rising of the mercury generally 
 indicates fair Aveather; the drop of the mercury indi- 
 cates bad weather. The fall of the mercury in sultry 
 weather is followed by thunder ; the rise of the mercury 
 in winter indicates frost. In frosty weather the fall 
 of the mercury precedes a thaw, and the rise is followed 
 by snow. Sudden changes in the barometer indicate 
 similar changes in the weather. Continued foul 
 weather may be expected if the mercury falls slowly; 
 on the contrary if it rises slowly continued fair weather 
 may be looked for. Changeable weather is indicated by 
 an unsettled barometer. 
 
 It is perhaps unnecessary to caution the maker of 
 the barometer to conduct the various operations of 
 filling and adjusting above a large platter or piece of 
 smooth paper, with the edges turned up to avoid un- 
 necessary waste of mercury. 
 
PART VI. 
 
 TELESCOPES AND MICROSCOPES 
 
 HOW TO MAKE A TELESCOPE 
 
 N 
 
 O ONE can look into the starry depths at 
 night without a feeling of wonder and awe, 
 nor is this feeling lessened when the mind 
 grapples the question of space and con- 
 templates the awful abysm that separates us from 
 even the nearest star, to say nothing of the points 
 of light faintly visible to the naked eye, nor of the 
 telescopic stars removed to such distances as to be- 
 wilder the mind and baffle the imagination in the 
 attempt to realize their remoteness. 
 
 Who does not desire to become more familiar with 
 these distant bodies and to possess all the knowledge 
 that can be obtained by observation? Much can be 
 done by the unaided eyes, and a great deal more can 
 be accomplished by means of a telescope of very mod- 
 erate proportions and power. x4n ordinary opera glass 
 is not to be despised, but of course an instrument with 
 a larger objective and a longer focus is much more 
 efficient and desirable. 
 
 Our engraving represents the telescope, its standard, 
 and the A^arious parts, in section and in detail. The ob- 
 ject glass. A, shown in the engraving, is a meniscus 
 lens 2| inches in diameter and 36 to 38 inches focus. It 
 is mounted in a wooden cell, B, having an internal 
 flange or fillet about tV inch wide, forming a true sup- 
 port for the lens and bearing against the end of the 
 paper tube, D, which forms the body of the telescope. 
 
 [ 207 ] 
 
208 
 
 HOME MECHANICS FOE AMATEUKS 
 
 The lens is retained in its ceH bj a flat strip, E, of brass 
 which is sprung into the cell and is pushed down 
 against the lens. The cell is fastened to the tube by 
 
 Fig. 208. A Simple Telescope. 
 
 common wood screws, which pass through the collar 
 into the paper forming the tube. It is perhaps needless 
 to say that the cell should be made of some thorou«hlv 
 
HCBIK ]\rp]CHANlCS FOR AMATEUKS 209 
 
 seasoned hard wood, which is not liable to atmospheric 
 influences. Hard maple answers a good purpose, but 
 mahogany is to be preferred. 
 
 To protect the objective Avhen not in use a cap, F, of 
 tin or pasteboard neath^ covered with morocco or 
 velvet is fitted to the cell. 
 
 The paper tube of which the telescope body is formed 
 is such as is commonly used for rolling engravings for 
 mailing. It is 3 inches external diameter and 32 inches 
 long (about 4 inches shorter than the focus of the 
 objective). The exterior of the tube is covered with 
 Java canvas attached by means of bookbinder's paste 
 (flour paste with glue added), and varnished when dry 
 with tw^o or three thin coats of shellac varnish. This 
 gives the tube an elegant and durable finish. 
 
 The focusing tube, G, which is of brass, I7I inches 
 internal diameter, and 12 inches long; is guided by a 
 turned wooden piece, H, fitted to the end of the paste- 
 board tube, D, and held hj three or four ordinary 
 round-headed wood screws. 
 
 The piece, H, has a shoulder, a, against which the 
 end of the pasteboard tube abuts, and only about three- 
 quarters of an inch of the piece, H, actually fits the 
 tube, the portion from 5 to c being tapered as indicated 
 in the engraving, and near the extreme inner end, 
 about 3^ inches from the shoulder, there are three 
 screws, d, used in collimating the focusing tube, G. 
 
 The bore of the piece, H, is somewhat larger than 
 the focusing tube, G, and is provided with a cloth lin- 
 ing, e, at each end to insure the smooth working of 
 the tube. 
 
 A short distance from the shoulder, a^ a mortise 
 about three-quarters of an inch square is made tlirough 
 
210 HOME MECHANICS FOR AMATEURS 
 
 the side of the tube, D, and the piece, H, and a trans- 
 verse slot, fj is formed to receive the wooden spindle, I, 
 which is enlarged in the middle to receive the rubber 
 thimble, J, and has on one end a milled head by which 
 it may be turned. The spindle, I, is held in place by 
 concave pieces, g^ which in turn are retained by the 
 curved plate, Jc, attached to the tube, D, by screws. 
 The rubber thimble, J, must be of sufficient diameter to 
 reach to and press upon the focusing tube, and the 
 latter has a series of transverse grooves filed in it. 
 This will insure sufiflcient friction to move the tube, 
 G, in and out when the spindle, I, is turned. This sim- 
 ple device replaces the usual focusing mechanism, and 
 is to be preferred to a rack and pinion, unless the latter 
 be perfectly made, and it is certainly superior on the 
 score of cheapness. 
 
 The cell, B, piece, H, and spindle, I, should be 
 blacked and polished on the outside, and the cell should 
 be left dead black on the inside. The interior of the 
 tubes should also be dead black. This surface may be 
 secured by adding lampblack to a little very thin shel- 
 lac varnish, and applying it to the inside of the tube by 
 means of a swab. The focal lengths of the lenses of 
 the astronomical eyepiece should be to each other as 
 three to one; the field lens, which is nearest the object 
 glass, having the greatest diameter and the longest 
 focus, and the convex side of each lens should be turned 
 toward the object glass. Their distance apart should 
 be one-half the sum of their focal lengths. These lenses 
 are mounted in a wooden cell, L, whose exterior is 
 fitted to the focusing tube, G, and grooved circumfer- 
 entially to receive a strip of cloth, which is glued in, 
 and insures a good fit. The cell is bored in ditferent 
 
HOME MECHANICS FOE AMATEUES 211 
 
 diameters to receive the field lens, h^ the diaphragm, i, 
 and the eve lens, y, all of which are held in place against 
 the shoulders formed in the cell by circular springs of 
 brass, which are sprung in as in the case of the object 
 glass. The e^^e aperture should be about -} inch, and 
 the aperture of the diaphragm should be about the 
 same. 
 
 It is well enough to make the diaphragm adjustable, 
 so that it may be moved back and forth to secure the 
 best position. It will be found, however^ that, if placed 
 just beyond the focus of the eye lens, it Avill give the 
 best results. 
 
 A circular recess, k, is formed in the face of the eye- 
 piece to receive a sun glass, which is retained in place 
 when in use, by a short curved spring, /. The sun glass 
 is simply a disk of very dark glass. It must, in fact, 
 be nearly opaque; some of the glass, known as black 
 glass, answers the purpose very well. 
 
 If but one astronomical eyepiece is made, probably 
 the most satisfactory combination would be: Field 
 lens, 1^ inches focal length ; eye lens, -^ inch ; distance 
 apart, 1 inch. It is advisable, however, to have three 
 eyepieces for different purposes — one of higher power 
 and one of lower power than the one described. 
 
 In this connection, I will describe a terrestrial eye- 
 piece, referring to the sectional view. Fig. 209, al- 
 though it is of little use to adapt such an eyepiece to 
 this instrument unless it is first provided with an 
 achromatic objective. It is then a powerful telescope, 
 which will enable one to see well for many miles. The 
 method of mounting the lenses described in connection 
 with the astronomical eyepieces will be followed here, 
 therefore little more than the diameter and focus of 
 
212 
 
 HOME MECHANICS FOU AMATEURS 
 
 the lenses and their distance apart need be given. 
 There are four plano-convex lenses, A', B', C, I)', 
 mounted in two pairs in Avooden cells, E', F', fitted to 
 the tube, G', which in turn is fitted to the focusing 
 tube, G. The cell, E', has a ^-inch aperture for the eye 
 and a bead which projects beyond the tube, G'. 
 The lens. A', is about tV inch in diameter and 1 inch 
 
 Fig. 209. Details of Telescope and ferrestrial Eyepiece. 
 
 focus. The lens, B', is f inch diameter and 1^ inch 
 focus. The lens, C, is tV inch diameter, 1| inch focus. 
 The lens, D', is f inch diameter and 1} inch focus. The 
 plane face of A' is If inches from the phuie face of 
 B', and a stop, IT, having a tV inch aperture, is placed 
 
HOME MECHAXTOS FOE AMATEURS 
 
 213 
 
 1^ inches fi'oin the face of the lens, A'. I/'rom the plane 
 face of the lens, IV, to the jilane side of the lens, C, 
 it is 3| inches. The distance between the plane side of 
 the lens, C, and the plane face of the lens, I)', is 1 J 
 inches. At a distance of iV iueh from the face of the 
 h^ns, C'^ there is a diaphragm, T, having a ^-inch aper- 
 ture. It will be observed that the convex sides of the 
 lenses, C D, are turned toward each other. 
 
 Fig. 210. Details of Telescope. 
 
 At the extreme inner end of the tube, G', there is a 
 diaphragm, K', of if aperture, which is held in place 
 by two circular springs. The interior surfaces must 
 be well blacked to prevent reflection. 
 
214 HOME MECHANICS FOR AMATEUES 
 
 I have given cheap yet efficient methods of holding 
 the lenses. If desired the reader may, of course, make 
 the mountings of brass, and fit the instrument up ac- 
 cording to his taste and ability. 
 
 The arrangement of the various parts is clearly 
 shown in the sectional view, No. 3, Fig. 209, and the 
 focusing device is shown in No. 3, Fig. 210. 
 
 In regard to the matter of collimation I have found 
 that by cutting off the ends of the paper tube truly in 
 a lathe, the cell, B, and the piece, H, Avill be meas- 
 urably true. To determine whether the focusing tube, 
 G, and cell, B, are axially in line, a truly cut cardboard 
 disk with a pin hole exactly in the center, may be 
 placed in the cell, B. A similar disk may also be placed 
 in each end of the focusing tube, G. 
 
 Now, by adjusting the piece, H, by means of the 
 three screws, (/, the three pin holes in the disks may be 
 readily brought upon the same axial line; then, if the 
 lenses have been carefully centered by the manufac- 
 turer, the telescope will be found sufficiently well 
 collimated. If, however, it is desired to ascertain 
 whether the lens is truly centered, it may be turned in 
 its cell, while the telescope is in a fixed position, and 
 directed at some immovable object. If the image moves 
 as the lens is turned, it shows that the work has been 
 carelessly done. 
 
 If there are doubts as to whether the axis of the 
 objective coincides with the axis of the tube, the tube 
 may be supported in V-shaped supports adapted to the 
 truly turned ends. Then by placing a candle at some 
 distance from the face of the lens, and turning the 
 tube in its V supports, at the same time viewing the 
 reflection of the candle in the lens, it will at once be 
 
 1 
 
HOME MECHAXICS FOR AMATEUES 215 
 
 known by the movement of the reflection that the cell 
 requires adjustment to render the axis of the objective 
 and that of the tube coincident. 
 
 With a telescope of this description a large number 
 of celestial objects may be examined with great satis- 
 faction. The Moon furnishes an unending source of de- 
 light, showing, as it does, a face that is ever changing 
 throughout the lunar month. Jupiter may be coming 
 into good position and affords an interesting study 
 of which one does not soon tire. The telescope de- 
 scribed will show the satellites in their varying posi- 
 tions from night to night. It will show the dark band 
 across the face of the planet, and will afford a realizing 
 sense of the magnitude of this great body. 
 
 Saturn may be in a good position for observation, 
 and his ring may be clearly seen. The meniscus len^ 
 will show a little color, and its definition Avill be quite 
 defective when directed to such bright objects as the 
 Moon, Jupiter, Saturn, Mars, or Venus with the 
 full aperture, therefore the aperture should be re- 
 duced by a diaphragm of cardboard. A little experi- 
 ment will determine the best sized aperture. For nebu- 
 lae, star groups, and double stars, the full aperture 
 should be used. The great nebula of Orion is an inter- 
 esting object ; many of the star groups are very pleas- 
 ing, the Pleiades for instance. The sun also, when the 
 spots are visible, is a satisfactory object for this instru- 
 ment. Of course, the sun glass will be applied before 
 the observer attempts to view the Sun, otherwise the 
 eye may be injured or destroyed. It may be that some 
 reader of this article may have a double or plano-con- 
 vex lens of long focus, which he might desire to press 
 into the service. Either of these may be used, but the 
 
216 HOME MECHAXICS FOE AMATEUES 
 
 meniscus is better. If a good job is made of the mount- 
 ings it will not be long before the meniscus, or the 
 piano or double convex lens will be supplanted by a 
 good achromatic objective, which will increase the 
 efificiency of the instrument many fold. Such a lens 
 is not very expensive. It may be procured from almost 
 any optician. 
 
 As to the telescope stand little need be said, as its 
 construction is so clearly shown in the engraving. I 
 will say, however, in the beginning, that there is no 
 danger of getting it too solid. If it is very clumsy it is 
 no matter. If it is slender it will be like a ''reed shaken 
 by the wind," only ''more so,'' as every tremor has the 
 benefit of the magnifying powers of the telescope and is 
 amplified to a wonderful extent. 
 
 There are undoubtedly better stands than the one 
 represented, but it is easily constructed and answers an 
 excellent purpose. From the ground to the toj) of 
 the hexagonal hub, M, it is four feet. Three of the al- 
 ternate sides of the hub are wider than the intermediate 
 ones, to receive the wrought iron hinges by which the 
 legs are attached. To attach the hinges, the pin is first 
 driven out; one-half of the hinge is then attached to 
 the leg, and the other half to the hub, M, when the pin 
 is replaced. 
 
 No. 1, Fig. 209, is a top view of the hub and the upper 
 portion of the legs. No. 4, Fig. 210, is a vertical section 
 on the line, g, fj, in Fig. 209. A H-inch hole is bored 
 through the hub to receive the standard, N, which sup- 
 ports the telescope and is clamped at any desired 
 height by the thumb screw, ni. To prevent marring the 
 standard a piece of sole leather is interposed between 
 the screw and standard. An arm, ??, is hinged to each 
 
HOME .MECHxVXlCS FOE AMATEUliS 217 
 
 of the legs and folds down upon the standard, so as 
 to spring the legs outwardly, and thus render the stand 
 very rigid. The lower ends of the legs terminate in 
 spikes, and a strap is attached to one of the legs to 
 fasten them all together when the instrument is not 
 
 in use. 
 
 The upper end of the standard, N, is reduced in 
 size, and made slightly conical for receiving a socket, 
 O, to the upper end of which is jointed an arm attached 
 to the V-shaped trough, P, in which the telescope is 
 secured by straps. The form of the joint is shown in 
 Fig. 210, which is a vertical transverse section taken 
 through the socket, O, trough, P, and body of the tele- 
 scope. A strong bolt, o, forms the pivot of the joint 
 between the socket, O, and trough, P, and is provided 
 with a wing nut by which it may be tightened. The 
 surfaces of the joint as well as the upper end of the 
 standard should be coated with black lead to insure 
 smooth working. A post set firmly in the ground, 
 while it cannot be moved from place to place, has the 
 advantage of being rigid, and forms one of the best of 
 cheap stands. A fixture screwed in the window casing 
 of a south window, and another attached to a north 
 window, afford solid supports for the instrument, and 
 have the additional advantage of permitting the ob- 
 server to remain under cover. 
 
218 HOME MECHANICS FOE AMATEUES 
 
 THE MICROSCOPE 
 
 The man ^yho has passed boyhood without knowing 
 something of wliat is revealed by the microscope, has 
 missed one of the pleasures of life, and has failed to 
 look into one of the most interesting and profitable 
 studies open to the seeker after knowledge. 
 
 Probably the best form of simple microscope for the 
 beginner is a Doublet, of which three forms are shown 
 in the engraving. If this cannot be had, a cloth tester, 
 or a jeweler's eyeglass, will show much which the eye 
 cannot see distinctly. The doublet consists of two 
 plano-convex lenses mounted in a short tube with their 
 convex surfaces facing each other, and separated by a 
 distance equal to one-half the sum of their focal 
 lengths. 
 
 The habit of using the lens creates the habit of ob- 
 servation, and this rapidly increases one's fund of 
 general information. 
 
 The doublet is convenient and inexpensive. Its 
 power, however, is fixed. If a different power is re- 
 quired another doublet will be needed. Probably 
 three-fourths inch is the most useful focus. 
 
 Better for real work is the microscope shown in 
 Fig. 212. It has a glass plate on which to place 
 the object to be examined, and is provided with a 
 mirror to reflect light from below up through trans- 
 parent or translucent objects. The arm which carries 
 the lens swings so as to bring the lens over any part of 
 the plate and slips readily up or down to bring any part 
 of the object into focus. The lenses are doublets. They 
 may be had of H inch, 1 in., ^ in., and ^ in. focus. 
 Probably the | inch and ^ inch will prove the most 
 
HOME MECHANICS FOR AMxVTEUES 
 
 219 
 
 serviceable^ The wooden base is beveled at either end 
 to form rests for the hands in manipulating the objects 
 and lens. 
 
 In a slide under the base is placed a metal plate 
 enameled black on one side and Avhite on the other. 
 This is to be placed on the glass stage when opaque 
 objects are under examination. 
 
 This instrument will not take the place of a com- 
 pound microscope, but it answers very well when only 
 
 Fig. 211. Dissecting Microscope. 
 
 a low power is needed. If the user develops a taste 
 for microscopy and purchases a regular microscope, the 
 dissecting microscope will still be of value to him in 
 the preparation and preliminary examination of objects 
 to be examined ])y the higher power of the compound 
 microscope, so that the purchase of a dissecting micro- 
 scope is only introductory to the study of microscopy. 
 Interesting objects for the dissecting microscope are 
 plant hairs on the back of the leaf of the Deutzia 
 
220 HOME MKCHAXICS FOE AMATEHES 
 
 j[>Ta('ilis, or S])ir;pa, and luany otlier loav(»s \\ith sur- 
 faces roii<ih to tlie toucli. ^Many of the mints and fig- 
 worts have hairs wonderfully branched. Pollen, 
 seeds, wings and antennae of butterflies, mosses, spore- 
 cases of ferns, insects, parasites, hairs, feathers, min- 
 erals, crystals, — all are interesting and instructive. 
 The formation of crystals on the glass stage is very in- 
 teresting. 
 
 Drop a small quantity of a solution of alum, com- 
 mon salt, sulphate of copper, or other chemical salt, 
 sal ammoniac for example, upon the glass stage and 
 allow it to evaporate while the operation is watched 
 through the lens. For best results spread the drop 
 of solution with the edge of a paper cutter or card into 
 a thin film. A little practice will enable one to make 
 a very uniform film in which the crystals form very 
 beautifully. 
 
 Of course the glasses must be perfectly clean. Per- 
 fect cleanliness is absolutely essential in every part 
 of microscopic work. Dust especially is the worst foe 
 of the microscopist. It is well nigh impossible to be 
 entirely rid of it, and every mote which remains is 
 magnified by the higher powers into a beam. 
 
 A bee furnishes a good object for dissection and 
 preparation. The wings and the sting are especially 
 interesting. The wings are provided with hooks de- 
 signed to engage a rib on the other half. It is stated 
 that no human being has ever been able to fasten the 
 wings together. The feet and respiratory apparatus 
 are also interesting. 
 
 By a little labor one may dissect from a flower or in- 
 sect interior parts of great interest. Indeed, it is by 
 dissection that most objects are prepared for perma- 
 
liOMK MKCliAXK'S FO\l AMATEUKS 
 
 iient preservation and use. The tools for tliis work are 
 few and simple, and altlioni];li those sold by dealers 
 are to be preferred, vet one may prepare for himself 
 such substitutes as will enable him to do really good 
 
 Fig. 212. A Practical Microscope. 
 
 work. Our space does not allow much to be said upon 
 this point. The indispensable articles are needles 
 and knives. Dissecting needles are simply sewing- 
 needles set in handles. Even a s])linter of wood or 
 
222 HOME MECHAXICS FOli AMATEUES 
 
 wooden iienliolder answers all purposes of a handle, 
 and the eye end of a needle may be pushed into it so 
 as to be firmly set in its seat. Seyeral sizes of needles 
 should be mounted ready for use. A small pointed 
 blade of a penknife will answer for cutting. A yery 
 suitable knife may be made by orinding the end of a 
 needle to an edge and sharpening it on a stone. These 
 tools though simple, are seryiceable. 
 
 To dissect a flower, for example, place it upon the 
 stage of the microscope and bring into focus Ayith the 
 lens so that it is distinctly yisible. At first use the 
 lens of longest focus. Then take a needle in each hand 
 and open the flower, while you look into it. Obserye 
 its petals, their colors, markings and hairs, if any are 
 present, its stamens, their shapes and pollen, its seed 
 vessel and any peculiarity. Many an exquisite yiew 
 into Nature's most beautiful recesses is to be had in 
 this way. So beautiful are many flowers that one feels 
 it to be almost a profanation of a sacred shrine to ex- 
 plore further. But still the unlocking of the shrine 
 may disclose more profound mysteries, so we proceed to 
 cut with one of our tiny kniyes across the seed yessel 
 which occupies the center of the flower. Notice the 
 symmetry of its arrangement, perhaps in three sections, 
 else in four or fiye ; sometimes as many as ten rows of 
 seeds may be found. It is a yery interesting point to 
 study the arrangement and place of attachment of the 
 seeds in the yessel. This mode of Ayorking is the mode 
 used b}^ all botanists in their preliminary study of a 
 plant. An entomologist studies an insect in the same 
 way. 
 
 After the limit of yision with the long focused 
 lens is reached, a higher power is taken and the search 
 
HOME MECHANICS FOR AMATEURS 223 
 
 is continued to the shortest focus the student may have. 
 All of the ''coarse anatomy" of an ol)ject is studied 
 by means of the dissecting microscope. The com- 
 pound microscope inverts the view of an object so that 
 a motion to the right seems to be toward the left, and 
 towards, seems to be from one. It is very difficult to 
 become accustomed to this inversion in dissecting, and 
 for that reason the compound microscope is rarely used 
 even by the most expert. Then, too, its field of view 
 is small, and high powers are not needed in dissecting. 
 
 The beginner is earnestly advised to study all sorts 
 of minute things which he may find, since discoveries, 
 surprises and most sublime views into the hidden 
 things of Nature await him at every turn. A most 
 useful book for this line of work is ''Common Objects 
 for the Microscope," which the student is advised to 
 buy. 
 
 But with even the highest skill there is a limit to the 
 use of simple magnifying glasses. The desire to know 
 what lies beyond must be gratified in other ways. A 
 compound microscope is the only instrument which 
 will meet this condition and disclose all that can be 
 seen by lenses. This consists of two lenses, one at each 
 end of a tube, which is in two parts, one sliding Avithin 
 the other. The lens nearest the object is the objective 
 and is really a very fine simple microscope in itself. 
 The upper lens, the eyepiece, increases the magnifica- 
 tion of the objective and enables the eye when in the 
 proper position to take in at once the entire picture 
 produced by the instrument, and to study it in detail. 
 
 The particular instrument shown in Fig. 211, 
 although very plain and simple, is exceedingly well 
 made, and very useful. It will receive the standard 
 
224 HOME MECHANICS FOK AMATEUES 
 
 objectives and ej^epieces. It has a very smooth rack 
 motion, which admits of very fine adjustment. The 
 magnification of a compound microscope is varied by 
 using- objectives of different focal lengths, eyepieces of 
 different powers, and by changing the length of the 
 tube. This microscope is usually provided with a half 
 inch objective which may be separated to form a one 
 and a half inch objective also, and an inch and a half 
 eyepiece. 
 
 If one wishes to put more money into the micro- 
 scope he will next need a one-half inch eyepiece and a 
 one-fourth inch objective. With these he will have six 
 degrees of magnification at his command, varying from 
 25 diameters to about 400 diameters. By diame- 
 ters is meant the number of times broader an object 
 appears. This is the usual mode of stating magnifica- 
 tion. The number of times an object is magnified is 
 found by multiplying the diameter by itself. Thus, 
 if a seed is magnified fifty diameters it is made to ap- 
 pear twenty-five hundred times its real size. 
 
 A microscope of the value of this one should be 
 handled with extreme care. There are certain simple 
 points to be observed in the use and care of fine glasses. 
 Never touch them Avith the bare fingers. It greases 
 them and injures their transparency. Wipe them only 
 with a very soft clean cloth, or bit of chamois skin. 
 The glass of which the lenses are made is very soft and 
 easily scratched. The finest dust may be composed 
 of hard grit, which Avill leave its mark upon the lens if 
 rubbed across it. It is Avell to blow the dust off be- 
 fore wiping the lens. Lenses are easily broken if 
 dropped. The most common accident is the dropping 
 of tli(^ obj(M-tiA^e Avhile screwing it into its place or re- 
 
 
HOME MECHANICS FOE AMATEUES 225 
 
 moving it. Even with care this sometimes happens. 
 There is but one way of screwing or unscrewing the 
 lens from the tube which is certain to prevent accident. 
 Take the lens between the first and second fingers of 
 the left hand, just as one would a cork or a lead pencil. 
 Now hold it in the position to be screwed into the tube 
 and turn it in wholh^ bv the right hand. Proceed in 
 the same manner in unscrewing the lens. No accident 
 can happen. 
 
 With this microscope fitted with the half inch separa- 
 ble objective and the one and a half inch e^^epiece an 
 exhaustless field of study and delight is opened to its 
 possessor. 
 
PART YII. 
 
