1 I TS 230 .S8 1916 I iiiiiliiiiiillli i I iitt fi Pill r,i!' illiililiilili V^^'',^"^ %.'^^''\°' V'*.^-\r 'o* *-'• ■ %.*' V ° . ■^^'"^'^^ . °^W.' .J"%. '^mJ . **^''** . °°^w*' ,J'\ ^^..9^' v.©^ .♦^ J^ % .-i ^^ Digitized by the Internet Archive in 2011 with funding from The Library of Congress http://www.archive.org/details/foundryworkpract01stim o CO O ,M w I 3 3 ^ i 2d:. FOUNDRY WORK A Practical Handbook on Standard Foundry Practice, Including Hand and Machine Molding; Cast Iron, Malleable Iron, Steel, and Brass Castings; Foundry Manage- ment; Etc. REVISED BY BURTON L. GRAY 1N8TRDCT0H IN FOUNDRY PRACTICE, WORCES i ER I'OLTTECHNIC INSTITUTE MEMBER, FOUNDRYMEN's ASSOCIATION ILLUSTRATED AMERICAN TECHNICAL SOCIETY CHICAGO 1916 Copyright, 1916, bv AMERICAN TECHNICAL SOCIETY COPYRIGHTED IN GREAT BRITAIN ALL RIGHTS RESERVED nCT \\ 1916 >GI.A438843 INTRODUCTION rr^HE making of a metal casting seems like a very simple opera- •■- tion — given a pattern, a flask, a supply of molding sand, and some molten metal; presto! it is done — but a little study de- velops the fact that there are few industries where more depends upon shop kinks and the many other essential things which make up a broad knowledge of a distinct trade than in foundry work. The industry, as such, is as old as our knowledge of brass and iron, the former having been made into castings from earliest times. Casting methods, however, have partaken of the general mechanical development of the last few years and today there is no com- parison as to the quality of castings, the complexity of the patterns cast, and the speed of manufacture, with the work of a few years ago. ^ In this article the methods of hand molding have been carefully discussed, including the many questions of pattern construction which are more or less closely associated with foundry work. The presentation also includes the uses of the various types of molding machines, which have become so popular within the last few years. Malleable iron practice has now become well standardized and this type of casting, particularly for small work requiring much dupli- cation, is very important. An excellent discussion of steel castings is particularly pertinent as this type of casting is fast displacing drop forgings for many classes of work. ^ Altogether the article represents a well-rounded and thoroughly up-to-date discussion of this important subject. The original author and the reviser, both men of broad experience, ha\'e combined to give the reader the benefit of their knowledge and it is the hope of the publishers that the book will be found instructive and interest- ing to the practical foundry man as well as to the general reader. •s45fs4»»l^'i CO H a w > o o w w H ^^ w > H §• CONTENTS PAGE Molding practice 1 Main branches 1 Molding equipment 3 Classes 3 Molding sand 5,6 Core sand 6 Graphite 7 Charcoal 7 Sea coal 7 Distinction 7 Fire clay 7 Parting dusts 8 Core binders 9 Tools 9 Flasks 9 Shovel 12 Rammers 13 Finishing tools 14 Clamps 17 Molding processes 18 Sand mixture 18 Sifting 19 Ramming 20 Gating. 24 Shrinkage heads 26 Pressure in molds 27 Common defects in castings 31 Typical molding problems 31 Flat joint 32 Coping out 35 Sand match 36 Split-pattern molds 38 Floor bedding 42 Open mold 45 CONTENTS PAGE Core work 46 Materials 46 Equipment 48 Conditions of use 50 Methods of making 53 Cylindrical cores 58 Setting chaplets 60 Projecting cores 60 Hanging cores 61 Bottom-anchored cores 61 Duplicating castings 66 Practical requisites in hand molding 66 Use of molding machines 67 Dry-sand work 89 Characteristic features 89 Molding engine cylinder 89 Making barrel core 92 Loam molding 94 Rigging 94 Materials 97 Principles of work 99 Simple mold 102 Intricate mold 104 Casting operations 109 Furnace parts 109 Blast 112 Running a heat 116 Foundry ladles 118 Pouring 119 Chemical analysis 123 Calculation of mixture 124 Fuel 126 Sand mixing 127 Cleaning castings 131 Steel work 136 Present development. 136 Processes 136 Characteristics of metal 136 CONTENTS PAGE Steel molds I37 Facing mixtures I37 Packing I39 Cores 141 Steel castings 141 Running a heat 141 Setting up molds 143 Cleaning castings 144 Annealing 144 Malleable practice 145 Comparative characteristics of metal 145 Testing 146 Production processes 148 Molding methods 149 Methods of melting 152 Iron mixture 156 Variation from gray-iron practice 159 Cleaning castings 160 Annealing 161 Finishing 167 Brass work 167 Metals 168 Mixtures 170 Production 171 Molding materials 171 Equipment 172 Examples of work 175 Melting 176 Cleaning 181 Shop management 182 Governing factors 182 Molding divisions 184 Materials 186 Handling systems 186 Cleaning department 187 Performance 188 Accident prevention 189 Checking 190 Keep's mechanical analysis 190 Arbitration-bar tests 191 o fe Si O o M .g o w Pi g 1^ Br l-H O gl Id FOUNDRY WORK PART I MOLDING PRACTICE Introductory. Foundry work is the name applied to that branch of engineering which deals with melting metal and pouring it in liquid form into sand molds to shape it into castings of all descriptions. In the manufacture of modern machinery three classes of castings are employed, each one having its individual physical properties, such as strength, toughness, durability, etc. These castings are as follows: gray iron; copper alloys, i.e., brass, bronze, etc. ; and mild steel. By far the greatest number of castings made are of gray iron, that is, iron which may be machined directly as it comes from the mold without any further heat treatment. The main purpose of this book is to explain the underlying prin- ciples involved in making molds for gray-iron castings, and the mix- ing and melting of the metals for such castings. The articles on Malleable Cast Iron as well as the articles on Brass Founding and Steel Casting emphasize only those features of the methods used which differ from gray-iron foundry practice. The article on Shop Management is intended to set students thinking on this subject; because the whole trend of modern shop practice is toward special- ization and system in handling every department of the work, in order to increase efficiency and reduce cost. DIVISIONS OF IRON MOLDING Main Branches. There are four main branches in gray iron molding: (1) green-sand work; (2) core work; (3) dry-sand molding; and (4) loam work. Green-Sand Molding. The cheapest quickest method of form- ing the general run of castings is by green-sand molding. Damp molding sand is rammed over the pattern, and suitable flasks are used for handling the mold. "Wlicn the pattern is withdrawn the 2 FOUNDRY WORK mold is finished, and the meta,l is poured while the efficiency of the mold is still retained by reason of this dampness. The mold may be poured as soon as made; and in case of necessity it may be held over a day or more depending upon its size. If the sand dries out, the mold should not be poured. Core Making. Core making supplements molding. It deals with the construction of separate shapes in sand which form holes, cavities, or pockets, in the castings. Such shapes are called cores. They are held firmly in position by the sand of the mold itself or by the use of chaplets. Core sand is of a different composition from molding sand. It is shaped in wooden molds called core boxes. All cores are baked in an oven before they can be used. The whole detail of their construction is so different from that of a mold, that core making is a distinct trade — a trade, however, that is generally considered a stepping stone to that of molding. Boys usually begin to serve their time in the core shop. Dry-Sand Molding. Dry-sand molding is the term applied to that class of work where a flask is used, but a layer of core sand mix- ture is used as a facing next to the pattern and the joint, and the entire mold is baked before pouring. This drives off all moisture and gives hard clean surfaces to shape the iron. It is used where heavy work having considerable detail is to be cast, or where the rush of metal or the bulk of it might injure a mold of green sand. Dry-sand molds are usually made up one day, baked over night, and assembled and cast the next day. Loam Work. Loam work is the term applied to molds built of bricks carried on heavy iron plates. The facing is put on the bricks in the form of mortar and shaped by sweeps or patterns depending upon the design of the piece to be cast. All parts of the mold are baked, rendering the surfaces hard and clean. After being assem- bled, these brick molds must be rammed up on the outside with green sand in a pit or casing to prevent their bursting out under the casting pressure. Simple molds can be made up one day, assembled, rammed up and poured the next, but it usually takes 3 or 4 days and some- times as many weeks to turn out a casting. Loam work is used for the heaviest class of iron castings for which, on account of the limited number wanted, or the simplicity of the shape, it would not pay to make complete patterns and use a FOUNDRY WORK 3 flask. In some cases the intricacy of the design makes a pattern necessary, and size alone excludes the use of sand and flasks. Selection of Method. No hard and fast rules exist for tlie selec- tion of the method by which a piece will be molded. Especially with large work, the question whether it shall be put up in green sand, dry sand, or loam, often depends upon local shop conditions. The point to consider is: How can the best casting for the purpose be made for the least money, considering the facilities at hand to work with? MOLDING EQUIPMENT MATERIALS Before taking up the making of molds, let us consider briefly the materials used, where they are obtained, and what is their particular service in the mold. Also we shall describe the principal tools used by the molder in working up these materials into molds. Classes. There are three general classes of materials for mold- ing kept in stock in the foundry, as tabulated herewith: Molding Materials Sands Facings Miscellaneous Molding sands Light Medium Strong Free sands Sharp or Fire Beach sand Graphite Charcoal Sea coal Fire clay Parting dust Burnt sand Charcoal Partainol Core binders Sands Quality. All sands are formed by the breaking up of rocks due to the action of natural forces, such as frost, wind, rain, and the action of water. Fragments of rocks on the mountain sides, broken off by action of frost are washed into mountain streams by rainfall. Here thry grind against each other and pieces thus chipped off are carried by the rush of the current down into the rivers. Tmnlilod along by tlie rapid current of the upper river, the sand will finally be doiiositnl where the stream flows more gently througli tlic low land stretches FOUNDRY WORK TABLE I Proportions of Elements in Sands Elkments Fire Sand (per cent) Molding Sands Core Sand (per cent) Iron Work Brass Light (per cent) Medium (per cent) Heavy (per cent) Light (per cent) (a) Silica SiOs Alumina (clay). . ..AI2O3 Iron oxide Fe203 Lime oxide CaO (b) Lime carbonate. . CaCOri Magnesia MgO Soda NaaO 98.04 1.40 .06 .20 '^14 82.21 9.48 4.25 '^68 .32 .09 .05 2.64 .28 85.85 8.37 2.32 .50 .29 .81 .10 .03 1.68 .15 88.40 6.30 2.00 .78 '^50 1^73 .04 78.86 7.89 5.45 .50 1.46 1.18 .13 .09 3.80 .64 85.50 2.65 .85 2^65 4.27 .04 .04 2.00 1.00 Potash K2O Combined water. . . . H2O Oro'anic matter. Specific gravity Degree of fineness 2.592 2.652 85 2.645 66 2.630 46 2.640 95 below the hills. Here the slight agitation tends to cause the finer sand and the clay to settle lower and lower down in the bed. Thus we find beds that have been formed in ages past; possibly with a top soil formed over them, so long have they been deposited. But on removing this top soil we find gravel or coarse sand on top; this merges into finer sand and this again finally into a bed of clay. Rocks, however, are very complex in their composition, and sands contain most of the elements of the rocks of which they are fragments. For this reason molding sands in different parts of the United States vary considerably. A good molding sand first of all, should be refractory, that is, capable of withstanding the heat of molten metal. It should be porous to allow the escape of gases from the mold. It should have a certain amount of clay to give it bond or strength, and should have an even grain. All of these properties will vary according to the class of work for which the sand is used. Elements. The two important chemical elements in such sands are silica, which is the heat-resisting element, and alumina, or clay, which gives the bond. Other elements which are found in the mold- ing sands are oxide of iron, oxide of lime, lime carbonate, soda potash, combined water, etc. The analyses shown in Table I, made by FOUNDRY WORK 5 W. G. Scott, give an idea of the proportions of these elements in the different foundry sands. Silica alone is a fire-resisting element, but it has no bond. These other elements help in forming the bond. But under heat, silica combines and fuses with them, forming silicates. These silicates melt at a much lower temperature than does free silica. Therefore with sands carrying much limestone in their make up, or with those containing much oxide of iron, soda potash, etc., the molten iron will burn in more, making it more difficult to clean the casings. The limestone combinations also go to pieces under heat, tending to make the sand crumble, which may result in dirty castings. The proportions given in Table I must not be considered as absolutely fixed, for no two samples of sand, even from the same bed, will analyze exactly alike. The table is instructive, however, because it indicates the reasons why the different sands are especially adapted to the use to which they are put in practice. Fire Sand. Such sand is used in the daubing mixture for repair- ing inside of cupola and ladles, and should be in the highest degree refractory, and should contain as little matter as possible that would tend to make it fuse or melt. Light Molding Sand. This sand is used for castings such as stove plate, etc., which may have very finely carved detail on their surfaces, but are thin. The sand should be very fine to bring out this detail; it must be strong, i.e., high in clay, so that the mold will retain every detail as the metal rushes in. On the other hand, the work will cool so quickly that after the initial escape of the air and steam there will be very little gas to come off through the sand. Medium Sand. Sand of this grade is used in bench work and light floor work, for making machinery castings having from |- to 2-inch sections. These will have less fine detail, so the sand may be coarser than in the previous case. The bond should still be fairly strong to preserve the shape of the mold, but the tendency of the large proportion of clay to choke the vent will be ofl'set by the larger size of the grain. This vent must be pro\dd(Hl for because the metal will remain hot in the mold for a longer time and m ill cause gases to form during the whole of its cooling period. Heavy Sand. This grade of sand is used lor llic largest iron castings. Here the sand must be high in silica and the grain coarse, 6 FOUNDRY WORK because the heat of the molten metal must be resisted by the sand, and gases must be carried off through the sand for a very long time after pouring. The amount of bond or clay must be small or it will cause the sand to cake and choke these gases. The detail is gener- ally so large that the lack of bond is compensated for by the use of gaggers, nails, etc. The coarse grain is rendered smooth on the mold surface by careful slicking. Core Sand. Core sand, often almost entirely surrounded by metal, must be quite refractory but have very little clay bond. This bond would make the sand cake, choking the vent, and render it difficult of removal from a cavity when cleaning the casting. Compared with medium molding sand, it shows higher in silica, although having less than half the proportion of alumina. Free Sands. Sands having practically no clay in them are called /ree sands. Of these there are two kinds in use: river sands, and beach sands. River Sand. The grains of river sand retain the sharp frac- tured appearance of chipped rock, and these little sharp grains help much in making a strong core because the sharp angular grains interlock one with another. River sand is used on the larger core work. Beach Sand. Beach sand is considerably used in coast sections because