./^\ ^^^*\ '^^^^'^^ °''^^*'' ./^''''^^ ^^^*' . ^^^^< %^** •'^'' ^^/ -'Sfe'' V** .' ^^ FOUNDRY PRACTICE A Text Book for Molders Students and Apprentices BY R. H. PALMER ii Molder, Foreman and Superintendent of Foundries ; Sometime Instructor in Foundry Practice at the Worcester Polytechnic Institute, Worcester, Mass. FIRST EDITION FIRST THOUSAND NEW YORK JOHN WILEY & SONS . London : CHAPMAN k HALL, Limited 1912 Copyright 191 1 By R, H. Palmer /:2 -7/^ 7' PBEBB OF THE FUBLIBHEBS PKINTING OOMPANT, NEW YORK, IT. 8. A. ©CI.A305218 PREFACE During his experience as instructor in foundry practice at the Worcester Polytechnic Institute, the author was "^ handicapped by the lack of a suitable text-book. The vol- ^v ume presented here follows the scheme of instruction used by him, and, beginning with the simplest type of mold, endeav- ors to lead the student and apprentice gradually through the more difficult lines of work in green and dry sand and loam. From the many possible examples which might have been used to illustrate the different practices, only those have been selected which are typical of the class of work to which they belong. It is recommended that the reader, whenever pos- sible, supplement his study of this book by actually making molds of the character described in the various chapters. It is impossible to learn the art of molding by reading only. Such other matters as the student of foundry work should be acquainted with are included in the book, these including the subjects of cupola practice, mixing and melting, cleaning and repair of castings, etc. The author has endeavored to make a text-book for the student, apprentice, and molder, rather than a reference work for the finished foundryman. His thanks are due to Mr. Robert Thurston Kent, M.E., for editing the manuscript and reading the proofs. R. H. PALMER. Belmont, Allegany Co., N. Y., October i, 191 1. CONTENTS CHAPTER PAGE I. The Mold — Its Form and the Methods of Making It, . . i Molding a Split Pattern 8 Molding a Split Pattern with a Web Center, 12 II. Irregularly Shaped Patterns, . > 15 Molding a Hand Wheel 17 Coping Down Irregular Patterns, 18 Molding in a Three-Part Flask 20 Molding with a False Cheek, 21 Molding Double Groove Sheave in a Three-Part Flask, . 22 Gear Molding, 25 III. Floor Molding, 30 Molding Lathe-Bed Legs • 30 Pouring Floor Molds 36 Molding Pulleys, 37 Molding Bevel Gears, 39 IV. Light Crane Floor Work, 43 Molding Wire-cloth Loom Frame 43 V. Bedding Patterns in the Foundry Floor, 48 Molding a Draw-Bench Frame in the Floor 49 Molding a Gap-Press Frame 58 VI. Molding Columns, 65 Ornamental Columns, 65 Round Columns 69 VII. Molding with Sweeps, 75 VIII. Molding Car-Wheels 84 IX. Skin-Dried Molds, 90 Molding an Engine Bed in a Skin-Dried Mold, .... 91 X. Dry-Sand Molds, 100 Molding a Corliss-Engine Cylinder in Dry Sand, . . . loi Molding Printing-Press Cylinders in Dry Sand, .... 108 VI CONTENTS CHAPTER PAGE XI. Loam Molding ii6 Molding a Cylinder in Loam, 120 Molding Balance Wheels in Loam, 128 Loam Mixtures, 132 Sweeping Loam Cores, 132 XIL Molds for Steel Castings, 134 XIIL Dry-Sand Cores, 138 XIV. Setting Cores and Using Chaplets, 156 XV. Gates and Gating, 163 Types of Gates, 168 XVI. Risers, Shrinkheads and Feeding Heads, 174 XVII. Treatment of Castings While Cooling, 176 XVIII. Cleaning Castings, 181 XIX. Molding Machines, 184 Power Squeezers, 185 Split-Pattern Machines, 190 Jarring Machines 194 Roll-Over Machines, 197 When to Use a Molding Machine, 202 XX. Mending Broken Castings, 204 Burning, 204 Thermit Welding 207 Oxy-Acetylene Welding, 208 XXI. Molding Tools, 210 XXII. Molding Sands, 217 Preparation of Sand for Molding, 226 Facing Materials, 228 XXIII. Iron and Its Composition, 234 Grading of Pig Iron, 237 Specifications for Foundry Pig Iron 239 Analyses of Castings, 241 Shrinkage of Cast-Iron, 244 XXIV. The Cupola and Its Operation 245 Calculation of Cupola Mixtures, 265 CONTENTS Vll CHAPTER PAGE XXV. The Air-Furnace and Its Operation, 271 XXVI. The Brass Foundry 275 XXVII. Foundry Equipment . 280 Glossary, 288 Appendix, 298 Circumference and Areas of Circles, 298 Surface and Volume of Spheres, 304 Weight and Specific Gravity of Metals, 307 Melting Points of Various Substances 308 Strength of Rope, ......' 309 Strength of Chains 310 Analyses of Fire-Clay, 311 Sizes of Fire-Brick, 312 Number of Fire-Brick Required for Various Circles, 313 Weight of Castings Determined from Weight of Pattern, . . .314 Dimensions of Foundry Ladles, 314 Composition of Brass Foundry Alloys, 315 Useful Alloys of Copper, Tin, and Zinc, 316 Composition of Various Grades of Rolled Brass, etc., .... 317 Shrinkage of Castings, 317 Sizes of Pipes for Tumbling Barrels, 318 Diameter of Exhaust Fan Inlets for Tumbling Barrels 318 Steel Pressure Blowers for Cupolas, 319 Capacity of Sturtevant High Pressure Blowers, 321 Speed, Capacity, and Horse-Power of Sirocco Fans, 322 Capacity of Rotary Blowers for Cupolas, 323 Diameter of Blast Pipes 324 FOUNDRY PRACTICE CHAPTER I THE MOLD— ITS FORM AND THE METHODS OF MAKING IT In all foundry practice, the mold is the essential feature. A mold is the form or cavity in a refractory material such as sand or loam, or in metal, into which molten metal is run or poured, and which determines the final shape of the poured metal after cooling. See Fig. i. While molds are made in many different materials, and of many different shapes and by diliferent methods, yet in their essential characteristics they are all alike. They are all made from a pattern, which may be of wood, metal, or other material ; except for the very largest molds, which are bedded in the floor of the foundry, and for certain other special kinds of molds, they are supported by and enclosed in a flask, which may be either of wood or metal, and which may be either rigid or hinged, the latter being known as a snap flask; they are formed in a material which will withstand the heat of the molten metal when it is poured into the mold, the more common materials being sand, either dry or green, loam, plaster of parts, and iron, the latter being used for chilled work such as car wheels, etc.; cavities in the casting, by which name the final product of the foundry is known, are formed by means of cores which may be either baked cores, or green-sand cores. Molding operations are variously subdivided. Thus, according to size, there is what is known as bench work, usually for the lighter class of castings, and floor work, for the heavier castings. According to materials of which the mold is com- 2 FOUNDRY PRACTICE posed, the work is classified as green-sand, dry-sand, loam, or chilled work. Another subdivision is hand work and machine work, depending on whether the mold is made by hand or in a molding machine. Each of these classifications may be still further subdivided, as will be shown in subsequent chapters. In order to introduce the student to the art of molding we will consider the simplest class of mold, and discuss the various operations in its production — a green-sand mold made at the bench, with a one-piece pattern, the entire pattern being Fig. I. — Opened Small Green-sand Mold in Snap Flask. placed in one section of the flask, and made without cores or other complications. In order that the description of the actual molding opera- tions may not be burdened with descriptions of tools and equipment, more or less irrelevant, and yet which are used in the work, it will be assumed for the time being that the reader is familiar with these, and with their use. Each piece of equip- ment and every tool mentioned, however, is described in detail in Chapter XXI devoted to tools and equipment, and THE MOLD the reader is referred to that chapter or to the glossary, page 288, for such information as may be necessary as to render the description more expHcit. Referring now to Fig. i, the pattern to be molded is shown at A. This is a rectangular block eight by five inches and five-eighths of an inch thick. It is to be molded in green sand in a snap flask, the two parts of which are shown at C and D. As the pattern is quite shallow the short sides are parallel. A deeper pattern will have a slight taper, to enable it to be with- drawn from the sand more readily. This taper is known as the draft. The lower portion of the mold, that contained in flask C, is known as the nowel or drag. The upper portion is called the cope. Fig. i also shows the usual arrangement of the molder's bench, com- prising the grating on which the actual work is done, the sand bin below it, and the tool rack above, on which is shown the usual equipment of molder's tools, consisting of rammers, brush, riddle, bel- lows, and a tool box contain- ing his small tools. 1 M board pattern on board Fig. 2. — Arrangement of Pattern and Flask ox Mold-board. In making the mold, the molder first places his mold-board on the bench, with the cleats on the board extending away from him, this being the most convenient position for rolling over the drag. The pattern A is placed on the mold-board as shown in Fig. 2, and the drag of the flask placed over it with the pins projecting downward on either side of the board. An 4 FOUNDRY PRACTICE iron band H is slipped inside the flask and rests on lugs or ears F, having slots cut in it to permit it to slip over these lugs. It is important that there be plenty of sand over the pattern when the mold is complete, not only to prevent the bottom board from burning but to hold the metal in the mold. In the present case, the pattern being shallow, there is no doubt on this score, but with a deeper pattern the molder will place his strike across the top of the drag and thus ascertain the distance between the top of the pattern and the edge of the flask, and govern his selection of the flask accordingly. Being assured that there will be a sufficient depth of sand over the pattern, sand is sifted on the pattern as it lies on the mold-board by means of the riddle until the pattern is completely covered. The molder then tucks the sand around the edges of the pat- tern with his fingers, but does not press it down on top of the pattern unless there is some special reason for so doing. The drag is next shoveled full of sand and heaped high. The sand is then rammed around the inside of the flask with the peen or sharp end of the rammers. The rammer is held at this time with the hidt inclining toward the center of the flask, so that the blow is somewhat outward in direction, compressing the sand at the edges of the mold. More sand is then shoveled on to the flask, the rammers are reversed, and the entire sur- face of the mold rammed. After ramming, the surplus sand is scraped off the mold by means of the strike. In order that the mold will bear firmly at all points on the bottom-board, which is next placed on what is now the top of the drag, loose sand is thrown on the mold and the bottom-board placed over it and rubbed to a firm bearing. Were this not done, and should there exist any space between the bottom- board and the mold, the pressure of the iron when poured might cause the mold to break or cause a distortion of the casting. After placing the bottom-board, the drag is rolled over, so as to bring the pattern, and also the joint or pin side of the flask, to the top, as shown in Fig. i . If the sand has been properly rammed, a perfect joint can be made by rubbing the palm of the hand over the surface of the nowel. If the ram- THE MOLD 5 ming has been imperfectly done, the sand should be tucked around the pattern with the fingers. The surface of the drag, or joint, is next brushed ofif with a soft brush or blown off with the bellows, the former method being preferred as it leaves the joint in better condition to receive the parting sand. Parting sand is now thrown over the joint to insure a good separation of the cope and drag, any excess sand being blown from the Fig. 3. — I'i^kningtheSand against THE Sides of the Flask. Fig. 4. — Butt-ramming the Surface of the Mold. pattern as it would cause the casting to have a rough surface. A small amount, however, will do no harm and will prevent the sand in the cope from adhering to the pattern. The cope D is next placed on the drag, the two parts of the flask being kept in their proper relation by means of the pins on the drag fitting into the ears on the cope. The iron band H is placed in the cope, although with this type of pattern, often called a flat-back — that is, a pattern molded entirely in the drag, and with a flat surface at the joint — it is not altogether necessary as there is no side pressure to be resisted. It may be stated here that these bands are necessary only in snap-flask work. The gate-stick which forms the hole through which 6 FOUNDRY PRACTICE the metal is poured into the mold is next placed in position, being driven down a slight distance in the sand of the drag. In ramming, it is important that the sand should be firmly rammed around the edges of the flask with the peen end of the rammer in order that it will withstand the side pressure of the molten metal. Care should also be used to keep the peen end of the rammer not less than one and one-quarter inches away from the pattern when ramming, as the sand must be porous enough to allow the gases to escape when the metal is poured into the mold. A mold can be rammed too hard and it also can be rammed too soft. The proper degree of firmness can be learned only by experience. The gate-stick is withdrawn from the sand and the cope is next lifted from the drag and placed at one side as shown in Fig. I. Any imperfections left on the cope which are not desired, are smoothed off with the slicker. These imperfections consist of excrescences on the mold due to holes or other imper- fections in the pattern. In finishing the mold the cope should be perfected before the pattern is drawn from the drag, as in case of damage to the cope the sand can be knocked out and the cope rammed up a second time, whereas this would be im- possible had the pattern been removed from the drag. The hole left by the gate-stick is beveled over at the joint so that the molten iron entering the mold will not wash sand in with it. The hole left by the gate-stick at the top of the cope is reamed out to a bell-shape to facilitate pouring of the metal. The sand around the pattern is next dampened by water squeezed from the sivab, which is passed gently around the edges of the pattern, care being taken to prevent the water from running on the pattern, which if constantly repeated, would cause the pattern to swell and become distorted. The object of wetting, or boshing, the sand around the pattern is to cause the various grains of sand to cohere and to prevent the sand from breaking when the pattern is withdrawn. The pattern is withdrawn by means of the draw-nail, which is driven into the pattern. The molder grasps the draw-nail with his left hand and, by means of a rapping-iron, jars the pattern THE MOLD 7 loose in sand by striking the draw-nail a few sharp blows, first on one side and then on the other, close to the pattern. He then lifts the pattern vertically upward, using the draw- nail as a handle, at the same time rapping it gently with his rapping-iron. When the pattern has been lifted to a point where the molder can feel that it is free from the sand, he balances it and moves it up and down slightly to make sure that it is entirely free and then with a quick motion lifts it directly upward entirely out of the mold. It is important that the pattern be drawn straight upward, as the slightest sidewise motion will break the edges of the mold at the joint, making necessary expensive and more or less unsatisfactory repairs. The pattern being drawn, any imperfections in the mold or breaks at the joint are repaired with the slicker. All imperfections having been repaired, a channel is cut in the sand from the impression in the nowel left by the gate- stick, to the mold. This channel is known as the gate or sprue and is made with the sprue- cutter. It is shown at 5. At £ a cavity is hollowed out in the cope, being known as a cleaner. Any dirt which may be washed through the gate with the iron will tend to rise to the surface and be caught in the cleaner and thus be prevented from passing into the mold. These various operations having been completed, the mold is closed, that is, the cope is placed on the drag, the pins on the drag fitting into the ears on the cope bringing the two halves of the mold into the same relation they bore to each other when they were rammed up. The mold is then placed on the floor at a point convenient for pouring metal into it and the fastenings on the flask are loosened, the flask opened up, and removed from the mold. Weights as shown in Fig. 5 are placed on top of the cope to hold it down firmly on the drag while the metal is being poured into it and to prevent the metal from working its way out of the mold through the joint. At this point, the importance of striking the sand evenly from the top of the cope becomes evident, for, should the weight not bear evenly at all points on the surface of the cope, the pressure of the iron in the mold will lift the cope 8 FOUNDRY PRACTICE away from the drag on the side on which the weight does not bear, and allow the iron to flow out at the joint, this being known as a run-out. Furthermore, if the weight does not bear all over the cope, a "strained casting" or one thicker than desired will result, often causing the rejection of the casting. The molds are placed on the floor for pouring as close together Fig. 5. — Molds Weighted for Pouring. as possible as shown in Fig. 5, only enough room being left between the different rows of molds to permit the molder to pass with his ladle. Here again the importance of proper weighting is evident, since the molder is in serious danger of being burned in the event of a break-out while pouring. Molding a Split Pattern Where the pattern is of such shape that it would be incon- venient or impossible to mold it with the pattern entirely in the drag, a split pattern is employed. Such a pattern is shown THE MOLD 9 in Fig. 6 and the mold made from this pattern in Fig. 7. This mold also illustrates the use of green-sand cores. One half the mold is in the drag and the other half in the cope. The line B, Fig. 6, on which the pattern is separated is known as the parting. Referring now