 ELECTRICITY 
 
 A PRACTICAL PRIMARY BATTERY 
 
 EVERY amateur who delights in "making things" 
 dabbles more or less with electricity. Most of 
 these are so situated that they have no access 
 to the large sources of supply of the electric cur- 
 rent, such as lighting stations can furnish, and if they 
 would do any real work must make their own genera- 
 tors and apparatus. It is to the assistance of such 
 that the present section is devoted. 
 
 The battery, represented by Fig. 213, can be made at 
 a minimum cost, and when made will give a maximum 
 of output. The materials to be purchased are glass 
 jars, porous cups, carbons, zincs, burrs, screws, bind- 
 ing posts and some sheet copper. 
 
 All the pieces for the cell come ready for use, except 
 the carbons, which are peculiar to the special form of 
 cell. As the cut shows, there is a ring of carbons to be 
 placed in the glass jar and to fit in the jar as closely as 
 may be without exerting pressure upon the jar. Six 
 plates of carbon are required for each ring. Each 
 plate has two holes of a size to fit the screws. The 
 holes may be made most easily by awls and reamers, 
 such as are to be found in a set of tools in an awl 
 handle. A little patience and experience will enable 
 any one to make the holes neatly. Carbon is very hard 
 and will wear a drill very fast. Hence, it is better not 
 to attempt drilling holes in a carbon plate. Of course 
 the holes should be equally spaced, if the appearance 
 of the finished work is to be considered. 
 
 [237] 
 
228 
 
 HOME MECHANICS FOR AMATEURS 
 
 The copper should be about l-32d of an inch in thick- 
 ness and about f inch wide. It can be bought of 
 this width, or cut by the dealer or by a smith with large 
 shears. A strip must be bent into a six-sided ring of 
 such size that when the carbons are fastened to it the 
 whole will slide snugly into the glass jar. It will be 
 better after one strip has been fitted to its place to 
 straighten it out and use it as a pattern, or template, 
 
 Fig. 213. A Practical Primary Battery. 
 
 by which to drill the holes in the rest of the copper 
 strips. They will then be all alike and interchange- 
 able. A template should also be used for making the 
 holes in the carbons, though all holes may be reamed a 
 little on one side or the other to allow the screw to pass 
 through. If the worker has no means of tapping a 
 thread for the screw, he should buy nuts for the screws 
 also. The holes in tlie copper strips may be punched 
 with a nail punch, if one has no means of drilling them. 
 
HOME MECHANICS FOR AMATEUES 220 
 
 For pimcliino' holes in this way the end of a stick of 
 hard wood shonld be nsed as a bed to rest the copper 
 upon ^A'hen punched. The strij) of copper which leads 
 up out to the binding post may be riveted to the ring, 
 or one end of the ring may be left long enough to bend 
 up a couple of inches above the top of the jar. The car- 
 bons should be long enough to reach above the jar so 
 that the metal parts shall not touch the glass. In this 
 battery the fluid employed will corrode metals very rap- 
 idly. To prevent the fluid from creeping up through 
 the pores of the carbon and reaching the copper, the 
 ends of the carbons should be dipped in hot melted 
 paraflftne and saturated by it before clamping them to 
 the copper ring. 
 
 The binding posts may be of any available form ex- 
 cept those Avith wood screws. A machine screw is nec- 
 essary because the binding post is to be clamped to the 
 copper strip by it. When these parts are screwed to- 
 gether the battery is ready to be assembled. 
 
 Nothing has been said about the sizes of jars and the 
 rest, since the cell may be made of a size to fit any jar 
 into which the porous cup apd carbons will go. Round 
 porous cups may be had from 1 J inches up to 5 inches 
 in outside diameter, and round glass jars may be had 
 from 2} inches up to 7 inches in inside diameter. There 
 is thus ample range of size for any one to consult both 
 the depth of his pocketbook and the quantity of current 
 which he wishes the battery to give. This is a point 
 not understood b}^ many amateurs. The voltage which 
 a cell gives is determined by the kind of chemicals used 
 in it and not by the quantities of chemicals consumed. 
 The current in amperes, which, the voltage being fixed, 
 the cell will give, and the work it can therefore do, are 
 
230 ITO.ArE .AEECHA^^rCS FOR AMATEIJES 
 
 determined by tlie (luanlity of clieiiiicals consumed by 
 the cell in its action. It nia}^ be stated as a fair aver- 
 age result that one pound of zinc will give 320 ampere 
 hours in a cell such as this. 
 
 Carbon plates can be had in a great vaiiety of sizes 
 and shapes. The best way is for the one contemplating 
 making the battery to write to a dealer in electrical 
 supplies and ask for a catalogue, which he will be glad 
 to furnish. All the parts can then be selected of proper 
 proportion to each other, so that they will go together. 
 Either the Daniell, bottle or Fuller zinc should be us-ed. 
 The cut shows the Daniell zinc. It is a good form be- 
 cause of the large surface exposed to the action of the 
 fluid. 
 
 The best solution for this cell is the chromic acid 
 fluid. It should be made by weight, taking chro- 
 mic acid 18 parts, water 60 parts, sulphuric acid, con- 
 centrated, 9 parts. A pint of water may be taken as a 
 pound, and a pint of the sulphuric acid as 1.8 pounds. 
 The chromic acid is a solid and can be most easily 
 weighed directly. Put the chromic acid into the water. 
 It dissolves readily. Then pour the sulphuric acid into 
 the mixture very slowly, a little at a time, stirring it 
 in thoroughly, else a disagreeable accident ma^^ be had 
 from the heat produced. It is considered by many that 
 this solution is improved by adding 1 part of chlorate 
 of potash. When it is cold it is ready for use. 
 
 The zinc in all cells of this character must be amal- 
 gamated ; that is, coated with mercury. This may be 
 done directly by dipping the zinc into the solution for 
 a short time and then rubbing mercury upon it, or, bet- 
 ter, by putting an ounce of mercury into the bottom of 
 each porous cup. Another way is to add to the solu- 
 
HOME MECHANICS FOR AMATEURS 231 
 
 tion in each porous ciij), as niiicli bisulphate of mer- 
 cury as Avill lie on a quarter of a dollar. The zincs 
 ^Yill then be amalgamated directly from the solution. 
 
 The cell may be set up in various ways with only 
 slight differences in the resulting current, durability 
 and constancy of action. \Ye will give four modes of 
 arranging the cells : 
 
 First — Fill the glass jar to within an inch of the top 
 and the porous cup to the same level with the solution 
 described above. 
 
 Second — Fill the porous cup with a mixture of water 
 10 parts and sulphuric acid 1 part, and the glass jar 
 with the chromic acid mixture given above. 
 
 Third — Fill the glass jar with the chromic acid solu- 
 tion and the porous cup with water to which table salt 
 has been added at the rate of 4 oz. to the pint. Sul- 
 phate of zinc may be used in place of salt, 6 oz. to the 
 pint. 
 
 F;our — Fill the glass jar with chromic acid solution 
 and the porous cup with clear water. This will start 
 slower than any of the other modes of filling, but will 
 work, because enough of the chromic acid solution 
 passes through the pores of the cup to act upon the 
 zinc. 
 
 The adaptedness of this cell for many uses is shown 
 by the fact that it can be arranged as a one fluid cell 
 also. Removing the porous cup hang the zinc in the 
 center of the glass jar by means of a board cover of the 
 jar through which a hole is made to receive the end of 
 the zinc. The fluid used will be the chromic acid solu- 
 tion. The zinc must be fully amalgamated before put- 
 ting it into service, and the bisulphate of mercury 
 should be used to maintain the zinc in condition. In 
 
232 HOME MECHANICS FOR AMATEURS 
 
 this form the cell gives its strongest current, but will 
 only last about half as long. 
 
 Whenever this cell is to be out of use the zinc should 
 be removed from the liquid. The porous cup should 
 be taken out and set in a dish of the same solution 
 as it contains. In this way all waste of the chemi- 
 cals is prevented. 
 
 The battery, as described, is one of the strongest and 
 most reliable primary batteries. With its strongest 
 current it readily heats fine iron and platinum wires. 
 With the porous cup it is adapted to drive motors, fans, 
 and excite electromagnets. A large battery will light 
 small incandescent lamps. Eight or ten cells, holding 
 two quarts each, will drive the motor of Scientific 
 American Supplement, No. 641, to full power, and run 
 a sewing machine or turn a small lathe, or do any other 
 equal work. The expense of maintenance is not great. 
 The liquid when it becomes green is exhausted and 
 must be replaced by fresh solution. The zincs can be 
 used till they are entirely dissolved. This battery is 
 not a toy, but a serviceable piece of working apparatus. 
 
 ELECTRIC LIGHTING FOR AMATEURS 
 
 It is now possible for any one to procure small incan- 
 descent lamps from the Edison Lamp Co. and from 
 most dealers in electrical goods. These little lamps 
 can be operated quite successfully by means of easily 
 constructed batteries. It is, of course, a little trouble- 
 nome, and the expense of the electric light produced in 
 this way is somewhat greater than other lights, but 
 amateurs can derive a great deal of satisfaction from 
 these experiments in electric lighting. 
 
 The battery may be made at home, from materials 
 
HOME MECHAXICS FOR AMATEUES 
 
 233 
 
 that may bo purcliased from the manufacturers of the 
 lamps or from any dealer in electrical supplies. Each 
 cell of battery consists of two plates of carbon 2 in. 
 wide, 4| in. long, and ^ in. thick, one zinc plate 2 
 in. wide, 4 in. long, and i in. thick, two strips of wood 
 i in. wide, ^ in. thick, and 4 in. long, two strong 
 rubber bands, and an ordinary tumbler. 
 
 The zinc is amalgamated by dipping it in dilute sul- 
 
 FiG. 214. A Simple Battery. 
 
 phuric acid (acid one part, water twelve parts), then 
 sprinkling on a few small drops of mercury, rubbing it 
 about with a swab formed of a piece of cotton cloth 
 tied around the end of a stick. Every portion of the 
 surface of the zinc should be covered with mercury. If 
 the amalgamation is perfect, it need not be repeated. 
 The carbon plates before use should each be heated 
 
234 
 
 HOME :\rECHAXICS FOR AMxVTEUES 
 
 at one end and satiirat(Ml witli paraffine for a distance' 
 of 1:^ in. from the upper eud (and no more) to pre- 
 vent the solution from ascending the plate by capillar- 
 ity. This is accomplished by heating the end of the 
 plate over a lamp and applying a piece of parafifine or 
 a paraffine candle until it is filled. No free paraffine 
 should be allowed to remain on the surface of the car- 
 bon, as it will interfere with making a good electrical 
 connection with the plate. 
 
 Fig. 215. A Tumbler Battery. 
 
 The zinc plate is placed between the two wooden 
 strips. The carbon plates are placed outside of the 
 strips and held b}^ the two rubber bands, as shown in 
 Fig. 214. 
 
 The connection between the carbon plates and the 
 wire leading away from the carbon pole is made by a 
 doubled strip, a, of copper, the ends of which are in- 
 serted between the Avooden strips and the carbon plates. 
 In a similar way a copper strip, h, is inserted between 
 
HOME MECHAN^ICS FOR AMxVTEITBS 
 
 235 
 
 the zinc plate and one of tlic wooden strips. Tlie 
 tumbler forming the battery jar should be deep enough 
 to allow the wooden strips to rest upon its rim, so as 
 to support the plates a short distance from the bottom 
 of the tumbler. 
 
 The ordinary bichromate of potash solution is used 
 in the battery. It is prepared by making a saturated 
 
 Fig. 216. A Convenient Bracket. 
 
 solution of common bichromate of potash in Avarm 
 water ; then, after cooling, adding very slowly a quan- 
 tity of common sulphuric acid, equal to about one-fifth 
 of the bulk of the bichromate solution. It is advisable 
 to add to the solution a very small quantity of bisul- 
 phate of mercury, say one-eighth ounce to the quart of 
 solution, to maintain the amalgamation of the zinc. 
 
236 
 
 HOME MECHANICS FOE AMATEUES 
 
 The salts known as tlie (\ k (\ battery e()ni])()nnd are 
 excellent and very convenient for use in batteries of 
 this class. It is only necessary to dissolve this com- 
 pound in water to form the exciting solution. 
 
 This material is sold in tin cans containing two or 
 three pounds. It absorbs moisture rapidly, so that 
 when it is to be used in small quantities it should be 
 transferred to a stoppered glass jar. 
 
 It is, perhaps, needless to say that great care should 
 
 Fig. 217. A Series of Connected Lamps. 
 
 be exercised in handling the solution, as it is poisonous 
 and destructive to clothing, carpets, etc. The same re- 
 mark applies to the battery compound. 
 
 One cell of this battery should be allowed for each 
 candle power of the lamp. The zinc of one cell should 
 be connected with the carbon of the next. Fig. 215. The 
 battery may be arranged as a plunger. Directions for 
 making a battery of this kind were given on page 110, 
 of volume 57, of the Scientific American. 
 
HOME MECHANICS FOR AMATEUES 237 
 
 In Fig'. 216 is shown a convenient bracket for snp- 
 porting small electric lamps. It consists of two cnrved 
 wires attached to a small piece of board by means of 
 screws, which also serve as binding screws for attaching 
 the wires. The lamp is suspended from eves formed in 
 the ends of the wires. This device may be used as a 
 standard, as shown at 1, as a hanger, as shown at 2, or 
 as a bracket, as at 3. 
 
 In Fig. 217 is shown a series of three small lamps 
 connected with three cells of battery. 
 
 The lamps in this case are connected in parallel or 
 multiple arc, i. e.^ one binding screw of each lamjD is 
 connected with one wire from the battery. The other 
 binding screws of the lamps are all connected with the 
 remaining pole of the battery. 
 
 Copper wire, No. 18 or larger, should be used for 
 making the connections. The battery Avill run continu- 
 ously with a single charge of the solution for about 
 three hours. Should the solution become warm and 
 give off hydrogen, the zinc should be reamalgamated at 
 the points where it is violently attacked. 
 
 THE ELECTRIC CHIME. 
 
 To secure practice in mechanics or in electrical work, 
 the amateur may as well construct something for 
 actual use. A very useful and pleasing electro-me- 
 chanical device is an electric chime to be used as a 
 door bell or call bell, or in connection with a clock. It 
 serves its purpose as a call and gives an ever-changing 
 series of harmonic notes. 
 
 The first step toward the construction of this device 
 is to purchase the toy known as the tubophone, and 
 
238 
 
 HOME MECHAXICS FOR AMATEUES 
 
 select three of the tubes which produce a chord, or if 
 the maker prefers it, he may buy a piece of mandrel 
 drawn brass tubing, f inch external diameter, with 
 walls sV inch thick, and cut off three pieces respectively 
 7f , 8|, and 9| inches in length ; each of these should be 
 laid upon two short pieces of soft woolen cord, with 
 
 Fig. 218. Electric Chime. 
 
 the cord touching at nodal i)oints, that is, at exactly 
 one quarter of the length from the end. Arranged in 
 this way the tubes give out a clear note when struck 
 with a small wooden mallet. By comparing these notes 
 with those of a piano or other musical instrument, the 
 tubes may be tuned. The pitch is raised by shortening 
 
HOME MECHANICS FOR AMATEUES 239 
 
 the tube, but as there is no practical way of lowering 
 the pitch after the tube has once been shortened, it 
 would be advisable to cut the tubes a little longer 
 than the measurements given. A baseboard having a 
 short standard is provided, and to the upper portion of 
 the standard is secured a board into which are driven 
 three pairs of wire nails, the nails in each pair corre- 
 sponding in position Avith the nodes of one of the tubes. 
 The tubes are suspended from these nails by soft 
 cord.^ passing around the tubes at the nodes or points 
 of no vibration, leaving the tubes free to vibrate at the 
 center and at the ends. 
 
 Now it remains to construct the electro-mechanical 
 device for striking the tubes. To the baseboard are 
 secured the angled ends of three strips of spring brass, 
 ^V inch wide and jV inch thick, which extend above 
 the tubes and carry small wooden mallets in position to 
 strike the middle portion of each tube. The mallets are 
 secured to the springs by means of ordinary wood 
 screws passing through the springs into the mallets. 
 
 Behind the springs, at or near their mid-length, is 
 placed a diagonal strip of wood, having secured to its 
 outer edge a strip of felt or chamois skin. The spring 
 strikes this piece and allows the mallet to strike the 
 tube and spring back without jarring. Behind the 
 springs is supported a small shaft on which is placed 
 a wooden cylinder about 1 inch in diameter and 2^ 
 inches long. In the cylinder and opposite the springs 
 are inserted wire nails, arranged to strike short in- 
 clined strips riveted to the springs. The nails are 
 placed so that they will strike the inclined strips in 
 different orders; for example: 1, 2, 3; 3, 2, 1; 2, 3, 1', 
 1, 3, 2. 
 
240 HOME MECHA^nCS FOR AMATEURS 
 
 A toy electric motor having a three-pole armature 
 is used for turning the cylinder, and two clock wheels 
 and a pinion are employed for reducing the speed. A 
 worm is placed on the armature shaft of the motor, 
 which engages the first of the clock wheels. This worm 
 may be cut in a lathe, but if this is inconvenient, a 
 wire may be wound spirally around the armature shaft 
 and soldered. It will, of course, be necessary to wand 
 the spiral so that it will fit the teeth of the clock wheel, 
 and the surplus solder should be scraped from the wire 
 to diminish friction. The motor is provided with bind- 
 ing posts to receive the battery wires. One or two cells 
 of dry battery will run the chime. The chime is used 
 in place of an ordinary call or door bell, or it may be 
 used in connection with a clock, as shown, for making 
 calls at certain hours. 
 
 The push button shown in the sectional view is made 
 to close the circuit when the chime is used in place of a 
 call bell or door bell. The button is readily made by 
 boring a small block. A, of hard wood in two diameters 
 to receive the head and back of the pearl collar button, 
 B, the back of which is held in place by the apertured 
 piece of veneering secured to the face of the block by 
 small screws, while the head of the button rests on a 
 curved brass spring, C, secured in a slot in the back of 
 the block, A, by a screw. The outer end of the spring 
 projects beyond the side of the block to receive one of 
 the circuit wires. This slot is tilled below the spring 
 with insulating material, and a brass plate, D^ is 
 secured to the back of the block. A, and has upon one 
 edge an apertured ear for receiving the other circuit 
 wire. The plate, /), is secured to the back of the block 
 by small screws. The free end of the spring, C^ is 
 
HOME MECHAXICS FOR AMATEUES 
 
 241 
 
 curved over to a point near the brass plate, Z), so that 
 when the spring is depressed by pressing the button. 
 By it will touch the plate and close the circuit. 
 
 The annexed diagram shows an appliance which en- 
 ables the chime to be used in connection with a clock. 
 
 JD 
 
 Fig. 220. 
 
 Push Button. 
 
 In front of the dial of an ordinary clock are secured 
 the rings, A, B, made of tV inch square brass wire. 
 The supports are of insulating material, and the rings 
 are concentric with the arbor carrying the hands. The 
 hands are bent outwardly to permit of extending over 
 the rings without touching them, and to insure the 
 hands against electrical contact with the rings a thin 
 short sleeve of paper is slipped over each hand near the 
 free end. Each ring has several small radial holes 
 bored in it to receive the brass nails, the heads of which 
 project sufficiently beyond the front surface of the 
 rings to enable the hands to touch them as they pass. 
 
 The circuit wires connecting the battery and the 
 chime are connected one with the outer ring, A, the 
 other with one of the springs of the cut-out switch 
 shown in the opening formed by the breaking away of 
 the dial. The other spring is connected with the inner 
 ring, B. The springs are insulated from each other. 
 
 On the sleeve which carries the hour hand is mounted 
 the crossed slotted cam, O, also shown detached in the 
 
242 
 
 HOME MECHANICS FOR AMATEUES 
 
 larger figure. In the slot of this cam is a boat-shaped 
 follower, which slides easily in the slot and is longer 
 than the width of the slot, so that it can, in following 
 
 FiiG. 219. Chime with Clock connection. 
 
 the slot, take tlie inner and outer portions of the slot 
 in alternation. The follower is pivoted to the angled 
 lever, a, Avhicli is pushed by the cam between the jiar- 
 allel springs and Avithdrawn from them in alternation 
 
HOME MECHANICS FOR AMATEURS 243 
 
 once in 12 hours. The object of this arrangement is 
 to cut out the chime at night and put it in circuit in the 
 daytime. The cam, C\ and the angled lever, a, are 
 insulated from the clock movement. 
 
 A switch, D^ is provided for throAving the device out 
 of action at any time. 
 
 It will be seen that the hour hand must come into 
 contact with the nail on the inner circle and the minute 
 hand must touch the nail in the outer circle to com- 
 plete the circuit, and cause the chime to sound. The 
 duration of the chiming is limited by the time the 
 minute hand is in contact with the nail. The clock 
 when arranged as here shown sets off the chime at 8 
 o'clock, 12 o'clock and 5 o'clock. It is now about to 
 ring the chime for 12 o'clock. 
 
 HOME-MADE ELECTRIC NIGHT LAMP 
 
 A very simple device, Avhich will produce a temporary 
 light of one-half of one candle-power, is shown in the 
 illustration. It will be found convenient for observing 
 the time at night, or for momentarily lighting a closet 
 or an area where the light of a candle or an oil lamp 
 would be objectionable. 
 
 The miniature electric lamp, and the dry batteries 
 used for lighting it, can be purchased almost an^^ where, 
 and the labor of putting these things together, with a 
 switch and suitable connections, is very slight indeed. 
 A one-half candle lamp requiring 1.58 amperes at 2.5 
 volts is the first requisite; then two cells of dry battery, 
 giving a current with a pressure of al)out 3 volts will 
 be needed, and last of all a small packing box, that will 
 just receive the batteries, should be selected. If a 
 
244 HOME ]\IECHANICS FOR x\MATEITES 
 
 lamp of liii>her voltage is chosen, more cells of battery 
 Avill be needed. A 4-yolt lamp Avill require three cells 
 of battery. A little more light will be secured with this 
 
 Fig. 221. Battery Box, cover removed. 
 
 ^■ 
 
 
 ■-^ 
 
 
 ^^ .-..-.»« 
 
 \ 
 
 
 
 
 WmmM 
 
 gggl^HBIHjIg^^^ 
 
 n 
 
 Fig. 222. Temporary Light. 
 
 combination, but it is not desirable to increase the num- 
 ber of cells beyond this, as the apparatus becomes at 
 once too bulky and too expensive. The best cond)ina- 
 
HOME MECHAXICS FOR AMATEUES 
 
 245 
 
 lioii is the one-half candle lamp will two cells of bat- 
 tery. After the lanip is procnred it slionld be tested mo- 
 mentarily' by means of two cells of dry battery, con- 
 nected in series. If the lamp is properly lighted, a 
 packing box which receives the batteries easily is se- 
 
 FiG. 223. Diagram of Circuit. 
 
 lected, and two small brass hooks, / cj, are straightened 
 and screwed into the box near the top. Small copper 
 wires are placed in electric contact with the hooks, f ()y 
 as sliOAvn in the diagram. At the top of the box is 
 placed a switch, consisting of a piece of spring brass 3 
 inches long and ^ inch wide held in place by a pivotal 
 screw, e, passing through a central hole in the spring 
 into the box. 
 
 In one of the views the lamp is represented as being 
 supported by a hollow Avooden column in front of a 
 clock. In this case one of the lamp wires is incased in 
 a very small rubber tube, to insure insulation ; other- 
 wise the construction is similar to that described. 
 
 Two cells of dry battery will light the lamp occa- 
 sionally for a long time, if used only an instant each 
 time; but if the lamp is used continuously, it runs the 
 battery down, so that it will require frequent renewal. 
 
 The wire from the brass hook, /, is placed in electrical 
 
246 HOME MECHxlXICS FOR AMATEURS 
 
 contact with this screw, c, and two brass screws, b c, 
 are inserted in the top of the box, to serve as contact 
 points for the switch. These screws are connected to- 
 gether and with the zinc pole of the cell, n' , by a wire. 
 The carbon pole of the cell is connected electricalh' 
 with the hook, //. The hooks are curved downwardly 
 and the terminals of the lamp, ii, are wound three or 
 four times around the ends of the hooks, / g, respec- 
 tively, so as to support the lamp above and in front of 
 the face of the watch, hanging' upon the hook, project- 
 ing from the front of the box. 
 
 The longer arm of the switch is turned up to form 
 a thumb piece, and is held normally out of contact 
 with the screw, h. By pressing the end of the switch 
 down into contact with the screw, h, an electrical con- 
 tact is formed which lights the lamp. By turning the 
 switch on its pivotal screw, e, it is brought into contact 
 with the screw, c, thus forming an electrical contact, 
 Avhich is prolonged until the switch is returned to its 
 original position. The movement of the switch is 
 limited by the screws, d d. 
 
 AN ELECTRICAL CABINET 
 
 An electrical cabinet is an assemblage of articles 
 which may be combined in various ways to produce 
 pieces of apparatus. By these a large number of ex- 
 periments are made accessible to the amateur at com- 
 paratively slight expense. 
 
 In Fig. 224 sectional drawings of the essential parts 
 are shown, drawn very nearly on a third scale. A are 2 
 coils, wound with 8 layers of No. 20, single cotton cov- 
 ered magnet wire, both being wound in the same direc- 
 
HOME MECHANICS FOE AMATEURS 247 
 
 tion. B, the cores and yoke of an electromagnet, the 
 cores of f| inch soft iron bar. C, the frame for support- 
 ing the electromagnet when used as the field coils of a 
 dynamo or motor as in Fig. 237. D, a wooden stand, 
 turned in a lathe, to be used as a support for the com- 
 
 FiG. 224. General View of Parts. 
 
 pass E, to form a galvanometer, as in Fig. 229. F, a 
 permanent horse shoe magnet. G, soft iron wires. 
 H, strips of copper. K, frames for telegraph sounders. 
 By the aid of the Figures for the several experiments 
 the practical amateur will have little difficulty in see- 
 
248 HOME MECHANICS FOE AMATEUES 
 
 ing how tliev are made and put to<^ether. The perma- 
 nent magnet and the compass can be purchased to bet- 
 ter advantage. The rest can be made with a lathe 
 and tools. Some No. 28 spring brass wire will be 
 needed for the springs shown on the telegraph sounder 
 
 Fig. 225. 
 Effect of Iron on a Magnet. 
 