it is relatively inexpensive, but its grains are all rounded smooth by the incessant action of the waves. It will pack together only as will so many minute marbles. For this reason it is used only for small cores. Facings Function. Foundry facing is the term given to materials applied to or mixed with the sand which comes in contact with the melted metal. The object is to give a smooth surface to the casting. They accomplish this in two ways: (1) by filling in the pores between the sand, thus giving a smooth surface to the mold face before the metal is poured; and (2) by burning very slowly under the heat of the metal, forming a thin film of gas between the sand and iron during the cooling process. This prevents the iron burning into the sand and causes the sand to separate from the casting when cold. FOUNDRY WORK 7 Different forms of carbon are used for this purpose because carbon will glow and give off gases, but it will not melt. The prin- cipal facings are graphite, charcoal, and sea coal. Graphite. Graphite is a mineral form of carbon. It is mined from the earth and shipped in lumps which are blacker than coal and are soft and greasy like a lump of clay. The purest graphite comes from the Island of Ceylon, India. There are several beds, however, in the coal fields of North America. Charcoal, Charcoal is a vegetable form of carbon. It is made by forming a shapely pile of wood, covering this over with earth and sod, with the exception of four small openings at the bottom and one at the top. The pile is set on fire and the wood smoulders for days. This burns off the gases from the wood, leaving the fibrous structure charred but not consumed. Charcoal burning is done in the lumber- ing districts. The charcoal for foundry facings should be made from hard wood. Sea Coal. Although sea coal contains a high per cent of car- bon, it is less pure than the other facings and gives off much more gas. Sea coal is made from the screenings from the soft-coal breakers. The coal should be carefully selected by the manu- facturer and be free from slate and very low in sulphur. Distinction. All facings are manufactured by putting the raw materials through a series of crushers, tumbling mills, or old- fashioned burr stone mills, and then screening them. The finest facings are bolted much as flour is. In the shop the molder distinguishes between facings or black- ings, and facing sand. Blacking consists of graphite or charcoal, and is applied to the finished surface of a mold or core. Facing sand is the name given to a mixture of new sand, old sand, and sea coal, which in the heavier classes of work forms the first layer of sand next the pattern. The use of the different facings will be clearly seen from the tabulation on page 8. Miscellaneous Materials Fire Clay. Fire clay comes from the same source that sand does. It is almost pure oxide of alumina, which is separated out from the sand by a combination of the chemical action of the waters of the streams. Fire clay has traces of the other impurities men- FOUNDRY WORK Characteristics of Facings Material Uses Action Charcoal Good facing for light molds; dusted on from bag after pattern is drawn. Mixed with molasses water for wash for small cores and dry-sand work. Mixed with some graphite and clay wash for blacking for heavy dry-sand and loam work; slicked over with tools. May be used as a parting dust on joint of bench molds. Burns at low enough temperature to be effec- tive before thin work cools. Resists moisture ; pre- vents sand surfaces from sticking together. Graphite Good facing for bench molds ; dusted on from bag; good for medium and heavy green-sand work. Applied with camel's hair brush, and sHcked over with tools. As heavy blacking for dry-sand and loam work, used as above. Good on heavier green sand because it is more refractory than char- coal, but still forms gas enough to keep metal from burning into sand. Sea Coal Mixed with facing sand in propor- tions from 1 : 6 to 1:12. See section on Molding. Helps to force vents through sand when mold is first poured, and pre- vents strong sand of the facing from caking, be- cause it continues to throw off gas after cast- ing has solidified. tioned in the analysis of molding sands. It is found in the lowest strata of the deposit beds. It is used to mix with fire sand in the proportion of 1 to 4 as the daubing mixture for cupola and ladles. Clay wash is a mixture of fire clay and water. The test for mixing it is to dip the finger into the wash and then withdraw it, whereupon there should be an even film of clay deposited on the finger. Clay wash is used as the basis of heavy blackings. It is used as follows: for wetting crossbars of flasks; for breaks in sand where a repair is to be made; to wet up the dry edges of ladle linings when repairing with fresh daubing mixture; in fact, any place where a strong bond is required at some particular spot. Parting Dusts. Parting sands or parting dusts must contain no bond. They are used to throw on to the damp surfaces of molds which must separate one from another. They prevent these sur- faces formed of high bond sands from sticking to each other. FOUNDRY WORK 9 The cheapest parting sand, and by far the most commonly used, is obtained by putting some burnt core sand, from the cleaning shed, through a fine sieve. Beach sand is also used as a parting sand, but the rounded nature of its grain weakens the molding sands more than does burnt core sand. Charcoal facing dusted from a bag makes an excellent parting dust on fine work. A dust manufactured expressly for the purpose and called "Par- tainol" is the most perfect material for fine work. This is applied from a dust bag. It is not only useful for sand joints, but is a great help if there is a deep lift on a pattern where the sand is liable to stick, or for a troublesome box in the core room. Core Binders. Although the materials for this purpose — flour, rosin, oil, etc. — are on the purchasing list of the general foundry buyer, for the purposes of this article they will be explained in detail under Core Work. TOOLS Under this heading only the hand tools and equipment used by the molder in putting up his mold are described. The mechanical appliances for reducing labor are described in a later section. Flasks. To use sand economically for molds, sets of open frames called flasks are used. Flasks consist of two or more such boxes. The lower box is called the drag or nowel, the upper box is called the cope. If there are intermediate parts to the flask they are called cheeks. Flasks are fitted with pins and sockets so that they will always register. Snap Flask. For small castings the molds are rammed up on benches or projecting brackets. Such work is termed bench icork and the flasks are usually what are known as snap flasks. They range in size from 9 by 12 inches to 18 by 20 inches. As is seen in Fig. 1, these flasks hinge on one corner and have catches on the diagonal corner. The advantage of the snap flask is that any number of molds may be put up with but one flask, and the flask removed as each mold is completed. There are several good snap flasks to be had on the market. ]\Iany foundries, however, make up their own. Each size of flask should have at least one smooth straight board called the mold hoard, the size of outside dimensions of the flask. 10 FOUNDRY WORK Rough boards or bottom boards of same size should be provided, one for each mold that will be put up in a day. Boards for snap work are made of from |- to 1-inch stuff, and should have two stiff cleats, as shown in Fig. 2, to hold them straight. Wood Flask. For heavier castings where the molds are made on the floor, box flasks are used made of wood or iron. In the jobbing shop, wood flasks are more economical, as they can more readily be altered to fit a variety of patterns, while in a foundry turn- Fig. i. Snap Flask j^g ^^^ ^ regular line of castings, iron flasks pay because they require less repair. Wooden flasks of necessity receive hard usage in the shop and grow weaker each time they are used. They will burn more or less each heat; they receive rough usage when the mold is shaken out; and often the flasks must be stored where they are exposed to all kinds of weather. It is economy, therefore, to build wooden flasks heavier than would be necessary if they were always to be used in their new condition. Fig. 3 shows the construction of a typical wooden flask; the sides project to form lifting handles; the ends are gained in to the sides. Through bolts, in addition to the nailing, hold the sides firmly. A detail of the pin is shown at A, and at 5 is a cast-iron rocker useful on flasks over 4 by 5 feet, to facilitate lifting and rolling over. The cleats make it a simple matter to alter crossbars. The Fig. 2. Mold Board crossbars should be not over 8 inches on centers. For more than 3-foot spans they should have short crossbars through the middle connecting the long ones. In flasks 4 feet and over there should be one or more iron crossbars and a f-inch through bolt with good washers to clamp the sides firmly to them. FOUNDRY WORK TABLE II Sizes of Wooden Flasks 11 Flask Sizes (6 inches deep) Material Sizes Arrangement Sides (inches) Cross- bars (inches) Short Cross- bars (rows) Iron Cross- bars (number' Up to 24 by 24 in. 18 in. to 24 in. wide up to 5 ft. long 24 in. to 36 in. wide up to 6 ft. long 36 in. to 48 in. wide up to 7 ft. long VA 2 2A 3 1 1 I'A 1 2 1 2 2 Note. For each additional 6-inch depth of cope or drag add 25 per cent to the thick- ness given. Table II shows thickness of stuff for sides and crossbars for average sizes of jobbing flasks. Illustrative Example. Find thickness of sides and bars in a flask 30 by 48 inches. By referring to Table II, it is noted that for lengths on the sides over 2 feet and under 5 feet the thickness of sides should be 2 inches. Fig. 3. Wooden Flask Similarly, for widths of flask of over 24 inches and under 3G inches, the thickness of crossbars should be Li inches. 12 FOUNDRY WORK Iron Flash. In Fig. 4 is shown the construction of a large iron flask suitable for dry-sand work. The pieces of the flask are usually cast in open sand from a skeleton pattern, all holes cored in. The crossbars are cast in the same way; they have a slot in the flange instead of holes to facilitate adjusting them. Trunnions and rockers are sometimes east on the sides in a core instead of being made separate and bolted on. Holes for pins are usually drilled through the joint flange. For pins, short iron bars are used temporarily in jrzirii? Fig. 4. Iron Flask closing. The thickness of metal varies from | inch to IJ inches, according to size of flask. In Fig. 5 is shown a typical form of iron flask used on some molding machines. The boxes are cast in one piece. The handles serve as lugs for the closing pins. Only one pin is fixed on each box. This makes the boxes irnterchangeable and capable of being used for either cope or drag. Shovel. For cutting and handling loose sand the molder uses a shovel with flat blade, as in Fig. 6, for it is often more convenient to let the sand slide off of the side of the shovel than off of the end. FOUNDRY WORK 13 This is especially true when shoveling sand into bench molds or molding-machine flasks. Sieve. The foundry sieve or riddle, Fig. 7, is used to break up and remove lumps, shot iron, nails, etc., from the sand placed next the pattern or joint. Sieves should have oak rims with brass or galvanized-iron wire cloth. In ordering, the diameter of rim and the number of meshes to the inch of the woven wire is given. Good sizes for the iron foundry are 16 inches to 18 inches diameter. No. 8 to 12 on bench work. No. 4 to 8 on floor work. Rammers. Rammers are used for evenly and quickly packing the sand in the flask. One end is in the shape of a dull wedge, called the peen end, the other is round and flat called the butt end. Of the rammers shown in Fig. 8, a is the type used on bench work; 6 is a floor rammer having cast heads and wooden shaft; c shows a rammer made up in the foundry by casting the Fig. 5. Flask for Molding Machine Fig. 6. Flat Blade Shovel Fig. 7. Foundry Sieve heads on the ends of an iron bar; d shows a small peen cast on a short rod — this is convenient for getting into corners or pockets on floor work. 14 FOUNDRY WORK Pneumatic Type. In shops equipped with compressed air a pneumatic rammer, as shown in Fig. 9, is sometimes used to butt off large flasks, and for ramming loam molds in pits. Finishing Tools. Molders' tools are designed for shaping and slicking the joint surfaces of a mold and for finishing the faces of the mold itself. Excepting the trowels, they are forged in one piece Fig. 8. Rammers Fig. 9. Pneumatic Rammers from steel. The trowels have steel blades and short round handles which fit conveniently into the grasp of the hand. All of the tools are ground slightly crowning on the bottom, and they are rocked just a little as they are worked back and forth over the sand to pre- vent the forward edge cutting into the surface of the mold. Of the sixty or more combinations of shapes on the market, the few illustrated represent the ones most commonly used in job- bing shops. FOUNDRY WORK 15 Trowels. Trowels, Fig. 10, are used for shaping and smoothing the larger surfaces of a mold. The square trowel a is convenient for working up into a square corner, and the finishing trowels b and c Fig. 10. Trowels Fig. 11. Slicks are more for coping out and finishing along the curved edges of a pattern. Trowels are measured by the width and length of blade. Slicks. Slicks are designated by the shape of the blade and the width of the widest blade. In Fig. 11, a is a heart and leaf; 6 is a :im3 (b) Co) Fig. 12. Lifters leaf and spoon; c is a heart and square; and fZ is a spoon and bead. These are in sizes of 1 mch to 1 f inches. They are used for repairing and slicking small surfaces. Lifters. Fig. 12 shows lifters used to clean and finish the bottom and sides of deep narrow openings; a is a floor lifter, made in 16 FOUNDRY WORK Fig. 13. Square Corner Slicks Fig. 14. Floor Swab sizes from \~ by 10-inch to 1- by 20-inch; 6 is a bench lifter, the sizes of which vary from -^ inch to f inch wide. Corner Slicks. Fig. 13 shows at a and b inside and outside square-corner sHcks, made in sizes of 1 to 3 inches; c is a half-round corner, widths 1 inch to 2| inches; and dh a, pipe slick made 1 inch to 2 inches. This style of tool is mainly used on dry sand and loam work. Sivahs. Swabs are used to moisten the edges of the sand about a pattern before drawing it from the mold. This foundry swab is a dan- gerous though useful tool. Its danger lies in the too free use of water around the mold, w^iich may result in blow- holes. A good swab for bench work is made by fasten- ing a piece of sponge, about double the size of an egg, to a goose quill or even a pointed hardwood stick. The point will act as a guide and the water may be made to run or simply drop from the point by varying the pressure on the sponge. Floor swabs, Fig. 14, are made from hemp fiber. They should have a good body of fiber shaped to a point, and should be made about 12 inches or 14 inches long. They will take up considerable water and deliver it from the tip of the point. In heavy work the swab is trailed lightly over the sand like a long bristled brush. Vent Rods. Vent wires are used to pierce small Fig. 15. Vent holcs through the sand connecting the mold cavity with ^°'^ the outside air. For bench work a knitting needle is the most convenient thing to use. It should have a short hardwood handle or cast ball on one end. Select a needle as small as possible, so long as it will not bend when using it. FOUNDRY WORK 17 Heavy vent rods are best made, as shown in Fig. 15, of a spring steel from ys ii^ch to | inch with the pointed end enlarged a little to give clearance for the body of the rod when run deep into the sand. Draw Sticks. Draw sticks are used to rap and draw patterns from the sand. In Fig. 16 are shown three kinds : a is a small pointed rod J inch to f inch in size, which gets its hold by simply driving it into the wood of the pattern; 6 is a wood screw welded to an eye for conven- ience; c is an eye rod with ma- chine-screw thread, which requires a metal plate let into the pattern. The plate is called a rapping plate and is made with separate holes not threaded, into which a pointed rapping bar is placed when rapping the