to Fig. 6, the method of molding is shown. The mold board / is placed as was the case for the rectangular, one-piece pattern described above and the drag half of the pattern D is placed as shown on the mold board with PATTERN ON MOLDBOARD PATTERN IN COPE SIDE VltW OF PATTERN 1 _X l_o_ijjLy ,p (" r" y -^ ^C^l ^ 4 i ,uu u il IL 1 r ^0 ^ 5^ TOP OF PATTERN <^ <^ ^ <^ <^ ^ H H H Pockets <^ ^ <^ ^ 'S> Fig. 6. — Method of Molding a Split Pattern. the parting down. The drag of the flask with its iron band L is placed in position exactly as was the case with the pattern described above. Sand is next riddled on to the pattern and tucked down with the fingers into the pockets between the ribs R and the ends S and laid up against the side of the pat- tern. The drag is then rammed up as in the first case, the bottom-board placed, rubbed to a bearing, and the drag turned over. On removing the mold-board, the joint is made by rubbing the sand from around the pattern with the palm of the hand. If the sand has been properly tucked down in the pockets and around the sides of the pattern, there is no need of using a 10 FOUNDRY PRACTICE trowel. If this has not been done and the sand is too soft around the pattern, fresh sand must be tucked in and sHcked with the trowel. The joint being made, the cope half of the pattern is placed on the drag half, as shown at M, Fig. 6, and parting sand is dusted on the sand joint. In order that the cope and drag halves of the pattern will align properly, dowel pins are provided in the cope portion as shown at C, Fig. 7, which fit in holes in the drag at D. The cope of the flask is Fig. 7. — Mold Made from F"ig. 6. then set, as shown at M, Fig. 6, with the iron band N inside of it. In order to strengthen the green-sand cores, E, the nails P, Fig. 6, are placed in position. These are necessary, as the sand has not sufficient strength to sustain itself in deep pockets, such as we have here, and would break of its own weight when the pattern is withdrawn. The nails are placed after about one-half inch of sand has been riddled into these pockets in the pattern. The nails are wet and are set heads down in the corners of the pockets. The gate-stick is next placed, sand is riddled into the cope, tucked down around the nails and pattern, and the cope is THE MOLD II rammed up. It should be remembered when ramming, that after having peened between the sides of the flask and the pattern, and the mold is being rammed with the butt of the rammer, that the same blow struck over the top of the pattern will pack the sand harder there than it will the sand alongside of the pattern, due to the fact that there is a smaller body of sand to absorb the shock of the blow. As the molten iron fills the mold, it drives ahead of it to the highest parts of the mold, the gases and steam generated in the mold. If the sand has been rammed too hard over the pattern, these gases may have ditftculty in escaping through the sand and, being pocketed in the mold, will expand and force the iron back through the gate, leaving an imperfect surface in the casting. It is essen- tial, therefore, in ramming, that the blows struck over the pattern shall be soniewhat lighter than those struck on the sand alongside the pattern. The cope being rammed up and struck ofif, loose sand is thrown on top of the cope, the gate-stick is removed, and the mold-board rubbed down on the cope in a similar manner to the bottom-board on the drag. At this point, the mold is vented with a vent-wire, provided a close-grained molding sand has been used, which is not permeable enough to permit the ready escape of gases through it. The venting is done by pricking the sand full of holes over the top of the pattern. To vent a mold properly, it is essential that the molder be able to carry in his mind the shape of the pattern, and he should trace in the sand the outline of the pattern, as it lies in the flask. Care should be taken not to drive the vent-wire into the pattern, as this will damage the pattern and cause imperfect castings. After venting, the mold-board is placed and the cope is lifted from the drag and laid on its back on the board. The pattern is next boshed and is then removed from the mold by means of a draw-nail. It is essential that the mold- board be rubbed to a firm bearing on the top of the cope, other- wise, in driving the draw-nail into the pattern, the pattern will be driven down into the back of the cope, and in this case, 12 FOUNDRY PRACTICE when the cope is turned on its side after the pattern is with- drawn, there would be danger of the sand in the back of the cope sliding out and ruining the mold. The parts of the pattern in the cope and drag being drawn, the mold is finished with the trowel or slicker, the gate in the cope is reamed out at the top, and the gate is cut in the drag from the impression of the gate-stick to the ribs in the mold, as they form the deepest parts. (See F, Fig. 7.) After cutting the cleaner G in the cope, the mold is closed, set on the floor, and weighted ready for pouring. Molding a Split Pattern with a Web Center In Fig. 8 is shown a pattern somewhat similar to that in Fig. 6, with the exception that there is a web A at the center. The green-sand pockets in the mold formed by Fig. 6, are in this case cut ofif by this web. The molding of this pattern is similar to the operation of molding the pattern shown in Fig. 6. The portion of the pattern with the web is molded in the drag, with two bands H inside the flask. The principal difference in the operation of molding is in the placing of the nails which strengthen the green-sand cores. After the pattern has been placed on the mold-board, sand is riddled over it until it has a depth of about three-eighths of an inch in the pockets of the pattern, after which nails of the correct length are wet or clay-washed and set with the heads down in corners of the pockets. Sand is then riddled on the pattern, tucked down, and the flask rammed up as usual. The nails are set in the green- sand cores of the drag to hold the pockets down and to support the corners, since, when the drag part of the pattern is rapped and drawn, the pocket of sand may be cracked away from the drag and when the melted iron is poured into the mold it will enter the crack and float the sand against the green-sand cores of the cope, thus spoiling the casting. The nails pre- vent this. Molding the cope of the pattern shown in Fig. 8, is carried out in the same manner as was the pattern in Fig. 6. In pat- THE MOLD 13 terns having pockets too deep to allow the use of nails, wooden rods or soldiers are used. These must be well soaked with water before using, inasmuch as dry soldiers will absorb moisture from the sand and swell, thereby cracking the mold. After soaking, the soldiers should be dipped in clay wash to enable them to hold to the sand. Too much emphasis cannot be laid on the fact that it is possible to ram a mold too firmly over the pattern. The proper degree of firmness can be learned only by experience, but a test can be made by applying pressure with the fingers to the finished mold. The face of the average small mold, prop- SIDE VIEW OF PATTERN PATTERN ON MOLDBOARD zy^ TOP VIEW OF PATTERN F Fig. 8. — Molding a Split Pattern with a Web in the Center. erly rammed, will yield slightly to pressure. If it is ram- med so hard that it is unyielding to finger pressure, it is certain that the gases will be unable to escape and a casting full of blow-holes will result. We have described above three simple molding operations in green sand. They are typical of all green-sand work, ex- cept that when large castings are made, modifications in the practice are necessary. Special arrangements must be made for strengthening certain parts of the molds, and also for venting, as will be described in later chapters. The bulk of foundry molding is done in green sand, and therefore many of 14 FOUNDRY PRACTICE the later chapters will take up in detail the making of molds in this material, describing the methods to be employed and the precautions to be taken. While green-sand molding is the most common, there are other varieties of molds employed for special purposes, which are also described in detail later in the book. Thus there is a skin-dried mold which is a green-sand mold with the surface baked by means of an oil or gas torch or a fire basket ; the dry- sand mold which is a green-sand mold baked in an oven, and which is employed for making steel castings and in other situ- ations where a particularly accurate casting is desired; the loam mold built up from a mixture of sand and clay, backed with brick work, employed for large castings where, the expense of pattern work is to be avoided; the chill mold made of iron, used for car wheels and other castings in which a particularly hard, close-grained surface is desired. These various molds all have their uses which will be enumerated together with the method of making them at the proper point in this book. For the present, however, we will confine ourselves to the further consideration of green-sand molds. CHAPTER II MOLDING IRREGULARLY SHAPED PATTERNS— COPING DOWN —MOLDING IN A THREE-PART FLASK— THE USE OF A FALSE CHEEK— MOLDING GEARS The patterns described in the previous chapter have been molded on a plain mold-board, cope side down, and have been rammed up in the drag. The joint has been made by simply brushing off the sand or slicking it with the trowel, which is all that is required with a pattern having a plain cope side, which allows it to lie on the mold-board while being molded. In Fig. 9, at C, D, E, and F, are shown patterns which it would be impossible to place on a plain mold-board and ram up in the drag, since they would not remain in position on the mold- board to cause the desired portion to come in the cope. To mold a pattern of this character, it is necessary to cope down, in order to bring the proper portions of the pattern in the cope and drag respectively, and also to permit the pattern to be drawn from the mold. Referring to Fig. 9, the method of molding these four patterns is shown. None of these patterns will lie in the cor- rect position on the mold-board and. therefore, a rough bottom-board is placed on the bench and on that an upset, a wooden frame of the required size and depth, is placed. The opening in the lower side, adjoining the bottom-board, is a trifle larger than that in the top side. The upset is usually attached to the bottom-board with screws. Sand is riddled into the upset and is rammed in the same manner as a flask, and struck off level with the top. The patterns to be molded are placed on the sand in any desirable position. The sand is then dug out under them, so as to allow them to sink in the sand to the same depth that it is desired they shall project into the cope when this is rammed later. The sand is then 15 i6 FOUNDRY PRACTICE roughly formed around them and a Httle parting sand dusted on. In Fig. 9, at A, is shown the bottom-board with the upset B attached to it, and the sand formed in place as de- scribed. The drag of the flask is next placed over the upset and is rammed up in the same manner as would be patterns laid on a plain mold-board as described in Chapter I. After rolling the drag over, this frame of wood with the sand in it, is lifted oft' and the parting is made to follow the shape of the Fig. 9. — Molding Irregularly Shaped Patterns with a Green-sand Match. pattern in the drag, thus causing the sand in the cope to ex- tend down on each side, so that the lower side of the pattern will be formed in the drag and the upper side in the cope. The line of parting having been determined in this manner, the sand is shaken out of the upset and the frame removed from the board. The frame is then placed on the drag in the same manner as would be the cope, the side with the small opening being down. The frame is rammed up in a similar man- ner to a cope and the sand struck off level with the top. The bottom-board is then rubbed to a bearing and screwed to the MOLDING IRREGULARLY SHAPED PATTERNS 1 7 frame. The upset is then Hfted off, being now what is termed a green-sand match, as shown at A, B. It is evident that the patterns C, D, E, and i^'can easily be replaced in their respec- tive positions in the match. The joint of the drag is then blown ofif with the bellows, fresh parting sand is dusted on, and the cope is rammed up and lifted off in the ordinary manner. The cope is shown at G. The joint is now blown off to free it of loose sand, the patterns are boshed and drawn from the drag, after which the mold is finished and the gate / cut to carry the iron to each one of the impressions left by the four patterns. The casting made from pattern F is to have a hole in it at L. This hole will be formed in the casting by means of a core which is shown vSet in position in the drag at K. The position of the core is determined by means of the core-print L on the pattern. This core-print will form holes in the cope and drag as shown at M. A vent-wire is run up through the cope from this core-print to permit the escape of gas from the core. The venting of the core itself is fully described in Chapter XIII, devoted to cores. The mold is now ready for closure, weighting, and pouring. The green-sand match may be used many times for ram- ming up the drag if care is exercised in handling it and in placing the patterns. In many cases, where but one casting is wanted from a pattern, the cope is rammed up in the same manner as an upset, and the pattern is bedded down in it and the drag then rammed up. After the joint has been made, the cope is knocked out and is again rammed up to form the cope of the mold. Molding a Hand Wheel Let us consider the operation of molding a hand wheel, the rim of which is set some distance forward of the hub. The wheel is laid on a level mold-board and strips of wood, one-half the thickness of the rim, are placed under the drag of the flask, in order to raise it so that one-half of the rim will come in the cope. Sand is rammed around the pattern, and 2 l8 FOUNDRY PRACTICE when the drag is rolled over and the mold-board removed, the rim of the wheel is found to be above the joint of the drag, by just the thickness of the wooden strips, this operation being termed upsetting the drag. The joint is then made and, as the hub of the pattern is lower than the rim, there will be quite a body of sand to lift out. The arms of the wheel being rounded on the edges, will add more. The parting is made by removing sand until the point is visible where the pattern begins to round under. After the joint has been made and parting sand has been rubbed on, some riddled sand is laid by hand on the slanting parting in order to make the parting sand remain in place. If the molding sand is riddled directly on the steep parting, it will slide down and carry the parting sand with it and the cope will stick to the drag and break the mold. There will be a considerable body of sand hanging from the face of the cope due to the recession of the hub from the rim of the wheel, and it is necessary to support this by means of a soldier, a piece of wood in this case, about eight inches long, one inch wide, and half an inch thick. These soldiers are placed, after being first dipped in the wash pot, by scraping the sand from the pattern adjoining the core- print in the hub, so that there is about five-sixteenths inch thickness of sand outside the core-print. One soldier is placed between the core-print and the slanting parting and another soldier is placed on the opposite side of the print with a nail quartering from the soldier each way. This gives four supports for the sand which is firmly tucked around them and rammed in the center, using a gate-stick for a rammer. The cope is then rammed up as usual, the gate-stick being set to gate into the rim. Coping Down Irregular Patterns Referring to the patterns in Fig. lo, P is a pattern which can be molded in the same flask with Q. Both these patterns require coping down in order to permit the pattern being drawn from the mold. The upset is rammed full of sand and each MOLDING IRREGULARLY SHAPED PATTERNS 19 pattern is bedded so as to throw it into the cope. The pattern P is placed in the upset in the position shown in Fig. 9, being set somewhat deeper than the thickness of the plate connecting the two lugs. It is parted as described above down to the middle of the bosses on the lugs, while the plate part of Q is placed in the upset to the depth of the plate containing the two square holes. The drag is rammed up, rolled over with the upset, and the upset removed. The joint is made and, when Fig. 10.