 Fig. 226. Decomposition of Water. 
 
 at the left, and some No. 18 spring brass wire to be 
 wound into a close spiral a little less than a half inch 
 in diameter, and cut up into pieces of about 3 turns 
 each to be used as connectors in place of binding posts. 
 
 In describing the several experiments such addi- 
 tional instruction will be given as the case may seem 
 to require. 
 
 The action of iron on a magnet is shown in Fig. 225. 
 Present the end of an iron rod to the compass. The 
 needle is drawn towards the iron and swings till it 
 points directly towards it. The magnet F may be used 
 for this experiment. The north or marked end of the 
 magnet repels the north end of the needle and attracts 
 its south end. As we say, like poles repel, unlike at- 
 tract. The brass and glass cannot stop the attraction. 
 Paper, wood, anything except iron, may be interposed 
 
HOME MECHANICS FOR AMATEURS 
 
 249 
 
 betweeu the magnet and the needle without destroy- 
 ing the attraction and repulsion. 
 
 The decomposition of water into two gases, oxygen 
 and hydrogen, by electricity is a very interesting ex- 
 periment. For its best exhibition platinum is required, 
 but as this is a very expensive metal a method is given 
 by which one gas can be produced. Fig. 226 gives the 
 arrangement of the apparatus. The light and heavy 
 parallel lines indicate cells of battery. Two at least 
 are required. A good form of cell is represented in 
 Fig. 229. The glass is a common tumbler. Two plates 
 of battery carbon and one of zinc are clamped together 
 by two bolts which pass through the four strips of 
 wood. Strips of sheet copper or brass, d and e, are 
 included between the strips; d is cut long enough to 
 
 Fig. 227. Galvanometer. 
 
 Fig. 228. Electroplating. 
 
 connect with both carbon plates. Two of the spirals 
 described above are pushed on these strips to receive 
 the copper wires used in forming the circuits. This 
 sort of connector is nearly as good as a regular binding 
 post and costs a mere trifle. 
 
250 
 
 HOME MECHANICS FOR AMATEUES 
 
 The fluid for the cells is made by dissolving in cold 
 water as much bichromate of soda as the water will 
 take up, and adding slowly and with constant stirring 
 one-tenth of the yolume of sulphuric acid. The plates 
 should only remain in the solution while they are in 
 actual use. 
 
 Fig. 229. Detector Galvanometer. 
 
 The tumbler shown in Fig. 226 is to be filled with 
 water and a little sulphuric acid added. Lacking the 
 acid, vinegar may be used in its stead. 
 
 With two cells fine bubbles of h^^drogen gas come off 
 slowly from the copper which is attached to the wire 
 leading from the zinc of the battery and rise to the 
 surface. The oxygen combines with the copper and 
 does not appear as a gas at all. If platinum were used 
 
HOME MECHANICS FOR AMATEURS 
 
 251 
 
 for the other strip oxygen would be giveu off from its 
 surface, since oxjgen does not combine with phitinum 
 under these conditions. This most interesting experi- 
 ment was first performed by Sir Humphry Davy many 
 years ago. 
 
 Fig. 227 shows how^ to arrange one of the coils A, 
 the compass E, the support D, and the battery as a 
 galvanometer. Place the coil so that its length is east 
 and west and place the compass over the coil. The 
 needle will lie crosswise of the coil. When the current 
 
 Fig. 230. Sucking Coil. Fm. 231. Lines of Magnetic Force. 
 
 flows the needle is turned from its north and south 
 position. The laws and meaning of this is explained 
 fully in the text books of electricity. 
 
 Electroplating has become one of the most important 
 industries. It can be performed with the apparatus of 
 Fig. 228. The arrangement is the same as that of Fig. 
 226, except that the tumbler is now to be filled with a 
 liquid containing the metal with which the article is 
 to be plated. To plate wnth copper a solution of copper 
 sulphate may be used, though carbonate of copper is 
 better; for nickel a double carbonate of nickel and 
 ammonia is used. The metal will be deposited on the 
 
252 
 
 HOME MECHANICS FOR AMATEURS 
 
 strip attached to the wire from the zinc, that one on 
 Avhich the hydrogen appeared when water was decom- 
 posed. The other strip must be of the metal with which 
 tlie plating is to be done. 
 
 Fig. 232. Mode of Inducing an Electric Current by a Magnet. 
 
 More instruction and much experience will be re- 
 quired for real work; but much pleasure can be de- 
 rived by watching the process in this simple manner. 
 Three or four cells should be used for depositing nickel. 
 
 If a copper wire is passed straight through the fix- 
 ture D, and the parts are set up as in Fig. 229, it will 
 constitute a detector galvanometer, suitable for large 
 currents, as the arrangement in Fig. 27 is adapted for 
 
 Fig. 233. Mode of giving an Electric Shock. 
 
 feeble currents. The wire in all cases must be placed 
 north and south, or lengthwise of the needle when at 
 rest. 
 
 The uses for an electromagnet in experimenting are 
 very many. It is the most important piece of electrical 
 
HOME MECHAXICS FOE xVMATEURS 253 
 
 apparatus, and was invented by Sturgeon of England 
 and also by Prof. Joseph Henry in America. Probably 
 neither knew the work of the other. Henry's inven- 
 tion led directly to the electric telegTaph. Fig. 230 is 
 given as an illustration of the power of a helix to draw 
 iron or steel into itself. If a strong battery is used 
 the pen is sucked into the coil with considerable force. 
 A large number of small Avire nails may also be held 
 up in the coil without visible support. It is wizard- 
 
 FiG. 234. Microphone. 
 
 like to see a piece of heavy metal hanging in the air 
 upon nothing. Numerous modifications of this curious 
 experiment will suggest themselves to an ingenious 
 person. 
 
 With the two coils A, put upon a U-shaped iron 
 rod f inch thick, as in Fig. 231, the beautiful mag- 
 netic phantom or magnetic field of force can be made 
 visible. The wires from the spools are connected to 
 the battery, which is not shown. Join the two spools 
 together so that the outside of the winding of one is 
 
254 HOME MECHANICS FOR AMATEURS 
 
 connected to the inside of the winding of the other. A 
 thin board is laid over the poles and iron filings sifted 
 over the board. Then tap the board gently with the 
 tip of a finger. The filings jump with sudden alac- 
 rity into lines, definite and exact. The figure shows 
 these lines. It means magnetic attraction. Now 
 change the connections. Join the two outside wires of 
 the spools to the battery and the inside Avires to each 
 other. The figure changes to one exhibiting repulsion. 
 The lines shun each other. 
 
 If blue print paper be pinned on the board and the 
 whole exposed in the sunlight, fine photographs may 
 
 Fig. 235. Electromagnet for Lifting. 
 
 be made of these beautiful figures. By using horse 
 shoe and bar magnets, endwise and flatwise, a great 
 variety of magnetic fields may be mapped. 
 
 Next arrange the apparatus as in Fig. 232. The 
 compass needle is strongly defiected from its north and 
 south position. Now remove the battery and close the 
 circuit. Plunge a bar magnet into the right hand coil. 
 The needle swings, though not so strongly as before. 
 An electric current is generated so long as the magnet 
 is in motion, either in or out of the coil. 
 
 If the cores of the coils in Fig. 232 are filled with 
 iron Avires a current may be generated by simply tak- 
 
HOME MECHAXICS FOR AMATEUES 
 
 255 
 
 iiio- the right hand coil in the hands, holding it north 
 and sonth and turning it over quickly. These effects 
 Avere discovered by Ampere, for whom the unit of cur- 
 rent is named. The student should look up the subject 
 in text books of electricity. 
 
 The giving of electric shocks to one's friends is al- 
 ways a pleasant pastime. One mode of doing this is 
 illustrated in Fig. 233. Of course no severe shock can 
 be given in this way. The metal handles of Fig. 238 
 should be connected to the open ends of the wires to 
 
 Fig. 236. Electric Telegraph. 
 
 the left. Scrape the ring along the file and a slight 
 shock will be felt by one who grasps the handles with 
 moist hands. The shock is produced by an induced 
 current. The arrangement is a very simple form of 
 induction coil. As the making of a strong coil is a 
 difficult matter, a special and full description of the 
 coil to be made should be obtained before undertaking 
 such a piece of work. 
 
 Fig. 234 is a microphone. Two bits of iron wire, or 
 bright wire nails, p, are connected to the Avires and laid 
 
250 
 
 HOME MECHAXICS FOR AMATEUES 
 
 on the top of a box made of thin wood as shown. Pine 
 is to be preferred. A sheet of iron is laid upon the top 
 of the electromagnet. On tapping the box gently a 
 much louder sound will be heard from the sheet of 
 iron, when all is working well. This effect is the basis 
 
 Fig. 237. % Dynamo or Motor 
 
 of the invention of the transmitter of the telephone. 
 If a telephone receiver is used in place of the electro- 
 magnet and sheet of iron, the feeblest sounds produced 
 on the top of the box are greatly intensified. The 
 microphone box may even be used as a telephone trans- 
 mitter if the wires are long enough to permit it to be 
 placed in another room, and all the parts are suflfi- 
 ciently delicate. 
 
 The arrangement of an electromagnet for lifting pur- 
 poses is shown in Fig. 235. By means of a spring 
 balance one may find the pull necessary to remove the 
 armature when the number of cells of the battery is 
 varied from one cell up to its full capacity. The iron 
 bar used as an armature should always be as large in 
 cross section as tlie iron core of the magnet. 
 
HOME MECHAXICS FOE AMATEUES 
 
 257 
 
 Fig. 236 will guide one in setting up a telegraph line, 
 with a station at each end. The key is simply a strip 
 of spring sheet brass. When not in use it is pressed 
 down and caught under the head of the screw beyond 
 it so as to close the circuit. The construction of the 
 sounder is so simple that it will not be given in detail. 
 The most diflticult part to adjust is the vibrating arm, 
 m, whose blows against the slot in the post to the right 
 produce the sound Avhich gives the name to the instru- 
 ment. The vibrating bar should not strike the electro- 
 magnet A\'hen it is pulled down, nor have a very Avide 
 range of motion. The bar must either be wholly of 
 iron, or better, have a block of iron riveted to it, since 
 brass is not attracted by a magnet. The tension of the 
 tine wire spring on the left determines the force neces- 
 sary to pull the bar down. 
 
 ^^^^^"^^^ 
 
 Fig. 238. Shocks by Rotating Coil. 
 
 To work the telegraph swing the key from under the 
 head of the screw which holds it down. This opens 
 the circuit. The bar of the sounder flies up. Now^ 
 press the key down till it touches the wires below it. 
 The current from the battery flows and the armature 
 is jerked down, giving a sharp blow on the post which 
 detains it. As the key is moved down and up the arma- 
 
258 HOME MECHAXICS FOE AMATEUES 
 
 tiire moves clown and up, produciug the clicks which 
 all have heard in a telegraph office. 
 
 By getting a Morse alphabet and mastering the art 
 of producing dots and dashes two persons may soon 
 learn to send messages to each other. 
 
 A model of a dynamo may be built from the parts, 
 A, B and C, of the cabinet. This is shown in Fig. 237. 
 The electro-magnet formed by A and B is fixed upon C, 
 and the circuit completed by short pieces of magnet 
 wire. The open ends to the left may be connected to 
 the galvanometer, I) and E, to detect the current. 
 
 The rotating coil, H, and the commutator J, are 
 somewhat difficult of construction. The coil consists 
 of about 100 turns of No. 20 single cotton-covered 
 magnet wire. The inner end of the wire is soldered to 
 one of the half rings of the commutator, the outer end 
 to the other half ring. 
 
 On whirling the coil rapidly a feeble current will be 
 produced. The current will be reversed, if the coil is 
 whirled in the opposite direction. 
 
 This tiny dynamo may be transformed into a series 
 Avound motor by connecting the battery in place of the 
 galvanometer. 
 
 By changing the connections as shoAvn in Fig. 238, 
 the electric current may be felt in the handles when the 
 armature is whirled rapidly. 
 
 Though the experiments described by no means ex- 
 haust the subject, nor the resources of the electrical 
 cabinet, still they place before the studious amateur 
 enough to employ many an hour most profitably, and 
 to incite him to further study and to higher work. 
 
HOME MECHAmCS FOR AMATEURS 259 
 
 SIMPLE ELECTRIC MOTOR 
 
 Almost every youug amateur mechanic is desirous 
 of making something having the ability to move and 
 show action. An electric motor does this; and while 
 the mechanic is making a good piece of machinery, 
 he is also learning the principles of electricity^ 
 
 The motor we shall describe is intended to turn a fan 
 or light machinery by means of a current derived from 
 a battery. It will drive a light sewing machine or 
 other machinery requiring a similar amount of power, 
 and it is so simple as to admit of being constructed 
 with the tools ordinarily possessed by an amateur. 
 
 To begin a motor at the right i)oint is very import- 
 ant. The first thing to be done is to construct the 
 armature — the part which revolves. On account of its 
 simplicity, Ave have selected the Gramme armature. 
 
 The core of this armature consists of a ring formed 
 of No. 24 sheet iron. A strip f inch wide and 8 feet 
 long (the length of a sheet) is carefully cut from the 
 sheet and wound upon a cylindrical piece of wood in 
 the lathe or by hand. The wood cylinder is If inches 
 in diameter and 1 inch thick, and in the edge is cut a 
 shallow notch of a depth equal to the thickness of the 
 sheet iron, as shoAvn in Fig. 240. In the iron, | inch 
 from the end is drilled a hole, countersunk to receive 
 a wood screw, which passes through the sheet iron 
 into the wood, and fastens the end in the notch in the 
 wood. The sheet iron thus attached to the wood may 
 be wound closely around the wooden mandrel without 
 a kink being formed by the inner end of the strip, 
 which is in the notch. 
 
 Before beginning the winding, a piece of strong an- 
 
260 
 
 HOME MECHANICS FOE AMATEUES 
 
 nealed wire, stove-pipe wire for example, is placed in 
 a handy position, and when nine layers of the iron 
 have been wound the strip is cut off and the binding- 
 wire is wrapped around the coil and twisted together 
 at the ends, to keep the sheet iron from unwinding. 
 
 Fig. 239. Electric Motor. 
 
 The wood and the coiled sheet iron are together 
 removed from the lathe (or vise if it is being done by 
 hand), and placed in a fire, which will heat the iron 
 to a cherry red and bum out the wood. The ring is 
 
HOME MECHAXICS FOE AMATEURS 261 
 
 then covered Avitli ashes and allowed to cool slowly. 
 This anneals the iron, and improves its magnetic per- 
 meability. 
 
 After removal from the ashes, and while the binding 
 wire is still in place, the ends are secured by passing 
 rivets through them ; the inner end, which was bent, is 
 cut off, and the ends are beveled with a tile, and all 
 the sharp corners are reduced by the same means. 
 
 The core of the armature is then covered with adhe- 
 sive tape (either electrical or bicycle tire tape), when it 
 is reafly to receive the magnet wire with Avhich it is to 
 be wound. The ring is divided into five equal sec- 
 tions, and marked with a pencil to show how much 
 space each coil of the armature is to occupy. There 
 are five coils on the armature, Avitli five layers in each 
 coil. No. 21 single or double cotton or silk covered 
 wire is used. It requires about 28 feet of wire for each 
 coil. The winding is a, slow and rather laborious 
 process. The length of wire for a coil is wound on a 
 sort of shuttle-stick f inch wide, 12 inches long, with 
 a notch in each end. The end of the wire is wrapped 
 twice or three times around the ring over a piece of 
 stout thread, which is tied around the wires to fasten 
 them together, to begin a coil. Of course, the begin- 
 ning is at one of the marks on the ring. 
 
 Now the shuttle is passed through the ring and 
 brought back over the outside until one layer covers 
 one space; then commencing the winding over the 
 first layer the second is laid on, then the third, fourth, 
 and fifth; all the layers are wound in the same way. 
 The last three or four turns are made over a stout 
 thread, which is tied when the last convolution is 
 made. 
 
262 HOME MECHANICS FOE AMATEUES 
 
 The other coils of the armature are made in the 
 same way, and when tlie winding is all on, the end of 
 one coil is twisted with the beginning of the adjacent 
 coil. A piece of well seasoned hard wood, hard maple, 
 for example, is bored to receive a piece of A inch drill 
 rod — Stubs or something equally good — which consti- 
 tutes the shaft. This rod is 4 inches long. A tV inch 
 hole is drilled transversely through it at or near the 
 center to receive a short pin which enters a slot in the 
 end of the Avooden hub. 
 
 This piece of wood is turned to fit the interior of the 
 armature, and is cut off about the same length as 
 the armature. The coils of the armature and the 
 wooden hub are now varnished with thin shellac var- 
 nish, and allowed to dry thoroughly. The armature 
 ring is then slipped into its place on the wooden hub, 
 and the hub and the ring are coated with two coats of 
 shellac varnish, one coat being allowed to dry before 
 applying the other. 
 
 The next thing to claim attention is the commutator. 
 This is a core of wood fitted to the armature shaft and 
 turned to fit a piece of brass or copper tube f or f 
 inch in diameter and f inch long. This tube is divided 
 into five divisions, and parallel lines, preferably slightly 
 spiral, are drawn from the divisional points marking 
 the places where the tube is to be sawed to form the 
 commutator bars. But before sawing, each end of 
 each space which is to form a bar is drilled, and the 
 hole is countersunk to receiv^e a small wood screw, 
 which passes into the Avood and holds the bar in 
 place when the brass tube is sawed on the lines to 
 separate the bars. After salving, the commutator is 
 turned smooth and round, or filed in the lathe with a 
 
HOME MECHANICS FOE AMATEURS 263 
 
 smooth file. The screws used in fasteniiii;' the commu- 
 tator bars must not touch each other or the shaft. 
 
 The twisted teniiinals of the coils are now stripped 
 of the winding at the ends and soldered to the commu- 
 tator bars, having been cut off the proper length to 
 reach to the commutator. 
 
 Before soldering, however, the ends of the terminals 
 and a small portion of each commutator bar are tinned 
 to facilitate the work of soldering. To tin the copper 
 
 Fig. 240. The Armature Core. 
 
 wire, a little pulverized rosin is rubbed on the ends of 
 the wires, and the solder is applied with a soldering 
 iron. 
 
 The commutator bars are tinned for J inch at the 
 ends nearest the armature ring in the same manner. 
 
 The terminals of the armature coils are bent so as 
 to touch the commutator bars at the tinned surfacef^; 
 the beginning of one coil and the end of the adjacent 
 coil being thus brought into contact with a commutator 
 bar. They are then soldered by applying a drop of 
 solder by means of the soldering iron. The wires are 
 
264 HOME MECHANICS FOE AMATEUES 
 
 thus made to answer tlie double purpose of conveying 
 the current to the commutator bars and of causing the 
 commutator to revolve with the armature. Acid must 
 not be used in soldering electrical connections. 
 
 To run smoothly, the armature must be in balance. 
 To ascertain whether it is in balance, place the arma- 
 ture shaft on the edges of two level straight-edges sup- 
 ported about 4 inches apart. If the armature will 
 stand in any position, it is balanced. If it rolls so that 
 one side after a few oscillations of the armature goes to 
 the bottom, the top must be made heavier to counter- 
 balance the bottom. Probably the best way to add 
 weight to one side of the armature is to apply it in the 
 form of solder to a band of wire about f inch wide 
 wound around the armature. Before this winding is 
 applied, a strip of mica f inch wide must be wrapped 
 around the armature and secured in place by shellac 
 varnish applied to both the armature and to the mica 
 and allowed to become nearly dry. It is not necessary 
 to use a continuous piece of mica ; it may be in several 
 pieces. When the armature comes to rest after oscilla- 
 tion, solder should be applied to the upper side of the 
 wire band until the armature will stand in any posi- 
 tion. If too much solder is applied, the surplus may be 
 removed by a coarse file. It is important to have the 
 armature as nearly in balance as possible. It will then 
 have very little vibration, or none at all, while running 
 at any reasonable speed. 
 
 Care should be used in all the operations connected 
 with this motor to insure entire success. 
 
 The next thing to be done is to construct the field 
 magnet, which in this motor is in the form of a ring, 
 as shown in Fig. 241. The core of the field magnet is 
 
HOME MECHANICS YOU xVMATEUES 
 
 265 
 
 formed by wiuding four strips of No. 24 sheet iron f 
 inch wide and 8 feet long upon a wooden core, as in the 
 case of the armature core. The form on which the 
 field magnet is wound being A inch larger in diameter 
 than the armature, and as this is variable, it must be 
 ascertained after the armature is wound and balanced, 
 on account of the variation in the winding depending 
 on the covering of the wire and the care with which it 
 
 Fig. 241. Field Magnet Core. 
 
 is wound. In the motor illustrated, the field magnet 
 ring is 2f inches internal diameter and 4^ inches ex- 
 ternal diameter. Before winding the field magnet core, 
 the ends of the 8-foot strips are scarfed or beveled off 
 and tinned, and then soldered together and coiled for 
 convenience. 
 
 The strips should be wound upon the form as tightly 
 as possible, and when the last layer is on, a stout wire 
 is wrapped around the outside and twisted together to 
 
266 HOME MECHANICS FOR AMATEUES 
 
 keep the sheet iron strip from imwiiKliuij^, as in the 
 case of the armature core. 
 
 As it is not necessary to anneal the field magnet, the 
 wooden form is removed by boring a hole through it 
 and then splitting the Avood so that it can be removed 
 piecemeal. The coil of sheet iron forming the field 
 magnet core is composed of thirty-three layers. 
 
 The ring is divided into four quarters by radial lines, 
 and midway between two of these lines, on opposite 
 sides of the ring, are drilled holes for rivets A inch in 
 diameter, the holes being countersunk slightly on each 
 side. These rivets with slight heads are inserted in 
 the holes, with the heads inside the ring. They are 
 then neatly riveted at the outside, leaving the inner 
 side as smooth as possible. To accomplish this, it is 
 necessary to move the binding Avire away from the 
 center of the field magnet ring. 
 
 When the two riAT^ts are in place, the binding Avire 
 may be remoA^ed; then in the same sections near the 
 ends are placed rivets, one at each end of each section. 
 The sections riA^eted in this manner form iuAvardly 
 projecting pole pieces. While drilling the holes for 
 the riA^ets, it is necessary to clamp the strips firmly to- 
 gether to prevent the drill chips from Avorking in be- 
 tAveen the layers of the magnet. Eleven layers of the 
 magnet ring are sawed out between the pole pieces to 
 make a space for the Avinding of the field magnet ; the 
 ends of the pole pieces are bcA^eled as shoAvn to facili- 
 tate winding. These spaces are covered with adhesiA^e 
 tape and are wound with four layers (about 45 feet) of 
 No. 18 magnet wire, either single or double, cotton or 
 silk covered. 
 
 One of the pole pieces will be at the bottom of the 
 
HOME MECHANICS EOE AMATEUES 
 
 267 
 
 field iiiai»uet and the other at the top when the motor 
 is conipk'te; tlierefore the winding on eaeh side of 
 tlie fiehl magnet l)egins at opposite sides of the same 
 pole piece, and is wound in the same direction to bring 
 the wire terminals near the base of the machine, and 
 
 Fig. 242. Electrical Connections of Motor. 
 
 to cause the current in the two windings to unite in 
 producing a north pole at the top of the magnet and a 
 south pole at the bottom, or vice versa. If a mistake 
 is made in the winding, this can be corrected in making 
 the connections. It is not necessary to unwind and 
 rewind. 
 
268 HOME MECHANICS FOE AMATEUES 
 
 The constriictiou of this magnet is open to criticism 
 on account of the disposition of the laminae, but this 
 construction is partly or wholly compensated for by the 
 large rivets, which bind the pole pieces and the body 
 of the magnet together. 
 
 The holes are drilled in the lower side of the magnet 
 and tapped to receive machine screws, which pass up- 
 ward through the base of the machine to hold the 
 magnet, which latter sits upon a small wooden saddle 
 about I inch thick in the middle. The field magnet 
 winding, as well as the iron core, is covered with sev- 
 eral coats of shellac varnish, for insulation and protec- 
 tion. 
 
 The journal boxes for the shaft are simply f brass 
 balls axially bored to receive the shaft, and having an 
 oil hole in the top. These boxes are each held in place 
 by two brass plates bored to receive the sides of the 
 balls as shoAvn, and attached to the sides of the square 
 wooden standards by screws. The shaft is allowed to 
 project at one or both ends sufficiently to receive a 
 pulley or fan. The armature is wrapped around the 
 sides with enough firm paper to cause it to fit tightly 
 into the field magnet, and after the shaft is made level, 
 the journal boxes are placed on the shaft, and the 
 standards which support them are sawed off the prop- 
 er length and secured to the base by scrcAVS, one for 
 each standard, passing upwardly through the base and 
 into the lower ends of the standard. To the base ad- 
 joining the standard at the commutator end is attached 
 a wooden block, to the ends of which are secured light 
 copper springs, which bear on opposite sides of the 
 commutator and act as brushes for conveying the cur- 
 rent to the armature. 
 
HOME MECHANICS FOR AMATEUES 269 
 
 The screws Avliich hold the lower ends of these 
 brushes also clamp the wires which extend downward 
 through the base, one being connected with one of the 
 binding posts which receive the battery wires, the 
 other brush being connected with the outside terminal 
 of one of the field magnet coils. The outside terminal 
 of the other field magnet coil is connected with the re- 
 maining binding post. The inside terminals of the 
 field magnet coils are connected together. The con- 
 nections are clearly shown in the diagram (Fig. 242). 
 The upper screws in the commutator brushes are used 
 for varying the pressure of the brushes on the com- 
 mutator as may be required; the brushes being bent 
 outwardly to admit of this adjustment. 
 