pattern, thus preserving the threads used for the drawbar. Clamps. In pouring, the parts of a mold must be clamped by some method to prevent the pres- sure of the liquid metal from sep- arating them, causing a run-out. For light work a weight such as shown in Fig. 17 is the most convenient. This is simply a pkite of cast iron 1 inch to 1| inches thick, with a cross-shaped opening cast in it to give considerable liberty in placing the runner in the mold. The weights are from 15 to 40 pounds, accord- ing to size of flasks. Floor flasks are fastened with clamps made of cast iron which are tightened by pr^'ing them on to a hardwood wedge. In Fig. 18 is shown how the wedge may first be entered and liow the clamping bar is used to firmly clamp the flask. For iron flasks Fig. 10. Draw Sticks Fig. 17. Wt-iglit Qlamp Wedgs Fig. 18. Illustrating Method of Clamping 18 FOUNDRY WORK used in dry-sand work the clamps are very short, as only the flanges are clamped together, as may be seen in Fig. 4. In that connection iron wedges are used instead of wood. Often the iron bottom board is clamped on and the joint flanges bolted together before pouring. MOLDING PROCESSES PRINCIPLES OF QREEN= SAND MOLDING, Good Work. There are certain principles underlying " -s^^ iron molding which hold good in all classes of founding, and a practical understand- ing of these principles is necessary for good work in any line. Aside from the fact that generally a mold is wanted which takes the least possible time to put up, three things aimed at in green- sand work are: (1) a sound casting, which is free from internal imperfections, such as blow holes, porous spots, shrinkage cracks, etc.; (2) a clean casting, which is free from dirt, such as slag, sand, etc.; and (3) a smooth casting, having a uniform surface free from scabs, buckles, cold-shuts, or swells. Sand Mixture. The natural sands best adapted to obtain these residts have already been dealt with. The methods of adding new sands vary with different classes of work. For light work the entire heap should be kept in good condition by adding a little new sand every day, for the light castings do not burn out the sand to a great extent. On heavier worK of 50 pounds and upward, the proportion of sand next the pattern is so small compared with that used simply to fill the flask, that it does not pay to keep the entire heap strong enough for actual facing. The heap should be freshened occasionally with a cheap molding sand, but for that portion of the mold which forms the joint surface, and especially that which comes in contact with the metal, a facing sand should be used. The range of new sand in facing mixtures on a lO-part basis, with sea coal in addition, is as tabulated herewith: FOUNDRY WORK Proportions of Facing Mixtures (Basis of 10 Parts) 19 Sand Sea Coal (additional part) New Ckl Free 3—6 6—2 1—2 i-l These proportions, and the thickness of the layer of facing sand, vary with the weight of metal in the casting. Too much new. sand tends to choke the vent and to cause sand to cake; too little new sand renders facing liable to cut or scab. Too much sea coal makes sand brittle and more difficult to work, and also gives off too much gas which is liable to cause blowholes in casting. Not enough sea coal allows the sand to cake, making cleaning difficult. Tempering and Cutting. To prepare foundry sand for making a mold, it must be tempered and cut through. This is now usually done by laborers. To temper the sand, throw water over the heap in the form of a sheet by giving a peculiar backward swing to the pail as the water leaves it. Then cut the pile through, a shovelful at a time, letting the air through the sand and breaking up the lumps. This moistens the clay in the sand, making it adhesive and puts the pile in the best condition for working. To test the temper, give one squeeze to a handful of sand. An excess of water will at once be detected by the soggy feeling of the sand. Now hold the egg-shaped lump between thumb and finger of each hand and break it in the middle. The edges of the break should remain firm and not crumble. Too much moisture will make excess of steam in the mold, causing blowholes. Not enough moisture renders sand weak and apt to wash or cut. Bearing in mind the nature of the materials we have to work with, we must now study the important operations inv(il\rd in making a sand mold. Sifting. The sand next to the joint and over the pattern should be sifted. The thickness of this layer of sifted sand varies from about | inch for light work to 2 inches on very hcaxy work. The fineness of the sieve used depends upon the class of work. No. 16 or 12 would be used for small name plates, stove plate, etc., while 20 FOUNDRY WORK No. 8 or 6 is good for general machinery work. On floor work, from 4 to 6 inches of sand back of the facing should be riddled through a No. 4 sieve to ensure more even ramming and venting. Ramming. The object of ramming is to make the sand hang into the flask and to support the w^alls of the mold agiinst the flow and pressure of the metal. The knack of ramming just right only Fig. 19. Setting Gaggers comes with continued practice and comparison of results. Hard ramming closes up the vent, causing blowholes. Iron will not "lay" into a hard surface. Soft ramming leaves a weak mold sur- face, and the flow of the metal as it enters the mold washes or cuts the sand, leaving a scab on one part of the casting and sand holes on another. A mold rammed too soft tends to swell under the pressure of the liquid metal, making the casting larger than the FOUNDRY WORK 21 pattern or leaving an unsightly lump on the casting. The bottom parts of a mold, being under greater casting pressure, must be rammed somewhat harder than the upper portions. Tlie joint also should be packed firmly, as it is exposed to more handling than any other part. Gaggers. Crossbars are put in the cope to make it possible to lift the sand with the cope without excessively hard ramming. As an additional support for the cope sand on large work there are Fig. 20. Chaplets used gaggers, which are L-shaped pieces of iron made from wrought or cast iron of from j^-inch to ^-inch square section. The force of sand pressing against the long leg of the gagger holds it in place and the short leg supports the sand about it. There- fore the gagger will hold best when the long leg is placed tight against the crossbar and is plumb. The long leg of the gagger should not project above the level of the cope, as there is much danger of striking it and breaking in the mold after the flask is closed. In Fig. 19 are shown the right and wrong ways of setting gaggers. Use of Chaplets. Chaplets should be used to su])]iort ])arts of cores which cannot be entirely secured by their prints wliicli are held in the sand of the mold. In Fig. 20 are shown the three ])rin- cipal forms of chaplets used, and how they are set in the mold; a is a stem chaplet; 6 is a double-headed or stud chaplct; and c is a form of chaplet made up of strip metal. 22 FOUNDRY WORK Pour That portion of the chaplets which is to be bedded in metal is tinned to preserve it from rusting, because rusty iron will cause liquid metal to blow. For small cores nails are often employed for this purpose, but only new ones should be used. With the stem chaplets the tails must be cut off when the casting is cleaned — the stud chaplet becomes entirely embedded in the metal. There are now manufactured and on the market many different styles of chaplets. In selecting the size and form for a given purpose the head of the chaplet should be large enough to support the weight of the core without crushing into the sand and thin enough to fuse into the liquid metal. The stem must be small enough to fuse well to the metal and stiff enough, when hot, not to bend under its load. Venting. In the section on Sands reference has already been made to gases which must be taken off from a mold when it is poured. There are three forms of these : (1) air, with which the mold cavity is filled before pour- ing; (2) steam, formed by the action of the hot metal against the damp sand during the pour- ing process; and (3) gases formed while the casting is cooling, from chemical reactions within the liquid metal and from the burning of organic matter, facings, core binder, etc., in the sands of the mold. It is of the greatest importance that these gases pass off quickly and as completely as possible. If they do not find free escape through the mold they are forced back into the liquid metal, making it boil or blow. This may blow the metal out through risers and runners, or simply form numerous little bubble- shaped cavities in the casting, called blowholes. These often form just below the skin of the casting and are not discovered until the piece is partially finished. Fig. 21. Use of Risers FOUNDRY WORK 23 Various Systems. One cannot depend entirely upon the porosity of the molding sands, but must provide channels or vents for the escape of these gases. For light work a free use of the vent wire through the sand in the cope will answer all purposes. On castings of medium weight, besides venting with the wire, risers are placed directly on the casting or just off to one side as shown in Figs. 19 and 21. These are left open when the mold is poured and provide mainly for the escape of the air from the mold. Heavy castings that will take time to cool, and thus keep facings burning for a long time after the mold is poured, require venting on sides and bottom as well as top. Fig. 21 shows side vents aaaa connecting with the air through the channel hhh cut along joint and risers ccc passing through the cope. At the bottom the vents connect with cross-vents dd run from side to side between the bottom board and edge of flask. Fig. 22 shows a mold bedded in the floor; the side or down vents connect at the top, as in previous examples, and at the bottom with a cinder bed about 2 inches thick, rammed over entire bottom of pit. The gases find escape from this cinder bed through a large gas pipe. Action During Pouring. In pouring, the gas from vents should be lighted as soon as may be. The burning at the mouths of vents helps to draw the gases from below and also keeps the poisonous gas out of the shop. It is customary to keep risers closed with small co^•er plates when large castings are being poured so that the air in the mold will be compressed as the metal rises in the mold. This helps sustain the walls of the mold and forces the vents clear so that they will act more quickly when the mold is full. These covers are removed occasionally to watch the progress of pouring, and are entirely removed when the metal enters the risers. Fig. 22. Mold Boclded in Floor 24 FOUNDRY WORK Gating. Gating is the term applied to tlie methods of forming openings and channels in the sand by which liquid metal may enter the mold cavity. The terms sprues and runners are also used in the same connection in some shops. Functions of Parts. There are practically three parts to all gates: pouring basin; runners; and gate, as seen in Fig. 21. The runner is formed by a wooden gate plug made for the purpose. The pouring basin is shaped by hand on top of the cope, and the gate proper is cut along the joint surface by means of a gate cutter. In all cases the gate section should be smaller than any other part so that, when pouring, the runner and basin may be quickly flooded; also that the gate when cold will break off close to the casting and lessen the work of cleaning. The object of gating is to fill the mold cavity with clean metal — to fill it quickly, and while filling, to create as little dis- turbance as possible in the metal. The impurities in liquid metal are lighter than the metal itself, and they always rise to the top when the melted metal is at rest or nearly so. Advantage is taken of this important property to accomplish the first of the objects mentioned. Fig 23 shows a good type of gate to use on light work. For reasons given, the point a should have the smallest sectional area. This section should be wider than it is deep as sho\\'n at h, because the hot iron necessary for light work runs very fluid. The runner should not be more than f to f inch in diameter. The pouring basin should be made deepest at point c, and slant upward crossing the runner. When pouring, the stream from the ladle should enter at c, flood the basin at once, and keep it in this condition. The current of the metal will then tend to hold back the slag, allowing clean metal to flow down the runner. Skimming Gate. When particularly clean castings of medium weight are required, some form of skimming gate should be used. Fig. 24 illustrates one of several practical forms. They all depend Fig. 23. Gate FOUNDRY WORK 25 I I for their efficiency upon the principle cited. In the illustration, a is the pouring basin and runner, 6 is a good sized riser placed about 3 or 4 inches from a, and c is a channel cut in the cope joint, connecting these two. The gate d should be cut in the drag side of the joint, just under the riser but at a right angle with the direction of c. The metal rushing down the runner is checked by the small size of the gate and so washes any dirt or slag up into the large riser h. The level of metal in this riser must be sustained by sufficiently rapid pouring until the mold is filled. In bench work and floor work, the greatest care must be used to have all parts of the gate absolutely free from loose sand or facing which would wash into the mold with the first flood of metal. On heavy work special skimming gates are not used, for the capacity of the pour- ing basin is very much greater than that of the run- ners which can be quickly flooded and thus retain the slag. Besides this, large risers are set at the sides or directly upon the casting, to receive any loose sand or facing that washes up as the mold is being filled. Fig. 22 illustrates this type. Important Conditions. As regards the filling of the mold quickly and quietly, these two conditions are closely allied. The shape and thickness of the casting are the important factors in determining the number and position of the gates. Aside from the fact that the gate should never be heavier than the part of the casting to which it attaches, the actual size of tlie gate opening is something that the molder must learn from experience. In arranging gates with regard to the shape of tlic ])attern, the following points should be borne in mind: Place gates where Fig. 24. Skimming Gate 26 FOUNDRY WORK c^ bn' ' Fig. 29. Diagram Showing Analysis of Liquid Pressure FOUNDRY WORK 29 By the rule just stated we first find the pressure per square inch at any given level by multiplying the depth by .26, and it is obvious that this pressure increases, the lower in the mold a point is taken. In Fig. 29, the pressure at a equals Ax.26. This also acts against the sides at ee. The pressure at b is h'X .26, and is exerted sidewise and downward. The pressure at c is /i"x.26. This point, being half way between the levels a and b, represents the average sidewise or lateral pressure on all of the sides. If this mold, then, is 11 inches square and 9 inches deep, with the pouring basin 6 inches above the joint, we have the following con- ditions: Area of a = 121 sq. in. Area of 6 = 121 sq. in. Area of c (one side) = 99 sq. in. Area of four sides = 396 sq. in. Height of h = 6 in.; pressure head = 1.56 lb. per sq. in. Height of ]/ =15 in.; pressure head = 3.90 lb. per sq. in. Height of A" = 10| in.; pressure head = 2.73 lb. per sq. in. Multiplying these together, we have the pressures on the various faces as follows: Upward pressure on a = 188.76 lb. Total pressure on side c = 270.27 lb. Total pressure on four sides = 1081.08 lb. Total downward pressure on b= 471.90 lb. A study of these figures shows the necessity of well-made flasks and bottom boards, for these must resist a greater pressure even than that required to keep the cope from lifting. They also show clearly why [^the lower parts of the casting resist the pres- sure of the gases more and require firmer ramming then the upper portions. Variation of Pressure Head. A difference in the way a pattern is molded may make a great difference in the weight required on the cope. Compare A and B, Fig. 30. Supposing this pattern is cylindrical in shape and with the dimensions as indicated, we would have the following basis: 30 FOUNDRY WORK Then