- -Odd-shaped Patterns which are Molded by Coping Down IN Drag or in Cope. ramming the cope, soldiers are used as described above, for lifting the sand around the lugs while the hanging sand over Q should take care of itself with a properly arranged parting. Pattern R requires a flask by itself. In molding, the end which is foremost in the illustration is thrown into the cope above the joint, the other end of the pattern being kept below the joint. This pattern is upset in the cope and coped down from the drag, requiring a very irregular joint. The two square holes in the end are formed by green-sand cores. It is unnecessary to place nails in these cores to hold them as, if 20 FOUNDRY PRACTICE they are well boshed and the pattern carefully drawn, they will remain in better shape in the mold than if nailed. Often nails in small green-sand cores do more harm than good, as in rapping the pattern, when drawing it, the nails in the core hold while the sand moves, thus breaking the core. Patterns 6' and T may be molded in the same flask and will require some coping down. The remaining patterns can be molded together as they can be best arranged, three or four in a flask, according to the ideas of the molder. Molding in a Three-Part Flask Fig. 1 1 shows a sheave together with the method of mold- ing it in a three-part flask. When molded in the three-part flask, the pattern is laid on the mold-board in the center of the ry::! Dragy -^^ Fig. II. — Molding a Sheave in a Three-part Flask. cheek D, as shown at C, the parting of the pattern being at E. The cheek is rammed up around the pattern, which operation tends to force the two halves of the pattern apart and thus make the sheave thicker than desired. To prevent this, the weight F is placed on top of the pattern, while the cheek is MOLDING WITH A FALSE CHEEK 21 being rammed. After the joint in the cheek is made, the drag M is placed and rammed up, nails being placed as shown. The cheek and drag are rolled over together and the second parting is made, after which the cope is rammed up, nails being set as shown at G. The cope is lifted ofT and the portion H of the pattern drawn, after which the cheek is lifted off, set aside, and the portion of pattern / drawn. After the core is set, the gate is arranged as shown at / in the cope. Molding with a False Cheek The method of molding with a false cheek is shown in Fig. 12. The pattern is placed on the mold-board as is shown in Fig. II, an upset often being used instead of a cheek. After Fig. 12. — Molding a Sheave in a Two-part Flask with a False Cheek. ramming up the cheek, removing the sand, and forming the parting on the line K, Fig. I2, the cope is placed on the cheek or upset, being raised by strips one-half the thickness of the pattern, so that, in the finished mold, half the pattern will be in the cope and the other half in the drag. The arrangement 22 FOUNDRY PRACTICE is the same at this point as shown in Fig. ii, at L. The board is rubbed to a bearing on top of the cope which then is rolled over, the strips removed, and a parting made at the line N, Fig. 12. The drag is placed and rammed up, the bottom- board is rubbed to a bearing, and the drag lifted ofT. Consider- ing now the flask A", Fig. 12, as a whole, the false cheek is shown between the lines K and A^, the cope being rammed up on one side of it and the drag on the other. The drag being lifted, one-half the pattern is drawn, the parting being on the line E. The mold is finished in the drag and the drag replaced, the whole fiask rolled, and the cope lifted. Bearing in mind that there is only the sand forming the outside of the sheave groove to hold the cope part of the pattern up, the cope portion of the pattern is carefully drawn from the sand. The core is set, the cope finished, and the gate is punched and the basin made as shown at /. Molding a Double Groove Sheave in a Three- Part Flask Frequently it is necessary to mold a double-groove sheave when only a three-part flask is available. The method of doing this is shown in Fig. 13, being a combination of the two methods above described. The pattern is laid on the mold- board and the cheek F rammed up, after which the cope G is made. The cheek and the cope are rolled over and the false cheek H made with a parting at X, after which the drag is made. The drag is lifted, together with a portion of the pat- tern L, to which are fastened the ribs AI. This portion of the pattern is drawn from the drag, which is finished and re- placed. The entire flask is then rolled over and the cope lifted together with the cope portion of the pattern. After draw- ing the pattern the solid cheek is lifted from the drag and the middle part of the pattern drawn. The pattern is parted on the lines C and D. The mold is now finished and closed. It may be poured either through the hub, as was the first sheave, or it may be gated. If the grooves in the MOLDING IN A THREE-PART FLASK 23 sheave are very deep, they should be supported with nails as shown in Figs. 11 and 12. At times, the sheaves are molded by using a pattern with a core-print around it and making a set of cores in a core-box. After the pattern is drawn from the mold, the cores which form the grooves in the edge of the sheave are set. Such a core would occupy the position of the false cheek KN, Fig. 12. If it is necessary to mold a sheave from a solid pattern, that is, one without a parting, the false cheek may be formed on Fig. 13. — Molding a Double Groove Sheave in a Three-part Flask, Using a False Cheek. two pieces of paper, cut to the shape of the circumference of the sheave, a parting being made by each sheet of paper. After the cope is lifted, the pieces of paper, having the cheek built on them, are pulled apart, thus drawing the sand side- ways out of the groove. The pattern is then lifted from the mold and the two parts of the cheek are pushed together in their original form. Molding Solid Shot Fig. 14 shows the arrangement of the patterns and gates in molding solid shot. The four patterns are rammed up in the drag, with the bottom of the patterns flush with the sur- face. Shrinkheads or risers C and a pouring gate D are formed 24 FOUNDRY PRACTICE in the cope. After lifting off the cope, whirl-gates F are cut from the pouring gate to cause the iron to enter the mold tangentially. This imparts to the iron entering the mold a swirling motion, which drives the dirt collected in the mold 5 Uat( D Shot Shot Joint of Shot mold PATTERNS DRAWN AND GATED o) To o) (o COPE SHOWING RISERS Fig. 14. — Mold for Solid Shot. toward the center and enables it, therefore, to rise in the shrinkhead, thus leaving a clean casting. As the shrinkhead is made large enough to supply molten iron to the body of the casting when it cools and shrinks, a clean, sound casting, free from blowholes and impurities, is secured. gear molding 25 Gear Molding Gear blanks, that is, the casting in which gear teeth are to be cut, must be free from dirt, blow-holes, and other imperfec- tions to a greater degree than the usual run of castings. In molding gear blanks, the mold is usually arranged so that the iron will enter at the hub in order that the face in which the teeth are to be cut shall be as far away as possible from the iron which first enters the mold, and which may carry with it dust or dirt which will render imperfect the face of the casting. In molding cast gears, that is, gears with the teeth cast on them, the sand must be selected with regard to the size of the teeth; the finer the teeth, of course, the finer the grade of sand that must be used. The sand having the smallest grains will naturally be selected for those gears having the smallest teeth, and as gears with larger teeth have to be molded, coarser- grained sand can be used. The operation of molding a set of gears will now be de- scribed. The patterns being in position on the mold-board, and the drag of the flask placed, sand is riddled over the pat- terns with a No. 12 riddle. The sand is carefully tucked in the teeth in the gear pattern and the drag rolled over and the joint made, coping down between the arms of the gear as pre- viously described, and the parting sand dusted on. It will be assumed that there are a number of gears to be made from the patterns, so therefore, after making the joint, the cope is placed with an iron band fitted to the inside, and is rammed up. The bottom-board is rubbed down on top of the cope, which is lifted off, placed at one side, and the snap flask re- moved. The cope part of the flask is then replaced on the drag and the regular cope is rammed up, lifted ofl", and set on its side. With a small brass tube, a hole is punched through the cope from the joint side, in the center of the mold of the hubs of the gears in the cope. After having lifted off the cope, the patterns are boshed, rapped, and drawn. The process of rapping and drawing a gear pattern is some- what different from the process of rapping and drawing an 26 FOUNDRY PRACTICE ordinary pattern. To rap a gear pattern sideways would distort the teeth and thus cause the finished gears to bind on each other when put in service. Furthermore, rapping the pattern sideways would tend to break the teeth in the sand from the body of sand back of them. When the pattern is withdrawn from the mold, these broken teeth would fall and make an imperfect casting. In rapping gear patterns, a raw- hide mallet is used and the pattern itself is tapped slightly, just enough to jar it free from the sand but not enough to distort or crack the teeth. To draw the pattern, a pair of tweezers are used, being placed in the drawhole of the pattern and spread apart so as to fill the hole. Lifting on the tweezers and drawing the pat- tern with his left hand, the molder gently taps the pattern with his mallet and as soon as it feels free of the sand, lifts it clear of the mold with a quick vertical motion. Should any sidewise motion be given the pattern while drawing it and a tooth thereby knocked down, it will be economy to knock the mold out of the flask and make it over a second time, rather than attempt to patch up the teeth. Care must be taken in tucking the teeth of the pattern to have the sand uniformly firm. Should soft spots be left in the sand forming the teeth, bunches will be formed between the teeth of the gear, and it will be rough. Should the sand be rammed too hard, the teeth will stick to the pattern and be broken. Hot iron must be used in pouring in order that the gear shall come out of the mold with sharp, clean teeth. A facing comprising one part of bolted seacoal and fourteen parts of fine tempered sand should be used between the teeth, other- wise difficulty will be experienced in cleaning the casting. To return now to the cope which was first rammed up and set aside. This is known as the false cope and is to be used as a match-plate on which the patterns are laid when the second mold is made. This match or false cope is placed on top of the bench and the cope part of the flask closed around it, with the joint up. The patterns are placed in the impressions in the cope, the drag put in position, and sand riddled in on top of GEAR MOLDING 27 the cope in the same manner that the drag was made for the first mold. The false cope and drag are then rolled over to- gether, the cope removed and set aside as in the first case, and the true cope made and finished as before. The use of the false cope in this case is to avoid making the joint every time a mold is made. Instead of using a false cope, an upset may be employed, having guides which fit the pins on the drag of the flask. At E in Fig. 15, is shown a horn gate. The use of this is described in Chapter XV. After the drag has been made, the horn gate patterns are placed in position as shown and the Fig. 15. — Method of Molding (.tEar Wheels, Illustrating Use OF Horn Gate. A, Cope of mold- B, drag of mold with pattern drawn; C, drag of mold with horn gate pattern set; D, opening of horn gate in cope. cope is set on the drag and rammed up, the sand being tucked in under the horn gates. These gates are larger at one end than at the other, and after being boshed, can be removed from the sand by letting them describe a sort of semicircle as they are drawn. A gate is cut in the center of the cope and is connected with each of the horn gates leading to the various gear molds. -The horn gates are placed so that the iron will flow to near the center of the gear. The green-sand cores in the molds 28 FOUNDRY PRACTICE are vented by means of a fine vent-wire before the patterns are drawn. Molding Gears and Splitting Them Fig. i6 illustrates the method of molding and splitting a bevel gear. The pattern is shown resting on the cope, and in molding is placed on the mold-board in the same position. The drag is placed around it with the pins down. Sand is rid- dled into the drag, which is next heaped full and rammed up. The flask used in this case is a tight flask and remains on the Fig. i6. — Molding and Splitting a Bevel Gear. mold when the latter is poured, and therefore no iron band is required inside of it. Before heaping the sand into the drag, the riddled sand is tucked into the teeth of the gears. After the drag has been rammed, it is rolled over and the sand is scraped away from the pattern down to the ends of the teeth. In this case the teeth are formed on an angle on the face of the drag, and we are obliged to cope down to the ends of the teeth in forming the joint. MOLDING AND SPLITTING GEARS 29 The cope is then made up, and after the mold has been tinished and parted, spHtting plates, shown at A, are set in the prints B in the mold of the hub in the drag. Pouring gates D are punched through the cope with a rod or tube of the proper diameter, and a pouring basin formed in the top of the cope. The following points may well be borne in mind in molding gears: In boshing a gear pattern avoid putting any excess of water on the mold, else it will be necessary to dry the pattern before using it again. Hard ramming on the point of a tooth makes a rounding instead of a sharp edge. A gear mold must . be rammed firmly to stand the strain of the molten metal and to keep the teeth from becoming fat. In winter the patterns should be warmed. At all times iron patterns should be smeared with barberry tallow mixed with naphtha. The tallow should be allowed to set until the naphtha has evaporated, when it may be applied to the pattern with a stiff brush. This will enable the pattern to be drawn from the sand so as to leave a perfect mold. Mending the teeth of small gear molds seldom pays. It is usually better to make the mold over. CHAPTER III FLOOR MOLDING The term floor molding is applied to work which is too large for the bench and which is molded either on the side floor or on the main floor of the foundry. The term is usually- applied to green-sand work. The patterns molded on the side floor are those which, while too large for the bench, can yet be handled by one or several men. Patterns molded on the main floor are usually those which require the services of a crane for handling the completed mold. Floor molding re- quires somewhat different equipment from bench molding and the procedure is also different. The castings being larger, the question of pouring so as to secure uniformity in the finished casting, without setting up undue strains in the metal, is also important. The matter of pouring will be discussed at the end of this chapter. In order to illustrate the practice of floor molding, we will consider the molding the legs of a lathe bed, shown in Fig. 17. In the first place, a rigid flask is used instead of a snap flask. This is a frame of wood C solidly nailed together, with tie- rods extending across it as shown. Furthermore, while the sand in a small flask, say up to fifteen inches square, properly tempered, will support itself when lifted with the cope, it will break away from the flask and fall when the flask is lifted if the latter is of greater area. Therefore some provision must be made to support the sand in the cope in the larger flasks which are used in floor work. This provision takes the form of ribs, such as are shown at E in the cope of the flask in the background of Fig. 17. These ribs or bars extend from one side to the other of the cope, being firmly nailed in place. At intervals, to keep them from being sprung sidewise, are cross bars M known as chucks. This construction forms, in effect, 30 FLOOR MOLDING 31 a series of copes extending from side to side of the flask. In order to tie all of these copes together, and form one cope as a whole over the casting, the sand must extend under the bars and chucks; therefore, the bars are made about three-quarters of an inch less in depth than the depth of the cope. The pat- tern which is under consideration, is of the flat-back type, that is, no part of it will extend up into the cope. The bars then extend down to a uniform distance from the joint of the Fig. 17. — P.-iTTERN OF Lathe-bed Legs Laid on Mold-board Ready for Floor Molding. mold. Should the pattern be of such shape that it is necessary for it to extend into the cope, a portion of the bars would be cut away to permit the pattern to fit under them, and to allow a thickness of about three-quarters of an inch to an inch of sand to come between the pattern and the bottom of the bars. The sand is necessary not only to protect the bars from com- ing in contact with molten iron and burning, but should the wood be allowed to form a portion of the side of the mold, molten iron coming in contact with it would tend to boil and 32 FOUNDRY PRACTICE thus make an imperfect casting. The edges of the bars are chamfered to a narrow edge at the bottom, so as to divide the sand near the joint as Httle as possible. In molding the pattern shown in the illustration, the mold- board is first rubbed to a firm bearing in the sand of the floor, loose sand to a depth of about two inches first having been shoveled over the space where the molding is to be carried on. The pattern is placed on the board as shown and the drag of the flask set around it with the pin holes G down. Sand is riddled on the pattern and around it to a depth of about two inches and is scraped up and laid against the deep upright sides of the pattern until its entire surface is covered with riddled sand. Ten-penny nails, dipped in clay wash, are set point down, one in each corner of the pattern and the sand tucked around them. It is often advisable in a deep pattern of this character to vent the sand in the corners with a vent-wire. The sand is next shoveled in from the heap, the point of the shovel being placed close to the pattern, and the sand slid ofif gently into the flask, to avoid knocking the riddled sand away from the pattern. After the pattern is well covered in this manner, sand is shoveled in without further precaution to a depth of about five inches and rammed around the pattern. In ramming, the sand should be struck a sharp blow with the rammer rather than merely pushed down. In floor molding, the long-handled iron rammer is used and in this first operation is held peen down, the sand being rammed alongside the flask and around the edges of the pattern, care being used to strike not closer to the pattern than one inch. Especial care must be used when ramming the sand in the pockets not to strike the pattern or to ram the pockets too hard, which will prevent the easy escape of gases from the mold. After the sand has been rammed to a depth equal to the height of the pattern, it is vented with the vent-wire, and is often trodden down with the feet. A second lot of sand is then shoveled in and the sand outside the pattern is rammed with the butt end of the rammer and also rammed over that portion of the pattern where it lies the deepest. At this stage, the molder must use his own judg- FLOOR MOLDING 33 ment as to how firmly the mold must be rammed and in time will be able to judge by the feeling of the sand under his ram- mer, whether or not the mold is rammed sufficiently hard. After