 If the motor is to be used for driving a fan, the base 
 will need to be set upon legs of some kind. In the 
 motor illustrated, the base is supported upon four in- 
 verted clothes hooks which support it 2 inches from the 
 table. 
 
 The oil cups are made of wood (soft maple or birch), 
 with stems extending down into the fV holes in the 
 spherical boxes; and in the portion of the wood above 
 the journal box is formed a cavity which will contain a 
 few drops of oil. The outside of the oil cup is varnished 
 with shellac except at the end of the stem, before any 
 oil is put in. This confines the oil to the cavity and 
 the interior of the stem and causes it to slowly feed to 
 the journal on which the stem rests. The fan can be 
 purchased for a small sum. It may be necessary to 
 bush it to fit the shaft. Either an 8-inch or a 10-inch 
 fan may be used. 
 
 Of course, a small pulley will be substituted for the 
 fan when the motor is used to drive a machine. 
 
270 HOME MECHANICS FOR AMATEURS 
 
 If the motor Avlien finished does not rnn in the de- 
 sired direction, this may be changed by transposing the 
 wire connections at the brushes, so as to change the 
 direction of the current in the armature. 
 
 SMALL ELECTKIC MOTOEiS FOK AMATEURS 
 
 Every piece of electric work done by a student or 
 amateur is of value, not only as an addition to his 
 collection of apparatus, but as a means of acquiring a 
 positive knowledge of electricity and of electrical appa- 
 ratus. The following engravings show a simple and 
 easily constructed motor, which very fully illustrates 
 the construction and operation of the Gramme motor, 
 and is well adapted to various uses requiring only a 
 small amount of power. 
 
 This motor was built by Mr. W. S. Bishop, of New 
 Haven, Conn., after the general plans of the simple 
 electric motor already illustrated and described in a re- 
 cent Scientific American, but the construction here 
 shown is more simple and more easily carried out. 
 The perspective view here given is two-thirds the 
 actual size. The front and side elevations and the 
 smaller detail view are full size. 
 
 The field magnet. A, is formed of a yoke of Norway 
 iron -f-Q inch thick, ^ inch wide and 2^ inches long. 
 In the yoke, near its ends and lA inches apart, are 
 drilled holes for receiving the quarter inch Norway 
 iron cores of the magnet, which are driven into the 
 yoke. 
 
 The polar extremities, a, of the field magnet are 
 curved to form a circular opening 2tV inches in diam- 
 eter. The winding of the field magnet may be applied 
 
HOME MECHAXICS FOE AMATEUES 271 
 
 to the magnet cores, as shown in the engraying, or the 
 wire may be wound npon spools fitted to the cores. 
 The spools are 1 inch in diameter and 1 J inches long be- 
 tween the heads. Upon each spool is wound 1 ounce of 
 No. 24 double wound, cotton covered magnet wire. The 
 yoke of the field magnet is fastened to the wooden 
 base piece of the motor by screws passing upwardly 
 through the base into threaded holes in the yoke. 
 
 The armature, B, consists of a small Gramme ring 
 mounted upon a wooden disk secured to the armature 
 shaft. The armature core, c, is a ring formed of a piece 
 of annealed iron wire. No. 13 B. & S. gauge, having its 
 ends beveled and drilled transversely to receive a pin, 
 as shown in Fig. 246. A core of this kind, although 
 theoretically not as efficient as a laminated core, 
 answers every purpose in this very small motor, and 
 greatly facilitates the construction of the armature. 
 The core has an outside diameter of If inches. The 
 outside diameter of the armature is 2 inches, and the 
 inside diameter IJ inches. Upon the armature core 
 are placed 12 coils, h, of silk covered, single wound mag- 
 net wire. No. 25 B. & S. gauge, separated by rings d of 
 soft iron Avire No. 13, the rings forming polar exten- 
 sions which add to the efficiency of the motor. The 
 armature coils are formed in a lathe on a mandrel, 
 separately, as shown in Fig. 247. This mandrel con- 
 sists of a piece of No. 11 wire having two collars f of an 
 inch apart, one of the collars being fixed and the other 
 being removable. Each coil contains 4 feet 4 inches of 
 wire wound in five layers. 
 
 To facilitate the removal of the coil from the man- 
 drel, the first layer is wound loosely. After winding, 
 and before removing the coil from the mandrel, the Avire 
 
272 
 
 HOME MECHANICS FOR AMATEURS 
 
 is cemented with paraffine or wax melted on the coil 
 with a warm iron. After twelve coils have been com- 
 pleted, they are strung upon the armature core, c, in 
 alternation with the iron wire rings, d^ and when the 
 
 Fig. 243. Perspective View of a Small Gramme Ring Motor. 
 
 core is filled, its ends are brought together and secured 
 by means of the pin, as shown. 
 
 The Avooden liub of the armature is now fitted to tlie 
 ring, but before the ring is secured on the hub, twelvt^ 
 
HOME MECHANICS FOll AMATEUKS 273 
 
 equidistaut holes are drilled transversely through the 
 hub, near its center, and in each hole is inserted a piece 
 of No. 12 copper wire one-half an inch long. The ends 
 of the pieces of copper wire are allowed to project one- 
 
 FiG. 243 A. Perspective View of Small Gramme Ring Motor. 
 
 sixteenth of an inch beyond the sides of the hub. The 
 ring is placed on the hub, and the ends of the wire pro- 
 jecting from adjacent coils, h, are twisted together and 
 attached by means of solder to the copper wire pins 
 
274 HOME MECHAXICS FOR AMATEURS 
 
 extending through the hub and forming the commu- 
 tator bars, the covering being removed from the ex- 
 tremities of the Avire. It will thus be seen that to each 
 commutator bar is connected the beginning of one coil 
 and the end of the adjacent coil, so that by means of 
 
 Fig. 244. Sectional Side Elevation of a Small Motor, 
 
 these connections the winding of the armature becomes 
 continuous. 
 
 The posts in wliich the armature shaft is journaled 
 are perforated near tlieir upper ends Avith a hole of a 
 size adapted to receive the armature shaft, and these 
 holes are counterbored from the inner surfaces of the 
 posts, and a wire of the same diameter as the shaft 
 
HOME MECHANICS FOR AMATEUES 
 
 275 
 
 is placed in the position of the armature shaft, and 
 Babbitt metal or type metal is poured into the open- 
 ings around the shaft, forming the journal boxes. A 
 hole is bored in the top of each post before casting the 
 metal, to form an anchorage for the journal box, and 
 after the casting, the anchorage is drilled through to 
 
 Fig. 245. Front Elevation of Small Motor. 
 
 the opening of the journal box to form an oil hole for 
 the armature shaft. 
 
 The journal box on the side of the commutator is 
 made to project beyond the inner face of the post to 
 receive the disk, f, which carries the commutator 
 springs, r/. This projection is made by clamping to the 
 post a piece of wood having in it a hole corresponding 
 
276 HOME MECHANICS FOE AMATEURS 
 
 Avitli that ill the post. After the journal box is cast, 
 the extra piece of Avood is removed, leaving a sleeve 
 upon which to place the disk, /. This disk is an inch 
 and a half in diameter and ti of an inch thick. 
 
 Fig. 246. Armature of Small Motor in Process of Construction. 
 
 To the inner face of the disk, /, are clamped the com- 
 mutator springs, g, by means of small blocks, as shown 
 in the perspective view, these blocks being held in place 
 by screws passing through the disk into threaded holes 
 
 Fig. 247. Apparatus for Winding Armature Coils. 
 
 ill the bh)cks. The commutator springs are curved 
 outwardly and their ends are turned backward to- 
 ward the disk, /, and their extremities rest upon the 
 commutator bars, as shown in Figs. 243 and 244. 
 
HOME MECHAXICS FOT^ AMATEUES 
 
 277 
 
 Tht' disk, /, and the chimpiuo blocks are made of 
 vulcanized fiber, which is strong and at the same time 
 a i'ood insulator. The commutator springs, g, are 
 nmde of hard rolled copper, and their inner ends are 
 adjusted so as to touch diametrically opposite commu- 
 tator bars. The best adjustuunit for the commutator 
 sprino-s is found by moving the disk, f , in one direction 
 or the other. It will be found that the maximum ef- 
 fect is secured when the contact surfaces of the com- 
 mutator springs are nearly in a vertical line. 
 
 The disk, f, is clamped in any desired position by an 
 ordinary wood screw, li, which passes loosely through 
 the post and is screwed into a wooden thumb nut bear- 
 ing against the outer surface of the post. The ter- 
 mi'iials of the field magnet. A, are connected directly 
 with the binding post and also with the outer ends of 
 the commutator springs, (j. as shown in Figs. 243 and 
 
 245. 
 
 With one cell of dry battery the motor makes about 
 1,800 revolutions per minute, but it does not develop 
 its maximum power until one or two cells are added in 
 parallel. Any of the dry batteries will run it for short 
 periods, but if it is required to run it continuously for 
 any length of time, one or two cells of Bunsen or a 
 Fuller battery should be used. 
 
 The motor being shunt wound, is practically self- 
 regulating. Its speed with any amount of battery 
 power does not much exceed 2,000 revolutions per 
 minute. 
 
278 
 
 HOME MECHAXICS FOE AMATEURS 
 
 HOW TO MAKE A SEWING MACHINE MOTOR 
 WITHOUT CASTINGS* 
 
 The accompanying drawings, together with the fol- 
 lowing instructions, will enable any mechanic of aver- 
 age ability to build a highly efficient motor that will 
 operate the heaviest of family sewing machines with a 
 
 Fig. 248. Sewing Machine Motor Made by an Amateur. 
 
 consumption of electrical energy only a trifle greater 
 than that required to maintain an incandescent lamp. 
 All the materials entering into the construction of the 
 motor may be procured in almost any town or small 
 
 * By Cecil P. Poole. 
 
HOME MECHAXICS FOR AMATEURS 
 
 279 
 
 city, and tlie total cost of tlic macliiiic, cxccptiiii»-, of 
 course, the la])or, slioiild not exceed five dollars. 
 
 The first operation is that of niakin.1!: th(^ magnet, 
 which consists of a bar of ordinary wron<»ht iron, 1^ 
 inches square and 19 inches lon^^-, bent (while red hot) 
 into a U, as shown by Fi"'. 248. After bendin.u^ the iron 
 into shape, cut out two concavities in the limbs, as indi- 
 cated by the dotted lines, to a circle of 4| inches diam- 
 
 -^~ -. 
 
 Q 
 
 Fig. 249. Field Magnet. 
 
 Fig. 250. 
 
 Field Magnet Ready for 
 Armature. 
 
 eter. The center of the circle of which the concave sur- 
 faces form arcs must be 5^ inches from the short part 
 of the U, known as the mai^net yoke, and exactly mid- 
 way between the magnet limbs, so that an equal amount 
 will be cut out of each limb. This cutting can be done 
 by any blacksmith, as it does not need to be precise in 
 the matter of the surfaces of the concavities, the only 
 object being to remove the bulk of metal that is to be 
 cut away in order to form the armature chamber. 
 
 Next smooth up the sides of the magnet on the fiat of 
 an emery wheel, rounding off the corners so that a face 
 
280 HOME MECHAXICS FOR AMATEUES 
 
 view of the ends of the limbs will be as shown in Fig. 
 254 ; the faces, f, f, should also be smoothed off with the 
 emery wheel, as these form the base of the machine. 
 Then bolt the magnet to tlie face-plate of the lathe so 
 that the center of the circle, a, to which the magnet 
 limbs were cut away coincides with the lathe centers, 
 and bore out the armature chandler to 4^ inches in 
 diameter, leaving the magnet as shown by Fig. 250 ; 
 the curved surfaces forming the armature chamber are 
 known as pole-faces. If the sides of the magnet (by 
 "sides" are meant the part facing the reader in Figs. 
 248, 250, and 253, and the corresponding part on the 
 other side of the magnet) were not ground to a true 
 parallel on the emery wheel, and asit is highly probable 
 that they were not, it is advisable to take a slight cut 
 over the whole side exposed while the magnet is on the 
 face-plate so as to have it perfectlj^ plane, and also take 
 a cut over the opposite side to insure parallelism. 
 
 The journal yokes and boxes come next. There will 
 be two bearings and yokes, one for each side of the 
 machine. Fig. 251 shows the parts necessary for one 
 yoke and bearing ; //, y are brass strips 6f inches long, 
 1 inch wide, and A inch thick, with rounded ends; h 
 is the box, made of a piece of round brass rod 1 inch 
 in diameter and 2 inches long over all, one end being 
 turned down to f inch diameter for a distance of f 
 inch, a f-inch hole being drilled through the center 
 and a ^-inch hole being drilled in one side far enough 
 to let the point of the drill through into the bore of 
 the box; c is the oil reservoir, consisting of a piece of 
 brass tubing 1 inch long, f inch in diameter outside 
 and f inch diameter inside, with one end permanently 
 stopped by a plug soldered in and the other end 
 
HOME MECIIAXICS FOI] A:\IATKrES 
 
 281 
 
 threaded for a distance of tV incli. The hole iii the 
 side of the box, h, is threaded to match the thread on 
 the end of the tube, c, which is packed with lamp 
 wick, filled with oil, and screwed in the box when the 
 machine is completed and ready to run. The yoke 
 strips, 7/, 7/, haye each a ^-ii^t'b ^i<>l^' diilbnl exactly in 
 the center, seyeral nicks being* filed in the edges of 
 these holes. Before putting the yoke together, tin the 
 edges of these central holes and tin the small end of 
 
 y y 
 
 O 
 
 o 
 
 Fig. 251 
 
 Fig. 252. 
 Parts of Yoke. 
 
 Fig. 253. 
 
 Placing Yokes in 
 Position. 
 
 Fig. 254. 
 Magnet with Yokes. 
 
 the box, h; then mount the st 
 box so they will be at right ang 
 so that the hole in the side of 
 two of the legs formed by the 
 whole at the center. Be sure 
 edges of the holes with solder. 
 
 When both yokes haye been 
 block of wood 1^ inches thick to 
 chamber in the magnet limbs 
 
 rips on the end of the 
 les with each other and 
 the box comes between 
 strips, and solder the 
 to fill the nicks in the 
 
 assembled, turn up a 
 fit closely the armature 
 without spreading the 
 
282 HOME MECHAXICS FOE AMATEURS 
 
 latter. This Mock sliould liavc a JJ-iiu-li linlc in the cen- 
 ter, and it will be better to drill the hole first, mount 
 the block on a f-inch mandrel and turn it up true with 
 the central hole. Put this block in the armature cham- 
 ber with its f-inch mandrel in the central hole, thread 
 one yoke on one end of the mandrel and the other on the 
 other end, turning the legs of each yoke to the position 
 shown by Fig. 253. Clamp the Avhole together securely 
 and drill four |-inch holes, h, h, h, h, through the mag- 
 net limbs and both yokes ; punch-mark one yoke and the 
 face of the magnet limb on Avhich it rests so that in 
 reassembling the machine the various parts will come 
 back to the original position in Avhich they Avere drilled ; 
 then take off the clamps and take off the yokes, remove 
 the yokes and wooden block and anneal the magnet by 
 heatina* it to a bright red and allowing the fire to die 
 out with the iron covered up in the coals. 
 
 For mounting the yokes permanently on the magnet, 
 four steel machine screws and eight distance pieces 
 will be required. The screws are \ inch in diameter 
 and 6| inches long under the head, and the head 
 should be slotted. The distance pieces to hold the 
 yokes away from the magnet are made from round 
 brass rod 1 inch in diameter ; two of them are 1 A inches 
 long, two are If inches long, two are 2x1 inches long, 
 and the remaining two are 2;^ inches long. Fig. 254 
 shows one yoke mounted, with its distance pieces, z, z, 
 z, z, and .s, .s, i<, s, represent the thread ends of the 
 screws. The yokes should be carefully fitted or trouble 
 may result from non-alignment of the bearings. 
 
 The armature structure comes next From some 
 dealer in armature stampings procure one hundred 
 rings of charcoal iron 4 inches in diameter outside and 
 
HOME MECHAXTCS FOE AMATEURS 
 
 283 
 
 3 inches in (liiuneler inside. These rin<j;s must not be 
 over iV ineli thick and preferably abont q\ inch thick. 
 Not all of the one hnndred will be needled, bnt many 
 will be spoiled in drilling. From a dealer in electrical 
 snpplies procnre two rings of vnlcanized fiber, the 
 same diameter ontside and inside as the iron rings, and 
 I inch thick. On the face of one ring space off twelve 
 eqnidistant points on a circle scribed around the cen- 
 ter of the ring's face midway between edges, as shown 
 by Fig. 255, in which the points are indicated by 
 
 Fig. 255. 
 
 Laying Out the 
 Armature. 
 
 Fig. 256. 
 Brass Disks. 
 
 Fig. 257. 
 
 Position of Holes 
 for Bolts. 
 
 Fig. 258. A Trapezoid. 
 
 Fig. 259. Tie Rod. 
 
 c, c, g, e, c, (/, c, c, g, c, c, g, those marked g being 90 de- 
 grees apart. Take two brass disks 4 inches in diam- 
 eter I inch thick, with a ^-inch boss 1 J inches in diam- 
 eter on one side, as shown by Fig. 256, which may be 
 obtained from any model making establishment, and 
 drill through the center a J-inch hole, indicated by 
 dotted line in the sketch. Clamp on the smooth side 
 of one of these disks the fiber ring that has been scribed, 
 letting the marked face come uppermost, and drill 
 four ^-inch holes at the points marked g, r/, g, g, on the 
 
^84 HOME MECHANICS FOE AMATEURS 
 
 face of the ring, through both the ring and the brass 
 disk. Next mount on a f-iueh mandrel a bhick of 
 wood 2^ inches thick and hirge enough to permit turn- 
 ing it down to a roller 3 inches in diameter; iustead of 
 turning it to measurement, however, uuike it fit snugly 
 into the interior of the iron and fibre rings. When this 
 block is turned to size, thread on one end of the mandrel 
 tlie brass disk that has only a central hole, next put the 
 unnuirked fiber disk on the wooden block, doAvn to the 
 brass disk, and follow with the iron rings, i:>utting on 
 last the fiber ring that has been drilled and then thread- 
 ing on the mandrel the brass disk that was also drilled 
 with the fiber disk. Turn the disk so that the holes 
 near its edge agree with those in the fiber ring under 
 it and compress the whole arrangement with clamps. 
 If there are so many iron disks that the fiber ring 
 cannot be drawn down oyer the end of the wooden cen- 
 tering block, take off enough to let this be done, as it 
 is imperatiye that all the rings and disks should be 
 accurately centered with each other. Then drill ^-incli 
 holes through the whole mass, entering the drill in the 
 holes already bored in the top brass disk and fiber ring. 
 These four ^-inch holes are for tie-bolts to hold the 
 armature core together. 
 
 When the drilling is finished, punch-mark each brass 
 disk and fiber ring near one of the :^-inch holes (the 
 same one in each case, of course), remove the clamps 
 and the brass and fiber loieces, run a wire through the 
 hole in the iron rings corresponding to the one marked 
 on the fibers and disks and tie them loosely together 
 until time to assemble the core. Then clamp the two 
 fiber rings together, with the marked holes in align- 
 ment, and drill through both rings a tV inch hole at 
 
HOME MECHANICS FOE AMATEURS 285 
 
 each point marked e^ leaving each ring as shown by 
 Fig. 257. 
 
 Next cut out of hard wood twenty-four trapezoidal 
 blocks (Fig. 258) f inch thick, f inch wide at one end, 
 -J inch wide at the other, and ^ inch long. In the 
 center of sixteen of these drill a iV iuch hole; in the 
 center of the other eight drill a j-inch hole. Pin the 
 sixteen trapezoids having small holes to the faces of 
 the two fiber rings, putting the pins through from the 
 back through the tV inch holes in the rings; the pins, 
 which must be of brass, should be a tight driving fit so 
 that the trapezoids will not tend to slip off, and the 
 faces of the latter should be coated with shellac varnish 
 to prevent their turning on the pins. 
 
 The tie-bolts, mentioned above, are of brass, fV inch 
 in diameter and 3f inches long, threaded at each end 
 for a distance of re inch. They must be insulated where 
 they pass through the core by wrapping paper on 
 them, gluing each layer and putting on enough to 
 make the insulated portion fit snugly in the ^-inch holes 
 drilled through the rings. Cut a strip of manila paper 
 2^ inches wide and wrap it tightly on the bolt, leaving 
 an equal length of uncovered metal at each end. When 
 the right thickness of insulation is obtained, drill two 
 tV inch holes in the bolt, exactly 2t6 inches from center 
 to center, and equal distances from each end (this dis- 
 tance, if the bolt has been accurately cut to the length 
 specified, will, of course, be || inch). Two nuts must 
 be also provided for each bolt, and two steel pins which 
 are driving fits in thexV inch holes,and slightly tapered. 
 One of these tie-rods, without its nuts and pins, is 
 shown by Fig. 259. 
 
 Then assemble the armature core on its woodeji cen- 
 
286 
 
 HOME MECHANICS FOR AMATEURS 
 
 tering block, using enough iron disks to make the iron 
 part measure 1| inches in thickness when compressed 
 and being careful to ha^e those of the J-inch holes that 
 were marked on the fibre pieces come in line with the 
 hole through which the wire holding the iron disks 
 together was run. Leave off the brass disks for the 
 present. Through each ^-inch hole put a tie-rod, clamp- 
 ing the structure until the steel pins can be put in the 
 holes in the tie-rods; enough iron disks should be put 
 in to prevent any looseness when the clamps are re- 
 moved. Fig. 260 shows the complete structure. After 
 
 Fig. 260. 
 
 Armature Ready for 
 Winding. 
 
 Fig. 261. Fig. 262. 
 
 The Slitted Tube for Commutator. 
 
 the tie-rods are pinned in place the remaining trape- 
 zoids are put on over the ends of the rods; a little 
 groove will have to be cut in the back of the trapezoid 
 to accommodate the steel pin in the end of the tie-rod. 
 The commutator comes next, and while it Avould be 
 advisable to buy a complete commutator, a very serv- 
 iceable one can be made with proper care in following 
 out the instructions given. If the l)ui]der prefers to 
 buy the commutator, tlie dimensions accompanying the 
 order must l)e tlu^se : Diameter of brush surface, 1 
 inch; length along the shaft, li inches; number of 
 
HOME MECHAXICS FOR AMATEURS 287 
 
 segments, 12. If the commutator is to be built along 
 with the rest of the machine, proceed as follows : 
 
 Take a piece of brass tubing, 1 inch in diameter out- 
 side, Avitli a wall about I inch thick, and measuring 
 2^ inches long. Slit it at twelve equidistant jwints 
 for a distance of 1| inches from one end, as shown by 
 Fig. 261, and insert the unslitted portion in a hole in a 
 block of wood that just fits the tubing; the block 
 should be 1 inch thick and nailed to a bench or other 
 support. Then bend outwardly the narrow strips made 
 by slitting the tubing until it looks like Fig. 263; the 
 wings should be brought to a right angle with the body 
 of the tubing not slitted, and hammered out flat. 
 Number the ^Svings" by means of punch marks, from 
 one up to twelve, and then carry the slits along the 
 length of the uncut portion of the tube, cutting it up 
 into twelve pieces like Fig. 264. Next turn up two 
 rings of vulcanized fiber 2 inches in diameter outside, 
 1 inch in diameter inside and } inch thick, and fit 
 around the circumference of each twelve steel screws, 
 ^ inch in diameter and f inch long over all, without 
 heads, as shown bv Fig. 265,. the screw-holes being car- 
 ried clear through so that the point of the screw may 
 emerge on the inside of the ring. Tut thirty-six strips 
 of oil paper (the kind used Avith copying books to pro- 
 tect the leaves from moisture) ^V in<'li thick, | inch 
 wide, and H inches long. Assemble the pieces of the 
 commutator in numerical order within the two fiber 
 rings, one ring at tlie wing end and one at the other 
 end of the tubular part, put three slips of oil paper be- 
 tween each x^air of neighboring pieces of tube, and 
 draw the segments toward the center by means of the 
 little screws until the oil paper slips are clamped so 
 
288 
 
 HOME MECHANICS FOH AMATEURS 
 
 tightly between the brass segments that they cannot be 
 pnlled ont with the fingers. In order to have the com- 
 mutator come together and form an api)roximately 
 true circle, a saw blade sV inch thick should be used in 
 cutting the segments out of the tube. Then by judi- 
 
 FiG. 264. One Segment. 
 
 Fig. 263. 
 
 Commutator Tube Before it is 
 
 Cut into Segments. 
 
 Fig. 265. 
 Fiber Ring with Screws. 
 
 Fig. 266. 
 The Commutator. 
 
 cious setting up on the screws the surface can be 
 brought sufficiently near to a true circle as to require 
 no truing up in the lathe. The protruding edges of 
 the oil-paper slips can be cut off even with the brass 
 with a sharp knife. 
 
 The core of the commutator may be made of wood; 
 
HOME MECHANICS FOR AMATEURS 289 
 
 mount a block ou a f-incli mandrel and turn it up to 
 the exact diameter of the interior of the commutator ; 
 then taper it slightly so that it will pass through the 
 commutator before binding, and drive it home as tight 
 as possible without straining the fiber rings that hold 
 the segments. Cut off the block ^ inch beyond the 
 wing end of the commutator and flush Avith the other 
 end. The complete commutator is shown by Fig. 266. 
 
 The next piece of machine work is the shaft, shown 
 by Fig. 267. It is turned up from a piece of |-inch bar 
 steel 10 J inches long. The dimensions are as follows : 
 A^ f inch diameter, 2tV inch long; B^ f inch di- 
 ameter, 1^ inches long; C^ J inch diameter, 3'^ inches 
 long; Z), f inch diameter, 3 A inches long. Last in the 
 list of machine work on the motor proper are the brush 
 holders, one of which is shown by Fig. 268, the drawing 
 showing two views. The holder is a piece of brass 
 tubing, ^ inch internal diameter and 1| inches long', 
 mounted on a piece of strip brass f inch wide and A 
 inch thick, the other end of which is bent into a loop, 
 as shown, and provided with an insulating bushing, t^ 
 of T6 inch fiber. The internal diameter of the bushing- 
 is a trifle over an inch when the clamping screw is 
 loose, and the diameter of the loop in the brass strip is, 
 therefore, 1^ inch maximum. This loop is intended to 
 fit around one of the distance pieces, z, Fig. 254, from 
 which it is insulated by the bushing, t. 
 