Area of circle a =113.10 sq. in. Area of circle b = 78.54 sq. in. Area of ring c'c' (b subtracted from a) = 34.56 sq. in. Total lift on cope A is 8 X. 26X113.10 =235.24 lb. The lift on cope 5 is 8 X .26 X 34.56 = 71 .88 + (8+5)X.26x78.54 = 265.46 ' Total lift on J5 =337.34 lb. 1 00 A -/2" J i -^o_ -lO- jOO c' Fig. 30. Diagram Showing Difference in Pressure on Cope Due to Placing of Pattern Variation of Pressure Distribution. Fig. 31 is an example of a core 5 inches square surrounded by 1 inch of metal, with a runner 6 inches high. We have here : Pressure per square inch on a is 7X.26 = 1.82 1b. Pressure per square inch on b is 12x.26 = 3.12 1b. The difference in these pressures is 1.30 pounds per square inch. Then for every foot of length in the core we must balance a lifting pressure on the bottom of the core of 5X12 X 3.12 = 187.2 pounds, until the metal covers surface a, when it will exert a counteracting down- ward pressure, and the strain on the chaplets will be only 5X12X1.30 = 78 pounds. u < — i ^'J ■ a 5" Core , K /Ol^ t Fig. 31. Diagram Showing Difference in Pressure on Top and Bottom of a Cube FOUNDRY WORK 31 Common Defects in Castings. Some of the ordinary defects which the beginner will find on his castings are as follows: Short Pourings. The amount of metal in the ladle is misjudged with the result that the mold is not completely filled. Blowholes. These come from gases becoming pocketed in the metal instead of passing off through the sand. This is due to hard rammmg, wet sand, etc. Cold-Shuts. These form when two streams of metal chill so much before they meet, that their surfaces will not fuse when forced against each other, as illustrated in Fig. 32. Sand Holes. These come from the ^. ,, ^ , , ^, Fig. 32. Cold-Shuts washing of loose sand or excess of facing into the mold cavity when pouring. They are usually bedded in the cope side of the casting. Scabs. Scabs show like small warts or projections on the surface of the casting. They result from small patches of the mold face washing off. They may be caused from too much slicking, which draws the moisture to the surface of the mold, making the skin flake under the drying effect of the incomuig metal. Swells. Swells are bulged places on a casting and are due to soft ramming which leaves the walls of the mold too soft to withstand the pressure of the liquid metal. Shrinkage Cracks. These are due to unequal cooling in the casting. They are sometimes caused by the mt)ld being so firm that it resists the natural shrinkage of the iron, causing tlie metal to pull apart when only partially cold. Warping. This occurs when these strains cause the casting to bend or twist, but are not sufficient to actually crack the metal. TYPICAL MOLDING PROBLEMS General Precautions. ^Yhen starting to ram a flask, see that the sands to be used are well cut through and properly tempered. Select a flask large enough to hold the pattern and have at least 2 inches clear of the flask all around for ])cnch work, and 4 to S inches on floor molds, depending upon the weight of tlie work to be cast. See that the flask is strong enough to carry the sand without racking 32 FOUNDRY WORK and that the pins fit. Have the necessary tools at hand, such as sieve, rammer, sHcks, etc. Jointing. Examine the pattern to be molded to see how it is drafted and note especially how the parting line runs. That part of the mold forming the surface between the parts of the flask is called the joint, and where it touches the pattern this joint must be made to correspond with the parting line. The joint of a mold may be a plane or flat surface, or it may be an irregular one. When the joint is a flat surface it is formed entirely by the mold board except with work bedded in the floor; there it is struck off level with a straightedge. W'hen it is irregular the drag joint must be coped out for every mold needed, that is, shaped freehand by the molder before making up the cope; or, by another method, the shape of the cope ^ — joint is built up first in a match frame with the cope part of the pattern bedded into it, and upon this form the drag may be packed repeatedly, receiving each time the desired joint surface without further work on the T.. on T. , molder's part. Fig. 33. Faceplate ^ Our first problems in molding illustrate these three methods of making the joint. It is aimed to give the directions for making up molds in as concise a form as possible. The student should refer frequently to the preceding sections and familiarize himself with the reasons underlying each operation. Flat Joint. In the small faceplate shown in Fig. 33, all of the parting line aaa will touch the mold board, so the joint will be flat. The draft is all in one direction from the cope side c, there- fore all of the pattern will be in the drag. Use a snap flask for this piece. Molding Drag. Place a smooth mold board upon the bench or brackets. Place the drag with sockets down upon this. Set the pattern a little to one side of the center to allow for the runner. Sift sand over this about 1| inches deep. Tuck the sand firmly around the pattern and the edges of the flask as indicated by the arrows in Fig. 34, using the fingers of both hands and being careful not to shift the sand away from the pattern at one point when tucking at another. FOUNDRY WORK 33 With Fingers Fig. 34. Molding Sand with Fingers Fill the drag level full with well-cut sand. With the peen end of the rammer slanted in the direction of the blows, ram first around the sides of the flask to ensure the sand hanging in well, as at 1 and 2 in Fig. 35. Next carefully direct the rammer around the pattern, as at S, 4, and 5. Do not strike closer than 1 inch to the pattern with the end of the rammer. Shifting the rammer to a vertical position, ram back and forth across the flask in both directions, being especially careful not to strike the pattern nor to ram too hard immediately over it. The student must judge by feeling w^hen this course is properly rammed. Now fill the drag heaping full of sand. Use the butt end of the rammer around the edges of the flask first, then work in toward the middle until the sand is packed smooth over the top. With a straightedge strike off the surplus sand to a level with the bottom of flask. Take a handful of sand and throw an even layer about \ inch deep over the bottom of the mold. On this loose sand press the bottom board, rubbing it slightly back and forth to make it set well. With a hand at each end, grip the board firmly to the drag and roll it over. Remove the mold board and slick over the joint surface with the trowel. Dust part- ing sand over this joint (burnt core sand is good on this work), but blow it carefully off of the exposed part of the pattern. Set the wooden runner or gate plug about 2 inches from the pat- tern, as shown in Fig. 23, page 24. In snap work the runner should come as near the middle of the mold as possible, to lessen the danger of breaking the sides, and to allow the weight to be placed squarely on top of the mold. Molding Coije. Set the cope on the drag and sec that llic liinges come at the same corner. Sift on a layer of sand about \\ inches deep. Tuck firmly with the fingers about the lower end of the ruimer and around Fig. 35. Molding Sand witli Rammer 34 FOUNDRY WORK Fig-. 36. Use of Iron Band the edges of the flask. Fill the cope and proceed with the ramming the same as for the drag. Strike off the surplus sand, swinging the striking stick around the runner so as to leave a fair flat surface of sand. Partially shape a pouring basin as illustrated in Fig. 23, with a gate cutter, before removing the runner. Draw the runner and finish the basin with a gate cutter and gently smooth it up with the fingers. Carefully moisten the edges with a swab and blow it out clean with the hand bellows. Lift the cope and repair any imperfections on the mold surface with the trowel or slicks. See that the sand is firm around the lower end of the runner. Blow through the runner and all over the joint to remove all loose parting sand. Slick over the sand which forms the top surface of the gate, between the runner and the mold. Having finished the cope, moisten the sand about the edges of the pattern with a swab. Drive a draw spike into the center of the pattern and w^ith a mallet or light iron rod, rap the draw spike ,slightly front and back and crosswise. Continuing a gentle tapping of the spike, pull the pattern from the sand. If any slight break occurs, repair it with bench lifter or other convenient slick. Cut the gate and smooth it down gently with the finger; blow the mold out clean with the bellows. No facing is needed if the castings The mold should now be closed and the snap Fig. 37. Weight in Position are to be pickled flask removed. Strengthening against Pressure. There are two methods used to strengthen these molds against the casting pressure. One is FOUNDRY WORK 35 to use an iron band which will just slip inside of the flask before the mold is packed, as in Fig. 36. The other is to slide a wooden slip case over the mold after the snap flask is removed, as in Fig. 37. In either case the weight, shown in position in Fig. 37, should not be placed on the mold until pouring time, lest by its continued pressure it might crush the sand. Coping Out. The second type of joint surface mentioned above is illustrated by the method of molding the tailstock clamp shown in Fig. 38. This is a solid pat- tern and rests firmly upon the mold board on the edges aa, but the parting line bbb runs below these edges. The bulk of the pattern drafts down from this line and so will be molded in the drag, while all above To mold the piece, set the pattern on the mold board, planning to gate into one end. Rain the drag, and roll it over, as described in the last example. With the blade of the trowel turned up edge- wise, scrape away the sand to the depth of the parting line, bringing the bevel up to the main level of the joint, about 2| inches from the pattern, as shown at Fig. 39, and slick this surface smooth with the Fig. 38. Tailstock Joint it will be shaped in the cope. Fig. 39. Coped-Out Mold finishing trowel or leaf and spoon. This process is called cnping out. Dust parting sand on the joint thus made. Be careful not to get too much at the bottom of the coping next the pattern. Pack the cope, then lift it, and finish the mold as directed. 36 FOUNDRY WORK Shape of Draft. In coping out, the molder practically shapes the draft on the sand of the drag. Aim to have the lower edge of the coping parallel with the main joint for a short distance, and then spring gradually up to it at about the angle shown in the sec- tion at c, Fig. 40, as this is the strongest shape for the sand. If made with an abrupt angle as in d, the cope sand will tend to wedge into the cut with the danger of a drop or break when the cope is lifted. In many cases, more especially in floor work, an abrupt coping angle may be avoided as follows : Set wooden strips, whose thickness is equal to the depth of the desired coping, under the edges of the drag when ramming up the pattern. (Use, for example, the hand wheel iiyr'--rilii;'l"li'- Fig. 40. Angle of Joint a 0:::=Q--1 J- ' ^' ,^ -i-f^^ ~f^^^ t-^ Fig. 41. Molding a Hand Wheel shown in Pattern Making, Fig. 114.) When the drag is rolled over, the sand will be level with the top of strips and pattern at aa, Fig. 41. Remove the strips and strike surplus sand off level with edges of drag hh, and slick off the joint. Proceed with the cope in the usual manner. In gating this pattern, and wheels generally, place a small runner directly on the hub. Sand Match. The solid bush- ing, Fig. 42, serves to illustrate the use of a sand match. For exercise work, use only one pattern. In practice, however, several small patterns are bedded into the same match. It is clear that in this pattern the parting line runs along the center of the cylinder, and to make a safe lift for the Fig. 42 FOUNDRY WORK 37 cope it should follow around the circumference of the ends abc, as shown by the heavy lines. The frame for the match is shallow, and of the same size as the snap flask with which it is used. It is provided with sockets to engage the pins of the flask. The bottom board is fastened on with screws. Fill the match with sifted sand rammed hard. Strike off a flat joint and bed in the pattern. Cope out the ends to the lower edge of the pattern, as shown in Fig. 43, flaring it well in order to make a good lift. Slick the whole surface over smooth. Rap and lift the pattern to test the correctness of the work. Replace the pattern. Dust on parting sand and ram the drag, tucking carefully in the pocket at each end. Roll the two over. Lift off the match, and set it to one side. The pattern remains Fig. 43. Use of Sand Match in the drag. Dust on parting sand. Set the runner and ram the cope as described. When the mold is opened and the pattern is drawn, it should be set back immediately into the match, ready for use again. Usage. On account of economy of construction in the pattern shop, irregularly shaped work is often made in one piece. The molder must then decide whether it is cheaper to cope out each joint or to make up a sand match. Where the number of castings required is small, or where the pattern is large, it is bettor to cope out. But where a number of castings is required it is cheaper to make up a sand match. For methods of making quantities of castings and the use of a more permanent match, see the section on Duplicating Castings. 38 FOUNDRY WORK In the foregoing the main use of the match was to save time. It frequently happens that a pattern is so irregular in shape that it will not lie flat on the board in any position. In this case, a match is absolutely necessary before the drag can be packed. For large patterns, the cope box of theflaskisused to bed the pattern into instead of a separate frame. After the drag has been packed upon it and rolled over, this first cope is dumped, and the box repacked /-^attern on mo/d I)oarc/ Fig. 44. Split- and Loose-Piece Patterns with the necessary gaggers, vents, runners, etc., required for casting. The first cope is then termed, not a match, but 3, false cope. For very light wooden patterns which may or may not have irregular parting lines, the pattern-maker builds up wooden forms to support the thin wood while the drag is being packed and to give the proper joint surface to the sand. This board serves exactly the same purpose as the sand match and false cope, but it is termed a follow board. See article on Pattern-Making. Split=Pattern Molds. So far the patterns used have been made in one piece, but a flat joint is the most economical for the molder, FOUNDRY WORK 39 when many castings are required. Generally such pieces as bushings, pipe connections, and symmetrical machine parts are made in halves; one piece of the pattern remaining in each part of the flask when the mold is separated. There are many cases, too, where, to make a flat joint for the mold, the pattern maker can separate one or more projections so as to have the main part of the pattern in the drag and to let these loose parts lift off in the cope. The small punch frame and the gas-engine piston, shown in Fig. 44, are examples of these two classes of patterns. At A, the sections through the patterns show the methods of matching them together. B shows the drag parts of the patterns in position for molding. At C, is the section through the mold and the plan of the drag showing how the gates are connected. Attention is directed to the use of the horn sprue — the sprue pattern is shown at a — by which the metal enters the mold at the bottom. If the gate were cut at the joint sur- face, there would be danger of cutting the sand on top of the green-sand core b as the metal flowed in upon it. Loose-Piece Mold. It often hap- pens that bosses or projections are required on a casting at right angles to the main draft lines of the pattern and below the joint surface. Examples of such cases are shown in Pattern-Making. In molding such work, care must be taken that the overhanging portion of sand shall be strong enough to support itself. Where the projection is deep, the mold should be strengthened by nails or rods, as shown in Fig. 45. These should be wet with clay wash and set into the sand, when the mold is rammed. Use of Green-Sand Core. Some work has projections on it which lie above or below the parting line in such