second ramming, the flask is heaped full, trodden down, rammed with the butt end of the rammer, and struck ofT level with the top of the flask. Loose sand is then thrown on and the bottom-board rubbed to a bearing the same as in bench mold- ing. The board is then raised and the mold well vented, after which the board is replaced and fastened by means of clamps, which extend from under the mold-board to the top of the bot- tom-board, being made firm by wedges driven under the toes of the clamps. The mold is then rolled over preferably to a point back of where the molding was begun. However, should the foundry be cramped for room, the flask can be twisted around and lowered on its original bed, and the drag rubbed to a firm bearing on the floor, sand having previously been thrown there for the bottom-board to bed in. The clamps are now removed, together with the mold- board, and the molder assures himself that the pattern rests solidly on the sand in the flask. Occasionally, with a thin pat- tern, the pattern itself may be warped and on the removal of the mold-board, a portion of it spring up from the sand. In such a case, the spirit level should be placed on the pattern and weights used to hold the pattern level until the joint is made. After making the joint, parting sand is dusted on, the weights removed, and one-half inch of sand riddled over the joint. To locate the position of the gate and the risers which are set in the cope, balls of molding sand are placed in the position desired for the gate and risers to ascertain whether these positions will be clear of the bars and chucks of the cope, and after the joint of the flask and the pin holes have been cleaned, the cope is put in position, having been first wet or clay- washed. Some of the molding-sand balls will probably be found to come directly underneath a bar in the cope and the gate-stick and gaggers must be shifted accordingly. The gate-stick must be set far enough away from a thin pattern of this character, to avoid danger of the gate breaking into the mold when the casting is 3 34 FOUNDRY PRACTICE poured. Gaggers (see Fig. 138, page 214) are next set. The gaggers should be of such size as to come close to the top of the bars, but they should not project above if it can be avoided. Gate-sticks and gaggers being in place, sand is riddled through a coarse riddle to a sufficient depth in the cope to permit it to be tucked firmly around the gaggers and between the pattern and the lower edge of the bars. In doing this, the molder places a hand on either side of the bar so that his fingers can push the sand underneath the bar from either side. The sand must be tucked firmly, otherwise soft places will be left in the mold which will cause trouble when it is poured. Sand is shoveled in next to a depth of about five inches, and rammed along each bar with the peen of the rammer. The peen is then held transversely to the bar and the sand cross-rammed. More sand is shoveled into the flask and is again peened, after which the flask is heaped with sand which is rammed between the bars with the butt end of the rammer. The loose sand is now struck off from the top of the flask with a wedge, special attention being given to the detection of any gaggers which may project above the bars. Should such a gagger be struck and loosened, the sand is immediately punched down alongside the gagger until it holds firm. The cope is then vented all over and the gate-sticks drawn, after which the cope is lifted off and placed on set-off boxes, that is, a box having ends and sides but no bottom or top. One edge of the flask is lowered on to these boxes, the other being raised in the position occupied by the drag in Fig. 17, being held up by a prop at the back. In this position the molder finishes it, by first feeling it all over to see that no soft spots have been left in tucking the bars, in which case they are repaired by first cutting up the sand slightly with the trowel and then pressing fresh sand into place and finishing it with the trowel. Should soft spots not be repaired, iron will force its way into them when the mold is poured and form excrescen- ces on the casting. The cope is finished in the usual m.anner, breaks in the sand being repaired, and shining spots in the FLOOR MOLDING 35 sand which indicate the presence of gaggers too close to the face of the mold are filled in with fresh sand. The joint in the drag is next brushed off and the pattern boshed and rapped for drawing from the sand. Instead of using a draw-nail or a bar set in a hole in the pattern for rapping, which would assuredly damage a light pattern such as is shown, the joint is cut down in a number of places around the pattern and the butt end of a wedge placed in these cuts against the pattern. Light blows are struck with a hammer on the wedge until the pattern is freed from the sand. The sand is then built up at the spots where it was cut out and the pattern is drawn by means of eye-bolts screwed into the pattern. In drawing a pattern of the kind shown, in fact in drawing practically all patterns used in floor molding, two men are required, one at either end. These must lift the pat- tern at exactly the same time and each must be prepared to stop lifting at a signal from the other which is given when either notices any indication of the sand breaking on the edges of the mold as the pattern is lifted. When this happens, the sand is pressed back in place and slicked over with the trowel before the pattern is drawn any further. The pattern being drawn, the mold is carefully looked over for imperfections and breaks in the sand. As far as pos- sible, broken sand is carefully replaced with the fingers, pressed back into position and dampened slightly. The face of the mold is then finished with proper tools at this point, and the entire mold is gone over in a similar manner until all broken parts are repaired. Sprues are now cut from the upright gates into the mold and the mold is cleaned of all loose sand by means of the bellows and lifters. As any sand which will not blow off, will not wash off under the influence of molten iron flowing over it, the bellows afford an indication as to whether there are any loose parts of the mold which have been over- looked. On a thin mold of this character, it is advisable to sprinkle a light coating of talc over which the iron will run freely and a cooler iron can therefore be used in pouring. The sprues and 36 FOUNDRY PRACTICE gates are arranged so that the iron will enter the deeper parts of the mold and also at the feet. In a mold of this character, peg-gates (see Fig. 129, page 171) are advisable. Cores are next set and the mold is closed. Five men are required for this operation with a flask of this size, one at each corner of the fiask while the fifth looks in under the cope as it is closed on the drag to see that no part of the mold falls down. It is es- sential that all four men lift and lower the flask simultaneously, otherwise they may warp the flask and thus cause a portion of the mold to fall. The man who watches to see that this does not happen is called the "peeker." The mold is now clamped, that is, the cope is fastened to the drag by means of clamps as shown at K, Fig. 17. These U-shaped pieces of iron are set with the legs of the U projecting over the edges of the cope and drag respectively, being fast- ened firmly in position by means of wooden wedges L driven under the toes of the clamps. The usual method of wedging the clamps is to pry the clamps on to the wedge rather than drive the wedge home with a hammer which might, from the force of the blow, jar the sand down into the mold. Pouring Floor Molds In pouring this mold, two ladles are used. The one from which the iron is to flow to the deeper part of the mold is poured a little in advance of the other. As there is no part of the casting above the joint of the flask in the cope, the rising of the iron in the gate indicates when the mold is filled. In general, in pouring side floors, the same ladles are used as for pouring bench molds. A sufficient number of ladles, how- ever, are used to pour the entire mold at one time. This some- times requires six to eight ladles, pouring simultaneously at different gates in order that the iron may reach all parts of the mold in a fluid condition. A large wash sink is a typical casting requiring pouring of this character. In pouring from many ladles, the men all start and stop pouring at a given sig- nal, thus avoiding straining the casting which might occur were FLOOR MOLDING 37 iron poured in the gate after the mold is filled, thus putting pressure, due to head, on the mold. Other classes of castings poured in this manner, include castings for cotton, woolen, and other light machinery. In pouring the light and heavy molds on the side floor, large ladles are often used holding from one hundred and fifty to three hundred pounds of iron, in which case several men are required to handle the ladle. Many castings made on the side floor may require several of these ladles. It is advisable to have available, in pouring a heavy casting, approximately the exact amount of iron required. Therefore, foundries are usually supplied with a number of ladles of varying sizes so that by a combination of sizes the required amount of iron may be brought to the mold. It often is necessary to pour one portion of the mold with very hot iron and another portion with slack or cooler iron. Different gates are therefore ar- ranged in which the two kinds of iron are poured from dif- ferent ladles. Such a case occurs when a casting has both light and heavy parts; the hotter iron is fed to the light part. It is evident from the foregoing, that floor molding requires that consideration be given to other points than the actual making of the mold. It is impossible in a book of this charac- ter to lay stress on all these points and the student is urged to observe the methods of more experienced molders when gating and pouring the various kinds of castings.. Molding Pulleys and Wheels on the Floor A common job of floor molding with green sand is shown in Fig. 1 8, where a wheel is to be molded and poured with a cast iron rim and hub, and with wrought-iron spokes set in the mold around which the iron flows. In the larger sizes of wheels of this character, provision should be made for pouring the rim and the hub separately. The mold is made up with the rim and hub pattern in the usual manner and after the mold has been opened and the pattern withdrawn, the wrought-iron spokes are set in place as shown. The ends of 38 FOUNDRY PRACTICE the Spokes which are to come in contact with the molten iron are coated with a mixture of red lead and benzine or naphtha. The rim is first poured, and, in shrinking, forces the spokes inward. After the rim has cooled the hub is poured. Wheels of this character are made weighing up to six tons and up to ,ten feet diameter. It is a quite common practice to cast iron around iron or steel shafts. If the shaft should be given a coating of liquid glass (silicate of soda) prior to being placed in the mold, the iron will lie quietly against this and when cold. Fig. li -Molding a Wheel in which Wrought-iron Spokes are to BE Set. a pressure of many tons will be necessary to separate the two. Aluminum paint often serves the same purpose well. In molding pulleys, the work is now ordinarily done on machines, which will take patterns up to, say, six feet diame- ter. Many pulleys, however, are still molded by hand. In some foundries it is customary to have as a pulley pattern, a rim, arms loose in the rim, and a loose hub. In molding, the rim is rammed up in a cheek, which may be part of a flask or a drag staked on the floor, having enough chucks around it to hold the sand, if the mold is of sufificient size to FLOOR MOLDING 39 require it. After the sand is rammed around the outside of the rim, it is rammed inside to the required depth and a hole dug at the center for the hub. The arms are placed inside the rims, at the proper distance below the top, and sand is tucked under them and around the hub, and the joint made. A lifting plate having projections of the shape of the spaces between the arms on its surface, is placed inside the pulley, the two projections between the arms being fastened together by clamps which pass over the arms and tie all the plates to- gether. A lifting screw is usually placed in three of the plates. The inside of the pulley, over the arms, is rammed up with the gate-stick in the center as if the upper half were molded in a cope. After ramming, the pattern is drawn and the cheek lifted. The rim is finished and the cope and drag halves of the center are marked so that they can be replaced. The upper half of the center is lifted off, the hub drawn, and the arms drawn from the drag with the hub. The center core is set and the cope half closed. The rim is then blackened and rings, half to three-quarters of an inch in thickness, are laid on the center, the runner built, and the center weighted for pouring. Molding Large Bevel Gears on the Floor Fig. 19 illustrates the making of a large bevel-gear mold. The pattern A is placed on the mold-board as shown, with the drag hub B in the center. The cope side hub is loose and is shown at E. The drag is placed with the joint side down and No. I Albany sand mixed with seacoal in the proportion of five parts new sand to five parts old sand to one of seacoal is tempered and riddled over the pattern. The facing is tucked in between the teeth to insure that the sand teeth thus formed shall be of sufficient hardness, and surplus sand is then scraped from the face of the teeth by hand. Facing sand is next riddled over the teeth and the drag rammed. The same precautions must be observed in ramming as were observed in the making of small gears at the bench, as described in Chapter II. After 40 FOUNDRY PRACTICE rubbing the bottom-board to a bearing, the drag is vented over the pattern, care being taken to avoid puncturing the sand teeth. The drag being rolled over, the joint is made by coping down around the pattern to the bottom of the outside of the teeth as shown at D, the sand being pressed firmly in between the teeth with the fingers while making the parting. Parting sand is rubbed on the face of the sand teeth and the cope hub E placed on the center of the pattern. Facing sand is laid around the tooth part of the joint to the proper thickness for setting the gaggers, and the cope placed on the drag. Gaggers are next set around the gear to lift the hanging sand formed by the outside of the teeth and over the pattern. Sand is then shoveled in from the heap, the flask bars are tucked, the gate-sticks set on top of the hub to form the pour- ing gate, and the cope rammed up. After the cope is lifted the hub E is drawn and the teeth around the pattern are boshed. The pattern is rapped very lightly as described in the operation of molding small gears in Chapter II, and drawn from the sand, and after the mold is finished, a light coating of talc or of lead mixed with talc, is dusted over the face of the mold. A vent-wire is passed through the core-print in the drag and core G of the proper diameter and length, is set after the vent hole in the tapered end has been filled with sand to pre- vent iron entering the vent holes. The cope is then closed on the drag. The gate-stick should be placed in the gate hole before closing the cope. The pouring basin H is built on top of the cope in order that a shallower cope may be used than would be necessary were the pouring basin to be built in the flask. It is thus seen that the molding of a gear on the floor is the same operation as molding a small gear at the bench, with the exception that, there being a larger body of sand contained in a larger flask, different means must be used to secure the sand. Furthermore, the flask is clamped instead of being weighted. In the flask N is seen the same gear with cores set to form a split gear for fastening in place on a shaft over the end of which the gear cannot be slipped. In molding this gear, the FLOOR MOLDING 41 mold is made exactly as before, but is gated so that the iron will enter on either side of the splitting cores L and flow up as evenly as possible on either side of them. The gates are shown at 5. The splitting cores L are extremely thin antl require special rodding to strengthen the sand. Insteatl of sand cores, iron plates, of the same shajie as the splitting cores, are sonic- times used, ha\-ing a thick coat of blacking dried on thcni in the o\-en to protect the jilate from the molten iron, and to Fig. 19. — Moi.niNi; I5i:vel (.".ears on the I'Loor. prevent the latter from burning on the i^kuc whiMi ihe mold is formed. It is e^'ident that the hubs for split gears nuisi be of special design and haxe prints on them, not onl>- for the center core but for the splitting core. Such hubs are shown in i\\^ flasks at .V and 0. In molding straight tootli spur gears, of twent\-four inches diameter and o\er. it is customar\- to place the gear pattern on the mold-board and to throw handfuls of sand, taken irom a heap alongside the m()ld-l)oar(.l, in l)etween the teeth. 