 The brush is a piece of round carbon, ^ inch in di- 
 ameter and 1 inch long; it should fit snugly within the 
 tube forming the holder, and a spiral spring, f inch 
 in diameter, made of No. 16 brass wire, must be pro- 
 vided to force the brush outwardly on to the com- 
 mutator. One brush holder is attached to the lower 
 
290 HOME MECHAISTICS FOR AMATEURS 
 
 left-hand distance-piece, c^, and the other to the upper 
 right-hand piece, the tubular part of the holder set- 
 ting verticalh^, between the magnet poles, with its in- 
 ner end not more than i inch from the surface of the 
 commutator. Electrical connection is made Avith the 
 brush arm by means of a piece of flexible cord, such 
 as is used in hanging incandescent lamps, one end of 
 the cord being soldered to a copper Avasher, which is 
 clamped under the head of the screw on the brush arm. 
 This cord is known as No. 18 cotton-covered lamp- 
 cord, and may be procured from any dealer. It should 
 be untwisted and one length used on each brush holder ; 
 the cord need not be more than 6 inches long. 
 
 We are now ready to wind the magnet and armature 
 cores. The armature core must first be covered all 
 around the outside surface with muslin; cut a strip 2 
 inches Avide and 25 inches long and, after varnishing 
 the periphery of the core with shellac, wind on this 
 muslin strip, being sure that it is tightly wound. If it 
 is pulled tight, it will make two layers; Avhen the 
 strip has been carried once around, varnish the surface 
 of what is on the core, and then wind on the other 
 layer of muslin. Then varnish the Avhole outside sur- 
 face. Cut out 24 strips of oil paper, each lye" inches 
 wide and 2 inches long, and bend up the edges, making 
 the crease ^ inch from each edge, so as to form shall oav 
 troughs the Avidth of AAiiich will be the same as the 
 space betAveen the trapezoids on the end of the core; 
 apply two of the troughs to the inside and outside 
 circles of the core, as shoAvn in Fig. 270, and tie them in 
 place with No. 40 or No. 50 scAAing cotton, one strand 
 at each side of the trough. Then wind on an old cot- 
 ton-spool 68 feet of No. 26 double cotton-covered mag- 
 
HOME MECHANICS FOR AMATEUES 
 
 291 
 
 net Avirc, hook the outer end around one trapezoid, as 
 in Fig. 271, and Avind into the wiring space between 
 this trapezoid and its right-hand neighbor a coil the 
 full width of the space, which should take 26 turns in 
 
 A 
 
 B 
 
 I — 
 
 
 Fig. 267. The Shaft. 
 
 width, putting five layers in, or 130 turns, to each coil. 
 When the first coil is done twist to the final end the 
 beginning end of the wire which is to wind the next 
 coil, and proceed with that one in the same way. Care 
 must be observed to put exactly the same number of 
 turns in each coil and to twist the ending of each coil 
 to the beginning of its neighbor on the right. When 
 the armature is wound, put on the brass disks that 
 were left off when the core was assembled, threading 
 the tie-rods through the holes near the edoes of the 
 
 Figs. 268 and 269. 
 Brush Holders. 
 
 Fig. 270. 
 
 Section Prepared for 
 Winding. 
 
 Fig. 271. 
 
 Beginning the 
 Winding. 
 
 disks, and putting the boss on each disk outside; clamp 
 the disks hard against the wooden trapezoids by means 
 of nuts on the tie-rods. The holes in the disks must 
 be bushed with little pieces of fiber tubing and a fiber 
 
g92 HOME MECHANICS FOE AMATEUES 
 
 washer must go under each nut, in order to insulate 
 the tie-rods from the disks; otherwise the armature 
 would run destructively hot. 
 
 Insert the shaft in the center of the structure, letting 
 that part marked B in Fig. 267 come on the side where 
 the ends of the armature winding are, and pin the 
 brass disks to the shaft through the bosses. The com- 
 mutator goes on the part of the shaft just referred to, 
 and it should be a driving fit, so as to obviate pinning 
 or keying it to the shaft. Then connect up the ends 
 of the armature coils to the lugs of the commutator, 
 leading each end straight out, parallel with the shaft, 
 to the nearest lug. If the ends were twisted together 
 in accordance with the directions, the result will be 
 as shown diagrammatically by Fig. 272. 
 
 Prepare for winding the magnet coils by making a 
 winding bobbin as follows : On a piece of board an 
 inch thick and 4 inches square lay out a square meas- 
 uring If inches on a side, the scribed square being 
 symmetrical with the edges of the board; clamp an- 
 other similar piece of board to the one marked, and at 
 the corners of the scribed square drill |-inch holes 
 through both boards; in the center of the square drill 
 a ^-inch hole. Then make a mandrel of ^-inch round 
 iron, the central part being full diameter and 2J 
 inches long, and the ends being turned down to pass 
 through the central hole in the board. Mount the 
 boards on the ends of the mandrel and run |-inch iron 
 rods through the corner holes, forming a sort of reel, 
 as shown by Fig. 273. Jam the boards against the 
 shoulders of the mandrel by means of lathe dogs on 
 the outer ends of the latter, and drive a nail in the 
 face of each board so that the dog will drive the board 
 
HOME MECHANICS FOR AMATEURS 293 
 
 without slip. The dogs must be so adjusted, of course, 
 as to drive both boards iu their proper augular posi- 
 tions, maintaining the parallelism between the ^-inch 
 rods and the mandrel that is necessary to form a per- 
 fect coil. 
 
 Mount this winding frame in the lathe and wind a 
 coil on it of No. 21 double cotton-covered magnet wire, 
 putting as many turns as possible (it should take sixt}^- 
 six) between the faces of the wooden blocks and mak- 
 ing the coil twenty-seven layers deep. The starting- 
 end may be secured to the projecting end of one of the 
 |-inch rods to give the necessary tension to the first 
 
 Fig. 272. Fig. 273. 
 
 The Winding. Reel for Winding Field 
 
 Magnet Coils. 
 
 layer of wire, and at least a foot of the starting end 
 should be left free. When the coil is finished, tie it at 
 each of the four corners with strong linen thread, 
 bending the final end sharply backward over one of 
 these corner threads to keep the top layer snug; take 
 the winding frame apart and varnish the coil all over 
 with shellac, setting it aside to dry while the second 
 coil is wound. This is exactly like the one already 
 wound. 
 
 Then take the journal yokes and their bolts and 
 distance pieces off the magnet and wrap the magnet 
 limbs with muslin from ^ inch above the bolt holes 
 up to the bend, putting two layers on each limb and 
 
294 HOME MECHANICS FOE AMATEURS 
 
 varnishing it on the outside of each layer. When this 
 is dry, turn the magnet upside down, thread on each 
 limb a fiber washer 3f inches square and i inch thick, 
 the hole in the Avasher fitting the magnet limb snugly ; 
 varnish the faces of the washers now uppermost and 
 slip the coils on the limbs down on the washers while 
 the varnish is wet, so that the latter will stick to the 
 coils. In putting on the coils, see that the beginning 
 end of each coil goes on first, so that when the machine 
 is set right side up the final end of each coil will be 
 nearest the armature. Follow each coil Avith another 
 fiber w^asher like those first put on the magnet, and 
 then reassemble the journal yokes and distance pieces 
 on the magnet, this time putting in the armature as you 
 go along and also putting on the brush holders and 
 brushes. The holders should be so adjusted that the 
 ends of the brush tubes are tV to ^ inch away from the 
 surface of the commutator. 
 
 The free ends of the magnet coils nearest the arma- 
 ture are connected to the brushes by means of flexible 
 lamp cord, as described in the instructions for making 
 the brush holders, the end of the flexible cord being 
 soldered to the end of the magnet wire close up to the 
 coil. Th upper ends of the magnet coils go to the ter- 
 minal block, which is a block of wood, 1 J inches square 
 and 4 inches long, bolted on the top of the magnet 
 yoke, and carrying two binding posts, which form the 
 terminals of the machine. The motor is bolted to the 
 table of the sewing machine, with one leg right on the 
 edge of the table and in such position that the pulley 
 of the motor, which must go on the end of the shaft 
 away from the commutator, is in line with the belt 
 pulley of the machine. The motor pulley should be 
 
HOME MECHANICS FOR AMATEUES 
 
 295 
 
 one-half the diameter of the pulley on the sewing ma- 
 chine, and be of the same width and depth of groove. 
 
 The regulator is shown by Figs. 274 and 275, the 
 former being the front view and the latter the back. 
 Referring to Fig. 274, A is a wooden arm, 9^ inches 
 long, I inch thick, and tapering from ^ inch to 1^ inches 
 in width. The narrow end is faced with a thin strip of 
 copper to make contact with the buttons, c^ which are 
 simple brass bolts with flat heads; the wide end of the 
 wooden arm is split to straddle the shaft, to which it is 
 pinned as well as clamped. L is the lever controlling 
 
 Fig. 274. 
 Regulator — Front View. 
 
 Fig. 275. 
 Regulator — Back View. 
 
 the arm, .4; it is made of |-inch round iron rod, bent 
 to form a right angle; the lever portion is 6 inches 
 long; the length of the horizontal portion on which 
 the lever. A, is mounted is the same as the width of 
 the sewing machine table on which the motor is to be 
 used. The back end of the shaft is journaled in the 
 base board, C,, and the front part in a wooden bearing, 
 B, which is bolted to the under side of the sewing ma- 
 chine table between the narrow drawer and the pan. 
 The baseboard, C^ is 6 inches wide (vertically) and 40J 
 inches long. It is fastened to the under side of the ma- 
 chine table, flush with the back edge. The lever, L, is 
 to be moved by the right knee of the machine operator. 
 
296 HOME MECHANICS FOE AMATEURS 
 
 The arm, A^ is normany held in its highest position 
 bv the coil spring shown, in which position the current 
 is cut oft the motor entirel}^ The contact buttons, Cy 
 are -J inch in diameter; the bolts of which they are 
 the heads are A inch in diameter and long enough to 
 protrude | inch on the reverse side of the base board. 
 This side is shown by Fig. 275. The resistance coils 
 consist of German silver wire, No. 20 B. and S. gauge, 
 wound into coils on a f-incli rod (the rod being re- 
 moved, of course, Avhen the coil is formed). The piece 
 of wire forming the upper coil should be 100 feet long; 
 the next coils contain 90, 80, 70, 60 and 50 feet of wire, 
 respectively, in the order named. The binding posts, 
 Tt and Toy are connected as shown, the connection be- 
 tween Ti and the iron shaft being made by means of 
 flexible cord which will follow the movements of the 
 shaft. On the front the shaft is connected to the cop- 
 per facing at the small end of the arm. A, by means of 
 No. 16 copper Avire. All the connections on the back 
 are made with No. 16 copper wire, preferably but not 
 necessarily insulated. 
 
 The back surface of the base board must be covered 
 with a sheet of asbestos over a thin sheet of fiber. The 
 ends of the resistance coils are twisted together and 
 soldered, and the connecting wires should be soldered 
 on at the same time. The coils are held on ordinary 
 porcelain knobs, fastened to the board by Avood screAvs. 
 The connecting wires should be bent into loops AA^here 
 they connect Avith the bolts, c^ and a copper Avasher 
 should go under each nut and on top of the loop of the 
 connecting Avire. 
 
 The connections betAveen the motor and the regulator 
 and the source of current supply are as folloAvs : From 
 
HOME MECHA^TICS FOR AMATEURS 297 
 
 T^ to one binding post on the motor, from T. to one side 
 of the supply circuit, and from the other binding post 
 on the motor to the other side of the supply circuit. 
 
 The motor above described will run satisfactorily on 
 any direct-current incandescent lamp-circuit of 100 to 
 120 volts pressure. If it is desired to build the ma- 
 chine for use in connection with a battery, the windings 
 will have to be changed as follows : Armature coils. 
 No. 13 wire, 8 turns wide and 1 deep, each coil; field 
 magnet coils. No. 8 wire, 5 layers deep, 18 turns per 
 layer, each coil ; regular. No. 13 wire, the coils having 
 one-tenth the number of feet specified above. 
 
 The battery to run such a motor must give 8 volts 
 and from 10 to 20 amperes, according to the load on the 
 motor ; consequently four cells will be required. 
 
 Should the reader desire to build a standard shunt- 
 wound motor of i horse power instead of the series- 
 wound type specified, the same frame may be used, 
 the onlv variation beino^ in the manner of windins:. 
 In order to wind the machine as a i horse power mo- 
 tor, to work on a 110 volt circuit, the armature coils 
 must consist of No. 27 wire, double cotton-covered, 
 each coil being 9 layers deep and 28 turns in width — 
 252 turns, total, per coil. The magnet coils will con- 
 sist of No. 25 wire wound to a depth of 39 layers, with 
 as many turns lengthwise as can be got in the space of 
 2^ inches allotted for the coil length; with careful 
 winding, 92 turns can be put in each layer, giving each 
 magnet coil a total of 3,588 turns. 
 
 In order to change the design into a \ horse power 
 motor, the magnet must be made of iron 2^ inches 
 square, instead of IJ inches, and the armature, shaft, 
 journal-yoke bolts, etc., must be made exactly 1 inch 
 
2^8 HOME MECHANICS FOE AMATEURS 
 
 longer, axiallj, than the above measurements specify. 
 The windings will be No. 24 wire on the armature, each 
 coil 5 layers deep and 21 turns wide ; No. 22 wire on the 
 magnet, each coil being 37 layers deep and 74 turns 
 long (or as many as the 2^ inch space will take). 
 The number of armature coils and all other data not 
 specified in this paragraph Avill remain precisely as in 
 the original instructions above. 
 
 A DESIGN FOR AN ELECTRIC LAUNCH MOTOR 
 
 For the propulsion of an electric launch a motor 
 must unite elements of efficiency, compactness, and 
 strength to a degree scarcely necessary in any other 
 situation. The design given here is for a motor of un- 
 usual simplicity of construction, which can easily be 
 built by an amateur at small cost. It is intended for 
 a boat of about 24 feet over all and 4 feet 6 inches 
 beam, drawing 18 inches, and is capable of propelling 
 such a craft at a speed of 7 miles per hour. Gearing of 
 all sorts has been dispensed Avith, the motor being 
 adapted for direct attachment to the propeller shaft. 
 While the description below refers primarily to a motor 
 for a craft of tliis size, dimensions are also given for 
 the construction of motors for smaller launches. 
 
 Without going into the details of calculation, it may 
 be stated that for such a boat the most efficient service 
 will be had from a four-bladed screw, about 14 inches 
 in diameter, 12 inches pitch, 35 per cent, blade area 
 (by which is meant with blades having a total project- 
 ed area equal to 35 per cent, of that of a 14-inch disk). 
 
HOME MECHANICS FOR AMATEURS 299 
 
 ui 
 
 S3 
 
 'So 
 
 d 
 o 
 
300 HOME MECHANICS FOE AMATEUES 
 
 rimuing' at 880 revolutions per minute. Such a screw 
 will absorb about 4 horse power. No very definite fig- 
 ures of speeds and powers can be given, as these de- 
 pend very largely upon the shape of the boat, its full- 
 ness fore and aft, the moulding of the runs, etc. The 
 motor described below will give a speed of 7 miles per 
 hour to a rather full-modeled boat of the size indicated, 
 when fully loaded to a displacement of 5,000 pounds. 
 This means, assuming that the boat itself weighs about 
 1,000 pounds, a carrying capacity for about ten or 
 twelve passengers. 
 
 The storage battery consists of 24 elements, arranged 
 in two series of 12 cells each, each cell being of about 
 80 pounds weight. These cells contains 13 plates each, 
 about 7f inches square, and are about 7^x8^ inches 
 square by 11 inches in height, these measurements be- 
 ing outside of the rubber containing jars. They should 
 be mounted in two Avooden boxes, about 8^ inches 
 wide by 11 inches deep inside and about 7 feet 6 inches 
 long. These make convenient seats in the boat, and 
 their lids may be covered with cushions. They should 
 be placed side by side amidships, as low as possible 
 and a little forward of the center of gravity of the boat 
 to compensate for the weight of the motor, which is 
 installed well aft. Such cells may be bought from 
 any one of several well-known American makers of 
 accumulators. Elements in glass jars should not be 
 used, on account of the danger of breakage. 
 
 For the smaller sizes of motor described below, or, in 
 other words, for smaller boats of the same general 
 type, the number of cells remains the same, but their 
 size may be proportionately reduced. With cells of 
 the same type, having plates of the size given, a 3 horse 
 
HOME MECHANICS FOR AMATEURS 301 
 
 ])()\\ er boat will require those having 9 plates and a 2 
 horse power boat those having 7 plates. 
 
 Terminals for charging should be attached to the 
 boxes containing the cells. It is by all odds the best 
 plan to charge the cells in the boat, and not to at- 
 tempt to remove them for this purpose. 
 
 The capacity of these outfits on one charge is about 
 3 hours' run at full speed, or about 7 hours' run at 
 about 4^ miles per hour, thus giving the boat in each 
 case a cruising radius of about 30 miles. If a larger 
 
 Figs. 277 and 278. Section of Coupling. 
 
 cruising radius is desired, it may be attained by the 
 use of larger cells, but, as these are heavier, their use 
 means a corresponding decrease in the passenger carry- 
 ing capacity of the boat. 
 
 The motor illustrated herewith is of a four-pole in- 
 closed type, waterproof and intended to be attached 
 directly to the screw shaft. Some form of flexible 
 coupling is recommended, that shown in Figs. 277 and 
 278 being very simple and easily made. It consists of 
 two cast iron flanges, the larger about 12 inches in dia- 
 meter for the motor to be described and proportion- 
 
302 HOME MECHANICS FOE AMATEUES 
 
 ately smaller for the smaller motors. These flanges are 
 mounted, one on the motor shaft and the other on the 
 propeller shaft, so that the smaller runs inside the 
 larger, with a clearance of about 1 inch all round. 
 
 In the cylindrical surfaces of each are cut eight win- 
 dows, the edges of which are rounded off as shown in 
 Fig. 278. Through these windows a piece of cotton 
 belting, 1 inch wide, is laced as indicated in the figure, 
 its ends being cemented together. The whole forms an 
 inexpensive and satisfactory coupling, which will 
 largely prevent any strain of the shaft due to the flex- 
 ure of the boat under loads in a seaway. 
 
 A thrust bearing, to take up the forward thrust of 
 the screw shaft, is also necessary. A simple and satis- 
 factory type is illustrated in Figs. 279, 280 and 281. 
 Upon the screw shaft are mounted four steel collars, 
 each about three times the diameter of the shaft and 
 about 1 inch thick. These are provided with set 
 screws. A cast iron box contains the brasses against 
 which these collars Avork. This box, it must be re- 
 membered, receives the whole forward thrust of the 
 screw, and must not only be made strong enough to re- 
 sist this, but also arranged to communicate the pres- 
 sure to the frame of the boat. A good plan for mount- 
 ing it is to place in the bottom of the boat a stout tim- 
 ber, long enough to l)e screwed to several of the after 
 frames, and arrange the thrust bearing with lugs for 
 four or six lag screws so that it may be securely at- 
 tached to this. In the size of boat described above, at 
 full speed, the forward push of the screw will be about 
 220 pounds, but in a sea, or if there is any obstruction 
 in the way, this may be easily doubled. 
 
 The box frame of the thrust block, as the illustra- 
 
HOME MECHANICS FOR AMATEUES 
 
 303 
 
 tions very clearlj^ show, is grooved to receive three 
 horseshoe shaped brasses, each about au inch thick. 
 These straddle the shaft between the collars, Avhich are 
 adjusted to bear equally on the brasses. The box is filled 
 with oil to a level so that the collars run in it, con- 
 stantly lubricating the bearing surfaces of the collars 
 
 J^ 
 
 M 
 
 w 
 
 Figs. 279, 280, 281. 
 Elevation, Plan, and Cross Section of Thrust Bearing. 
 
 and brasses. If one of the brasses heats, it may be 
 lifted out and turned around or replaced with another 
 without stopping the boat. A light hinged cover com- 
 pletes the thrust block. For the smaller sizes of motors 
 indicated three collars on the shaft and two brasses 
 will be sufficient. 
 
 The shell of the motor, Figs. 282 and 283 is a cylin- 
 
304 HOME MECHAXICS FOR AMATEURS 
 
 (Irical iron casting carrying the four polar projections, 
 A. It is shown in the drawings with a perfectly plain 
 exterior, but it should be provided Avith feet. These 
 are not shown in the drawing, as they should be made 
 to fit the shape of the hull. 
 
 At each end of the heavy field ring is a cylindrical 
 projection, Cy stiffened with four columnar ribs, R^ to 
 receive the cap screws which fasten on the end plate. 
 The field casting may be finished on the lathe in two 
 operations. It should be chucked and the field bored 
 out to a diameter of exactly Gre inches. Upon the ac- 
 curate boring of the field and turning of the armature, 
 or, in other words, upon keeping the air spaces as small 
 as possible, will depend much of the satisfactory per- 
 formance of the motor. 
 
 The end surfaces for the reception of the end plates 
 are trued off at the same time the field is bored, and 
 the seat, aS*^ for the brush holder ring, B^ is also turned. 
 There is no necessity for any finish on the exterior of 
 the field cylinder or any other machine work upon it 
 except drilling and tapping four holes in each end to 
 take the cap screws holding on the end plates. After 
 the field is bored all sharp edges and corners left on the 
 polar projections should be neatly rounded off with a 
 file. 
 
 The two end plates are exactly alike, each carrying 
 a bearing IJ inches in diameter by 3 inches long for 
 the armature shaft. They should be cast of bronze or 
 gun metal, and need not be more than ^ inch thick. 
 In the one at the commutator end four windows should 
 be cut, opposite the normal position of the brushes, so 
 that these may be observed while the machine is run- 
 ning. 
 
HOME MECHANICS FOR AMATEUES 305 
 
 W77r///77777. 
 
 1 
 
 D 
 
 ^ 
 
 m^fmmm^m m^m 
 
 
 Figs. 282 and 283. Longitudinal and Cross Sections of 
 Motor Shell. 
 
306 HOME MECHANICS FOR AMATEURS 
 
 The brush holder ring, B, Figs. 283 and 285, is of 
 brass or bronze, 9^ inches outside diameter and i inch 
 thick. It carries the four brush holders, one of which 
 is shown in section in Fig. 285 and in elevation in 
 Fig. 2S6. Any design of radial brush holder may be 
 used, but the simple form shown is easy to make and 
 very satisfactory. The body of it consists of a brass 
 box, cast in one piece with the stud going through the 
 ring, B. This is finished out to allow the coppered 
 carbon brush, IJxlfxf inches in size, to slide easily 
 through it. A forked piece straddling the upper cor- 
 ner of this box carries a finger Avhich is pressed upon 
 the butt of the brush by the steel spring and thumb 
 screw arrangement shown. 
 
 The dimensions of the shaft are clearly indicated in 
 the drawing. The commutator is by far best bought, 
 though the drawing furnishes a sufficient indication of 
 a simple form to enable an amateur to make it him- 
 self if he so desire. It has 48 segments and should be 
 4 inches in diameter, 2 inches face, and bored for a IJ 
 inch shaft. 
 
 The core of the armature is 6 inches diameter and 8 
 inches long. The end plates of steel, -} inch thick, hold 
 together the mass of soft iron disks of which it is com- 
 posed. These should be a little larger than 6 inches 
 diameter in the rough, as the core must finish exactly 
 to this figure. If it comes out a little small, the field 
 bore, which should wait upon the construction of the 
 armature, must be made as nearly as possible A inch 
 larger. 
 
 It is useless to japan or insulate the disks. Put 
 them together as they are, tighten up the nut, N, Fig. 
 285, on the shaft and pin it in place. Then true off the 
 
HOME MECHANICS FOR AMATEURS 307 
 
 surface in the lathe by very light cuts with a sharp tool 
 at rather high speed, using an abundance of soapy 
 water on the tool. A mirror-like surface may be at- 
 tained in this way. 
 
 While the armature is in the lathe it should be scored 
 for the binding wires which will hold the coils in place. 
 The grooves for these should be turned, each about 4 
 inch wide by a scant iV deep, one near each end and 
 one in the middle. 
 
 Fig. 285. Armature Core, Shaft, and Commutator. 
 
 The next operation is milling out the slots for the 
 winding. There are 48 of these, each i inch wide and 
 ^ inch deep, equidistantly spaced around the core. In 
 milling out armature slots, the tool should turn at a 
 fairly high speed, the feed be very slow and the cut 
 light, and an abundance of oil should be used. If no 
 milling machine is at hand, the slots may be planed, 
 great precaution being taken to keep the cut very light 
 indeed. 
 
 The best w^ay to line up the frame of the motor and 
 to be sure that the armature is properly centered in the 
 
308 HOME MECHAXICS FOR AMATEURS 
 
 field bore, is to wrap the armature core with one or two 
 layers of thin paper, until it fits neatly in the field 
 bore, put on the heads at the ends of the machine, and 
 cast Babbitt metal in the bushings. If the end plates 
 are marked so that they can be put back in the same 
 way, the armature will be found to be correctly cen- 
 tered. Unless this is done the electrical balance of the 
 motor will be disturbed, and the brushes will probably 
 spark and give trouble. 
 