a way that it cannot be molded by either of the foregoing methods. Examining the patterns for some of this work, we find two entire parting lines with the pattern made to separate between the two. Such patterns require between the drag and cope an intermediate body of sand, Fig. 45. Strengthening Mold with Iron Rod 40 FOUNDRY WORK from the top and bottom of which the two parts may be drawn. In small work, as illustrated by the groove pulley, this inter- mediate form is held in place by the sand joint of the cope and drag, and is termed a green-sand core. The method of molding i'iii'-fit'iffi Fig. 46. Section of Mold such a piece is given in Pattern-Making, Part I. To provide for pouring the casting, a runner should be placed on the hub of the first part packed C, Fig. 46, which shows a section of the mold before either part of the pattern has been removed. When the flask is rolled over to remove the final part C of the pattern, the runner is on top ready for pouring. Fig. 47. Part Section of Mold Showing Use of Core-Iafting Ring Fig. 48. Pattern Shown in Fig. 47 with Mold Complete Core-Lifting Ring. Another method used does away with rolling the entire flask. A core-lifting ring is first cast slightly larger in diameter than the flange of the sheave, and having such a section as shown in a, Fig. 47. The ring is set in position in the middle of the inverted drag, the pattern is held central inside of the ring by the recess in the mold board. Pack the drag, roll over, and remove the mold board. Tuck the green core all around and FOUNDRY WORK 41 Fig. 49. Casting for Ten-Inch Nozzle slick off the top joint of the core. Pack the cope in the usual way, lift it oflF, and draw the cope pattern. Now, b}^ means of lugs cast on this lifting ring, the green core may- be lifted off of the drag pattern, allowing it to be removed. Replace the ring and close the cope; and the mold is com- plete, as shown in section. Fig. 48. Three-Part Mold. In larger work, where the parting planes are farther apart, this intermediate body of sand is carried in a cheek part of the flask, and we speak of it as three-part work. Fig. 49 shows a casting for a 10- inch nozzle, the mold for which illus- trates this class of work. Here the pattern is separated just above the fillet of the curved flange. Fig. 50 gives a view of the mold, showing the way the joint is formed. This casting should be made on the floor. Select a square flask, 4 inches on a side larger than the diameter of the flanges. The cheek should be as high as that part of the pattern which is molded in it. There should be two projecting bars on opposite sides of the cheek to support the sand, and crossbars in both drag and cope. These should be well wet w^ith clay wash before using the boxes. Set the pattern centrally inside the cheek, and place a runner stick just the height of the pattern in one corner of this box. On account of the depth of the cheek, the sand must be rammed in two courses. Sift enough facing sand into the box to cover the joint and 5 inches up around the pattern to a depth of aliout 1\ Fig. 50. Casting of a Nozzle 42 FOUNDRY WORK inches, tucking about the pattern with the fingers. Fill in about 5 inches of loose sand and before ramming tuck around the ends of the side bars, compressing the sand between the finger tips, having a hand on each side of the bar, as illustrated in Fig. 51. Now use the peen end of the floor rammer in the same general way as the hand rammer is used in bench molding. Guide the rammer around the sides of the flask and bars first, then direct it toward the bottom edges of the pattern. As the sand gradually feels properly packed at this level, direct the blows higher and higher up. Proceed in this way to within about 1 inch of the drag joint. Make this joint by ramming in sifted facing sand, being careful to tuck it firmly under- neath the flange. Cope this joint to the shape of the curved flange. Dust on parting sand. Place the drag in position and ram it up in the usual way, only using facing sand next the joint and pattern. Place six long gaggers to strengthen the sand which forms the inside of the casting. Clamp the drag to the cheek and roll them over. Test, repair, and dust parting sand on the joint. Try the cope. The bars should clear the pattern and joint by about 1 inch. Set the cope runner about 2 inches to one side of the cheek runner and set the riser in the corner opposite. Sift on facing sand and tuck well with the fingers under the crossbars. Shovel in well-cut sand and finish packing the cope. Form a pouring basin, and vent well. Lift the cope. Draw the pattern from the cheek. Join the runners on the cope joint and connect the mold with the riser. Lift the cheek and repair it. Draw the drag pat- tern. All of the mold surfaces should have black lead facing brushed over them with a camel's hair brush, and this facing slicked over. Cut a gate on the drag joint. Close the cheek on the drag. Close the cope on the cheek, and the mold is ready for clamping. Floor Bedding. Owing to the development of the electric crane, there is much large work now rammed in iron flasks and rolled over, which was formerly always bedded in the floor. This method is still much used in jobbing shops to avoid making a complete large flask. Fig. 51. Tucking Sand under Bars FOUNDRY WORK 43 The mold shown in Fig. 52 illustrates the principal operations involved. The casting is a flask section for a special steel-ingot mold, and in design is simply a heavy plate braced on one side by flanges and ribs of equal thickness. For convenience in ramming between Iron Rods Fig. 52. Caating of Flask Section the flanges, portions of the top plate of the pattern are left loose, as seen in Fig. 53. Pit. Dig the pit for the mold 10 inches larger on each side than the pattern, and about 6 inches deeper. Having screened some hard cinders through a No. 2 riddle, cover the bottom of the 44 FOUNDRY WORK Fig. 53. Bedded-In Work pit with them to a depth of 3 inches. Ram these over with a butt rammer, and at one end set a piece of large gas pipe. Put a piece of waste on the top of this to prevent its getting choked with sand. Ram a 3-inch course of sand over the cinder bed and strike it off _,, „. , level at the depth of the These P'leces Loose ^ _/_ i^ ^V, pattern from the floor line. Sift facing sand over this where the pat- tern will rest; set the pat- tern, and with a sledge, seat it until it rests level. Remove the pattern and with the fingers test the firmness of packing all over the mold. Vent these faces through to the cinder bed, and cover the vent holes with a |-inch course of facing sand. Now replace the pat- tern, and bed it home by a few more blows of the sledge. The top of the pattern should now be level and flush with the floor line. Seat the runner sticks, and, to prevent the sand on the bottom of the runners from cutting, drive 10-penny nails about f inch apart into this surface untU the heads are flush. Ram the outside of the mold the same as if in a flask, and strike a joint on top. Ram green sand between the inside webs of the pattern, and strike off at the proper height with a short stick a. Fig. 54. Drive long rods 3 inches apart into these piers to pass through to solid sand below the cinder bed. Vent all around the pat- tern, outside and inside, through to the cinder bed. On top of the inside piers cover these vent holes with facing sand, ram, and slick to finish; then cover with the loose pieces of the pattern. Cope. Try the cope and stake it in place; set the risers and vent the plugs. Ram the cope, slicking off level for about 2 inches around the top of the risers, to receive a small iron cover. 'Runner Stick ^ Floor Line Fig. 54. Section Showing Method of Molding FOUNDRY WORK 45 Lift the cope, repair, and face with graphite. Draw the pattern with the crane and finish the mold. Connect the outer vent holes by a channel with the vent plug. From the end of each core print bbhb, Fig. 53, vent through to the cinder bed, and set the cores. Close the cope. Set the runner box against the side of the cope and build a pouring basin with its bottom level with the top of the risers. In weighting, great care must be exercised not to strain the cope. Place blocking upon the top ends of cope. Across these lay iron beams which will be stiff enough to support the load, and pile w^eights Fig. 55. Leveling a Bed for Open Sand Work on these, as shown in Fig. 52. Now wedge under the beams to the crossbars of the cope at necessary points. Open Mold. There is a large class of foundry rigging, such as loam plates, crossbars, and sides to iron flasks, which may be cast in open molds. As there is no head of metal, the beds must be rammed only hard enough to sui)port the actual weight of the metal, or it will boU. To msure uniform thickness in the casting, the bed must be absolutely level. Drive four stakes aaaa, as shown in Fig. 55, and rest the guide boards ^^ on the top of these. By using a spirit level lb, make 46. FOUNDRY WORK these level, and bring them to the same height by testing with the straightedge B. The space between the guide boards A A should be filled with well-cut sand even with their tops dd. Sift sand over the entire surface. Strike this sand off f inch higher than the guides, by placing a gagger under each end of the straightedge, as it is drawn over them. Tamp this extra sand to a level with the guides by rapping it down w^ith the edge of the cross-straightedge, and the bed will be as shown in Fig. 56. We can now proceed to build up Pouring Ba'sin Seqmenr ' Block ' Oi^erf/ow" Fig. 56. Open Sand Mold to a segment of pattern, or with a sledge drive a pattern into this surface. The pouring basin should drain itself at the level of the top of mold, and an overflow may be cut on one edge to drain the casting to any desired thickness. CORE WORK Reference has been made in the first part of this article, under Divisions of Iron IVIolding, to the general difference between core work and green-sand work. This, and the section on Sands, the reader should review carefully. Dry=Sand Cores Materials, Sand. Here, as in green-sand molding, the prin- cipal material used is a refractory sand. In molding sand, however. FOUNDRY WORK 47 the alumina or clay forms a natural bond in the sand. To meet the necessary requirements of cores we must use a naturally free sand as a base, and give it bond by adding some form of organic matter as a binder, then bake the core. Binders. The most common binders are the following four materials: Ordinary wheat flour is an almost universal material for use as a core binder. Every one is familiar with its action when moistened and baked. The hard vegetable gum rosin— a. by- product of the manufacture of turpentine — for use as a core binder, should be reduced to a powder. It melts under the heat of the oven, flows between the grains of sand, and upon cooling binds them firmly together. Linseed oil, made from flaxseed, acts in a way similar to rosin; a small proportion of oil together with some flour makes a very strong core. Glue, which is obtained from animal hoofs and from fish stock, is also used to some extent as a core binder. It should be dissolved in water before mixing with the sand. Tempering. A weak molasses water is used for tempering the sand for small cores; and on the larger work the same purpose is served by clay wash. There are many patent combinations of the above or similar materials put on the market as core compounds. There are two classes of these: dry compounds, and liquid com- pounds. The advantages claimed for them is that they are more economical — (1) because a smaller proportion of the compounds is sufficient to obtain the desired results; and (2) because a large proportion of the sand may be used over and over again. Reinforcement. Among other necessary core-room supplies are: annealed iron wire No. 6 to No. 16, and round bar iron in sizes {-inch, f-inch, f-inch, f-inch, and |-inch, which are cut to length as needed, and are bedded in the core sand to strengthen the core, as will be demonstrated later. Venting. A supply of clean cinders must be available also for venting larger cores. Small wax tapers make good vents for crooked cores. There is also a patented wax vent for sale on the market. Facing. As before stated, charcoal with some graphite is the principal facing material used on cores. It is always applied in liquid form by dipping the core or by using a flat brush ha\iiig extra long bristles. 48 'FOUNDRY WORK Fig. 57. Spraying Can Equipment. General Tools. The general tools of the core room are similar to those already mentioned. A piece of iron rod very often replaces the regular rammer on account of the small size of the opening into which sand must be packed. The trowel is the most common slick, because most of the sur- faces which require slicking are flat ones formed by striking off after packing the box. Except in the largest work, the entire face of the core is not slicked over, so a variety small slicks is not needed. A spraying can, shown in Fig. 57, is used for spraying molasses water over small cores. Fill the can two-thirds full and blow into the mouthpiece. Small cores are made up on a flat bench, the sand being in a small pile at the back. Larger boxes are rammed up on horses or on the floor, as is most convenient. Baking. After being made up, cores are baked on core plates. The smaller plates are cast perfectly flat. Plates over 18 inches long are strengthened by ribs cast about 1 inch from the edge, as shown in Fig. 58; this keeps the plate from warping, and admits of its being picked up readily from a flat bench top or shelf. Ovens are built with reference to the size of the cores to be baked. A good type of small oven is illustrated in Fig. 59. It can be run very economically with either coal or coke, and bakes cores up to 2 inches in diameter within half an hour. Each shelf is fastened to its own door, and, when open for receiving or removing cores, a door at the back of the shelf closes the opening. This prevents a waste of heat. Fig. 60 shows the section through an oven suitable for the largest work, including dry-sand and loam molds. The fire box A is situated in one corner at the back; its whole top opens into the oven. At the floor level diagonally opposite is the flue B for conducting the Fig. 58. Core Plate FOUNDRY WORK 49 Fig. 59. Small Core Oven Fig. 60. Core Oven for Large Work 50 FOUNDRY WORK waste heat to the stack C. The entire front of the oven may be opened by raising the sheet-steel door. Two tracks side by side !ll!JI!|!il!!!l||il!l|l|||!ll||Mixi:;:''"^.:-'''!i'!!!! i^';;' 'S""!'!"!!'i!'!'