42 FOUNDRY PRACTICE Sand rammed in this fashion forms very firm teeth. After the teeth are formed, sand is scraped away from the outside of the pattern and fresh sand is riddled into the flask and tucked up around the outside of the teeth after which the mold is rammed up as any other mold would be. Gear patterns are often molded by using the floor as the drag and bedding the pattern in it. Usually where the face of a gear is quite deep, and the pattern has coarse teeth, nails or pieces of rods are set in the teeth of the gear. Suppose the depth of the face to be fourteen inches. After the gear is ram- med up a distance of three inches, nails or spikes are laid radially in the teeth and it is rammed up three inches more, after which additional nails are inserted. The operation is repeated at a depth of nine and twelve inches. Thus the teeth formed in the sand will be fastened by the nails to the main body of sand back of the teeth. They are thus stronger and resist the strains of pouring better, and also are better able to sustain the weight of the cope. This practice is adopted only with gears of rather coarse teeth and weighing from four hundred pounds to several tons. CHAPTER IV LIGHT CRANE FLOOR WORK Molds which are to be made under the crane, require con- siderable skill on the part of the molder and only the more experienced men should be entrusted with this work, inasmuch as the castings made are large and the spoiling of one, due to poor molding, involves considerable loss. A typical mold made on the floor is illustrated in Figs. 20 and 21, being one side of a wire cloth loom frame. The finished casting weighs about four hundred and fifty pounds, but in pouring it, two ladles are used in order to obtain the proper distribution of the iron in the mold. An iron pattern B, Fig. 20, is used. This is placed on a mold-board which is bedded level on the floor. The drag of the flask is placed around it, joint side down. The pattern must bear firmly on the mold-board, or else wedges must be driven between it and the board, or the corners of the board wedged up until it comes in contact with the pattern. The pattern is then covered with a mixture of seacoal facing in the proportions of one part seacoal, five parts new No. i Albany sand and five parts heap sand. This mixture is wet with water, shoveled over, tramped down and riddled through a No. 4 sieve, after which it is riddled through a No. 8 sieve on to the pattern, being then carefully laid against the sides. Sand from the heap is then riddled through a No. 3 sieve over the facing sand, after which sand is shoveled in over the entire surface to a depth of five inches. Sand is now rammed adjoining the sides of the flask and around the pattern, the rammer being kept about one inch from the pattern, as in ramming flasks on the side floor. The sand is then rammed with the butt end of the rammer between the openings in the pattern and in the remain- der of the flask, excepting immediately over the pattern, which 43 44 FOUNDRY PRACTICE would cause the sand to be too hard at this point. An ad- ditional five inches of sand is then shoveled in and peened down along the edges of the flask and trodden down all over the drag and afterward butted with the butt of the rammer, over the pattern, in addition to the other portions. This operation of adding sand and ramming it with the butt is continued until the flask is completely filled. It is then struck off and leveled, the bottom-board placed and rubbed to a bearing, after which the drag is vented over the pattern, the bottom-board replaced and clamped to the mold-board with the flask between them. Fig. 20. — Pattern of Wire Cloth Loom Frame on Mold-board Ready FOR Making Drag. The total weight of the flask, pattern, and sand is about forty- four hundred pounds and the services of the crane will be required to roll it over. A chain is placed around the drag and hooked over the crane hook, after which the crane raises the flask clear of the floor. While suspended in the air, it is turned over and lowered on the original bed of molding sand with the mold board up. The ends of the mold-board are leveled, a spirit level being used for this purpose, and sand is rammed under the cleats of the bottom-board to maintain the le\'el. After removing the mold-board, the joint is made as in ordinary small castings. Parting sand having been dusted on the joint, the pattern is covered with a seacoal facing to a depth of three-eighths of an LIGHT CRANE FLOOR WORK 45 inch, and the cope, previously wet down, is placed on the drag, after which gaggers are set. Gate-sticks are set and sand tucked in between the bars of the flask in exactly the same manner as is done in side floor molding. In side floor work, considerable reliance is placed on the clay washing of the bars of the cope to retain the sand in place, but in crane floor work, the flasks being larger, careful gag- gering is required, as the bars cannot be depended on to hold Fig. 21. — Drag of Wire Cloth Loom Frame on Floor. Cope is Stand- ing Against Wall. the larger body of sand. When placing the cope, should it be found that it does not bear evenly on the drag, it should be clamped down to it, or if it is too stiff to permit of this, the cope should be wedged up and care must be taken to see that this wedge is replaced when the mold is closed for pouring. Referring now to Fig. 21, it will be noted that the top of the pattern is coped out and gaggers, with long shanks, are required to lift the hanging belly of sand in the cope. In set- 46 FOUNDRY PRACTICE ting these gaggers, they are placed so that they will assist in supporting each other, and in proportion to the size of the flask a greater number are used than in side floor work. After the sand has been tucked in between the bars and the pattern, sufficient sand is shoveled in between the bars of the cope to form a ramming and the cope is rammed up as in side floor work. After the top has been scraped off, the cope is well vented. The crane is then brought over the center of the Fig. 22.- -WiRE Cloth Loom Frame Mold Clamped Ready for Pour- ing AND Bound Down with Binder. cope and chains are hooked into staples or eyes set in the sides of the cope flask and the cope lifted and set to one side, one edge resting on set-off boxes as shown in Fig. 21. Care must be exercised in doing this as any jar is liable to shake sand from the cope. Therefore, strain should be brought on the chains gradually, and lifting and lowering commenced slowly. It is almost invariably the case, that when the cope is lifted, some parts will be broken down. When these are repaired, the sand should be nailed to insure its remaining in place. The LIGHT CRANE FLOOR WORK 47 cope being finished, a coating of silver lead is applied, over which a light facing of talc is dusted. The joint being brushed off, the pattern is boshed and rapped. Eye-bolts are screwed into the pattern and it js lifted from the sand by the crane, the pattern being rapped as the crane lifts it. The mold is finished and the gate D is cut and also a second gate at E. The principal body of iron enters through this and therefore it is made considerably larger than the other. Sharper iron is poured through this gate than through E. At X a gate is cut to the riser. The mold being finished, cores are set in the prints formed by the core-prints F and G on the pattern. Sand is slicked around them and the mold coated with silver lead over which talc is dusted. The cope is now lowered on to the drag, being guided to the point where the pins enter the pin holes by the wooden guides H. Before lowering the cope, flour is placed on all the small cores to indicate whether or not the cope bears on them. When the cope comes to a bearing one clamp is set on each side to give the same conditions which will ensue when the mold is finally closed. The clamps are then removed, the cope lifted and examined and the cores resting in the prints AA placed, after which the mold is closed and clamped as shown in Fig. 22. In order to prevent the cope springing at the center, when poured, blocks of wood are set at either end of the flask and a rail clamped across them as shown in Fig. 22. Wedges are driven between this rail and the bars of the flask. Paper is laid over the top of the cope, which is lighted when the mold is poured and gases escape from the vents. The gases escaping from the vents in the drag will be lighted with a red-hot skimmer. CHAPTER V BEDDING PATTERNS IN THE FOUNDRY FLOOR.— MOLDING A DRAW-BENCH FRAME IN THE PIT.— MOLDING THE FRAME OF A GAP PRESS Often large patterns are molded in pits in the foundry floor, cope and cheek plates being the only part of the flask used. In this way, the floor is used as a drag and a large part of the expense of flask manufacture is avoided. In case the foundry floor is damp, tanks of large size are sunk in the floor and molds made in them. If this is not done, the floor being slightly damp, the inside of the pit may be lined with tar paper. Work of this character is usually known as pit molding. Most of the molds made in pits are of green sand, although skin-dried molds are also made. Instead of using but one pattern in the flask, the molder is, in many cases, given patterns of various sizes and shapes which he is required to mold in a certain space in the floor. For instance, at the foundry of R. Hoe & Co., New York, printing press manufacturers, it is the custom for two molders to work together, assisted by two helpers and to use a cast iron cope fourteen feet long by five and one-half feet wide, molding in the floor enough patterns to fill the space covered by the cope. The space allotted to a molder, on work of this character, is termed his "floor." When the number of castings desired from a medium-sized pattern is small, they often are molded in a hole dug in the floor. Assume that there are several pipes to be made, each three feet long and six inches diameter. A hole is dug in the floor about four feet long, in order to allow for the core-prints in the pattern, and four and one-half inches deep. Where the flanges come on the end of the pipes, the hole is made deep enough and wide enough to accommodate 48 BEDDING PATTERNS IN THE FOUNDRY FLOOR 49 them. Molding sand is riddled in the hole and the pattern placed in it with the joint side up. A long block of wood being placed on top of the pattern, the pattern is driven down into the sand the proper distance by pounding on the block, thus ramming the sand underneath the pattern. The pattern is now weighted in position and riddled molding sand laid along- side of it by hand. Sand is then shoveled in from the heap and is peened down around the pattern with the rammer. If necessary, the pattern will be rapped down and lifted out and the flange pattern fixed up, after which the pattern is replaced and the sides rammed up. The sand being rammed even with the top of the floor, the joint of the pattern is made and the cope part of the flask placed over the pattern. Parting sand is dusted on and the cope made up in the ordinary manner. Before lifting off the cope, the molder drives down in each corner of the cope on the outside, an iron rod or a wooden stake about twelve inches long to act as guide when lifting and re- placing the cope. The cope is then lifted and finished, the pattern is drawn and the drag finished, after which the cope is replaced and weighted for pouring and the stakes removed when the mold is ready to pour. Instead of weighting the cope, it may be held down by bolting it by means of binders across the cope, which engage bolts rising from binders underneath the mold. This method will be described in detail in the description of the next mold. Molding a Draw-Bench Frame in the Floor Having described the construction of a comparatively small mold, we will now take up the process of bedding a rather large pattern in the floor. Assume that we have the pattern shown in Figs. 23-27. This is a comparatively shallow pattern, long and narrow. We will also assume that it is to be molded in a pit prepared for a much larger pattern. The pit is first dug in the foundry floor, say sixteen feet long, nine feet wide, and six feet six inches deep. Referring to Fig. 28, hinders of cast iron, spaced four feet on centers, are placed 4 50 FOUNDRY PRACTICE across the bottom of the pit. The ends of the binders should be in line and the tops leveled to a straight edge, after which sand is firmly rammed between and around them. Each binder has a vertical slot in each end in which an eye-holt with a nut and washer on the lower end, is slipped, as shown in the illustration. Sand is then rammed around the end of the binders and that between them is struck ofif level with the top. Iron plates, one inch thick, are placed on top of the binders, covering them and extending to within six inches of the eye- bolts. Six-inch square timbers are stood on end inside of each eye-bolt and on top of the binder. These pieces of timber are allowed to extend above the floor line about four inches. Sand is rammed around the bottom of them and scantling is nailed from one to the other at the top as shown. The end timbers are also tied across the ends with scantling. On top of the iron plates is laid about five inches of molding sand, on top of which is placed a cinder bed, both firmly ram- med. Over the cinder bed, straw or newspapers are placed, to keep the sand, which is later rammed on top of the cinders, from working down among them and filling the voids in the cinder bed which are depended upon to bring the gas from under the casting to pipes which extend from the cinder bed to a little below the top of the floor line, as shown in Fig. 28. In the top of the pipes, a plug of rolled bagging is placed to prevent sand entering while the mold is being rammed. This is removed before the mold is poured. The timbers are sawed off flush with the floor line, a cord being used to give the proper alignment. This will give more accurate results than any attempt at measuring the timbers and sawing them off before placing. The pit thus prepared, is for a pattern four feet six inches deep. It can be used for a smaller pattern by simply filling the pit to a greater or less depth with sand. Referring now to Figs. 23-27, the pattern is placed on the floor in the position in which it is desired to pour it and its outline traced in the sand. This indicates the amount of space required for the pattern, which is then re- moved and the pit excavated to a sufficient depth to permit MOLDING A DRAW-BENCH FRAME IN THE PIT 51 52 FOUNDRY PRACTICE molding the pattern, a deeper hole being dug at one end to accommodate the projection on the pattern. The cinder bed is placed, covered with newspapers, and the gas pipes put in position. On top of the cinder bed, molding sand is rammed to conform to the line F of the pattern. Fig. 26. The pattern is then placed in the pit and leveled to the proper height with wedges F, Fig. 30. The portion of the pattern DD, Fig. 26, is removable. This is removed and the remaining portion of the pattern is weighted at the ends, and facing sand tucked under the edges of the pattern. The construction of the pattern is such, that this work can be done both from the inside and the outside, while the weights hold the pattern in place. The wedges F are removed as they are reached in this operation. Gate cores are placed at the ends of the pattern and also upright gates. Facing sand is laid up against the side of the pattern and black sand is shoveled in around it to a depth of about five inches and is then firmly rammed, first with the peen and then with the butt of the rammer. Inasmuch as these first ram- mings of sand receive the greatest side strain from the melted iron when the mold is filled, this portion of the operation must be carefully done. The facing sand, lying loose at the top and adjoining the pattern, is scratched away and when the core- prints C, Fig. 26, are reached, the pins which hold them to the side of the pattern are removed. These pins are usually made of three-sixteenths-inch wire, one end of which is turned over and extended through the core-print into the pattern. The outside being rammed up, the inside of the pattern next receives attention. Facing sand is laid against the sides of the pattern and blcvck sand is rammed inside. When the sand has reached the proper height, five-eighths-inch iron rods are driven down in the green-sand core, formed inside the pattern, as shown at G, Fig. 30. The pattern is faced and sand rammed up in it until it is within three-quarters of an inch of the top, when the sweep D, Fig. 27, is used to true the facing sand in the last three-quarters of an inch. The green- sand core is vented, care being taken that the vent-wire passes MOLDING A DRAW-BENCH FRAME IN THE PIT 53 \ through the newspapers or straw into the cinder bed. The vents are then filled with sand at the top and the face at the top of the mold is made up with the fingers. The covering boards forming the top of the pattern are then re- placed and the joint is made level with the upper surface of the pattern. The joint being made, parting sand is dusted on, the cope is placed, rapped down, staked, and then hoisted ofif. Attention is here called to the manner in which the cope is barred through the center as shown in Fig. 31. Facing sand is next spread over the pattern and the joint, after which the cope, first being wet down or clay- washed, is lowered into place. Gate-sticks and gaggers are set, black sand is riddled into the cope and tucked in between the bars and pat- tern. Sand is then shoveled into the cope to a depth of about five inches and rammed with the peen of the rammer. Enough rammings of sand are added to fill the cope level full. The final ramming of sand is butted with the rammer and the excess sand cleaned ofT. In ramming up the cope, the space between the lines of chucks, CC, Fig. 31, is not rammed up with sand, but is left open and the cope well vented. The gate-sticks are now removed and the cope hoisted ofif. The joint is brushed off and the mold is vented all around the pattern at a dis- > \ 54 FOUNDRY PRACTICE tance of about one and one-quarter inches from the edge of the pattern after the latter has been boshed. The pattern is now rapped and drawn, the gate-sticks removed, and the mold finished with trowel, slicker, and lifter, and wherever square corners of sand have been left on the inside of the mold by the pattern they are rounded off to form fillets in the cast- ing. This is a point which should always be remembered, for unless a fillet be placed in the corner of a casting, strains will be set up when the casting cools and it will have a tendency to break through the corner. Referring to Fig. 27, at A will be noted a partition extend- ing the length of the casting formed by a corresponding space in the mold. As the green-sand core C is struck off level at the line of pattern B, this core extends only partially into the pattern. The balance of the space is occupied by dry- sand cores hung from the cope. These are shown at E and straddle the green-sand core, leaving a space between them and the green-sand core into which the iron flows to form the partition F. In order to obtain the right thickness of metal on the sides of the casting, pieces of board, of the same thickness as the casting is to be, are placed over the green-sand core, after which the cores E are lowered into position on these boards. After they are correctly placed, the