 The winding to be described is of the sort known as 
 a four-pole lap winding, and is one of the simplest and 
 easiest to make of the various forms of interlocked 
 windings. Each of the forty-eight coils used is shaped 
 in the forming apparatus shown in Figs. 287, 288 and 
 289. This is in two parts, a frame for winding the 
 coils and a former for bending them. The frame is 
 simply a piece of board with two i inch round metal 
 pins driven in it, these being lOf inches apart, out to 
 out. Around these, as clearly shown in Figs. 288 and 
 289, are wound six turns of No. 14 B. & S. gauge double 
 cotton-covered wire, the starting end of the coil being 
 marked by twisting a loop in it, as shown in Fig. 289. 
 The ends of the wire should be left longer than the illus- 
 tration shows them, say about 6 inches. When this 
 coil is completed, it should be tied in at least four 
 places with small thread to keep it in position when it 
 is removed from the two pins, and it should be well 
 shellacked with rather thin varnish. It is extremely 
 advisable to make up at least five or six of the boards 
 shown in Figs. 282 and 283, as this enables the winder 
 to allow the coil to dry to the proper consistency of 
 "tackiness" before it is removed from the frame, and 
 also permits the coils to be made much more rapidly 
 
HOME MECHAOTCS FOR AMATEURS 
 
 309 
 
 than if it were necessary to wait each time for the wire 
 to dry out before winding the next. 
 
 The correct state of dryness of the shellac for the 
 next operation must be learned by experience. It is 
 when it is at its stickiest. When this condition is 
 reached, the coil is removed from the frame and placed 
 in the apparatus shown in Fig. 287 to be formed. This 
 machine is made of a wooden base board, on Avhich is 
 screwed a hard wood shaping piece of the dimensions 
 shown and about J inch thick. Two hinged pieces, as 
 shown, are provided, so that when the straight coil as 
 
 r^ 
 
 ^- 
 
 Fig. 286. 
 Brush Holder. 
 
 Figs. 287, 288, 289. 
 Board for Forming and Bending Coils. 
 
 it comes from the winding board is laid centrally upon 
 the forming piece, and both the hinged pieces bent 
 over, it will be bent into a form somewhat like a wide 
 inverted U. The illustration shows a coil of only one 
 layer being bent. There will be, of course, six wires in 
 each side of the coil, or twelve in all to be bent. 
 
 When this bending operation is completed, and be- 
 fore the shellac is finally hard, the bent coil must be 
 pulled apart so that six of its wires, those tied to- 
 gether on one side, may be laid in a slot of the armature, 
 and the remaininor six wires, formino: the other Ions: 
 
310 HOME MECHANICS FOE AMATEURS 
 
 straight side of the bent coil, laid in the slot 90 degrees 
 away. In other words, the coil, when it is put on the 
 armature, must reach from slot 1 to slot 13, assuming 
 that they are consecutively numbered. The appear- 
 ance of the finished coil, ready to put on the armature, 
 is indicated by Fig. 290. 
 
 A glance at Fig. 291, which shows the end of the arm- 
 ature partially wound, will make this clearer. The 
 
 Fig. 290. Completed Coils, Ready to be Mounted on Armature. 
 
 Fig. 291. End of Core, Showing Arrangement of Coils. 
 
 coils, if properly bent, will lie close together on the 
 heads of the armature and produce the very neat and 
 simple interlocked end arrangement shown in the il- 
 lustration. 
 
 When all the forty-eight coils are in place, the arma- 
 ture is ready for banding. In the shallow scores on 
 the surface are laid thin strips of mica, the armature 
 being in centers on the lathe for this operation, or 
 
HOME MECHANICS FOE AMATEURS 311 
 
 otherwise mounted so that it can be turned around. 
 It is better to catch the mica strips under a cord 
 wrapped around tlie core a few turns than to attempt 
 to stick them on with shellac. On the mica is Avound 
 the band, consisting of about No. 24 gauge German sil- 
 ver or hard brass wire wound under the strongest ten- 
 sion it will stand. The band should net be more than 
 Tg inch wide, the number of turns depending, of course, 
 on the gauge of the band wire. Above all, care must 
 be taken not to have this so large or the mica so thick 
 that the bands project above the armature surface, as 
 the clearance space is very small and the bands are 
 liable to injury in putting the armature in place or re- 
 moving it. 
 
 When the band wire is wound on, it is soldered wnth 
 five or six little dabs of solder, not continuously, and 
 the ends cut off. Three bands will be required, one 
 within about ^ inch of each end of the armature core 
 and the other at the middle. 
 
 The commutator is held from turning on the shaft 
 by a feather (not shown in the illustrations), and is 
 sufficientl}^ held endwise by the ninety-six Avires sol- 
 dered into it. To connect these, take the beginning 
 end of any coil, marked by the little loop twisted in it, 
 and solder it and the ending end of the next coil in 
 regular order, either way, into the slot in the tail of 
 the commutator bar nearest in line. Proceed around 
 the armature in this regular order, being very careful 
 to bring the ends out neatly and not to pull the head 
 of the winding to pieces in so doing. No acid should 
 be used as a flux in soldering commutator connections. 
 The only safe thing is rosin. A narrow edged solder- 
 ing iron that will go into the slot in the commutator 
 
312 HOME MECHANICS FOR AMATEUES 
 
 bar will be found very convenient for this work. It is 
 well to wind some tape around the inner hub of the 
 commutator before beginning the soldering. When it 
 is finished, a layer of stout cord should be wound on 
 over the bunch of ends going to the commutator to keep 
 these from spreading from centrifugal action when the 
 armature is running. These commutator connections, 
 ready for the cord wrapping, are shown in Fig. 292. 
 
 The armature is completed by being returned to the 
 lathe, where a light cut is taken over the commutator 
 
 Fig. 292. End of Completed Armature, Showing 
 Commutator Connections, 
 
 to true it and cut off any straggling wire ends. The 
 armature should be baked over night in an oven to 
 thoroughly dry it out before it is attempted to use it in 
 the motor. 
 
 On each of the four poles of the field is fastened, with 
 small brass angle x)ieces, as clearly shown in Figs. 282 
 and 283, a coii consisting of twenty-five turns of No. 
 6 B.& S. gauge wire, arranged in five layers of five turns 
 each. These coils are wound on a wooden former and 
 taped. Their inner ends should be marked in some 
 convenient way, and they should be connected to- 
 
HOME MECHAOTCS FOE AMATEUES 313 
 
 gether so that tliey magnetize the fields alternately 
 north and south when a current is sent through the 
 four in series. Calling them A^ By C, and D, this is 
 done thus : Bring out the outer end of .4 through a 
 hard rubber bushing in the commutator end plate (the 
 end plate at the commutator end of the motor), then 
 connect the inner end of A to the inner end of B, the 
 outer end of B to the outer end of C, the inner end of 
 C to the inner end of Z), and bring out the outer end of 
 D through another bushing. 
 
 Two other bushings are provided for bringing out 
 the ends of the wires to the brushes. The four brushes 
 are connected in two pairs, opposite brushes being con- 
 nected together and to one of the leading-out wires. 
 These connections should be made with No. 8 wire and 
 the leading-out wires should be No. 6 flexible rubber 
 insulated cable. 
 
 Should it be desired to construct motors of this type, 
 but of less power, the same general instructions should 
 be followed, the diameter of the armature and casing 
 being the same, but their lengths different. Below are 
 given dimensions and speeds for motors of two and 
 three horse power; where a dimension is not given, it 
 is the same as that described above for the motor of 
 four horse power. The slots for the three horse power 
 armature should be J inch wide and | inch deep; for 
 the two horse power armature, \ inch wide and tV inch 
 deep. 
 
 The motor now being complete, the next part of the 
 boat's equipment is the controller. The design sho^Vn 
 is exceedingly simple and easy to make. Referring to 
 Figs. 293, 294, and 295, which show it in section, 
 and Fig. 296, which is a diagram of its connections, its 
 
314 HOME MECHANICS FOE AMATEUES 
 
 construction and operation ^Yill be readil}^ understood. 
 It has been thought best not to complicate its con- 
 struction by attempting to combine the ahead and 
 astern controlling movements with those for speeds, so 
 two handles are provided, one giving half the full 
 speeds and the other for reversing the boat's direction. 
 These are, however, for convenience, mounted at the 
 two ends of the cylindrical case of the controller. The 
 best material for this is wood. It should be about 10 
 or 12 inches in diameter outside, and about 1 inch thick 
 
 ( 
 
 n 
 
 
 
 n 
 
 
 
 'U 
 
 u 
 
 Fig. 293. 
 
 Cross Section of Speed End 
 
 of Controller. 
 
 Fig. 294. 
 
 Longitudinal Cross Section 
 
 of Controller. 
 
 by about 9 or 10 inches long, and is conveniently built 
 up in the way described above for the pattern for the 
 field casting. It should be of wood on account of the 
 insulating properties of that material. 
 
 In this wooden cylinder are mounted two wooden 
 disks, about an inch less in diameter than the internal 
 measurement of the containing cylinder. These two 
 disks are turned by the two handles — the speed and 
 direction handles — and carry on their surfaces copper 
 
HOME MECHANICS FOR AMATEUHS 315 
 
 sectors which are set into the Avood so as to leave a 
 smootli surface for rimning imder the connecting 
 points. These are well shown in cross section in Fig. 
 298, which is a partial cross section of the speed con- 
 trolling end of the apparatus. They consist of brass 
 tubes about 1 inch in diameter, 4 inches long, and tV 
 inch thick, containing a spring and a contact piece 
 (brass or copper), fitting the tube neatly and pressed 
 by the spring into contact with the surface of the disk. 
 Nine of them will be required. 
 
 Fig. 295. Cross Section of Reversing End of Controller. 
 
 At the speed control end of the apparatus the turning 
 disk carries two short sectors on opposite sides, these 
 being connected together as shown, and two longer sec- 
 tors extending through about 80 degrees of the cir- 
 cumference. These are also folded over on to the back 
 of the disk, as shown by dotted lines in Fig. 286, so that 
 two of the spring contacts may also bear upon this sur- 
 face. The easiest way to make these sectors is to cut 
 the parts out of tV inch sheet copper, and mount them 
 
316 HOME MECHANICS FOE AMATEURS 
 
 on the Avood with small countersunk wood screws. 
 The circumferential and flat parts of the sectors last 
 described may well be soldered together after they are 
 in place on the disk. In all cases the sector should be 
 let into the wood so that there will be no shoulder to 
 catch against the spring contact when the disk is 
 turned. 
 
 At the speed control end of the apparatus four of the 
 spring contact tubes are mounted, bearing upon the 
 edge of the disk as shown ; the four being in opposite 
 pairs 60 degrees apart. In the interior of the c^din- 
 drical case of the controller are two partitions as 
 shown in Fig. 294, the one nearest the speed control 
 disk just described carrying two of the spring contacts 
 bearing on the flat sectors as shown by the dotted lines 
 in Fig. 293. These bear at points on the same diameter 
 connecting two of the edge bearing contacts. 
 
 At the other end of the controller is mounted the 
 mechanism for reyersing, which is shown in partial 
 section in Fig. 295. This consists also of a disk carry- 
 ing on its edge three sectors, two of them only long 
 enough to be entirely in contact with the spring con- 
 tacts as shown, and the other long enough to bridge 
 two of them, about fifty degrees. Three of the spring 
 contacts are mounted bearing on these, 30 degree? 
 apart. The long sector is connected to the further of 
 the two short ones, while the middle sector is connected 
 to the piyot of the disk and thus to the bushing in which 
 it turns. As Fig. 294 shows, this is made quite long, 
 as this contact has to carry large currents. It should 
 not be less than three inches long, the piyot being a 
 piece of one inch shafting. 
 
 Eeferring now to Fig. 296, the operations of the con- 
 
HOME MECHANICS FOR AMATEURS 
 
 317 
 
 troller will be easily understood. It shows the connec- 
 tions for half speed ahead. The diagram shows the 
 two sides of the controller separated, for the sake of 
 clearness, but it is, of course, understood that they are 
 no further apart than the two ends of the wooden box 
 in which they operate. The fuse shown in the circuit 
 between the pivot of the reversing controller and the 
 inner spring contact is mounted in the middle division 
 of the box, which should have a door for access. It 
 should be an ordinary single-pole Dorcelain fuse block 
 
 Fig. 296. Diagram of Controller Connections. 
 
 carrying a fuse blowing at about 75 amperes. For 
 the 3 horse power motor it should blow at 60 amperes, 
 and at 40 amperes for the 2 horse power motor. 
 
 The controller box is easiest made of some soft wood, 
 such as wiiite pine. It should be liberally varnished 
 outside and lined inside with asbestos paper, glued or 
 tacked in place. The two disks should be of hard 
 Avood. On the exterior of the box should be marked 
 the positions for the various speeds and directions, or, 
 if the constructor feels so disposed, he can mount a 
 position cam and roller on each pivot. 
 
318 HOME MECHANICS FOR AMATEUES 
 
 The controHer may be placed anywhere in the boat, 
 but preferably where it can be manipulated by the 
 pilot's left hand while he steers with his right. All the 
 wiring between the batteries, motor, and controller 
 should be run with good quality rubber covered wire, 
 No. 4 gauge, and preferably in iron armored conduit, so 
 that it may not be disturbed by passengers walking 
 on it. 
 
 The 24 cells of battery may be conveniently charged 
 from a 110 volt source of supply by the use of a resist- 
 ance. This should be of about 3 ohms and is conven- 
 iently made of iron wire, about No. 14 gauge. About 
 350 feet of it will be required, and this nmy be conven- 
 iently coiled up in loose coils and hung in a frame. 
 It should not be confined, but allowed to have free cir- 
 culation of air, as it Avill warm up considerably. The 
 charging current should be about 20 amperes. Full 
 charge is determined either by the voltmeter, which 
 will then read 50.5 volts- or by the ''boiling" of the 
 cells. It is a waste of current to attempt to further 
 charge a cell after it begins to ''boil.'' 
 
 If the amateur so desires he may make his own cells, 
 but he is likely to have more satisfaction with those 
 lie buys. For the larger size of motor described these 
 cells should be made with plates 8 inches square, 15 
 lead plates and 16 zinc plates to each cell. 
 
HOME MECHANICS FOR AMATEUES 
 
 319 
 
 THE EDISON DYNAMO Oil MOTOK 
 
 It is one thing to make a dynamo or motor from 
 explicit instructions and quite another thing to design 
 a machine adapted to generate or be operated by a 
 particular current. The former is purely mechanical 
 
 Fig. 297. Small Edison Dynamo or Motor. 
 
 and within the range of most machinists and amateurs, 
 while the latter is entirely within the province of the 
 electrical engineer or electrician. AA'hen the work of 
 machine building proceeds simultaneously with the 
 
320 HOME MECHANICS FOR AMATEURS 
 
 study of fundamental principles, real progress is made. 
 For the benefit of those who proceed in this Avay, and 
 in answer to many inquirers, we give a detailed descrip- 
 tion of an Edison 0.25 kilowatt machine, designed for 
 use as a dynamo for supplying a current for five Edison 
 standard lamps, or for use on the Edison circuit as a 
 quarter horse power motor. 
 
 Before beginning the description of the machine it is 
 but fair to say that it is thoroughly well made in every 
 particular. The insulation in every part is very per- 
 fect, and the whole is so well made that any single 
 machine built by a mechanic or amateur could but 
 suffer by comparison with it; and furthermore, we 
 doubt if any maker of a single machine could even 
 purchase the materials required for the price asked for 
 the machine by the regular manufacturers. Therefore, 
 if the machine is wanted, we advise a purchase. If 
 experience is wanted, the making of the machine comes 
 first in order, with a probable purchase to follow. 
 
 The base, which is of brass, is made hollow, as 
 shown. It is 14 in. long, 7| in. wide. If in. deep at 
 the ends, with two IJ in. elevations at the middle for 
 receiving the cast iron pole pieces of the field magnet, 
 which are each secured to the base by two small tap 
 bolts extending upwardly through the base and into 
 the pole pieces. 
 
 The upper surfaces of the pole pieces are truly faced 
 for receiving the cylindrical field magnet cores, w^hich 
 are made of Swedish iron, 2f in. in diameter and 4^ 
 in. long. These magnet cores are each held in position 
 by a threaded stud screwed into the pole piece and 
 entering magnet core. Each core is provided with a 
 vulcanized fiber collar at each end, which is | in. thick 
 
HOME MECHANICS FOR AMATEUES 321 
 
 and I in. wide. Upon each core, and between the 
 fiber collars, is wound 5^ lb. of No. 24 silk-covered 
 copper wire, with a wrapping of thin varnished paper 
 between the layers. The cores, before winding, are 
 thoroughly insulated with the same material. The 
 
 Fig. 298. Side Sectional Elevation of Dynamo. 
 
 fiber collars are each held in place by three conical- 
 headed screws entering the end of the core, with their 
 heads projecting beyond the body of the core. To the 
 inner and outer ends of the winding of each arm of the 
 magnet are attached pieces of larger wire to avoid 
 
322 
 
 HOME MECHANICS FOE AMATEUliS 
 
 breakage, and the iuuer ends are led out through 
 grooves in the fiber collars. The yoke, of Swedish 
 iron, is 2f in. wide, 2^ in. thick and 7^ in. long. It 
 is held in position on the cores by two ^ in. bronze 
 studs, each threaded at the upper and lower ends, and 
 furnished with a collar which fits into the counter- 
 
 FiG. 299. Side View of Field Magnet, Partly in Section. 
 
 bored part of the hole in the yoke. The studs are 
 squared at the upper end to receive a wrench, and a 
 nut is placed on each stud above the yoke for clamp- 
 ing it securely after adjustment. The machine is regu- 
 lated or adapted to any work requiring less than its 
 full power by raising the yoke more or less. The yoke 
 
HOME MECHANICS FOR AMATEUKS 333 
 
 is provided with an eye, by means of which the ma- 
 chine may be lifted. 
 
 Front and rear boards of mahogany are arranged on 
 opposite sides of the yoke, and held in place by brass 
 plates at the ends. 
 
 The outside ends of the field magnet coils are con- 
 nected with binding posts on the rear board. 
 
 A variable resistance of ten or fifteen ohms is in- 
 serted between these posts when the machine is used 
 as a dvnamo. In the front board, at the right hand 
 side is secured a bronze casting known as the right 
 hand motor head field magnet terminal. This is 
 
 FIG. 300. Switch on the Edison Dynamo or Motor. 
 
 adapted to receive the line wire, also one of the leads, 
 the upper end of which is screwed to the casting. The 
 lower end of the lead is secured to a lead termina 
 attached to a block of wood secured to the right hand 
 pole piece. At the right hand side of the machine a 
 similar arrangement of the lead is found, but the up- 
 per lead terminal is made in two separate parts, one 
 attached to the lead, the other being connected with 
 the line; both being furnished with copper switch 
 tongues. The switch arm turns on a stud projecting 
 from the front board and carries a loose triangular 
 switch plate of copper, having a knife edge which 
 
324 HOME MECHANICS FOE AMATEURS 
 
 readily enters between the switch tongues. The switch 
 has a T-handle of hard rubber, by means of which it 
 is turned. A stop pin projecting from the front board 
 limits the rearward movement of the switch arm. 
 
 The inside end of the right magnet coil is connected 
 with the right hand lead, and the inside end of the left 
 
 Fig. 301. Diagram of Winding of Edison Armature. 
 
 hand magnet coil is connected with the lower half of 
 the left hand lead terminal. 
 
 At opposite ends of the base there are plane surfaces 
 to which are secured the self-oiling bearings of the 
 armature shaft. Each bearing has a hollow standard 
 lurnished with a cap, Avhich, together with a cross 
 piece in the hollow standard, forms a support for the 
 
HOME MECHANICS FOR AMATEURS 325 
 
 spherical central portion of the bronze sleeve forming 
 the journal box proper. 
 
 This sleeve is shorter than the outer portion of the 
 bearing, and is slotted across the top to allow two 
 brass rings to ride upon the armature shaft. These 
 rings dip in the oil in the hollow standard, and as they 
 
 Fig. 302. The First Two Coils and Commutator Connections. 
 
 revolve carry oil to the shaft in quantities more than 
 sufficient for the purpose of lubrication. The oil is 
 distributed throughout the bearing by means of spiral 
 grooves formed in the inner surface of the journal box. 
 The surplus oil drops back into the hollow standard. 
 A screw plug in the lower portion of the standard 
 allow^s of the renewal of the oil. The bearings at 
 
326 HOME MECHANICS FOR AMATEURS 
 
 opposite ends of the machine are alil^e, except that the 
 cast iron support of the bronze journal box, at the 
 commutator end of the armature, is turned on its inner 
 end to receive the brush yoke. 
 
 The steel armature shaft is 16J inches long and i 
 inch in diameter at the journals, and H inch in diame- 
 ter between the journals. The larger part of the shaft 
 
 Fig. 303. Arrangement of the Layers at End of Armature Core. 
 
 is 9^ inches long. Sufficient end chase is allowed in 
 the armature journals to cause the surfaces to wear 
 smoothly. 
 
 On the central portion of the armature shaft is 
 placed a wooden sleeve, liV inch in diameter; on 
 this are mounted the thin sheet iron disks forming the 
 armature core. These disks are 2f inches in diameter. 
 
HOME MECHANICS FOR AMATEURS 
 
 327 
 
 They are arranged in series of five, with tissue paper 
 between the disks, and between the series of five are 
 placed several thicknesses of paper. Enough disks are 
 clamped together on the shaft to make this portion 
 of the core 3^ inches long. The cast iron disks be- 
 tween which the sheet iron disks are placed are ^ inch 
 in thickness and 2J inches in diameter. One of them 
 is fixed on the shaft, the other being held in place by a 
 hexagonal nut screwed on the shaft. The cast iron 
 disks have their outer corners rounded, and in the 
 
 Fig. 304. The Ends of the Armature Core. 
 
 edge of each are formed thirty-two equidistant radial 
 slits tV inch wide. In these slits are inserted slips of 
 vulcanized fiber for separating the different pairs of 
 coils during the operation of winding. 
 
 It is impossible to describe the Edison winding with- 
 out depending mainly on the diagrams, Figs. 301 and 
 302. There are two series of coils ; that is to say, there 
 are two coils in each division of the armature There 
 are thirty-two bars in the commutator, which are num- 
 bered consecutively from 1 to 32. 
 
328 HOME MECHANICS FOR AMATEURS 
 
 The armature core and shaft are thoroughly insu- 
 lated by means of paper coated with an adhesive var- 
 nish. Jute string ribbon is wound on the face of the 
 core as a further protection. 
 
 The wire used on the armature is No. 21 copper wire, 
 double covered; the inner covering being of silk, the 
 outer of cotton. 
 
 i^eaving an end out for connection with the commu- 
 tator coil, No. 1 is begun at 1 and wound in four lay- 
 ers, with six convolutions in each layer, the outer ter- 
 minal coming out at 1'. These ends are marked re- 
 spectively 1 and 1' in such a manner as to avoid any 
 possibility of the detachment of the marks. If this 
 caution is observed, much trouble may be avoided. 
 A good way to mark them is to place a tag of parch- 
 ment, or parchment paper, on each end of the wire, 
 with the number marked on. 
 
 After winding coil No. 1 the armature is turned half 
 w^ay over and coil No. 2 is wound and marked in the 
 same way, with 2 on the inner end of the coil and 2! on 
 the outer end. The coil is then reversed and coil No. 
 3 is wound and its ends are marked in the same w^ay, 
 and so on until the first series of coils is finished, the 
 last coil of the series being marked 16 and 16'. 
 
 The first coil of the outer series is No. 17-17'. This 
 is wound on the top of coil No. 1. The armature is 
 turned over and No. 18 is wound on the top of No. 2, 
 and so on until all of the outer coils are in place. 
 
 Before winding, the inner end of each wire is 
 wrapped in jute string ribbon to a point within the 
 end of the armature core, and it is further protected 
 by a TNTapping of thin adhesive tape. The outer end of 
 the coil is covered in the same way. 
 
HOME MECHAISTICS FOE AMATEURS 329 
 
 About three pounds of No. 21 wire are required for 
 the armature. The length of wire in the first inner 
 coil is 26 feet 6 inches. The length of wire in the last 
 outer coil is 35 feet. 
 
 The commutator cylinder* is formed of 32 bronze 
 bars having beveled ends and radial arms for receiv- 
 ing the wires. These bars are clamped in position on 
 a sleeve having an under-cut flange, by a countersunk 
 washer and a nut screwed on the sleeve. Mica is 
 inserted between the commutator bars, between the 
 bars and the sleeve, and between the ends of the bars 
 
 Fig. 305. The Armature with Parts Broken Away. 
 
 and the flange and the washer. The radial arms ex- 
 tending from the commutator bars each have a slot in 
 the end for receiving the terminals of the coils. 
 
 The coil terminals are arranged in groups of 16, the 
 wires of each group being parallel. The terminals are 
 carried around and attached to commutator bars 
 which are about 90° from the planes of the coils to 
 which they belong, thus maldng the winding more 
 symmetrical and at the same time permitting of a bet- 
 ter arrangement of the brushes. 
 
 The coil terminals are inserted in the slots of the 
 arms of the commutator bars and soldered with soft 
 * For further points on Commutators, see Supplement 600. 
 
330 
 
 HOME MECHANICS FOR AMATEURS 
 
 solder, the connections being made in accordance with 
 the diagram, Fig. 301. 
 
 The wires, where thej cross at the back and front 
 end of the armature, are separated by sheets of mica. 
 Where the winding crosses at the rear end of the arma- 
 ture the wires are spread out so that they are only 
 one layer deep. 
 
 Fig. 306. The Brush Yoke. 
 
 When the winding of a coil is finished, the terminal 
 is fastened by stout threads inserted in the coil before 
 winding the last three convolutions, and tied after the 
 coil is complete. 
 
 A vulcanized fiber collar, a little larger in diameter 
 than the commutator, is slipped over the commutator 
 bars and placed against the radial arms of the bars 
 as shown. The edge of the collar is grooved and a 
 canvas cover is fastened to the collar by tying it in 
 the groove. It is then drawn over the terminals and 
 
HOME MECHANICS FOR AMATEURS 331 
 
 fastened by the first ring of binding wire on the arma- 
 ture. At the opposite end of the armature a similar 
 collar and cover are provided. 
 