!i!li!!!!!i!l!! 1 Fig. 61. Cast-iron Car accommodate cars upon which heavy work is run into the oven. Fig. 61 shows a good form of cast-iron car. The wheels are designed on the roller principle to make it easier to start the car when heavily loaded. For medium work smaller ovens of this type are used. Racks similar to the one shown in Fig. 62 may be bolted on the sides, arranged to hold the ends of the core plates; and the car may carry a line of double racks to increase the capacity of the oven. Conditions of Use. As mentioned before, cores form those parts of a mold which are to be nearly or entirely surrounded by metal; in other words, such parts as would be in danger of breaking or require too much work to be constructed in green sand. The object, then, in making cores is to insure a better casting and to reduce costs. Cores are held in position by means of core prints (see Pattern-Making). The main weight of the core is supported by these prints and through them all vent must be taken off and all sand removed in cleaning. Therefore, cores must be stronger than green sand, because, whether large or small, they must stand handling while being set and must not cut or break during pouring. Fig. 62. Rack They require greater porosity than green sand because their vent area is limited and their composition contains more gas forming material. Furthermore, cores must lose all their FOUNDRY WORK 51 bond by the time the casting is cold, so that the sand may be easily removed no matter how small the available opening. These conditions are obtained by using a coarse free sand and a binder. To give additional strength when necessary, iron wire or rods, or cast-iron core arbors are bedded in the core. These serve the same purpose in a core that the flask does in green- sand work. Binder. The action of the binder enables the sand to retain its shape when the box is removed, and renders the core hard and strong when baked. In the mold the intense heat of the metal gradually burns out the organic matter or binder, leaving the core without bond. In this condition, the sand may readily be removed. Too much binder tends to make the core sag out of shape before baking, and blow when metal strikes it; that is, give oft' more gas than the vents can carry away. With too little binder the sand does not bake hard, and cuts when the mold is poured. The effectiveness of all binders, especially flour, depends upon their thorough mixing with the sand. The especial value of rosin and oil lies in the fact that by melting under the oven heat they form a more perfect bond with the sand. Many intricate cores are now made with an oil mixture, without using rods or wires, which formerly were considered absolutely necessary for strength. Such cores must be well supported when green, must be thoroughly baked, and handled with much care until they are cold. Core-Sand Mixture. No universal mixture for core sand can be given, as sands vary so much in different localities. The mixtures, as shown on the following page, illustrate approximate proportions. In preparing core sand, the different ingredients should be measured out, thoroughly mixed, and sifted while dry. Temper the mixture a little damper than molding sand. Too much moisture makes the sand stick to the box. Not enough makes it hard to work and gives a crumbly surface if dried. Facing. Blacking for light work should include one cup of molasses to a pail of water, into which is worked powdered charcoal until an even black coating is deposited upon the finger when dipped into the blacking and out again. 52 FOUNDRY WORK Core Mixtures Materials Small Cores (parts) Large Cores (parts) Intricate Smaller Cores (parts) Beach sand Fire sand Molding sand Sharp fire sand Strong loamy sand Flour Rosin Oil ■ 10 1 8. 2 n 15 15 1 2 15 5 2 1 Tempering means Molasses water Clay wash Molasses water For heavy blacking there should be used about 2 parts charcoal and 1 graphite, mixed into thick clay wash. Miscellaneous. In finishing small cores, they should be sprayed with weak molasses water while green, then well baked and removed from the oven. When cool enough to handle, they are dipped into the blacking; then put back in the oven until this facing has dried. For large cores the blacking is applied with a brush before baking. All cores should be baked as soon as made, for air-drying causes the surface to crumble. Cores must not be set in a mold while they are hot, or the mold will sweat, that is, beads of moisture will form on the inside faces. This would make the mold blow when poured. A core should be rammed evenly and somewhat harder than a mold. Too hard ramming will make the sand stick in the box, besides giving trouble in casting. Too light ramming makes a weak core. From the very nature of cores, the matter of venting them is very important and often calls for much ingenuity on the part of the core maker. For simple straight work a good sized vent wire is run through before the box is removed. Half cores have their vents cut in each half before pasting together. Cinders are rammed in the center of large cores connecting through the prints, with the mold vents. For crooked cores, wax ventc are rammed in the center — the wax melts away into the sand when the cores are baked, leaving smooth even holes. This is illustrated in one of the following examples. FOUNDRY WORK 53 Methods of Making. The examples here given serve to ilhis- trate the principal methods used in making cores. Small Cylindrical Core. The simplest form of core is one which can be rammed up and baked as made by simply removing the box. Short bolt-hole cores, etc., are made in this way, as shown in Fig. 63. Fig. 63. Short Bolt-Hole Cores Set the box on a flat bench top. Hold the two halves together by the clamp A. Ram the hole full of core sand by the use of a small rod. Slick off the top; run a good sized vent wire through the middle of the core. Remove the clamp. Set the box onto the core plate, rap the sides, and carefully draw them back from the core. Symmetrical Shapes. Larger cylindrical cores, up to about 1| inches diameter, are rammed in a complete box also, only they are rolled out on their sides, as shown in Fig. 64. This, however, tends to make a flat place on the side, from the weight of the sand supported on this narrow surface. For this reason cylindrical cores of large diameter, and many symmetrical shapes, are made in half boxes. See Pattern-Making, Figs. 110, 208, 213, and 219. Such boxes are rammed from the open side. Wires are bedded when necessary about in the middle of the half core. The fingers and the handle of a trowel are often used to ram the sand, and with the blade of the trowel the sand is struck off and slicked to the le\el of the top of the box. When baked, two half cores are held with their flat sides together, and any slight unevenness in the joint removed by a gentle rubbing Fig. 64. Large Cylindrical Cores 54 FOUNDRY WORK motion. A vent channel is then scraped centrally on each half. Paste, made of flour and molasses water, is applied around the edges and the two halves pressed firmly together; care is taken to see that they register all around. The core should then be placed in the oven to dry out the paste. When pasting cores of 6-inch diam- eter and over, it is well to bind the halves at each end with a single wrap of small w^ire. Proper Seating. Wherever possible, core boxes should be made with their widest opening exposed for packing the core, and designed so that the core may rest, while being baked, on the flat surface formed by striking off at this opening. Core plates will sometimes become warped. When a core would be spoiled by resting it directly upon such a plate, the unevenness is a Fig. 65. Bedding a Crooked Core overcome by sifting upon the plate a thin bed of molding sand and seating the core on this. Crooked Shapes. All cores cannot be made with a flat surface for baking, as illustrated by a port core, the box for which is shown in Pattern-Making, Fig. 251. This core must be rolled over on a bed of sand. Using an oil mixture, ram the core carefully, bedding into it several wax vents. These should start near the end which will touch the main cylinder core and lead out of the end which will enter the chest core. To get this crooked core on a plate for baking, a wooden frame is roughly nailed together, which is large enough to slip over the core box when the loose pieces have been drawn off of the core, as shown in A, Fig. 65. The space on top of the core is now filled with molding sand, rammed just enough to support the weight of the core. The edges of the frame project above the highest points of the core and form guides for striking off this sand and seating a core plate, as at B, FOUNDRY WORK 55- Fig. 65. Box, frame, and plate are now firmly clamped and rolled over, and the frame and box removed, leaving the core well bedded on the plate ready for the oven, as at C. In manufacturing plants quantities of cores are often required which cannot be baked on a flat plate. To save the time and material necessary to roll each core onto a bed of sand, metal boxes are made, Pattern-Making, Figs. 233 and 234:, and the core is baked in one part of the box. Only one casting is required of the larger portion of the box. The smaller part is duplicated for every core required for the day's mold. Rod Reinforcing. Mention has been made of the use of wires for strengthening small cores. In making larger ones, there is a greater weight of sand to cause strain in handling the core, and proportionately greater easting strain. To resist these stresses a systematic network of rods is bedded in the core while being rammed, as shown in the sectional view. Fig. 66. Heavy bars aabb extend the length of the core to give the main stiffness. Smaller cross-rods rest on these at the bottom and top, and with the small vertical rods tie the whole core together. At even distances from each end lifting hooks c are placed. Cross-rods through the lower eyes of these hooks bring all the strain of the lift on the long heavy core rods. The holes in the top of the cores where the lifting hooks are exposed, are stopped off when the core is in the mold, by moistening the sides of the holes with oil and filling up with green sand. Cinders are packed in the middles of such cores. They aid in drying the core. They furnish good vent, and they allow the sand Network of Rods in Cores 56 FOUNDRY WORK A /ran Core Arbor A\ Fig. 67. Sections Siiowing Use of Cast- iron Core Arbor to give when the casting shrinks, thus reheving the strain on the metal itself . Use of Arbors. For the largest class of cores for green-sand work, cast-iron core arbors are used, of which a very satisfactory type is shown in Fig. 67. This consists of a series of light rings, A, carried on a cast-iron beam, B. The rings are of about |-inch metal cast in open sand and set about 8 inches on centers, and may be wedged to the beam. The beam has a hole at each end for lifting the core. This skeleton is made up and tried in the box before the work of ramming the core is begun. It is then removed and given a coat of thick clay wash. A layer of core sand is first lightly rammed over the inside of the box, and the core arbor seated into this. The full thickness of core-sand facing is then firmly rammed, and the entire center filled with well- packed cinders. Vents through the facing at both ends provide for the escape of gases from these cinders. Sweeping. Often, when but one or two large cores are wanted, the cost of making a box is saved by sweeping up tlie core. This is illustrated in the pipe core shown in Fig. 68. The pattern-maker gets out 2 core boards and 1 sweep. The boards are made by simply nail- ing together 3 thicknesses of |-inch stuff, with the grain of the middle piece crossing that of the others to prevent warping. The outer edges of the boards have the exact curve of the outside of the pipe pattern, and at the ends is tacked a half section of the core, shown at aa. One sweep does for both boards. The curve is cut the exact half section of the core. The edge h equals the Fig. 68. Pipe Core FOUNDRY WORK 57 thickness of metal in the casting, and the stop c acts as a guide along the outer edge of the board. In making up this core, a thin layer of core sand is spread on the board and the outline of the core swept. On this the rods with their lifting hooks are bedded, and the vent cinders are carefully laid along the middle. The whole general shape is then rammed up in core sand larger than required, and by using the sweep it is brought to exact size. The core is then slicked off, blackened, and baked while still on the board. When both halves are dried, they are pasted together, the same as with smaller work. To J- jm ' ai. ' , ! i"!i t WfliiM 1 Fig. 69. Core jMachine prevent breaking the lower half when turning it over to paste, it is rolled over on a pile of heap sand. Core Machines. For making stock cores, round or square, several styles of core machines have been put on the market witliiii the last few years, of which the one illustrated in Fig. 69, is a good representative. This is arranged to be driven by hand or by power. The core sand is placed in the hopper, and by means of a horizontal worm at the bottom it is forced through a nozzle under just the right pressure to pack the core firmly. A clean-cut vent hole is left in the middle of each core. As the core is forced from the nozzle it is received on a corrugated sheet-steel plate, which is moved 58 FOUNDRY WORK along to the next groove when the core has run to the full length of the plate. The advantage of the machine is that with it an apprentice boy can produce a true, smooth, perfectly vented core, in very much less time than could possibly be done by hand-ramming. Setting Cores Cylindrical Cores. Plain Fitting. Among the following exam- ples showing typical ways of setting and securing cores in molds and of connecting vents, the bolt-hole core, shown at A, Fig. 70, illustrates the simplest form of core to set.- Only a drag print is necessary; the flat top of the core should just touch the cope surface of the mold. The level may be tested by a straight stick or by Fig. 70. Bolt-Hole Core Fig. 71. Calipers sighting across the joint. If the core is too long, one end may be filed off a little, if too short, a little sand may be filled into the bot- tom of the print. For longer cores, especially hub cores, a taper print is placed on the cope side of the pattern, and the same taper is given to the end of the core; this guides it to the exact center when the mold is closed. Numerous examples are shown in Pattern- Making. The exact length of the core should be obtained from the pattern with a pair of calipers, as shown in Fig. 71. One point of the calipers should then be placed on the taper end of the core, and the print filled in, or the core shortened in case of variation from the right length. It is well to make a vent hole from the center of each print before setting the core. With pattern and core boxes properly made, little difficulty should be experienced in setting small horizontal cores for hollow bushings, pipe connections, etc. (See Pattern-Making, Figs. 110, FOUNDRY WORK 59 203, and 210.) The core must fit the print or a poor casting will result. The sand supporting the prints must be tucked firmly enough to withstand the lifting pressure on the core. A scratch # I Air ^enf a\ b ^^^^mi^^^^^^^^^^^^^^^f^i^t^ ^y m& If )\))ji/fyr7r-^/f?y^7c^^^^=;<~^^ M ' ^ a Fig. 72. Supported Body Core with the point of the trowel along the joint surface from the end of the print to the edge of the flask, will usually take care of the vent. For larger cores of this character crossbars made to fit snug against the core print are nailed in both drag and cope. See aaaa, Fig. 72. These hold the core absolutely firm. The spaces 66 in the cope, are not packed until the core is set, when it is a simple Fig. 73. Setting Core below Surface matter to ram these spaces and take off an air vent directly from the center of the core. Holes below Joint Level. There are two methods of coring holes below the level of the joint. One is shown clearly in I'ig. 7o. 60 FOUNDRY WORK IZ IT 1 [Fig. 74. Gage for Setting Chaplets A stock core is set in the bottom of the prints; a wooden template, shown at b and b', is set over the core, and the print a is then packed with molding sand, or stopped off, as it is termed. The other method is shown at B and B', Fig. 70. Here that part of the core which will shape the hole through the casting, is formed on the end of a core which exactly fills the print. A single oper- ation sets the core and stops off the print. For this reason this method is used where a large number of such holes are to be cored. Setting Chaplets. In setting chaplets, the height of the lower one may be tested with a rule, with a straightedge rested on the prints, or by a gage similar to that shown in Fig. 74. A small boss is usually formed by pressing the trowel handle into the mold where the chaplet is to go. The cope chaplet is not fastened until the mold is closed, then the stem can be properly wedged down under a Dar clamped across the top of the mold. Projecting Cores. Balanced Type. In work where a hole must project well into the casting, but [not all the way through it, a balanced core is often used. Such a case is illustrated by the rammer head, Fig. 75. When making this core, let the vent extend through the entire length, then stop up the vent at the small end with a bit of clay after the core is baked. It is not always practicable to enlarge the print as shown here, but when possible, it reduces the length of print necessary to balance the projecting end and ensures accurate depth to the hole. Heavy Form. Heavy projecting cores must be supported by chaplets, as illustrated in Fig. 76. Vents tnay be taken off through a channel and air riser as explained in the section on Venting. Fig. 77 shows the shape of the print on the pattern for this mold at a, the jrVerfi Fig. 75. Small Balanced Core FOUNDRY WORK 61 pockets formed by the core are shown at bb, and c indicates the position of the gate. Hanging Cores. A core is frequently used to avoid