cope, Fig. 29, is lowered over the mold, being guided to place by the stakes B, driven into the floor. Hook bolts are passed through the openings A, Fig. 31, and attached to staples provided for the purpose at B in the cores. Gate-sticks are placed at where the gas is to escape from the cores and wedges are driven in between the bars of the cope and the top of the cores to insure the cope bearing solidly on the cores in order to hold them in position to give the proper thickness of metal when the mold is poured. The spaces between the bars XX at either end of the cope, and between chucks C C, left open when the cope was ram- med up, are now rammed with black sand and the gate-sticks forming vents are drawn. The clamps H, Fig. 31, are now laid in position as shown and by means of the slotted bars D, MOLDING A DRAW-BENCH FRAME IN THE PIT 55 56 FOUNDRY PRACTICE slipped over the hook bolts to the cores, previously mentioned ; the cores are firmly held in position by screwing the nuts on the bolt down on the slotted bar. The cope is next hoisted as is shown in Fig. 29 with the cores hanging from it. The mold is examined, the boards on top of the green-sand core are removed, the name-plate core is placed, and the cores X, Fig. 30, set in position. Necessary repairs to the mold are made and its entire surface is given a coat of silver lead. Gates are cut to connect the upright gates in the cope with those in the floor. The cope is then finally lowered and held down with binders which span the pit. Blocks of wood are placed on the cope underneath the binders, after which the bolts I, Fig. 2^, are hooked into the eye-bolts in the floor, the tops being set in the slots in the ends of the binders, when by screwing down the nuts, the binders are made to bear firmly on the cope. Care should be" taken in tightening the binders as the nuts at the end will exert considerable leverage and crush the mold if screwed down too far. Runner boxes, shown in Fig. 27, at the ends of the cope, are placed and runners built as indicated in Fig. 31. In order to avoid any great head on the casting, due to excessive height of the runner boxes, the flow-off D is built, which conveys any excess of iron to a basin in the floor. Gases escape from the mold through the pipes Q, Fig. 30, and through the gates lead- ing from the cores. These gases are lighted as soon as they begin to flow. Eye-bolts, timbers, and vent-pipes are all kept below the floor level in this type of mold, so that they will be out of the way. When access is needed to them, they can easily be reached by a slight amount of digging. In order to compare the foregoing method of molding with the ordinary way of molding in a flask, consider what would be done with the same pattern in a flask. It would be placed on the mold-board, cope side down, with a drag around it as in Fig. 32. The pattern would be faced with facing sand on the outside and the sand rammed in alongside the pattern as in molding any plain pattern, until the top of the pattern MOLDING A DRAW-BENCH FRAME IN THE PIT 57 1 » !z; oi Q o g Q >-; o 58 FOUNDRY PRACTICE -^l. is reached. The upright gates B and the inlet gates D would then be placed as shown, the inside of the pattern cleaned out, faced, and the green-sand core formed, rods being placed as before and the core vented. The remainder of the drag then would be rammed up, the sand struck off, and the bottom- board rubbed to a bearing. The bottom-board would be lifted off, channelways formed in the bottom of the drag by striking it with the strike, edge down, after which the molder would then vent the drag all over. The channelways conduct the gas from the vents to the edge of the mold. The bottom- board would next be replaced and clamped and the drag rolled over. After the joint is made, the cope is made exactly as before, the principal differ- ence being that the cope is guided by pins on the flask instead of stakes in the floor. Fig- 33 shows the mold closed and clamped and ready for pouring. < -1r-rjt— u Q <; Q o u Q o w m < Q o 2; Molding a Gap-Press Frame In Figs. 34-37 are shown the patterns of a gap-press frame, which can be molded in the same pit used for the patterns described above. A pit is dug MOLDING A GAP-PRESS FRAME 59 between the upright posts, deeper than the pattern, and the sand and cinders riddled and separated. When the hole has a depth of about lO inches greater than the depth of the pattern, a cinder bed about three inches thick is made and gas pipes provided for carrying gas away from the bottom of the mold when it is poured. A timber D, Fig. 36, is placed as shown. This is used later for holding the chaplets supporting the core. Molding sand is then rammed up over the cinder bed, newspapers first having been placed on it, and shaped to conform to the under side of the pattern as nearly as possible. The pattern is then placed, being blocked and wedged to its proper position and weighted to hold it in place while sand is being rammed under it. The parting of the pattern is at ^, Fig. 35, and that part of the pattern below the parting is bedded in the pit as shown in Fig. 36. The core-print for the main core is at B, Fig. 35, and a flat iron plate is placed under this print to support the weight of the heavy main core. A slab core is set so as to bear against the face of the feet, as they must be fairly true and also carry a heavy strain due to the weight of the finished casting. Sand is rammed underneath and facing is tucked under the pattern, the wedges and blocks being removed as they are reached and replaced with firmly rammed sand. When the pattern is finally resting on a bed of sand, the stakes AA, Fig. 37, are driven and the pattern lifted from the pit. The entire face of the mold is well vented, the vents extending down into the cinder bed. The face of the mold is then made up with the fingers and finished as far as possible, after which the pattern is replaced and rapped down to a solid bearing. The stakes are now removed, facing sand laid against the pattern, and black sand is rammed solid- ly around it, struck off, and the joint made. The joint being made, parting sand is dusted on the joint, and the cope half of the pattern placed on the drag. The cope, Fig. 38, is lowered over the pattern and staked in place with stakes X, after which it is lifted and wet down or clay- washed. The pattern is then covered with facing sand, which is laid up against any portion to which it does not adhere readily and it is also spread over 6o FOUNDRY PRACTICE the joint. A slab core is placed against the foot, this core being arranged with a staple which will permit it to be wired to the cope. Gate-sticks and risers are placed and long-stem gaggers set in position. As" the pattern is heavy, it is necessary to provide some means of supporting it in the cope, since it might H A - Fig. 36 "^A •^ FiQ.39 Bjil THE FINISHED Fig.35 CASTING THE PATTERN Fig. 34 THE PATTERN Figs. 34-39. — Molding a Gap-Press Frame. fall out when the cope is lifted. Accordingly, wood screws, with eyes in the end, and extending through the cope into the pattern are provided. After the pattern is covered with facing sand, black sand, to a depth of about two inches, is shoveled in and rammed with short iron hand rammers. In MOLDING A GAP-PRESS FRAME 6 1 many large copes, such as this, the bars are stopped off some distance above the patterns and the sand is shoveled in and rammed with these rammers instead of being tucked in by hand as is the case with smaller patterns. The black sand is now filled in, in several rammings, until the top of the foot is reached. A riser for a flow-off is placed on top of the foot as it is the highest part of the mold. If gas pockets in a mold, it always does so at the highest point, and the provision of a flow-off to enable some of the iron to run away from this point, will produce a casting sound and free from blow-holes. After placing the riser, sand is filled in the flask and rammed until the cope is filled. The top is then cleaned of loose sand, well vented, and the core at the foot properly secured. Gate- sticks and risers are removed and the cope lifted off. The cope is set up on one side and the wedges and rods in the eye-bolts, holding the pattern in the cope, are removed. The holes left by them are filled up and the cope rolled over on its back. The pattern is drawn and the cope finished and given a coat of silver lead, which is rubbed on with the hand on the heavier parts and brushed on with a camel's-hair brush on the lighter. Channelways and g^tes are cut in the cope, both to conduct the iron to the mold and to act as cleaners. Before the drag portion of the pattern is drawn, the screws, holding the pattern to the base, are removed, freeing the base from the main part of the pattern. In the corner formed by the foot of the bracket, iron rods five-eighths inch diameter, are driven to support the sand when the iron flows around this corner, which is well vented down to the cinder bed. After this is done, the foot portion of the pattern is drawn and the mold finished. When finishing the drag and cope, large-headed nails are pushed into the face of the mold, around the jaw, and also around the edges of the base. This is to prevent the heavier parts of the casting from scabbing when the iron is poured. When finishing the cope and blacking it with lead, this black- ing is omitted from that part of the mold forming thin portions of the casting, as there is a liability to cold-shutting the iron with a heavy facing like lead. A lighter facing, with less sea- 62 FOUNDRY PRACTICE coal, is used on these portions. The mold being finished, it is gated and nails are pushed down into the sand in front of the gates, to keep the face of the mold from being cut by the iron flowing into it. At one end of the mold there is no core-print for the main core. Consequently, it must be held up by chap- lets. Accordingly, these are cut to length, sharpened on one end, and driven through the sand in the floor, into the timber D, Fig. 36, and allowed to extend above the face of the mold a distance equal to the thickness of the casting, as shown at F, Fig. 36. The main core / is then set, one end resting in the core-print, the other being held up by the chaplet. At the end, resting in the core-print, provision is made for gas to escape through suitable vents in the mold. Cores K and L are next set and then the shaft core, one end of which rests in the core K, while the other is held up by a chaplet G in the core-print. The cope is rolled back and the gate-stick placed in the gate hole. The runner B, Fig. 38, is built and an iron ring placed around the riser C. Two pieces of pig iron are placed on each side of the gate-stick, forming the flow-off D. Pieces of clay one inch diameter, and a little higher than the thickness of the casting, are formed and set on the cores at the points at which it is desired that the chaplets shall be placed. The cope is closed on the mold, and is then immediately removed and examined and repaired if necessary. It frequently hap- pens in closing the cope over the cores that parts of the cope are broken. In order to see that the cope bears prop- erly on the cores, flour or white sand is placed on such parts as may be doubtful of bearing properly. These will leave a mark on the dark sand of the mold on the removal of the cope. It being found that the cope bears as desired on the joint and cores, the vent-wire is run up through the cope, and chaplets are set at the points where the pieces of clay have marked the mold. The stems of the chaplets are made long enough, so that when they are pushed up through the holes in the cope made with the vent-wire they will extend about a quarter of an inch above the top of the cope and still leave in the mold a length of chaplet equal to the thick- MOLDING A GAP-PRESS FRAME 63 ness of the casting. The chaplets are held from falling down by pieces of soft clay squeezed around the top of the stem projecting through the cope. The vent-wire is also used to form outlets through the cope for the gas driven ofif from the cores. Paste is placed on the edges of the cores so that the iron cannot "fin" over them, and thus enter the vents and prevent the escape of gases which would then back into the mold and ruin the casting. It is advisable, before placing the cope temporarily, to arrange pieces of thin rope or belt lacing from the vent openings in the cores to the outside of the mold. These should be covered with sand and be below the joints. When the mold is finally closed, and just before pouring, these ropes or belt lacings should be pulled out, thus leaving a clear vent from the core. If clay be filled in around the rope or lacing before sand is filled in around them, it will be impossible for iron to enter these vents, even should it overflow the cores. In places where the cope does not bear as it should, the sand in the floor is built up or parting sand is filled in on the joint. With very large castings, what is termed a clay worm — a roll of common fire clay about fourteen inches long — is laid at the back of the gate. This being soft, it is easily flattened by the weight of the cope when it is finally closed and prevents the iron straining out the back of the pouring gate at the joint. The cope is now finally closed and the riser C covered so that nothing will drop into the mold. Binders .4, Fig. 38, are placed on top of the cope as shown, blocks of hard wood or iron being placed between the binders and the edge of the cope. The binders are held down by hook bolts engaging with the eye-bolts in the floor as before. In order to keep the main core from rising when iron is poured in the mold, the binders £ are passed underneath the binders A, being held by wedges. Wedges G are pushed in between these binders and the top of the chaplets. A certain disadvantage in pouring is encountered in that the jaw portion, which must be the strongest part of the cast- ing, is heavy, while the lightest part is the leg. The iron must 64 FOUNDRY PRACTICE be poured hot enough to run to all the light parts of the cast- ing, including the leg, and this is too hot to give the best results with the heavier portions. Let us consider molding the same pattern in a flask. The drag portion of the pattern is placed on the mold-board and a slab core placed against the foot, while an iron plate is laid on top of the core-print. The drag of the flask is set around the pattern which is then covered with facing sand and successive layers of facing sand around the pattern of the leg. The flask is filled up with rammings of black sand and struck off. Bottom-boards are rubbed to a bearing, the drag vented, and the bottom-boards replaced. The clamps are placed in posi- tion and the drag rolled over. The cope is then finished as before. Still another method exists of bedding which must be practiced with many different styles of patterns. The pattern is blocked and wedged to the proper height in the hole and black or heap sand is tucked and rammed under it, the block- ing and wedges being removed as reached. When the pattern has been rammed completely on its under surface, it is staked and removed and the sand bed below it well vented down to the cinders. The entire face of the mold is covered with facing sand to a depth of three-quarters inch and the pattern replaced and rapped down to ram the facing sand into the bed of black sand. The vents in the black sand take care of the gas from the facing sand of which the face of the mold is made. CHAPTER VI MOLDING COLUMNS Cast-iron columns are still used to a certain extent to support the floors of buildings and also for ornamental pur- poses on the fronts. The illustrations, Figs. 40-42, show the pattern and method of molding a rectangular ornamental col- umn. The pattern is made with separate side pieces A to which are attached pieces of moulding to give an ornamental finish. These are pinned on to the side pieces' so that they may be removed during the process of molding. The pattern itself is made solid and is shown at B. In molding, the floor is used as a drag, the pit being prepared as described in Chapter V. The pattern is placed in the pit and leveled and a facing sand, comprising one part seacoal to fourteen parts molding sand, is laid up against the pattern. Black sand from the heap is rammed firmly against the facing sand. As each suc- cessive ramming of sand is laid in the mold, the facing sand is firmly rammed against the pattern with a hand rammer and fresh facing placed against the pattern. As the sand in the mold rises to the point at which the pieces of moulding a are pinned to the pattern, the pins holding the moulding are with- drawn, and it is supported by the sand. The facing of the pattern and the ramming of black sand is then continued until the floor line is reached where the joint is made. The cope is now placed in position and rapped down to insure its bearing solidly on the sand. If there is but a small amount of sand around the pattern and there is danger of the mold being crushed in when securing the cope, pieces of board are placed under the cope and on the sides near the center. In this case pieces of plank are nailed to the sides of the cope and stakes are driven against them into the floor to act as guides when the cope is lifted on or off; otherwise stakes C, Fig. 42, are used 5 65 66 FOUNDRY PRACTICE for this purpose. The cope is then lifted off and clay washed or wet down; the pattern is brushed off, parting sand placed on the joint and facing sand riddled over the pattern, except at its center. The facing sand is left off the pattern at the center as it has a cooling effect on the iron which, in this case, will be poured from the ends of the mold. Were seacoal facing to be used at the point where the flow from opposite directions solid eattern with pieces pinned on vct ^o, Fig. 40 COPE CLOSED ON AND SECURED Fig. 42 Figs. 40-42. — Molding an Ornamental Building Column in the Sand. meets, there would be the liability of a cold shut forming and thus destroying the casting. In place of the seacoal facing at this point, a mixture of old and new sand is used. The cope is now replaced, and gate-sticks D and E set to form the pouring gates and risers. Gaggers are set and the sand shoyeled in to the proper depth for tucking the bars. Extreme