 Before covering the terminals with the canvas they 
 are wound with twine to give the end of the armature 
 
 Fig. 807. Details of the Brush Holder, the Commutator Cylinder, 
 and Brush-holding Jig. 
 
 a symmetrical shape. The winding is varnished with 
 shellac before its cover is applied, and the cover is 
 varnished after it is secured in place. 
 
 The binding rings are formed of brass wire, wound 
 tightly over a layer of mica interposed between the 
 wire and the binding. The binding wire is secured by 
 clips and soft soldering. 
 
 The brush yoke is provided with wooden handle by 
 
332 HOME MECHANICS FOE AMATEURS 
 
 which it may be moved and a binding screw by which 
 it is clamped in the position of use. In mortises in the 
 ends of the yoke are placed insulating blocks, in which 
 are inserted the brush-holding studs. These studs are 
 each provided with a nut for clamping the brush 
 holder cables which communicate with the leads at the 
 side of the pole pieces. 
 
 On each brush-holding stud is placed a sleeve fas- 
 tened with a set screw, also a loose sleeve connected 
 with the fast sleeve by a spiral spring concealed with- 
 in it. The loose sleeve is furnished with a brush clamp 
 for holding the brush, which bears on the commuta- 
 tor cylinder with a yielding pressure. The brushes are 
 formed of spring copper wires fastened together at 
 their outer ends with soft solder. 
 
 A jig goes with each machine for clamping the brush 
 and guiding the file while renewing the brush ends. 
 
 The speed of the motor on a 125 volt circuit is 2,400 
 revolutions per minute. The speed at which the arma- 
 ture is to be driven in order to generate a current hav- 
 ing an E. M. F. of 125 volts is 2,730 revolutions per 
 minute. 
 
 According to the new rating the machine here de- 
 scribed is a 0.5 kilowatt machine, which, when used as 
 a generator for supplying lights, will generate suffi- 
 cient current to bring to full candle power nine 16 C. 
 P. 112 volt lamps, and when used for power it is a | 
 horse power motor at a rated volt. It is guaranteed to 
 give 0.47 horse power at | of its rated volts. 
 
HOME MECHANICS FOR AMATEURS 333 
 
 THE UTILIZATION OF 110 VOLT ELECTRIC 
 CIRCUITS FOR SMALL FURNACE WORK* 
 
 It occurred to the writer in wiring up a couple of 
 experimental arc lamps across the feeders of an in- 
 candescent lighting system, that a laboratory electric 
 furnace could be operated on a series carbon plan, 
 without disturbing the protecting fuses of the circuit. 
 This idea of concentrating a pair of arcs within a 
 small crucible or furnace, using only the amount of 
 resistance wire located in the tops of the lamps, proved 
 to be crude, the current taken being excessive upon 
 introducing a charge for fusion, when its character 
 embodied fair electrical conductivity. In order to 
 obviate this difficulty, as well as to compensate for the 
 lowering of resistance due to eddy currents between 
 the carbons, a triple series arc was formed requiring 
 only a short length of German silver wire to steady 
 its action. With this arrangement the most success- 
 ful results were attained, and with the furnace, as 
 finally constructed upon this plan, many metallurgical 
 processes were carried on, a 12 ampere fuse placed in 
 each leg of the current supply being sufficient. The 
 little furnace illustrated in Fig. 308 is capable of pro- 
 ducing calcium carbide in twenty minutes from the 
 time the current is switched on, the fuses remaining 
 intact throughout the operation, if a short length of 
 resistance wire is introduced into the circuit. With 
 this arrangement it is possible to separate the carbon 
 electrodes 3^ inches without extinguishing the triple 
 arc. It is the intention of the writer to describe in 
 detail the construction of this little plant, and fur- 
 * By Nevil Monroe Hopkins. 
 
334 
 
 HOME MECHANICS FOE AMATEUES 
 
HOME MECHANICS FOR AMATEURS 335 
 
 nish carefully prepared directions for making small 
 quantities of calcium carbide. This compound is 
 chosen because of its exceedingly useful and interest- 
 ing characteristics, and because of the numerous in- 
 quiries the writer has received in regard to its forma- 
 tion on a small scale. Calcium carbide is a highly 
 refractory body, its preparation requiring the highest 
 temperatures, and its successful production by means 
 of this small electrical equipment urges experimenta- 
 tion with other compounds requiring less energy and a 
 lower temperature. 
 
 Fiff. 309 will enable us to understand the mounting 
 and connecting of the carbons, being a plan view of 
 the system. The steps in putting together this little 
 equipment should consist in forming and lining the 
 furnace proper. The shell is made from sheet iron, 
 cut to exactly incase one of the common sizes of fire 
 clay slabs. The exact size and shape of this furnace 
 is, of course, immaterial, provided the length is not 
 over 13 inches from end to end, as shown in Fig. 311. 
 Should the length exceed 13 inches, standard electric 
 light carbons would not prove long enough to meet at 
 the center. As the fire clay slabs adapted to our pur- 
 pose vary somewhat in length, definite dimensions are 
 not given, but those shown in Fig. 310 will be found 
 useful as guides, and are approximately suited to the 
 average sized slab sold for backing up fire places and 
 stoves, which are plane on one side and fluted on the 
 other. Having procured four of these slabs, the sheet 
 iron (No. 18 or 20 gauge) may be marked off carefully 
 and bent to form the shell. The overlapping sides are 
 drilled through and securely riveted together. One of 
 the fire clay pieces is now placed in the shell on either 
 
336 HOME MECHANICS FOE AMATEURS 
 
 C I 
 
 O 
 
 MM I I I II 
 
 "1 
 
 I I I I I I 13] 
 
 
 II ' 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 • • ^ 
 
 
 
 
 
 
 ! 1 ^ 
 
 
 
 
 
 
 
 
 
 
 
 
 \ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 > 
 o 
 O 
 
 bo 
 
 fl 
 
 '3 
 rt 
 a 
 d 
 
HOME MECHANICS FOR AMATEURS 337 
 
 side (the fluted surface next to the iron) and a large 
 fire brick drojjped in between them. These large fire 
 bricks come with a recess in the top, as represented 
 in Fig. 308, Avhich is desirable for collecting small 
 fusions. If the three pieces of fire clay fit nicely in 
 the shell, the fire brick is removed temporarily, and 
 our attention given to cutting one of the slabs in half 
 to form the ends of the lining. 
 
 In Fig. 310 a section of the shell is shown, where A 
 represents one of the side slabs in position, running 
 from end to end, as illustrated by the horizontal shad- 
 ing. These slabs may be had about 12| inches in 
 length by about 8 inches in width and 2 inches thick, 
 which serve for this lining nicely. The end pieces 
 must be cut off at an angle to form the bottom of the 
 incline leading into the furnace. These are repre- 
 sented in the drawing by section, in oblique lines. The 
 fire clay is cut with a cold chisel and hammer, w^ork- 
 ing slowly with uniform blows, exercising some little 
 patience, until the pieces have the proper shape. The 
 angle must be determined by trial with the shell, which 
 is cut down by means of heavy shears, within 5 inches 
 of the bottom, being about 5J inches in wddth. The 
 metal flap, resultant of this cutting down, is sharply 
 bent over and cut off, the edge being smoothed with 
 a large flat file. A band of iron riveted around the 
 top, as illustrated, crowns the opening, and must be 
 adjusted as to height, by the size and thickness of 
 the fire clay lining which has been procured. 
 
 To complete the furnace proper, it is only necessary 
 to put in place the angle pieces, and secure in position 
 temporarily four pieces of glass, in order to form the 
 top of the inclined entrance. The wooden brace, B, 
 
338 HOME MECHANICS FOR AMATEURS 
 
 is cut to the proper length to press the vertical glasses 
 (shown in simple ruling) against the end pieces of fire 
 clay, and small Avooden blocks made to support the 
 glass plates on the incline, as illustrated, leaving a 
 2-incli space. The height of the vertical glass plates 
 must be just equal to the height of the side slab, 
 Ay and the inclined pieces must come nicely in 
 contact witli them. The two spaces formed, C and 
 Dy are now filled in with ^^stove fix-' or other fire clay 
 compound made plastic by the addition of a little 
 water. This compound may be had ready to mix, and 
 is applied with a trowel. The glass plates must be 
 left in position over night, in order that the material 
 which they support may set. They are then with- 
 drawn together with the wooden brace, and the fire 
 brick dropped into the bottom to stay. An additional 
 quantity of the stove compound is made up, and all 
 cracks and crevices plastered in. When this finally 
 sets, a strong and durable furnace is produced. It 
 should be heated up slowly for the first time uncovered, 
 in order to expel all moisture. The top, which con- 
 sists of the fourth piece of slab, is cut through by means 
 of the cold chisel, and is afterward smoothed with a 
 large rasp. 
 
 The method of suspending the cover is illustrated in 
 Fig. 311, the iron bands coming over the fire clay walls, 
 on the inside, being thus protected from the heat of 
 the arcs. Having completed this portion of the work, 
 the base, platforms, and screw feed must be put to- 
 gether. The base, upon which the entire plant rests, 
 consists of a heavy pine board, 4 feet in length by 8 
 inches in width. The furnace is mounted upon three 
 common bricks (2^ inches in height) and placed at 
 
HOME MECHANICS ¥011 AMATEURS 339 
 
 the center of the board to facilitate the design and 
 construction of the inclines, which must be very ac- 
 curately pitched, in order that the carbons may be fed 
 into the furnace Avithout coming in contact with the 
 openings. Should they touch, however, a couple of 
 mica sheets must be applied as a precaution against 
 short circuits. These inclines are made from 1 inch 
 pine boards, 6 inches in width and 16 inches in length. 
 These boards are mounted upon upright pieces of wood 
 of the same weight for trial, but are not screwed on 
 until the screw feed is put in place, which is attached 
 
 /] A 
 
 I. .3- 
 
 8 ^^1^ *• 
 
 1=3 
 
 Fig. 312. Sections of Clamp as applied to Screw Feed. 
 
 from underneath. Of course the inclines must be care- 
 fully adjusted to any specific furnace, but the height 
 of the front and back supports will be about 8 and 3^ 
 inches respectively. These may be attached at once by 
 means of strong angle irons as illustrated in Fig. 308. 
 To form the screw feed, select a large sized furniture 
 maker's clamp, with Avooden screws at least 18 inches 
 long. Fig. 312 illustrates such a clamp, the sections 
 to be sawn through to make the bearings and screw 
 collars being marked in dotted lines. The sections 
 marked S S will be found to contain the screw threads, 
 and serve for the center traveling pieces upon which 
 
340 HOME MECHANICS FOE AMATEUES 
 
 the blocks and electrodes are mounted. The sections 
 1, 2y 3, and 4 serve for simple bearings, after being 
 carefully drilled through with a bit and brace, ex- 
 ercising great care in boring, to secure centrally located 
 straight holes. These are screwed on to the board 
 from underneath, and as the wood from which the 
 furniture clamps are made is very hard, gimlet holes 
 must be provided for the reception of the screws to pre- 
 vent splitting. These gimlet holes must have consider- 
 able depth. Upon the traveling pieces are mounted 
 two blocks 6 inches long, 4 inches wide, and about 1^ 
 inches in thickness. Three brass tubes are carefully 
 mounted upon each of these, of the right size to receive 
 electric light carbons (the longest kind, copper coated) 
 with a tight fit. These tubes are secured as shown in 
 Fig. 309 by means of heavy brass straps. The car- 
 bons are placel in position, about an inch of the end 
 left protruding to allow brass spring clips to be pushed 
 underneath. With this spring adjustment, the car- 
 bons can be quickly withdrawn or easily regulated. 
 The connections, which should consist of double in- 
 sulated wires (No. 16 gauge), are soldered to these 
 clips in the manner indicated. It will be observed by 
 referring again to Fig. 308 that the carbons may be 
 slowly withdrawn by turning the screw, or they may 
 be pulled out of the furnace by the handle of the screw 
 when it is necessary to remove the furnace from the 
 base. 
 
 The furnace is now ready for connecting up and a 
 trial. Adjust all six carbons carefully, making sure 
 that they are all in contact. When the triple arc once 
 forms, they require very little attention, and, as stated, 
 will continue to burn when the distance between their 
 
HOME MECHANICS FOR AMATEUES 341 
 
 ends exceeds 3 inches, Avith a charge of coke and lime 
 as the conducting medium. Fig. 313 shows the scheme 
 of proper connections with a 110-volt electric lighting 
 sj^stem. The main conductors, or feeders, are repre- 
 sented at the bottom by heavy horizontal lines and are 
 joined as indicated direct to a porcelain fuse block, F. 
 This connection should be made as near tlie meter as 
 possible, in order to avoid annoyance from intermedi- 
 ate fuses. In addition to this, the capacity of the meter 
 
 Fig. 313. Diagram of Connections, with Ammeter and Voltmeter 
 
 arranged for studying the Behavior of Compounds 
 
 within the Arc. 
 
 should be ascertained, which should allow of a 25 am- 
 pere load. In other words, a 45-light meter will be 
 large enough, a standard 16 candle power lamp taking 
 about 0.6 ampere. Place a 12-ampere fuse in each side 
 of the fuse block, as shown, and join the same to a 
 small knife switch, /s'. Should the reader possess an 
 ammeter (of fully 50 amperes capacity), it should be 
 included in the circuit, and a voltmeter should be 
 
3^2 HOME MECHAmCS FOR AMATEURS 
 
 joined across the connections of the arcs if possible. 
 The resistance, R, consists of 20 feet of doubled Ger- 
 man silver wire, No. 22 gauge, Brown & Sharpe.* 
 
 To make this resistance in convenient shape, the 
 wire should be wound about a large fire clay slab, 
 which serves for sufficient insulation and resists the 
 effect of the heating up. This slab with its wire must 
 not be placed near woodwork. The furnace should be 
 run for fifteen or twenty minutes, for the first time 
 without its cover and without a charge, moving the 
 carbons back and forth and testing their centering, etc. 
 Should the arc go out, the feed is screwed down until 
 contact is again made and the incline rapped with a 
 mallet in order to cause the points of the carbons to 
 vibrate or rub together. In doing this work with the 
 cover off, use strongly smoked glasses to protect the 
 eyes from unnecessary strain. Having mastered the 
 handling of the equipment we are now ready for 
 experimentation, and will proceed direct with the prep- 
 aration of calcium carbide. To produce a laboratory 
 quantity of this compound, follow closely the direc- 
 tions given. Weigh out 18 ounces of good unslaked 
 lime (calcium oxide, CaO), and reduce to a granulated 
 form in a large iron or porcelain mortar. Phice this 
 portion of the charge on a large sheet of manila paper 
 and prepare for the grinding of the coke. Do not at- 
 tempt to use charcoal, as it is too light and floury, 
 oxidizing away in the air without combining with the 
 lime. 
 
 Select either good coke or procure a lot of broken 
 electric light carbons, and weigh out 16 ounces of the 
 
 * This wire requires much care in handling, and, if allowed to 
 tangle or kink, breaks very easily. It is very brittle. 
 
HOME MECHAMCS FOE AMATEIJES 343 
 
 fragments. These must now be pounded to small 
 pieces and afterward granulated in the iron mortar to 
 about the same size as the pieces of lime. The coke 
 and lime should now be thoroughly mixed together on 
 the large sheet of paper preparatory to grinding in an 
 iron coffee mill. These mills come all of iron, designed 
 to screw up against the wall, and are equipped with a 
 regulating device for grinding coarse or fine. The 
 money put in a mill of substantial character will be 
 well invested, as it will prove of great value in a 
 laboratory or experimental shop for reducing many 
 substances to powder. The granulated lime and coke 
 are poured into the mill and ground to the finest meal, 
 passing the mixture through several times to insure an 
 intimate mixing as well as a fine powder. Should a 
 mill not be at hand, the charge may be reduced to the 
 proper fineness, although requiring much more labor, 
 by means of the large iron mortar. The pestle of the 
 mortar is ground to the right and the mortar rotated 
 to the left with the palm of the left hand. There is a 
 little knack in doing this, and with a little practice, 
 but with considerable work, the lime and coke may be 
 suitably prepared for fusion. 
 
 The powdered charge must be put away in airtight 
 receptacles, if it is not intended for immediate use, as 
 the lime in the finely powdered state quickly slakes if 
 left in contact with the air. Should we use the mix- 
 ture without thoroughly grinding, which is a very 
 dark slate color, it will be found a very light gray 
 upon shutting down the furnace after a run, showing 
 that most of the carbon has gone off as carbon dioxide 
 and carbon monoxide, leaving the unfused lime behind. 
 We can now start the furnace for actual work and 
 
344 
 
 HOME MECHANICS FOE AMATEURS 
 
 feed four or five ounces of the charge in the arc as 
 soon as well started, observing the voltmeter and am- 
 meter, if a study of the resistance of furnace fusions 
 is to be made. The carbons are drawn gradually apart, 
 and additional quantities of the charge added from 
 time to time. The cover is kept on as much as possi- 
 ble, only removing it to add more material and to heap 
 
 Fig. 314. Furnace for making Solders and other Alloys having 
 Low Melting Points. 
 
 the compound about the triple arc by means of a 
 spatula. After a twenty minutes' run, during which 
 time the compound is frequently heaped about the 
 points of the electrodes, the switch may be opened 
 and the furnace allowed to cool. Should one of the 
 fuses bloAv out during the run, it should be immedi- 
 ately replaced by one of the same capacity and a small 
 
HOME MECHANICS FOR AMATEURS 345 
 
 amount of additional German silver wire added to the 
 circuit, although the 20 feet of the double material will 
 probably afford all the protection necessary and steady 
 the arcs in a very satisfactory manner. 
 
 A variable rheostat of low resistance included in the 
 circuit would be a great convenience, allowing the cur- 
 rent flow to be adjusted to the capacity of the fuse 
 wires to a nicety. A few runs with the furnace will 
 enable one to become quite expert in forming calcium 
 carbide, working with a 3-inch arc without allowing it 
 to go out. When the furnace has cooled, a number of 
 large masses of the carbide will be found in the bot- 
 tom of the fire brick hearth, which may be thrown 
 immediately upon water to obtain acetylene gas or 
 stored away in airtight cans or jars for future use. If 
 left open in the air, it is slowly attacked by moisture 
 and is decomposed. Before suggesting other work for 
 small preparations, the introduction of a very small 
 crucible furnace may be of interest. Fig. 314 illus- 
 trates the simplest form of crucible equipment de- 
 signed for operation on the 110-volt circuit, with six 
 or eight 32 candle power lamps arranged in a bridge 
 in multiple as indicated. A large sand crucible or or- 
 c^Jnary flower pot is filled with granulated fire clay or 
 other poor conductor of heat, and a smaller crucible 
 placed inside. The whole is stood on a fire brick and 
 the large pot or crucible is provided with a clay cover 
 having holes for the reception of two carbon electrodes. 
 The stands sold for supports in chemical laboratories 
 make the most convenient holders for the carbon rods. 
 
 The furnace depicted in Fig. 315 is capable of doing 
 more work, in fact, as much as may be wished for on a 
 small scale, if the experimenter is so situated that he 
 
346 
 
 HOME MECHANICS FOR AMATEURS 
 
 may have as much current as he wants. The small 
 crucible is drilled through the bottom, and one of the 
 electric light carbons cemented in place, or simply held 
 in position by a tight fit. The outer incasement in 
 
 Fig. 315. Furnace for melting Brass, Copper, etc., for Harder Alloys, 
 
 and reducing Small Quantities of Metallic Oxides 
 
 to their Respective Metals. 
 
 this design consists of a large flower pot, supported 
 on a small iron ring stand, also to be had from chemi- 
 cal dealers. This is covered by a heavy plate of mica 
 with a central hole for the carbon. By putting in 
 series two or three rheostats the current may be easily 
 
HOME MECHANICS FOE AMATEURS 347 
 
 controlled, and if heavy fuses are installed, and if 
 there is no fear of injuring any meter, a very fierce 
 and intense arc may be maintained. Use only the cop- 
 pered carbons, and solder their connections to them. 
 The writer suggests experimentation with alloys, in 
 connection with these small crucibles (sand crucibles, 
 plumbago, or graphite), using borax in some cases and 
 charcoal in others (here the light floury charcoal is 
 to be preferred), in order to fuse the bodies in a neutral 
 atmosphere. 
 
 By using an excess of charcoal constantly in the 
 crucible, the inert carbonic acid gas which is formed 
 will expel the oxygen from the crucible and prevent 
 oxidation of the metals experimented with. Nearly 
 all the metallic oxides may be reduced in the presence 
 of carbon with a sufficiently high temperature, provid- 
 ing an interesting field for work. Small masses of 
 aluminum and aluminum bronze may be formed in 
 the crucible furnace illustrated in Fig. 315, or in the 
 large triple arc equipment, although only on a very 
 small scale. Aluminum oxide (AI0O3) may be directly 
 reduced in the arc in the presence of carbon by intro- 
 ducing an intimate mixture of the oxide and powdered 
 graphite. The aluminum oxide may be bought, or may 
 be prepared on a very small scale from clay or alum 
 as follows : Digest 8 ounces of clay in a mixture of 
 hydrochloric and sulphuric acids in a glass flask ( HCl 
 3 parts, H.SO4 1 part) for about an hour. The fluid 
 is mixed with four or five ounces of water and filtered. 
 An excess of ammonia (ammonium hydroxide) is 
 added, and the white precipitate collected on a large 
 filter and allowed to dry. It is then mixed with the 
 graphite and the two ground together. From alum, it 
 
348 HOME MECHAmCS FOE AMATEURS 
 
 is only necessary to add the ammonia to a strong solu- 
 tion of alum in water, and treat the resultant precipi- 
 tate in a like manner. Of course this process is only 
 a little chemical exercise, and is only given for the 
 benefit of those who wish to attempt the entire process, 
 although of no commercial value, the manufacture of 
 aluminum embodying entirely unlike methods. 
 
 For the benefit of those who have never experimented 
 with the electric arc, the writer includes in the sug- 
 gestions offered a pair of strongly smoked glasses, to 
 be worn whenever the arc is exposed. To work with- 
 out glasses is to expose the eyes to severe strain and 
 possible injury. 
 
 EECORDING TELEGEAPH FOE AMATEUES 
 
 If the question of utilit}^ controls one in making and 
 trying a piece of apparatus, it is useless to expect to 
 realize anything in the way of profit from the record- 
 ing telegraph illustrated and described; but a few in- 
 terested amateurs can co-operate, and with a wire and 
 transmitter for each can secure a practical knowledge 
 of the workings of some of the large telegraph systems 
 and of some of the applications of electricity, which 
 could not be secured in any other way. The expense 
 would be slight, when there is a joining of amateurs 
 for one purpose. 
 
 It is assumed that an ordinary sounder is available 
 for the central office recorder, and that every sub- 
 scriber will furnish a transmitter, a wire to communi- 
 cate with the central office recorder, and battery suffi- 
 cient to operate one branch of the central office system. 
 
 In making the central office recorder, a common 
 sounder is pressed into service. It is provided with a 
 
HOME MECHANICS FOE AMATEUES 349 
 
 stylus-holder which is clamped to the free end of the 
 armature lever. The stylus is a piece of steel wire 
 1-16 inch in diameter and 1 inch long, with a rounded 
 and hardened point. It is clamped in place by a set 
 screw. 
 
 Fig. 316. 
 The Receiving Instrument of the Recording Telegraph. 
 
 Under the free end of the armature lever is journaled 
 an arbor, carrying a wooden roller having a V-shaped 
 peripheral groove at the center, exactly under the 
 
350 HOME MECHANICS FOE AMATEUES 
 
 stylus; so that when a paper strip passes over the 
 roller, the stylus can make a slight depression in the 
 paper, when the sounder magnet is actuated. 
 
 The principal features of this telegraph are a sim- 
 ple transmitter for giving fixed calls, like a call box, 
 and the mechanism for carrying the paper tape over 
 the grooved spool and under the stylus. The roll of 
 tape as purchased from the dealer is carried on a 
 wooden reel, supported by a standard at the rear of 
 the sounder. Between tAVO standards in front of the 
 sounder are journaled two rollers, a h. The roller a 
 is flanged and provided on its periphery with three or 
 four rubber bands, to give it frictional contact with 
 the paper tape. The lower roller h is covered with a 
 piece of rubber tube and the shaft of this roller carries 
 a small governor c, for regulating the speed of the 
 tape. The tape extends over the roller h, thence down- 
 ward under the flanged roller d, then upward to a 
 fastener. The roller d is provided with a weight which 
 actuates the mechanism. 
 
 It will thus be seen that the paper tape is carried 
 through the machine by the action of the weighted 
 roller d, and its motion is regulated by the governor c. 
 The governor c consists of a slotted hub /, links g g, 
 pivoted in the slots of the hub, a slotted sliding block 
 /i, placed loosely on the shaft of the roller h, weighted 
 arms l i pivoted in slots in the block h^ and pivotally 
 connected to the outer ends of the links g g, and a light 
 spring, ;'-, tending to draw the weighted arms i i toward 
 each other. The block h is provided with a leather 
 washer /, which produces necessary frictional contact 
 with the standard, when the weighted arms are thrown 
 out by centrifugal action. The tape reel is provided 
 
HOME MECHANICS FOE AMATEURS 351 
 
 with a slight spring for cheeking its motion when the 
 paper feed stops. In the side of the block which car- 
 ries the stylus is inserted a small stud, in which is 
 clamped a wire ni, having its free end near the side of 
 
 Fig. 317. Diagram of the Receiver, 
 
 the roller a, flattened and turned up at right angles. 
 The flattened end of this wire m lies in the path of a 
 small pin projecting from the roller «^, so that when- 
 
352 HOME MECHANICS FOR AMATEUES 
 
 ever the armature lever is drawn down b}^ the magnet, 
 the pin is released, and the roller a is allowed to turn, 
 but when no current passes the magnet, the armature 
 lever rises and brings the flattened end of the wire m 
 into the path of the small pin, and stops the movement 
 of the roller a, and consequently arrests the progress 
 of the paper, until the pin is released by another ac- 
 tion of the armature lever. Binding j^osts placed at 
 the rear of the sounder are connected with the magnet 
 electrically in the usual Ava^^ To transmit a signal 
 over a line connected with this instrument, it is not 
 necessary to understand the telegraph alphabet, nor to 
 know anything in regard to telegraphy. The signals 
 are pre-arranged, so that the operation of sending is 
 purely mechanical. 
 