a deep lift for the cope. Suitable wire hangers, shown at a, Fig. 78, are bedded in the core when it is made. In setting the core, small annealed wire about No. 20 or ■Veni Fig. 76. Large Balanced Core Fig. 77. Shape of Print on Pattern for Projecting Core No. 24 gage is looped through the hangers, passed through small holes made in the cope, and fastened with a granny twist over an iron bar on top. This bar should bear on the sides of the cope and the core be brought up snug in its print by wedging under its ends. The rigging need only be strong enough to support the w^eight of the core, for the pressure of metal will force this core firmly into its print with little danger of shifting it. For heavy cores, a lifting eye, as previously illustrated in Fig. 66, takes the place of the wire hanger, and the core is hung by means of a hooked rod with a nut on the end. As shown in Fig. 79, this rod passes through a long washer which bears on a pair of rails, or similar stiff rigging. Bottom=Anchored Cores. Where possible, the placing of cores in the bottom of molds should be avoided, for in this position, being much lighter than molten iron, they must be secured against a pressure tending to float or lift them. This pressure is propor- tionate to their depth below the pouring basin. But the metal Fig. 7S. Section Showing Use of Wire Hangers 62 FOUNDRY WOKK at the bottom of a mold is cleaner and more sound than that at the top. Therefore, planer beds, large faceplates, and pieces of this character are usually cast face downward, making it necessary to anchor the T-slot cores in the bottom of the mold. In some cases, such cores may be held down by driving nails so that their heads project somewhat over the ends of the core, as shown in Fig. 80. If this method is not strong enough, pointed anchors, with a foot on one end, are run through a hole in the core, and are carefully driven into the bottom board, as shown in Fig. 81. Where the work is bedded into the floor, a plank must be set to receive these anchors just below the cinder bed. As in the case of lifting eyes, the holes in the core, into which the foot on the anchor is driven, are smeared with oil and stopped off with green sand. Fig. 79. Section Showing Use of Lifting Eye for Heavy Cores iJoint Line Fig. 80. Section Showing Use of Nails to Hold Cores in Place Fig. 81. Section Showing Use of Anchors to Hold Cores in Place Qreen=Sand Cores Expediency in Use. Many times the jobbing foundry may find it expedient, where patterns and core boxes are furnished by the customer, to make certain changes which will reduce the cost of production; for, unhappily, the patterns furnished sometimes FOUNDRY WORK 63 show a great desire on the part of the pattern-maker to produce the patterns cheaply, without making due allowance for difficulties encountered in the foundry. Fig. 82. Half Core with Box Built around It Typical Instance. The practice of substituting green-sand cores for dry sand has many possibilities. As an example, consider the case of a flange and spigot pipe 72 inches long and 6 inches tfo^el or Drag Fig. 83. Completed Mold for Core inside diameter. The pattern furnished was satisfactory, as was the half-core box, until it was found that the number to be made each day was gradually increasing and the number of half cures 64 FOUNDRY WORK to be dried was seriously interfering with the production of the regular cores required. It was decided by the foundry management Fig. 84. Cast-iron Arbor to Carry Core Fig. 85. Mold with Two Halves Together to adopt the use of a green-sand core, and not only relieve the core ovens, but also effect a considerable saving in core sand and core FOUNDRY WORK 65 binders. To make a green-sand core it was necessary to make the core box. The method used was as follows: First, a half core was made in the original box, and when this Fig. 86. Complete Core Placed on Horses was dried it w^as placed on a new mold board as shown in Fig. 82, Over this was placed lagging of the desired thickness for the casting, as shown in the figure; then over this were placed the loose pieces Fig. 87. Complete Mold with Grcen-Sand Core in Position h to form the ends of the box and part of the hinge r, also forming a part of hinge on drag half of box, and e and g acting as strength- ening ribs. 66 FOUNDRY WORK With these loose pieces in position the drag was duly ramnned and rolled over, the cope was rammed and the dry-sand core secured in and lifted off with the cope. The loose pieces were withdrawn from the drag, and the mold was properly finished; when closed and poured, this gave a satisfactory casting of the drag half of the core box. The cope half was made in the same way, the only change being in the shape of the loose pieces forming the ends as seen in Fig. 83. An arbor being required to carry the green sand, it was made of cast iron, as shown in Fig. 84. To make the green-sand core, first riddle sand in the drag half of the core box; next place the arbor as shown in Fig. 83; then fill and carefully tuck the sand under the flanges on the arbor. The cope is simply filled with sand and rammed, and both drag and cope are struck off level with the joint. The two halves are now closed, as shown in Fig. 85, when the cope may be rolled back to its former position and the core removed from the drag half of the box by lifting an arbor extending through the end of the box. The core should be placed on horses as shown in Fig. 86, so that it may be repaired if necessary and blackened. Fig. 87 shows the complete mold with green-sand core in position. In this way a satisfactory core box was made without heavy expense for patterns, as the foundry carpenter or flask man was able to produce the loose pieces from a rough sketch furnished by the foundry foreman. DUPLICATING CASTINGS Practical Requisites in Hand Molding. Devising methods for increasing production and decreasing its cost is one of the important problems of modern engineering in the foundry as well as elsewhere. In the jobbing foundry where there is a great variety not only in the patterns themselves, but in the number of castings called for from each pattern, the molder makes up a sand match as already described. On this match he arranges such an assortment of pat- terns as will fill his flask, and beds them into place. From a well- made sand match two or three hundred molds may be made up. When the desired number of castings is made from one pattern on the match, that one is removed and another one which fits in its place is substituted. FOUNDRY WORK 67 Gated Patterns. For manufacturing purposes thousands of the same casting may be required, calling for more durable patterns and match. Metal patterns are made and as many as can be cast in a flask are soldered to a smoothly finished metal gate pattern. With a draw screw inserted in this gate, all of the patterns may be drawn at once. Two steady pins should be screwed and sweated into the drag side of the gate pattern. These should be of small round brass rod and should project below the deepest point of the patterns, for they guide the pattern as it is being drawn and prevent it from swaying and breaking the edges just as it leaves the sand. Patterns so arranged are termed gated patterns. Permanent Match. When such patterns have a flat joint, a special mold board should be provided, and the patterns stored on the same board. When the joint is irregular, a permanent oil match should be made. Make a strong hardwood frame the size of the flask and about 1 inch deep, with the bottom board arranged to screw on to the back. Nails should be driven into the inner sides hanging parallel to the bot- tom board. Measure the quan- ^^^•''- °" "'^''^^ tity of sand needed to fill this match. INIix thoroughly and, while dry, put through a fine sieve one-half this quantity of burnt sand, one-half new molding sand, and about one-fortieth litharge. Temper the same as molding sand, using boiled linseed oil. Ram up the drag and joint the mold very carefully. Put on the match frame and ram up with the above mixture; strike off, and screw on the bottom board. Remove the drag and allow the match to dry for a day with the patterns left in it. A coat of shellac when dry improves the surface. Fig. 88 shows a set of gated patterns bedded in a hard match. Use of Molding Machines. Types. Although there are many styles of molding machines on the market, these may be classified under four general types as follows: stripping-plate machines; squeezers; roll overs; and jar or jolt-ramming machines. The benefits derived from the use of these machines are manifold. 68 FOUNDRY WORK Advantages. If no consideration were taken of the increase in production possible by their use, the improvement in the quality of castings alone would oftentimes warrant their installation, as the decrease in cost of machining castings produced by this method pays good dividends on the investment. The use of unskilled work- men on these machines is no small item in their favor. Stripinng-Plate Machine. The stripping-plate machine is best adapted to that class of work which offers difficulties in drawing the pattern from the sand. Fig. 89 shows a pattern for a cast gear mounted on the strip- ping-plate machine. It is obvious that it would require a consider- able degree of skill to produce this class of work by the hand-molding method. The pedestal base of the machine has a flat top. The stripping plate is supported above this by a rigid open framework. Working in guides carried on the sides of this framework is the draw- ing frame, made to rise or descend by a strong crank and connecting rod. On top of this drawing frame and parallel to the stripping plate is screwed the plate to which the pattern is fastened. The stripping plate is cast with an opening which leaves about 1 inch clear all around the pattern. When both pat- tern and stripping plate are properly set in place, this space is filled with babbitt metal, this being an' easy way to secure a nice fit. In many cases there may be an interior body of sand to be supported when the pattern is drawn. To accomplish this stools are used. A leg screwed into the stool plate supports the stool at the exact level of the stripping plate. The stool plate is fastened to the flat top of the machine inside of the box-like framework which supports the stripping plate, as seen in Fig. 90. A flask is inverted on the machine, rammed, vented, and struck off. Movement of the crank lever at the side draws the pattern; Fig. 89. Typical Molding Machine FOUNDRY WORK 69 and the mold then is removed and set on a level sand floor, tnus doing away with bottom boards. A second stripping plate and pattern is used for ramming the cope boxes. Fig. 90. Molding Stool with Pattern in Place Pulleys are manufactured on molding machines of this tyY)e, as shown by the equipment illustrated in Fig. 91. The rim patterns Fig. 91. Pulley Molding Machine have the form of long hollow cylinders and can readily be set for any desired width of face. The hub carrying the core print separates 70 FOUNDRY WORK from the spokes, lifts off in the mold, and is drawn by hand. The arm patterns are so flat and smoothly rounded that the mold is Fig. 92, Simple Molding Machine or Squeezer Fig. 93. Match Plate Courtesy of Tabor Manufacturing Company, Philadelphia, Pennsylvania easily lifted off of them with little fear of breaking the sand. The cope and drag molds are both alike for a pulley mold. FOUNDRY WORK 71 Squeezer. Fig. 92 shows a type of machine known as the hand squeezer, which only packs the sand. Here the patterns are carried on two sides of a plate set between the cope and drag, as in Fig. 93. Both boxes are filled with sifted sand and set on the machine. The boards are made to follow inside of the flask. The molder's weight on the lever compresses the sand. Fig. 94. Hand Squeezing Machine with Cope and Drag Patterns Attached to Portable Table Courtesy of Arcade Manufacturing Company, Freeport, Illinois The sprue is cut by a thin hollow steel tube called a sprue- cutter, which is pressed through the cope sand by the molder before separating the flask. In separating the mold the cope is first lifted from the drag, and the plate is gently rapped and lifted from the drag. To make a clean lift when parts of the patterns project in the cope, a second molder raps with an iron bar between the battens of the bottom board while the cope is being drawn off. 72 FOUNDRY WORK Such machines are used chiefly on thin work which vents and solidifies very rapidly — for the outer surfaces of the drag and cope are apt to be rammed so hard that they might choke the vent on heavier castings. A somewhat different style of hand squeezer is shown in Fig. 94, which shows both cope and drag pattern plates attached to a portable Fig. 95. Beginning the Operation with Hand Molding Machine. Two Halves of Flask in Position Courtesy of Arcade Manufacturing Company, Freeport, Illinois table. Beginning the operation, the table holding the plates is turned face up with the two halves of |the flask in position as shown in Fig. 95. After the sand is thrown in the flask and the surplus scraped off, the bottom boards are placed in position and held by four clamps. Next, the table is rolled over as in Fig. 96. The ramming or squeezing operation is accomplished by pulling down FOUNDRY WORK 73 the long lever at the left of the machine, as shown in Fig. 97. At this point the clamps holding the cope and the bottom are auto- matically released. Fig. 98 illustrates the method of drawing the patterns. The lever is slowly lifted with the left hand, while the operator raps the vibrating pin with a mallet held in the right hand. When the long Fig. 96. Table Rolled Over Preparatory to Squeezing Courtesy of Arcade Manufactxtring Company, Freeport, Illinois lever is returned to its upright position, the two halves of the mold rest on the sliding platform. This is drawn forward in the position shown in Fig. 99. The mold is then closed, the flask removed, and the completed mold carried to its position on the floor for pour- ing. Snap flasks are best adapted for this style of machine. Roll Over. The roll-over machine which is illustrated by Fig. 10(1, has the pattern mounted on a wooden match plate as shown at vl, 74 FOUNDRY WORK which when in position to receive flask is resting on pins at BB. The mold is rammed by hand in the usual manner, the bottom board being clamped on by a special device to the frame C. The mold is next rolled over and rests at A. The pattern is withdrawn by the use of the foot pedal E, the operator meantime rapping the match plate Fig. 97. Hamming or Squeezing Operation Courtesy of Arcade Manufacturing Company, Freeport, Illinois with a wooden maul. This type of machine is best adapted to side floor work, the grate bar here shown being a good sample. Poicer Operation. The above-mentioned types show only hand machines which have been in general use for a considerable period of time, but the last decade has shown a wonderful change in this branch of foundry practice; indeed so great is the advance that FOUNDRY WORK 75 hardly a month passes that there does not appear some new featuer. The most important advancement, of course, was the adaptation of power, usually compressed air being resorted to, but more recently there has been quite a tendency to utilize electricity. Poiver Squeezer. Fig. 101 shows compressed air applied to the squeezer type of molding machine. This machine is designed Fig. 98. Drawing the Pattern.s. Use of Mall Courtesy of Arcade Mnnufacluring Company, Freeporl, Illinois especially for use in molding light snap-flask work in large or small quantities, and the method of pattern fitting depends ujxin the number of castings to be made from one pattern. A careful study of the line drawing of this machine shown in Fig. 102 should give a clear understanding of the working parts of the power squeezer, the numbered ones being identified as follows: 76 FOUNDRY WORK Fig. 99. Two Halves of Mold in Open Position Courtesy of Arcade Manufacturing Company, Freeport, Illinois 1. Yoke 20. 2. Left-hand stop for yoke 21. 3. Yoke handle 22. 4. Pressure gage 23. 5. J-inch air cock 24. 6. Eye bolt 25. 7. Left-hand strain bar 26. 8. Right-hand strain bar 27. 9. Right-hand yoke stop 28. 10. Platen 29. 11. Knee-pad rod 30. 12. Air hose from knee valve to 31. vibrator 32. 13. Air hose from knee valve to 33. supply 34. 