care must be used in this operation in castings of this character, since any soft spots left in the mold will form lumps on the casting and destroy their value for ornamental purposes. After tucking the bars, the cope is rammed up, vented in the usual way, the cope hoisted off, turned over on its back and MOLDING COLUMNS 67 finished. The joint is brushed off and the pattern drawn. The pieces of moulding a remain in tlie sand when the pattern is drawn, and they now are drawn inward into the mold and lifted out. Should these pieces be of any considerable depth, thus leaving a considerable body of sand hanging over them, the mold is nailed on the upper surface of the cavity left by these pieces. The side pieces A are now placed in the mold, one on either side, and the center or green-sand core built. These side pieces are the same thickness as the casting is required to be. A mixture consisting of one-half old sand and one-half new sand is tempered and the side pieces faced with it. Black sand is rammed firmly against this facing until a height of about six inches below the top of the casting is reached. The sides of the core are then vented and two channelways of cinders are formed, extending the length of the green-sand core into the body of sand around the mold. In order to do this, the joint must be broken up somewhat. Pieces of pipe are placed to bring the vent from the cinder beds to the outside of the mold as described in Chapter V. The cinders used should be, roughly, five-eighths inch diameter and should not come closer than four inches to the side of the mold. After tamping them with the rammer, paper is placed over them, it also being kept back four inches from the edge of the mold. Should the paper be allowed to extend to the edge, iron would find its way into the sand through the crack formed by the paper, and raise the face of the mold. The sand is now rammed on top of the paper to within a short distance of the top of the side pieces, when it is struck off with a sweep running on the side pieces. These latter extend above the surface so that the sweeps will not bear on the joint when used. The whole surface is then vented down to the cinder beds. The surface of the mold must be soft enough for the gas to escape easily and allow the melted iron to lie quietly on it. The casting being very thin, will be scabbed and in- jured should the iron boil while covering this green-sand core. Making the face of this core is usually done by hand. In order 68 FOUNDRY PRACTICE to form it to the proper height to give the correct thickness, the sweep G is first used. The first sweep used left the sand about three-quarters of an inch below the final face of the core. The same mixture of sand which was used to face the inside of the side pieces is now used to make up the upper face of the center. This sand is pressed lightly down in place by hand or it is thrown in handfuls down on the surface. The sweep G is then used to true the sand from / to /, Fig. 42. At point /, a recessed panel X is formed and sweep H is used to sweep the sand out to a greater depth at the center of the core, where this panel is to come. This sweep is used from J to K after which the sweep G is used to complete the surface from K to M. The top of the center is now finished and the side pieces drawn, fillets first being formed on the edges. The mold is then blackened over its entire surface, except at the center, with plumbago. A slight coating of talc is then dusted over the entire surface to assist the flow of iron through the mold. Gates are next cut for pouring, being shown by the dotted lines R, Fig. 42, and also gates to the risers. Flour or white sand is placed on the joint and the cope is lowered into position. The cope is then raised and the mold examined to see if the cope bears solidly as will be evidenced by marks in the white sand or flour, necessary repairs are made, pouring basins and heads or flow-offs from risers are built, and the cope is lowered into place. The cope may be secured either by means of binders as described in Chapter V, or it may be weighted down. Iron for a casting of this character must be poured sharp, that is, extremely hot. A point which has been omitted in the description of the making of the mold is the provision of a camber in the pattern in order that the casting shall come straight when cooled. As the sides of the casting are thin, when the melted iron is poured the lower part of the thin side fills quickly and sets hard before the top of the casting is set. This almost instant cooling of the sides, combined with the later cooling of the top, causes the shrinkage in the sides and top to be unequal. The shrinkage of the top tends to draw the ends upward and thus give a bent MOLDING COLUMNS 69 casting, or to crack the casting if the moulding on the sides lias been left off or if the iron is not especially soft. If the sides are heavier than the plate forming the top of the casting, the casting will cool at about the same rate in all parts and thus avoid bending. There are one or two methods of avoiding this bending of the casting. One is to make the pattern with a slight camber in it, the ends being at a lower level than the center. Another method is to force the ends of the pattern down in the mold, below the level of the center, so that, with either method, the mold itself is curved in the opposite direc- tion to that in which the casting would curve in cooling. The same shrinkage effects will occur with the mold made in this manner, but the casting originally being curved in the opposite direction, the shrinkage in cooling will pull it straight. By using a solid pattern and ramming it up to get the ex- terior surface first and then making the center by means of side pieces as described, the pattern is easier to mold and castings of the desired thickness are more likely to be obtained. The side pieces should be provided with straps and eye-bolts for drawing them out of the sand as shown in the illustration. There is but little chance to rap them while drawing, and they are usually drawn by means of a hook in the eye-bolt, the other end of the hook being attached to a lever. While bearing down on the lever, the hook or top of the eye-bolt is rapped slightly. Molding a Round Column In many foundries it has been the custom to use split pat- terns in molding round columns, drawing one-half of the pattern from the drag and the other from the cope. Other foundrymen prefer to use the solid pattern. In molding, the pattern would be laid in a frame, the drag being placed on top in the usual manner, rammed up, rolled over, and the joint made. The cope would then be rammed up and the pat- tern rapped through the cope, thus avoiding a seam showing on the casting. Another method would be to bed the pattern in the floor, if only a few were to be made, and to stake the 70 FOUNDRY PRACTICE cope In position as in molding the ornamental column described earlier in this chapter. Fig. 43 shows a column pattern placed on a board as described with the drag around it ready to be rammed up and rolled over. Round columns are frequently provided with brackets to support I-beams. The column shown in Fig. 43 has such a JF^ Fig. 44. SIDE VIEW of mold of column with brackets in cope and drag. Fig. 43. column patternin novel. _A. Faced to receive pattern \i ^T .A_ IT ^ deeper than pattern Jk. "^ Figs. 43-45. — Molding Columns. bracket which will be molded in the drag, while Fig. 44 shows a column with brackets to be molded in both cope and drag. This latter column illustrates some special devices adopted in molding. For instance, it will be noted that the bracket B extends to the top of the cope. A head of iron of greater depth than this is required in order to insure the filling of the mold of the bracket. To make the cope of the requisite depth re- quired to provide this head, and also to provide the necessary thickness of sand over the pattern, would entail unnecessary expense and also render the flask more difficult to handle. It MOLDING COLUMNS 7 1 would also necessitate a greater amount of time to ram up the deeper cope. In order to avoid these features, the cope is simply boxed over at the bracket and at each end of the flask where the pouring gates are located. In the author's opinion, the cheapest manner of molding round columns, when there are a number to be made, is to make a solid pattern and use a drag of the required length, width, and depth. The drag should be placed on the molding- board and leveled with the joint side up. Sand from the heap is rammed to a point very near the joint, but so formed as to leave a trough through the center. The sweep F, Fig. 45, is then used and the sand is swept out to a depth of about three- quarters of an inch greater than the half diameter of the pat- tern. Facing sand, mixed according to the thickness of the column, is then spread on the surface left by the sweep and the sweep G, raised from the joint of the flask about one- quarter inch, is used to form the facing to the shape of the pattern. The pattern, if free of brackets, is then laid in the trough so formed and rapped down until the block of wood H, which is used as a gauge, rests on the top of the pattern and the joint of the flask. If a bracket is to be made on the lower side of the casting, sand is dug out of the trough where the bracket is to be formed, and after the pattern is placed in position and rapped down, facing sand is laid around the bracket and sand rammed in against it and against the pattern where needed. The same gauge that was used to set the pattern is now used as a sweep to sweep the sand from each side of the pattern at the joint. The joint is vented, after which the cope is placed and rammed up with gate-sticks and risers in their proper places. The pattern is rapped through the cope, a gate-stick having been placed over a hole in the pattern, provided for this purpose. The rapping bar is entered through this hole, which, after the removal of the bar, is filled up. The cope bracket is pinned to the cope side of the pattern and when the cope is hoisted off, the bracket is found in it. In ramming up the cope, the spaces / and / between the ends of the flask and the first bar are not rammed up. The gate-sticks are set between the 72 FOUNDRY PRACTICE ' next two bars as at K. The runner boxes D, which are usually free from the cope, are not rammed up with the cope, but later after the mold is closed. After the cope is rammed up, it is rolled over and the bracket has the sand secured around it, usually by means of spikes, and the bracket pattern is drawn. It is frequently ad- visable to ram a dry-sand core in the mold against the face of the bracket which is to be used as a seat for the I-beam. After the pattern is drawn, the face of the mold is felt and any soft spots filled up with a pipe slicker. The cope is then given a coat of silver lead and the chaplets for holding down the cores are placed as described in Chapter XIV. The joint of the drag being brushed off, a channel is formed alongside the drag which is dampened with the bosh. A vent-wire is bent and run from this channel under the pattern, thus venting under the pat- tern and alongside of it to the side of the flask. As the sides were previously vented toward the bottom-board, before the joint was made, the escape of gases from the drag is thus pro- vided for. The mold is now finished and blacked. In gating round columns, the gates are made on the ends, alongside the core on both sides of the mold. The iron fills the column poured in this manner with slacker iron than when the mold is gated along the sides. The mold being finished, the core is calipered and also the pattern. One-half the dif- ference in diameter between the two is the distance which chaplets must project above the surface of the mold in order to support the cores in the proper position. In selecting the chaplets, it should be remembered that with a large body of iron flowing into the mold, a much larger diameter is required than for smaller cores. For a thickness of casting of one and one-half inches in the column, we would use a chaplet with a stem about one-half inch diameter. Using a lighter chaplet will probably permit the core to settle as the chaplet would soften under the influence of hot iron and the weight of the core would cause it to crush and thus permit the core to settle. On the other hand, chaplets used in the cope must be stiff enough to withstand the pressure of the core being floated MOLDING COLUMNS 73 upward by the entering iron. The chaplets are driven clear through the drag, into the bottom-board, which they should enter for a distance of about three-eighths of an inch. The number of chaplets to be placed in the cope and drag depends on the size and general arrangement of the cores. No fixed rule can be given except that it is better to have too many rather than too few chaplets. It is much easier with a long column, to make and set the core in two pieces rather than in one. The cores are butted together at the center of the mold, one end resting in a core- print at either end, the other end of each piece being supported at the middle of the mold by chaplets. To prevent the cores shifting sidewise, due to iron entering one side of the mold more rapidly than the other, chaplets are placed on either side of the cores at the ends where they are butted together. These chaplets are wedged in place by a wedge driven between the end of the chaplet and the side of the flask. After placing the chaplets, flour or sand is arranged on the joint to afford a tell-tale as to whether the cope bears on the cores or on the joint. In the ends of the flask at the joint are holes through which are shoved short rods into the vent holes in the end of the column cores, as shown at 0, Fig. 44. Sand is then rammed in the spaces / and J, after which the rod is removed, leaving a clear hole from the vent of the core to the outside of the mold. Two or more vent holes are sometines left in the core, depend- ing on its size, and as many vent rods are used as there are holes in the core. It is advisable to put a little paste on the ends of the cores before closing the mold in order to exclude iron which might find its way over the cores and thus stop the vent hole. The pouring boxes D and E are next placed and pouring basins P built. These boxes are fastened by driving a nail a short distance into the cope. In securing the cope, clamps are used and binders are placed to hold the core down through the agency of the chaplets, wedges being driven between the ends of the chaplets and the binders which are clamped across the top of the flask. 74 FOUNDRY PRACTICE The iron used in pouring should be cooled until it is quite dull for the larger and thicker columns, and it is advisable to feed the larger sizes of columns through the riser on the bracket to avoid shrinkage. Columns seldom shrink the full allowance — one-eighth inch to the foot — and for that reason column patterns are usually made with a smaller shrinkage allowance. It is important that the same iron mixture be used in pouring all the columns of a given lot, particularly ornamental columns; otherwise there will be a difference in the shrinkage, resulting in columns of varying lengths. When molding columns of the following approximate di- mensions — fourteen feet long, six inches wide, and sixteen inches deep, with a thickness of one-half to five-eighths inch — it is best to mold them on edge to avoid troubles due to the shrinkage curving the column in cooling. In many cases, castings with heavy parts must have these parts uncovered in order to permit them cooling more rapidly. The entire casting is then cooled more nearly at a uniform rate and warping is thereby avoided. The pattern for a fluted column is usually made in quarters, and the two quarters of each half are hinged together, where a space comes between the flute and the out- side, as shown in Fig. 46. A piece of flat iron is let into the joint side to hold the quarters apart and in this way form one-half of the pattern. The two halves are pinned together. teriTfor aFlutS ^^ molding, the cope and drag are molded as Column. a plain pattern. To draw the pattern, the screws holding the pieces of flat iron in place are removed and the two quarters closed together, sufficient material being cut away from each quarter to form a V-shaped opening the entire length of each half of the pattern. After closing together the pattern can be lifted out of the mold. The method of making cores for columns is described in Chapter XIII. CHAPTER VII MOLDING WITH SWEEPS The expense of pattern work for certain classes of castings of a regular form may be avoided by the use of a sweep. Such castings as circular boiler fronts, tank heads, pulley rims, and similarly shaped castings can easily be molded by this method. In addition, certain irregular-shaped castings may be partially swept out in green-sand molds, the balance of the mold being finished by means of pattern pieces. The sweep consists of a board, one edge of which is shaped to correspond with the surface of the casting and, on drawing it across the sand, it leaves a surface in the mold of the desired shape to make the casting. In Figs. 47-50, the method of molding a ribbed tank cover, by means of sweeps, is illustrated. The casting is a circular piece of dished cross-section with four ears, slotted to receive bolts, placed at equal intervals around its circumference. In molding it, two or three sweeps are used, according to the ideas of the molder, and no pattern work is necessary excepting for the four ears and for the ribs on the under side of the dished portion. In making the mold for this casting, the first operation is to set the spindle seat in the floor. The spindle seat consists of a socket for the spindle of the sweep, and is mounted on four cross arms, extending horizontally from the body of the socket. A hole is dug in the floor of such depth that the top of the spindle seat will come level with the floor line when the spindle seat is leveled in it. The spindle is placed in the seat and by means of spirit level is plumbed until it is truly vertical, wedges being driven under one leg or the other of the spindle seat, to throw the spindle in the necessary direction to bring it vertical. Sand is then rammed