 The signal board shown in detail in Fig. 318 was 
 invented and patented years ago by William Hadden, 
 but the patent has long expired. This simple device 
 consists of a board, a few inches wide, and perhaps 
 twice the length, depending on the number and length 
 of the messages sent. The board here shown is 4^ inches 
 wide, 7 inches long, and J inch thick, with as many 
 longitudinal grooves formed in it, as there are signals 
 to be given. The signal board must be of very hard 
 wood, and the dots and dashes of the signals are formed 
 by sewing No. 30 plain copper wire through holes ex- 
 tending through the board, from the grooves in front 
 to the grooves in the rear. As the signal transmitter 
 is at present constructed, the copper wire sewed 
 through the first set of holes represents the letters of 
 the Morse alphabet from A to F, with a dash between 
 each letter. The sewing in the second groove repre- 
 sents the letters from G to J, The sewing in the third 
 
HOME MECHAXrCS FOR AMATEURS 
 
 353 
 
 groove represents tlie letters from K to .]/, and so on. 
 All of the wires forming these letters are connected 
 together at the top of the board, by a wire on the back, 
 which is in electrical connection with the binding post 
 seen to the right in onr vi(nv of the signal apparatus. 
 The binding ])ost at the opposite edge of the board is 
 
 Fig. 318. View of the Transmitting Apparatus. 
 
 connected on the back of the board with a third bind- 
 ing post, at the lower end of the board. The third 
 binding post is connected by a flexible cord with a 
 wire, having a flattened end, and provided Avith a 
 wooden handle. Sending a signal consists simply in 
 drawing the flattened end of the wire with a uniform 
 
354 
 
 HOME MECHANICS FOE AMATEUES 
 
 speed down one of the grooves. The first two binding 
 posts, being connected with the binding posts of the 
 recording instrnnient and with a battery, when a signal 
 is sent, the recorder is released automatically, and the 
 detent is constantly withdrawn from the pin in the 
 roller, so long as the signal is being sent, and the mes- 
 
 A j 
 
 1 
 
 1 
 
 1 
 
 1 
 
 U \ 
 
 1 
 
 2 1 
 
 / j 
 
 ^1 
 
 /! 
 
 p\ 
 
 1 
 
 
 
 
 
 1 
 1 
 
 1 
 
 Si 
 
 3 j 
 
 
 A 
 
 
 1 
 
 
 
 C 
 
 1 
 
 i 
 
 1 
 
 1 
 
 1 
 
 
 4 : 
 
 d\ 
 
 1 
 
 1 
 
 1 
 
 x\ 
 
 
 6\ 
 
 f X 
 
 M 
 
 s\ 
 
 ' 
 
 ? \ 
 
 7 1 
 
 f 1 
 
 m\ 
 
 1 
 
 1 
 
 
 s\ 
 
 
 1 
 
 T\ 
 
 
 / 1 
 
 9 : 
 
 G 1 
 
 N\ 
 
 1 
 
 
 
 
 
 
 Fig. 319. How the Board is Wired for the Morse Alphabet. 
 
 sage is thus recorded. When the signaling stops, the 
 recorder is stopped by the action of the detent. 
 
 Several transmitters may be connected with the 
 recorder, and one wire in each case may be dispensed 
 with, by grounding the other at each end. 
 
 The recorder will run long enough to record a long 
 signal or several short ones with one raising of the 
 weight carried by the paper tape. 
 
HOME ]\IECHAXICS FOE AMATEUIiS 
 
 355 
 
 HOW TO :make telephones and tele- 
 phone CALLS 
 
 On January 30, 1894, the Bell telephone patent ex- 
 pired and the invention became the property of the 
 pnblic; so that whoever desires to do so can make, 
 l)ny or sell telephones withont fear of infringing: the 
 
 Fig. 320. Details of Construction of the Bell Telephone. 
 
 rights of any one. This applies only to the hand in- 
 strument now nsed as a receiver. Patents for other 
 telephone apparatus still remain in force; but enough 
 is available for actual service. With two hand instru- 
 ments and a suitable call, telephonic communication 
 may be maintained, under favorable conditions, over 
 
356 HOME MECHAXICS FOR AMATEURS 
 
 a line eight or ten miles long, no battery being re- 
 quired. 
 
 To avoid the effects of induction and to secure the 
 best results, a metallic circuit is required. It has been 
 said, on good authority, that with hand telephones 
 used as transmitter and receiver, conversation has 
 been carried on between New A^ork and Chicago, using 
 a metallic circuit formed of heavy copper wire and 
 having very low resi^^tance. The words, it is said, 
 were as distinct as where a transmitter is used, but the 
 volume of sound was somewhat less. 
 
 For the benefit of those Avho are desirous of making 
 telephones for their own use, or for sale, we present 
 perspective and sectional views of the latest and most 
 improved form of telephone, all of the parts of which 
 are shown in reduced size. 
 
 The handle is made of hard rubber and the cap, 
 which is also the mouthpiece, is of hard rubber. The 
 diaphragm. A, is clamped at the edge between the cap 
 or mouthpiece and the body of the handle. Very thin 
 ferrotype plate has generally been used for the dia- 
 phragm, but thin taggers iron, Avhen protected by a 
 coat of shellac or other suitable varnish, is said to an- 
 swer better. 
 
 The compound magnet, B, used in the telephone, i.^ 
 composed of four thin, flat bar magnets, a, arranged 
 in pairs on opposite sides of the flat end of the soft iron 
 pole piece, c, at one end, and the soft iron distance 
 piece, d, at the opposite end, the magnets being 
 clamped to these pieces, with like poles all in one di- 
 rection. The space in the center of the magnet be- 
 tween the pole piece and distance piece is filled with a 
 strip, (J, of wood. 
 
HOME MECHANICS FOK AMATEUES 357 
 
 The cjlindrical end of the distance lYwre which ex- 
 tends beyond the mai>net is bored and tapped to re- 
 ceive the screw by which tlie magnet is held in place 
 in the handle. The cylindrical projecting end of the 
 pole piece extends to within 1-100 or 2-100 of an inch of 
 the diaphragm. In other words, it is placed as near the 
 diaphragm as possible without being touched by the 
 diaphragm when the latter vibrates. 
 
 On the pole piece, c^ is placed a wooden spool, r, on 
 which is wound No. 34 (Am. W. G. ) silk-covered cop- 
 per wire. The wire fills the spool, and its ends are al- 
 lowed to project one or two inches. The wire may be 
 wound on the spool in either direction, and it is im- 
 material which pole of the compound magnet adjoins 
 the diaphragm. 
 
 The resistance of the winding varies from 70 ohms 
 as a minimum to 200 as a maximum. When the in- 
 strument is to be used both as transmitter and receiver, 
 and especially Avhen it is on long lines, the resistance 
 should be 100 olims or more. No. 36 wire is used for 
 the winding where the resistance is great. Of No, 34 
 wire, 263 feet will be required for 70 ohms resistance. 
 For 100 ohms, 373 feet are required. For 150 ohms, 
 343 feet of No. 36 are required. 
 
 In the end of the handle are inserted two binding 
 posts, to which are attached insulated wires (No. 18), 
 which extend toward the diaphragm, their free ends 
 being soldered to the terminals of the fine ware on the 
 spool, so that when the telephone is connected up in 
 circuit Avitli other telephones the current will pass from 
 one of the binding posts through one of the coarse 
 Avires, through the fine wire coil, through the other 
 coarse wire to the other binding post. 
 
358 
 
 HOME MECHAXICS FOR AMATEURS 
 
 The Bell telephone has a disk of flexible rubber 
 slipped over the pole piece and over the ends of the 
 coarse wires as a guard against short circuiting. A 
 screw eye is inserted in the end of the telephone handle 
 for suspending the instrument when not in use. 
 
 This telephone, Avhen used in the manner suggested, 
 requires neither battery nor induction coil. It is 
 therefore easily connected up for use by electrically 
 connecting the binding posts of one instrument with 
 the binding posts of another. When a number of tele- 
 phones are connected in the same line, the matter 
 
 Fig. 321 
 
 Single \Vire Circuit. 
 
 is not quite so simi)le. There are many ways of ar- 
 ranging the circuit ; we give diagrams of two, one for 
 one line wire with ground connections, the other for 
 a metallic circuit, Avith a separate circuit for calling. 
 
 In the single wire circuit each instrument on the line 
 is provided with a double switch cut into the line as 
 shown in Fig. 321, the pivots of the switch arm a «', be- 
 ing connected with the line wire. The switch arms 
 are pivotally connected with a bar of insulating mate- 
 rial, so that they will move together. The arms, a a'y 
 mav l)e brought into contact with the points, d, (V , e. 
 
HOME MECHANICS FOR AMATEURS 
 
 359 
 
 ('', and /. A magneto call box is connected with the 
 points, d (/', and the arms, (/ a', are left normally on 
 these points, as shown in dotted lines, so that when 
 any magneto in the line is operated the others will 
 ring. All on the circnit have a special call. 
 
 The one called will know whether the signal comes 
 from the east, west, north or south. Suppose it to 
 come from the east, the switch is placed in the position 
 shown in full lines. This cuts out the magnetos, 
 grounds the western section of the line through the 
 point, c, and connects the eastern section with one 
 
 Fig. 323. Metallic Circuit. 
 
 end of the telephone cord through the point, c\ the 
 other telephone connection being grounded through 
 the points, / e, and ground wire. If the call is from 
 the west, the switch arms, a a', are brought into con- 
 tact with the points, c' /. The arms, a a', are always 
 left on the points, d, d'. Outside the terminal stations 
 the line is connected with the ground or arranged as 
 shown in Fig. 322, with the line grounded through the 
 magneto or telephone. 
 
 In the metallic circuit shown in Fig, 323, the termi- 
 nal telcDhones are connected with the ends of the line 
 
360 HOME ]\IECHAX1CS FOK AMATEURS 
 
 wires. Intermediate telephones are cut into the line 
 hj means of a double switch, as shown in the cut, in 
 which g shows the intermediate telephone cut out, h 
 shows it connected with the east and i Avith the west. 
 
 A third wire grounded at the ends, and including a 
 magneto for each telephone, runs parallel with the 
 metallic circuit. In this case all of the bells ring at 
 once, and individual signals must be agreed upon. 
 
 It is obvious that the information here given in re- 
 gard to the construction of the telephone may be de- 
 parted from in minor points, such as the construction 
 of the handle and mouthpiece, but everything relating 
 to the magnet, the coil, and the relation of the magnet 
 and diaphragm, should be strictly followed. 
 
 No telephone line is complete without a signal of 
 some kind which will serve to attract the attention of 
 a person in the vicinity of the instrument. A battery 
 call answers very well for short distances, but for a dis- 
 tance of from one to twelve miles or more, the battery 
 has been found impracticable and the magneto call is 
 generally employed. This instrument not only serves 
 a good purpose in connection with the telephone, but 
 it answers very well indeed for general signaling pur- 
 poses. It is always ready for action, and does not in- 
 volve the care of a battery. 
 
 The line drawings presented herewith are one-third 
 the actual size (linear measurement) of the instru- 
 ment, and the perspective view is also one-third of the 
 actual size; the only dimension not obtainable from 
 the drawings is the depth of the signal box, which is 3 
 inches. As all of the dimensions may be obtained from 
 the engravings, it Avill be unnecessary to repeat them 
 in the descriptive matter. 
 
HOME MECHANICS F01{ A^IATEUKS 
 
 361 
 
 The pole pieees, A A', between which armature, B, 
 revolves, are formed of soft gray cast iron, with ears, 
 a a, at the top and the ears, ?>, at the bottom, separat- 
 ed by bars, C C, of non-mat>netic material, such as vul- 
 canized fiber, hard rubber, or they may be made from 
 hard wood, well varnished or saturated with paraffine 
 to prevent them from shrinking or swelling. The pole 
 pieces, A A', are clamped to the bars, C C, before they 
 are bored out. They are bored out to loosely fit the 
 
 Fig. 324. Magneto-Telephone Call. 
 
 armature, B'. The pole pieces are provided with flanges, 
 r, which rest upon the bottom of the casing and are 
 drilled to receive screws, (/,, by means of which the mag- 
 
362 HOME MEC^HAXrCS FOE AMATEURS 
 
 net is secured in place in the casini*. In the pole pieces, 
 A A', above the ears, h, are drilled and tapped holes, (\ 
 for receivino the stnds, /, by which the horseshoe mag- 
 nets are secured to the pole pieces. The studs, /, are 
 drilled for receiving keys, (j, by which the magnets are 
 clamped in place. 
 
 The compound magnet, 2, is composed of three flat 
 steel bars forming U-shaped magnets, //, //', /r, with 
 the space between the poles adapted to receive the pole 
 pieces, A A'. The magnet Jr, fits over the adjoining 
 edges of the magnets, // Jt\ and the three magnets are 
 drilled to receive the studs, /, which extend through 
 the magnets and into the pole pieces, the parts being 
 clamped together by keys driven through the holes in 
 the studs, as shown in the perspective view. 
 
 The armature, B, is the Avell known H type of Sie- 
 mens, made of soft gray cast iron, the shaft, i^ being 
 cast integrally with the body of the armature. The 
 part, j, which rec(4ves the wire is narrower and shorter 
 than the polar extremities of the armature. The arma- 
 ture is turned so that its convex sides will revolve very 
 near but not in contact with the i3ole pieces. The 
 shaft at the ends of the armature is turned, and to one 
 end is fitted a sleeve, k, of insulating material (vul- 
 canized fiber or hard rubber), on Avhich is placed a 
 brass ring, I. In the inner side of the metallic ring, I, 
 is inserted a stud, n, to which is soldered one terminal 
 of the arnmture coil, the other terminal of which is 
 soldered to a screw, 11, inserted in the shaft, i. The 
 armature is wound in the same manner as an electro- 
 magnet, the wire being carried around one arm of the 
 armature until one-half of the wire is in place. It is 
 then carried across the central portion of the arma- 
 
HOME MECHANICS FOK AMATEURS 
 
 363 
 
 ture and wound upon the other arm of the armature. 
 The wire used is No. 34 silk-covered wire, there being 
 about 1^ ounces of wire upon the armature, or enough 
 to Qive it a resistance of 200 ohms. 
 
 
 f 
 
 7 
 
 1 / 
 
 n' 
 
 
 t 
 
 h 
 
 h' 
 
 
 
 c 
 
 (d) 
 
 
 G' 
 
 
 1 
 
 % J- 
 
 Fig. 325. Details of Magneto-Call— the Generator. 
 
 To the bar, (\ is secured a brass plate, E, b}^ means 
 of screws which pass through the plate and into the 
 bar. In the plate, E, opposite the center of the bore of 
 the pole pieces, there is a bearing for one end of the 
 shaft of the armature, and in the opposite or upper end 
 
364 HOME MECHAXICS FOPt AMATEUES 
 
 of the brass plate, E, there is a bearing for the driving 
 shaft, F. To the opposite end of the bar, C, and to 
 the bar, C, is secured a plate, E', which is also pro- 
 vided with bearings for the armature shaft and for 
 the driving shaft. To the bar, C, is secured a curved 
 spring, c, which bears upon the insulated ring, I, and 
 this spring is connected by a wire, p^ with a binding 
 post, q, at the top of the casing. 
 
 Upon the end of the armature shaft, i^ outside the 
 plate, E', is placed a pinion, r, and upon the shaft, F, 
 is placed a spur wheel, s^ which engages the pinion, r. 
 The shaft, F, is held in place in the machine by a screw^ 
 inserted in the end of the shaft, and a washer held by 
 the screw against the end of the shaft and bearing 
 against the plate, E. The crank, C, by which the shaft, 
 F, is turned, is screwed on to the end of the shaft 
 through an aperture in the side of the casing. On 
 the stud, f, projecting through the front of the magnet 
 is placed a contact spring, t, which is clamped by the 
 key which holds the magnet in place. 
 
 The mechanism thus described comprises the mag- 
 neto generator Avhich generates the alternating cur- 
 rent required for operating the magneto bell. The 
 machine is held in place in the casing by the screws, 
 d, as already described, and the back of the casing is 
 cut away to let the magnet, h^, into the back, thus 
 economizing room. To the cover of the casing is at- 
 tached the magneto bell, H, the magnet and armature 
 of which are placed within the door, Avhile the bells 
 are placed on the outside of the door, the hammer ex- 
 tending through the door and between the bells. 
 
 The body of the magneto call consists of a curved 
 casting, u, which is secured to the inner face of the 
 
HOME MECHANICS FOR AMATEVHS 
 
 365 
 
 door and provided with loops, v v' , for receiving the 
 soft iron pole pieees, w ic' , of the bell uiai»net. These 
 pole pieces are held in place in the h>ops, r r', by 
 screws passing throngh the side of the loop and bear- 
 ing against the pole piece. The convex side of the 
 casting, //, is provided with a rectangnlar notch, a', 
 for receiving the L-shaped permanent magnet, 5', which 
 is held in its place by a screw passing through the 
 
 Fig. 326. Details of Magneto-Call— the Bell. 
 
 magnet into the casting. To the L-shaped magnet, V, 
 is secured a plate, c, which is bent twice at right 
 angles, and in the bent ends of which are inserted pivot 
 screws supporting the armature, d, which extends 
 downward between the adjacent ends of the pole pieces, 
 ic If'. The armature is covered by a strip, e', of cop- 
 per, and in the end of the armature is inserted a wire, 
 
366 HOME MECHAXICS FOR AMATEURS 
 
 /, carrying at its extremity a bell liaminer, g'. To the 
 outer surface of the door, and on opposite sides of the 
 bell hammer, are supported two bells, I, by studs, i'j 
 projecting from adjustable plates, /, pivoted to the 
 door at one end and provided with a curved slot at the 
 opposite end for receiving a clamping screw, w^hich 
 passes through the slot and into the door. By means 
 of this device the bells may be adjusted so that each 
 will receive a stroke cf the same power from the bell 
 hammer, //'. 
 
 The spools on the pole pieces, 7r w', contain about 
 H ounces of No. 34 silk-covered copper Avire. They 
 are wound in the same direction, and the inside ends 
 are connected together. The outer end of one spool 
 is connected with the upper hinge of the casing, which, 
 in turn, is connected with the binding post, g'; the 
 outer end of the remaining spool is connected with a 
 strip, Ic, of copper attached to the door and connected 
 with a plate, /', which comes into contact with the 
 spring, /, when the door of the casing is closed. 
 
 On the top of the casing there is a plug switch, 
 Avhich also answers as a lightning arrester. The rear 
 plate of the switch is provided with the binding post, 
 m, which is connected with the ground. The binding 
 posts, q q\ receive the ends of the line wire, the con- 
 nections being made as showm in the section on the 
 telephone, pages 358-360. 
 
 When the call is placed at the end of the line the 
 call box is grounded by inserting the plug, r, between 
 the rear or ground plate and the front plate that is 
 not connected with a line wire. When it is desired to 
 cut the call box out of the line, the plug is inserted in 
 the circular space between the two front plates, the 
 
HOilK MECHANIC'S I'Olt AMATEUKS 
 
 367 
 
 current passing from one end of the line through one 
 of the binding post to the other portion of the line. 
 When the i-.rnuiture, B, is turned by revolving the 
 crank, (1, opposite ends are alternately presented to 
 opposite poles, the consequence being that the rapid 
 changes of magnetism in the armature induce alter- 
 nate pulsations in the winding of the armature which 
 operate the polarized bell of the instrument, also the 
 polarized bell of the distant instrument, both being 
 uormallv in the circuit. 
 
 While talking over the line it is important to cut 
 out the magnet on account of its resistance, and while 
 signaling over long distances the signals are more 
 effective if the telephones are cut out of the line. 
 
 These machines can be purchased for |4, and we 
 therefore doubt if it is profitable to undertake to make 
 them ; however, they may be made without fear of legal 
 complications, as they are not patented. 
 
 THE END. 
 
Index 
 
 ^ Page 
 
 Barometer 201 
 
 Bas-Reliefs 69 
 
 Battery, Primary 227 
 
 Brass, Burnished 78 
 
 Cabinet, Electrical 246 
 
 Cabinet, Wall 40 
 
 Caloric Engine 176 
 
 Carving, Wood 26 
 
 Centering 106 
 
 Chasing 126 
 
 Chime, Electric 237 
 
 Chucking 112 
 
 Cutters, Rotary 136 
 
 D 
 
 Drills and Drilling 99 
 
 Dynamo, Edison 319 
 
 E 
 
 Electricity 227-367 
 
 Electric Lighting 232 
 
 Engines and Boilers, Model, 
 
 169-184 
 Engines, Running 175 
 
 Page 
 
 Fluted Work, Turning 10 
 
 Frames 36 
 
 Furnace, Electric 333 
 
 G 
 
 Gear Cutting 152 
 
 Glass, Stained 51 
 
 Grilles and Gratings 31 
 
 Grinding and Polishing . , 92 
 
 H 
 
 Household Ornaments .... 31 
 Hygroscope 198 
 
 Index Plates 147 
 
 Iron Work 73 
 
 K 
 
 Knives, Moulding 9 
 
 Knurling 126 
 
 Lamp, Electric Night 243 
 
 Launch Motor, Electric... 298 
 
 Lathe, Foot 96 
 
 Lathe, Inexpensive 1-7 
 
 Lathe, Woodworking on a. 8 
 
 [369] 
 
370 
 
 INDEX 
 
 M PAOE 
 
 Majolica, Imitation 49 
 
 Metal Turning 119 
 
 Metal Working .89-168 
 
 Meteorology 187-205 
 
 Microscope, The 218 
 
 Model Making 155 
 
 Motor, Edison 319 
 
 Motor, Sewing Machine . . 278 
 Motor, Simple Electric ... 259 
 
 Motor, Small Electric 270 
 
 Moulding Knives 9 
 
 Moulding, Wood 11 
 
 O 
 
 Ornament, Feather 39 
 
 Ornaments, Household ... 31 
 
 P 
 
 Plaster Objects 85 
 
 Portiere 57 
 
 Pseudo-Ceramics 41 
 
 R 
 
 Rain Gauge 193 
 
 Repousse 61 
 
 S 
 
 Sawing, A Wrinkle in ... . 25 
 
 Sawing Metals 89 
 
 Saw, Scroll 12 
 
 Saw Tooth 21 
 
 Saw, Wood 8 
 
 Paok 
 
 Scroll Saw 12 
 
 Silver Work 94 
 
 Slide Rest 143 
 
 Soldering 90 
 
 Spinning Metals 160 
 
 Stained Glass 51 
 
 Steadying 106 
 
 Steam Engine 169 
 
 T 
 Telegraph, Recording .... 848 
 Telephone, How to Make.. 355 
 Telescope, How to Make... 207 
 Telescopes and Micro- 
 scopes 207-225 
 
 Thermometers 194 
 
 Tooth, Saw 21 
 
 Turning, Wood 6 
 
 V 
 Vases 41 
 
 W 
 
 Wall Ornaments 35 
 
 Water Motor 181 
 
 Weather Vane 189 
 
 Whittling 16 
 
 Wind Pressure Gauge .... 190 
 
 Wire, Things in 75 
 
 Wood Carving 26 
 
 Wood Turning 6 
 
 Wood-Working 1-29 
 
 Work Bench 14 
 
Tools for Home Mechanics 
 
 |j^:,^,|l|,|lfeil|l|l|lll|l|l|l|l|||l|l|l|l|l|l|l|lpi|l|l|l|l|^l|l|l|^^ 
 
 E#> y:;,i:;^i;L?i.ij.^i.ij.iiij.,^i,i.^ 
 
 Sargent's Planes 
 
 are firsl-class goods throughout; well made and nicely 
 finished. 
 
 Sargent's Screw Drivers 
 
 are superior tools that are appreciated by good mechanics. 
 
 Sargent's Saws 
 
 are perfect. There are no better saws than these in the 
 world. 
 
 Sargent's Squares 
 
 are standard goods, carefully made from best steel. 
 
 Sargent's Steel Hammers 
 
 are made from solid cast steel. They are of the highest 
 grade. 
 
 Sargent's Augers and Bits 
 
 are branded " U. S." They are meant for use day in 
 and day out. 
 
 SARGENT & CO. 
 
 New Haven, Conn. ; New York ; Philadelphia ; Boston ; Chicago 
 
OUR Catalog 
 
 GOODELL-PRATT COMPANY 
 
 TOOLS 
 
 Number u 
 
 GPvEENFJELD.MASSU.SA. j 
 
 snows 
 
 128 
 
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 Labor 
 Saving 
 
 Tools 
 
 It will be sent FREE to any address on 
 receipt of a request mentioning this book 
 
 YOURS TRULY 
 
 GOODELL-PRATT Cmm 
 
 GREENFIELD, MASSACHUSETTS, U. S. A 
 
Tffi FRANKLIN 
 MODEL SHOP 
 
 ^ Sets of Castings and Materials in the rough or semi- 
 finished for the Franklin Model Gas Engine and the 
 Franklin Model Dynamo. Send for Catalog M. 
 
 ^ The latest scientific novelty, Aeolicraft Model Yacht. 
 Sails on a Tight Wire. Write for booklet. 
 
 Franklin Horizontal Gas Engine 
 
 ^ Materials furnished for Constructing any of the Appara- 
 tus or Devices described in this Dook. Prices on application. 
 
 ^ Electrical, Experimental and Fine Tool 
 Work. Correspond- 
 ence solicited. 
 
 arse 
 
 11 & Weed 
 
 129-131 West 31st St. ^^ 
 
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 Gas Engine 
 
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