around the spindle seat until 75 76 FOUNDRY PRACTICE the hole in the floor is filled. The sand around the spindle is then swept off level by means of the sweep. This is a plain piece of board about four inches wide and of any desired length and with a beveled lower edge. Attached to one end, by means of bolts, is a finger which fits snugly over the spindle, being Sweep Finget 'Bolt [Cope Line of Castii^ H^ragLineof Casting ElG. 47 SWEEPING COPE SIDE PATTERN FIG.50 COPE SIDE PATTERN WITH RIBS IN PLACE .D ^E Fig. 48 SETTING SPINDLE SEAT Figs. 47-50. — Sweeping a Ribbed Cover Plate Mold. fastened thereto, and permits the sweep and the spindle to be revolved. The sand being rammed down around the spindle, the sweep is revolved and sweeps off any surplus sand, leaving a level and true bed of sand. The sweep finger is then removed from the spindle and a bottom-board with a hole in the center, lowered over the MOLDING WITH SWEEPS 77 spindle, or the spindle may be removed from the seat, the bottom-board placed in position, and the spindle re-inserted in the seat through the hole in the bottom-board. The drag of the flask is then placed on the bottom-board with the joint up and is wedged up a short distance by means of wedges set from the inside of the flask. The sweep for forming the cope side of the mold is bolted to the sweep finger and leveled. The end of the sweep is allowed to rest on a trowel laid on the joint of the drag while it is being leveled so that on removing the trowel, the sweep has a clearance from the drag of the thickness of the trowel. In certain cases a guard is placed around the spindle to prevent sand from passing through the hole in the bottom-board. Such a guard is shown at G. Cinders are next spread over the bottom-board and covered with paper, after which the drag is rammed full of sand. When it has reached the proper height, the sweep is revolved, tracing in the sand a circular cavity of the exact shape of the bottom of the sweep. The sand should be rammed in the drag as hard as possible preparatory to this operation. When it has been struck off, after sweeping, it is slicked and parting sand is dusted over the joint, and sometimes over the face formed by the sweep. Instead of parting sand, paper is sometimes laid over the swept surface, being first wet in order to make it con- form to the exact shape of the mold. The use of paper makes a very clean parting, whereas, if parting sand is dusted on, it must later be brushed off which not only tends to make a rough surface on the casting, but, if not thoroughly removed, is liable to be washed off when the casting is poured and make dirt in the casting. The ribs which are to be cast in the cope and for which patterns are required, are placed as shown at / in the plan of the cope, Fig. 50, being held in place by a few nails pushed into the sand alongside of them. The spindle is then removed and the green-sand core / having been formed, a bunch of waste is placed in the hole left by the spindle. The cope of the flask is then placed in position, gaggers set, and the cope rammed up as for any ordinary mold, the patterns for the ears first being 78 FOUNDRY PRACTICE placed in position. After venting, the cope is turned over, the ribs and ear patterns drawn, and the edges, where the ribs unite with the body of the casting, filleted. The gates are prepared as desired and the cope is blackened with plumbago. The next operation is to sweep out the drag. It will be remembered that in sweeping out the drag first, what was known as the cope sweep was used. This was for the purpose of forming a recess the exact size of the projection of sand desired in the cope. In order to give thickness to the casting, the drag must be swept out to a greater depth than was done by the cope sweep. The drag sweep used is of exactly the same shape as the cope sweep, but is as much deeper than it as the casting is thick. The drag sweep is bolted to the sweep finger, the sand is dug out from over the bunch of waste, and the waste removed from the spindle hole, after which the spindle is set. A gutter is dug from the spindle to the outside of the flask of sufS- cient depth to permit the sweep to rest on the trowel on the joint. The sand is dug up to about three-quarters inch below the edge of the sweep, the sweep is revolved, and the surplus sand removed. The drag is thoroughly vented down to the cinder bed, after which facing sand, properly tempered and riddled, is thrown, a handful at a time, on the face of the mold where it will stick. The entire face of the mold is covered in this manner, the sweep being revolved as the sand is thrown, in order to form a surface of the desired shape. The face is examined for soft spots which are repaired as found and the spindle is removed. The mold is finished, blackened, gated, and made ready for pouring in exactly the same manner as any other mold. It may be well at this point to call attention to some things that should be borne in mind in sweeping molds. We have de- scribed above the method of sweeping a comparatively light casting. If instead the casting should weigh several tons rather than a couple of hundred pounds, the operations of molding would be the same, but the greater amount of metal would bring considerably greater strain on the face of the mold, particularly on the drag, and certain precautions must be ob- MOLDING WITH SWEEPS 79 served to take care of this. After ramming up the cope as above described, the drag would be dug out in the same manner as for the lighter casting. The sweep is made so that it can be lowered three-quarters of an inch below what is to be the face of the mold or a third sweep is made, which will sweep out the sand to this depth. After digging out the sand from the drag, in the manner described, black sand is solidly rammed on the face to the line of this third sweep or to the edge of the sweep lowered below the level of the face. The surface thus formed is thoroughly vented, after which facing sand is thrown on as was done for the lighter casting, and the face of the mold is finally finished. The object of using this third sweep or its equivalent, and making a solid face on which facing sand is built, is to provide an evenly rammed surface for the mold. If there is any dif- ference in the strength of the mold, in different portions, the casting will be distorted. If the hard-rammed sand is left uneven when digging off the face and the facing sand simply thrown down on it as described, the molten iron filling the mold will soon discover the point at which this facing sand is the deepest and at this spot will cause the sand to give. In other places, where the sand was not cut away to the same depth, the facing will be harder and, therefore, the surface of the cast- ing will be found to be uneven, being at the proper level over the hard portions and having projections at those points where the facing sand was deepest and therefore soft. It is evident, therefore, that by ramming the surface at a depth of three- quarters of an inch below the face of the mold, and then building the face of the mold on this surface, the pressure of the molten metal is resisted evenly over the entire surface of the mold and a casting with a true surface is the result. The lack of care in making this firm under-surface, is often responsible for the failure to obtain good results with swept up molds. Oftentimes, patterns molded by bedding them in the floor or a flask, may have a portion of the mold made by a sweep and the balance made by placing the pattern on it and tucking the sand under those parts of the pattern which are irregular 80 FOUNDRY PRACTICE in shape. In this way, the pounding of the pattern into the bed is avoided. To illustrate this method of molding, we will consider the case of a tank bottom, eight feet long, five feet wide, and five-eighths inch thick, which is to be bedded in a flask. A bed of sand is first made on the floor where the center of the flask will rest, being made one foot wide and a trifle longer than the flask. This is made three inch thick and is trodden down firmly and is struck off with a straight edge. On this a bottom-board is placed and the drag set, being raised about five-eighths of an inch from the bottom-board by means of wedges driven between them from the inside of the flask. The bottom-board is then wedged up on one side until it has an inclination of about five-sixteenths inch in two feet. Cinders are next spread over the surface of the bottom-board and covered with paper, after which straight-edges G, Figs. 51 and 52, are placed and raised to the desired height by means of bricks and wedges H, or they may be made of sufficient depth to rest directly on the bottom-board. They are leveled and secured at the desired height and sand rammed in around them to prevent their movement sideways. Black sand is then rammed over the cinders until it is about level with the top of the straight-edges. The sweep I is used with the notched side down, the bottom of the sweep being notched so that the edge / is five-eighths inch below the edge of the straight- edge, to sweep out the sand between the straight-edges to that depth. The bed of sand is then thoroughly vented down to the cinder bed, after which a mixture of seacoal facing, in the ratio of one seacoal and fourteen sand, thoroughly tempered and riddled, is spread on the bed between the straight-edges, until its surface is slightly above the straight-edge. The sweep with the straight side down is then used, a block of wood one- eighth inch thick being placed under each edge, and the sand swept level. The blocks are removed, and one man holding an end of the sweep on the straight-edge, a man on the other end strikes the straight-edge a blow with the opposite end. The sweep is moved gradually across the width of the mold, the sand being pounded down in this way, first by the man at one MOLDING WITH SWEEPS 8i end and then by the man at the other. This process will ram the sand solidly, and a casting weighing many tons can be poured on it without danger of rough spots being formed, due to -soft places in the mold. The bed being made, the pattern is placed on it, weighted down, and sand rammed around the edges. The joint is made and the cope rammed up, the gates being set so that hot iron shall flow into the mold up to the last moment of pouring. It will be recollected that, at the beginning of operations, we wedged the bottom-board so that one side of the flask was higher than the other. This was done so that the iron, in Sweep Sand above H' Straight edge, G— • ' Cx H- :^ Figs. 51-52. — Molding a Tank Cover Plate with a Sweep. pouring, would fill the lower side of the mold first and rise along the face of the mold as it fills. If the mold were to be level, the iron would cover the entire lower surface of the mold before it reached the upper surface. The lower portion of the mold would require covering with liquid iron immediately or cold shuts would result which might ruin the casting. By causing the iron to flow into the mold from the higher side, this trouble will be avoided and a slacker iron can be used. A slight coating of talc over the entire face of the mold will assist in the rapid flow of the iron. We will now consider the case of a pattern which is to be molded in part with a sweep and the remainder tucked up. Referring to Fig. 53, the method of molding the face of the 6 82 FOUNDRY PRACTICE segment of a large built-up fly-wheel is shown. In molding these segments, it is desired to have the face as nearly as possible on the same circle as the finished wheel, leaving merely enough stock for finishing. Two cast-iron guides A are ar- ranged to rest on timbers B in the flask and using a similar sweep to that described in the operation of making the tank Fig. 53. — Molding Segment of Built-up Fly-Wheel. bottom, a bed is made on which the pattern is to rest, the sweep being guided by the guides A. After the bed is made, it is vented to the cinder bed which has previously been made at the bottom of the flask and, on top of this bed, a face is built of facing sand on which the pattern is placed. In gating this mold, the pouring gates must be further apart for large- diameter wheels, say thirty feet, than for smaller wheels of ^' ..,., Fig. 54. — Molding a Former for Sheet-Metal Work Without a Pattern. ten or fifteen feet diameter. With the smaller wheels, the iron flowing in and being given a quick turn due to the smaller di- ameter, will be given a whirling motion and will thereby cut the face of the mold, producing a scabbed casting, unless the mold is of the proper hardness. Fig. 54 shows the method of making the mold, known as a former for sheet-metal work, without a pattern. Two boards MOLDING WITH SWEEPS 83 with the size of the inside of the former cut in them as shown at A are set in ends of the flask and sand rammed firmly between them and swept ofif level with the top of the inside of the guides A. The pieces F, shown by the cross-hatching, that were sawed out from the guides along the line A, are then replaced and sand rammed between these pieces and the ends of the flask. Damp parting sand is slicked on to the steeper parts of the face of the mold and dry sand dusted on the flat portion. The cope is now placed on the drag and rammed up and removed. The end pieces F are now removed and the sand dug out be- tween the guides. A sweep notched somewhat deeper than the thickness of casting desired as shown by the distance between the lines AD Is used to strike the sand ofT along the line D, the sand beirg f rmly rammed and vented. The face of the mold is built up to the line B, a sweep notched a distance equal to AB being used. The mold is finished and gated in the usual manner. CHAPTER VIII MOLDING CAR-WHEELS Cast-iron car-wheels having a chilled tread are cast in molds formed partly of molding sand and partly of cast-iron. The pattern used in forming the mold is what is termed a solid pattern, being made in one piece and having on it core-prints. The flask in which the wheel is molded and cast consists of three parts: The drag in which the flange side of the wheel is molded, the wheel being poured flange side down; on top of the drag, a cheek or chill of cast-iron is placed to form the tread and part of the flange; on top of the chill rests the cope in which the face of the wheel is molded. Over the center of this is a raised part in which the pouring basin is built. The flask rests on a perforated iron bottom- board through which the gases escape from the drag. The entire flask is of cast-iron and the cope is provided with radial bars of the shape of pattern to hold the sand in the cope. The cast-iron chill is chambered and connected to a water supply for cooling the chill if required. The raised part of the cope is provided with ears to take the tops of chaplets which hold down the lightening cores around the hub of the wheel. Oftentimes, before the wheels are molded the chill part of the flask is oiled in order to prevent it sweating, or gathering dampness from the warm sand. If this is carelessly done, or if the chill is warm, the oil may find its way to the bottom of the chill, leaving dry spots on the face on which moisture may condense and thus crack or make a bad place on the tread of the wheel. To avoid this, sometimes lead is mixed with the oil, or, instead of oil, lampblack and shellac are mixed, first killing the lampblack with alcohol. The chills are coated with this mixture, as one would black a pattern. In molding, the pattern is placed in the chill portion of the 84 MOLDING CAR-WHEELS 85 flask with the flange side up, the face of the wheel sliding down in the chill a distance equal to the width of the tread. The flange of the wheel rests in a part of the chill which is formed to receive it. The drag is placed over the chill and the pattern is covered with a mixture of facing sand, consisting of ten parts of old molding sand from the heap, two parts of new molding sand, and one part seacoal. This mixture is riddled into the drag through a number six sieve, and the facing is laid up against the ribs and evened off to a depth of five- eighths inch over the pattern. The drag is then shoveled full of sand and peened around the edge of the flask, trodden over and butted off. The sand is next struck off flush with the top of the drag and about three-quarters of an inch of loose molding sand is thrown over the drag, after which it is vented and the bottom-board rubbed to a bearing. The bottom-board is then clamped to the flask and by means of a yoke, which is hooked to the trunnions on the chill, the flask is raised and rolled over. It is then lowered on to two rails. Care should be taken that these rails are level and at the same height, as it is important that a car-wheel mold should fill evenly with iron in order to avoid the chill cracking the wheel. After the gate-sticks are set to form pouring gates, facing sand is riddled over the pattern and heap sand is shoveled in until the cope is filled flush with the tops of the bars. The sand is then peened between the bars, after which the cope is heaped full of sand which is trodden down and then butted off". The pouring basin is built and the sand scraped from above the bars of the cope, and the cope is vented all over and the gate- sticks removed. Cope and chill are then bolted together and hoisted by means of the yoke, leaving the pattern in the drag. The cope is finished, blackened with silver lead, and the chaplets set to hold down the ring or lightening core. The chill is given a coating of lard oil, or of shellac and lampblack, or some one of the various mixtures made for application to chills. The pattern is then drawn from the drag, which is finished and blackened with silver lead, and a vent-wire is run down through the core-prints to the bottom-board, after which one 86 FOUNDRY PRACTICE of the ring cores shown in Fig. 55 is placed with the three pro- jections in the prints in the drag. The center core is next set. Usually the sand is first cut up to form a ring around the vent hole so that the core may press down on it and thus prevent the iron from running under the core into the vent hole. Before Wheel ElaTige Wheel Tread' . TOP OF MOLD PouringTKad j^arf Sawed Chamber in ^ z' *" ! ' Bottom Board Chilled Face of Wheel ■YfTM vwtrgii rtf