14. Hose guard 35. 15. Knee pad 36. 16. Knee starting valve 37. 17. Cylinder base 38. 18. Piston 39. 19. Piston ring Counterbalance spring Adjustment block for spring seat Adjustment-block set screw Trunnion Bracket for lower spring seat No. 5 snap oiler Trunnion shaft Pop throttle-valve lever Valve-lever stud Throttle-stop segment Valve sand guard Valve spring for exhaust Adjustable strain-bar stop Valve body L hose nipple Straight hose nipple Valve bracket Taper pins, trunnion to shaft Blow valve Blow-valve hose FOUNDRY WORK 77 Attention is called to the fact that the production of the power squeezer exceeds that of the hand squeezer by 15 to 30 per cent. For description of various ways of mounting patterns, see Pattern- Making. Power Roll-Over. A power roll-over power-draft machine is shown in Fig. 103. This is designed to handle side floor work, Fig. 100. Roll-Over Molding Machine with Pattern Withdrawn Courtesy of Tabor Manufacturing Company, Philadelphia, Pennsyhania and has a straight draft of S inches and sufficient power to roll over a weight of 1000 pounds. It will be noted that as in the hand roll- over the patterns are mounted on Wooden match plates, the small expense of which makes this style of machine very effective in job- bing shops where but few castings are made from a pattern at a time. In Fig. 104 is shown the latest type of this machine with the flask shown in position ready for bar ramming. Fig. 105 shows the 78 FOUNDRY WORK mold partly rolled over; the mold rolled over and partly with- drawn is shown in Fig. 106. The view given in Fig. 107 shows the finished mold on one side and the pattern back in place. The working parts of the above machine are shown in Fig. 108, and are as follows: 1. Roll-over frame 2. Air cylinder 3. Link 4. Wedge leveling device 5. Adjustable support for leveling device 6. Operating valve and lever 7. Vibrator The plunger is made hollow and acts as an oil tank into which air under pressure is admitted when the machine is to be operated. When air pressure is admitted to the plunger, the oil is forced through Fig. 101. 10-Inch Squeezer Operated by Compressed Air Courtesy of Tabor Manufacturing Company, Philadelphia, Pennsylvania FOUNDRY WORK 79 a port into the cylinder, causing the plunger to rise and by means of its link connections to roll over the mold which is deposited on the leveling device. After the flask has been undamped air is again admitted to the plunger, causing the pattern to be drawn vertically the full draft of the machine, at which point the link Fig. 102. Elevation of Tabor Squeezer Showing WorkinR Parts connections cause the roll-over frame to return to its iiiilial ])()sition ready to receive another flask. JoU-Ramnmig Machine. The jar or jult-rannning machine is used for all classes of work from liglit work uj) to the largest floor work made in green sand, the limit Ix-iiig only the {•a]):icity of the 80 FOUNDRY WORK machine itself, which varies from a few hundred pounds to many thousands of pounds. Large engine beds are a good example of the castings produced on the heavy-duty machines. Fig. 103. Power Roll-Over, Power Draft Molding Machine with 12-Inch Straight Draft Courtesy of Tabor Manufacturing Company, Philadelphia, Pennsylvania Fig. 104. Latest Type of Tabor Molding Machine with Flask Ready for Ramming Patterns mounted on heavy wooden match plates are used in the manner hereafter described. The flask is first placed on the drag FOUNDRY WORK 81 half of the pattern board, and the flask filled with sand. By the use of an upset, usually about 4 inches deep, it is possible to heap sufficient sand on the flask to insure its being filled after the ramming has taken place. The flask must be securely clamped to the pattern plate, when both may be listed by the traveling crane and placed on the table of the jarring machine, which in the heavy-duty machines is on the foundry-floor level; the working parts of the machine being below and resting on a rigid concrete foundation. Here, air under Fig. 105. Machine with Mold Parlly Rolled Over Courtesy of Tabor Manufacturino Company, PJiilndrlphia, PrnnsyJn pressure is allowed to enter the cylinder, and, acting on the i)hinger, which in turn lifts the table usually about 4 inches, when the air is suddenly exhausted, allows the table to drop heavily on the anvil. The number of blows required to pack the sand must be determined by experience. The time required to ram the largest mold is but a small fraction of that consumed by hand-ramming. Fig. 109 is an illustration of one of the simplest styles of this type of machine. Fig. 110 shows the working parts of the same machine. 82 FOUNDRY WORK Fig. 106. Mold Completely Rolled Over and Partly Withdrawn Courtesy of Tabor Manufacturing Company, Philadelphia, Pennsylvania Fig. 107. Finished Mold on One Side and Pattern in Place Courtesy of Tabor Manufacturing Company, Philadelphia, Pennsylvania FOUNDRY WORK 83 /?-_ t Fig. 108. Diagram of Working Parts of the Tabor Molding Machine Fig. 109. Simple Type of Jolt-Ramining Machine Courtesy of American Molding Machine Company, Terre Ilauie, Indiana A quite distinct style of jolt machine, called an electropneumatic jolt-ramming machine, is shown in Fig. Ill, the unique feature being the motor-driven compressor without a clutch, spring, cam. 84 FOUNDRY WORK ■Table S Encased (^uide Pins Forcerit- C^uicle Surface Piston oiler arotjnci Fig. 110. Section of American Jolt-Ramming Machine Fig. 111. Krause Electropneumatic Jolt Rammer Courtesy of Vulcan Engineering Sales Company, Chicago, Illinois Fig. 112. Section of Krause .Tolt Rnmmnr Showing Transmission and Unique Compressor 86 FOUNDRY WORK or valve. A very little study of Fig. 112 should make clear its radical features. Automatic Squeezer. Fig. 113 illustrates an automatic molding machine of the squeezer type. The operator places the flask and bottom board in position, then by simply pressing on the starting lever the fillmg of the flask with sand, the ramming and the drawing of the pattern is completely automatic and accomplished in about Fig. 113. Automatic Molding Machine of the Squeezer Type Courtesy of Berkshire Manufacturing Company, Cleveland, Ohio eight seconds or some six or seven hundred molds per day. This machine is best adapted to the production of small duplicate work such as small pipe fittings. Roller- Ramming Machine. The very distinctive type of mold- ing machine shown in Fig. 114 is known as the roller-ramming machine. It is best adapted to long work of comparatively thin cross-section, of which a cornice section would be a good example. This class of work could not be produced readily on any of the FOUNDRY WORK S7 previously mentioned types of machines, drawing of Fig. 114. Fig. 115 is a detailed c .« .£ fe J2 e §^ I I c o «= Cci 1- o The success of any and all molding machines depends on tlie intelligent selection of the type best suited for the work in hand. Fig. 115. Plan and Elevation of Moldar Roller-Ramming Machine FOUNDRY WORK 89 DRY=SAND WORK Characteristic Features, This branch of molding becomes a separate trade in shops where the work is done continually. The dry-sand molder must use the same precautions as the green-sand molder in setting gates and risers, and in fastening his sand with crossbars and gaggers. At the same time, he works with a core- sand mixture next his patterns and backs this with a coarse moldmg sand, so that he must combine the skill and judgment of both the green-sand molder and the core maker. The venting of dry-sand work must be ample, as in the case of cores, but it is simpler than in core work, because the core mixture surrounds the casting so that vents may be taken off in all directions. Iron flasks are used, generally provided with trunnions to facilitate turning. The facing mixture is the same as that used for making large cores, as discussed in the section on Core Work; the remainder of the flask is packed with the same sand after it has been used. The patterns are made and used the same as with green sand, only they should be brushed over with linseed, crude-oil, or other heavy oil, before ramming. In some shops oil is brushed over the joint before parting sand is thrown on. " After the pattern is drawn, the mold is finished by applying a heavy coat of good black wash. When the sand has absorbed the moisture so that all glisten has disappeared, this blacking is slicked over. Great care must be exercised in this operation, for too much slicking will draw the moisture to the surface again and result in scabs on the casting. Molding Engine Cylinder. Engine cylinders are a representative line of work for dry sand. Consider a simple type of cylinder, such as shown in Pattern-Making, Fig. 244, to ha\'e a bore of from 16 to 26 inches, and with the exhaust-outlet flange placed above the center of the cylinder. To facilitate setting the cores, the pat- tern may be split through the steam chest. The flange just men- tioned should be molded in the drag, and should be made loose and draw in the opposite direction from the main pattern. The cylinder core should be made on a barrel, as will bo explained later, and the mold poured on end to insure sound metal and to reduce the casting strain on the port cores. The flask is made with a round opening in one end to allow the core to project through it. This opening is larger than the diameter of the core to allow for 90 FOUNDRY WORK gates and risers. There must be another opening at the side of the flask adjacent to the steam-chest core to provide for fastening these cores. Iron plates serve for flask boards and there should be a hole in the drag plate in line with the exhaust core to allow for venting and fastening its end. One-half of Fig. 116 shows the end view of the flask. The other half shows a section through the middle of the completed mold. Here A is the hollow cylinder core, B is the chest core, C the live- steam core hung in the cope, and D the exhaust core. The flask is packed in a manner similar to green sand. Use of Cover-Core. The method of molding the exhaust flange, however, has not previously been explained. To do this. Fig. 116. Molding a Cylinder proceed packing the drag until the pattern is covered. Tuck the facing carefully underneath the flange, setting in rods as in core work, to strengthen the overhanging portions. Make a flat joint, FG at the level of the top of the flange, then carefully fit over the priru of the flange the cover-core E, and fix its position with nails driven into the joint at its corners. Now remove the cover-core, draw the flange, and finish that part of the mold with black wash and slicking. When this is accomplished, replace the cover-core, place a short piece of pipe over its central vent, and finish ramming the drag. This method may be used in many cases, both in dry-sand FOUNDRY WORK 91 and in green-sand work where a small detail of the casting requires a separate joint surface. A sectional plan looking down on the drag is shown in Fig. 117. When the mold has been properly finished and baked, the drag is brought from the oven and set on a pair of stout horses. The cylinder core is first set in place, then the exhaust core is set in its Fig. 117. Sectional Plan of Fig. IIC Looking Down on Drag drag print and held close to the cylinder core, while the port and chest cores, previously pasted and fastened, are lowered into the chest print. The chest print is cut a little long at aa, to allow its core to be drawn back slightly, while the exhaust core is entered into its place between the port cores. Then all of the cores are set forward into position, the chaplets hh set, the space aa tightly packed again, and the anchor bolts cc placed in position and made fast. 92 FOUNDRY WORK The drag print of the exhaust core is made fast from underneath the drag plate. When all the cores have been firmly fastened, the cope is closed on, and the two boxes clamped at the flanges and set up on end. The runner R and the riser S were cut and finished before baking; the basins must be built in green sand after the mold is closed. Making Barrel Core. Loam is used here for the outer shell of the core. It is probably the simplest job in which a loam mix- ture is employed, and is made by a core maker more frequently than by the higher paid loam molder. Barrel cores are used where the core is long and can best be supported at the ends only; for example, in gas and water pipes and cylinder work. Loam. Loam is a facing mixture, of the consistency of mortar, applied to the face of the core or mold. It contains fire sand with a bond of strong porous molding sand moistened with a thick clay wash. A small proportion of organic matter in the shape of horse manure is put in to aid the bond and to leave the crust of loam more fragile by burning out as the casting cools. Proportions of the mixture will vary according to locality, but the principles already cited hold here as with other molding compounds. With too much bond the loam works easier but tends to choke the vents when casting. With not enough it is weak and is liable to break, cut, or crumble under strain. A t\'pical mixture is as follows: Loam Mixtures Material Mixed by Hand (parts) Mixed by ^IIT:l (parts) 1 Fire sand Strong coarse molding sand Horse manure 10 4 10 3 2 Temper Thick clay wash. Thick clay wash The advantages of loam cores are that they are lighter, cheaper to make, and carry off the gases faster than do dry-sand cores. Method. The method is as follows: A piece of pipe about 3 inches smaller than the outside diameter of the core is selected to form the center. The pipe is perforated with a large number of holes. If the pipe is more than 3 or 4 inches in diameter, centers FOUNDRY WORK 93 or trunnions are riveted in the ends to serve as bearings. The pipe is arranged to revolve freely on a pair of iron horses, as shown in Fig. 118. A crank handle is attached by which the pipe may be turned. A couple of wraps of hay rope are first given around one end of the pipe, and the loose end is pinned flat by a nail run under these strands. Tight wrapping is then continued to the other end of the pipe, where the rope is fastened in a similar manner and cut off. Hay rope should be made of long wisps tightly twisted. Sizes vary from f to 1 inch. \Yhere only a small amount of hay rope is used, it is bought ready made. Foundries using large quantities Fig. lis. Alaking Loam Core for Cylinder are equipped with one or more machines built especially for making this rope. The first coat of loam is rubbed on with the hands, then well pressed in with the flat side of a board as the barrel is slowly revolved. When this has set, the core board A is placed in position, and the roughing coat worked on to the core to within about I inch of finished size. The core is now dried in the oven. Placing the core again on the standards, the finishing coat of slip is applied with the core board while the core is still hot. The diameter is tested with calipers and brought to required size by slight adjustment of the sweep board A. When the core has been built to size, move tlie loam back from the edge of the board .1, then withdraw the board while the barrel is still in motion. 94 FOUNDRY WORK Slip. Slip or skinning loam is made by thinning regular loam as it is rubbed through a No. 8 sieve. The heat of the core is usually sufficient to dry this slip coat enough so that black wash may be brushed on and slicked, as in dry-sand work, before running the core into the oven again for its final baking. The service of the hay rope on a barrel core is twofold: it fur- nishes a surface over the smooth metal of the barrel to which loam will adhere; and it is elastic enough to give as the casting shrinks around the core. The hay slowly burns out after the casting has set, and this frees the barrel so that it can easily be withdrawn and used again. LOAM MOLDING Skill Required. The loam molder requires the greatest all- around skill in the whole range of foundry work. He must know all the tricks of the core room and dry-sand shop, and most of those in green sand. Added to all this he must have a practical working knowledge of the principles of drawing and must possess to a large degree the foresight of the designer. In order to save time and lumber in the pattern shop, only a set of sweeps is provided if the mold is simple, and these, with blue prints of the piece wanted, are all the molder has to work from. In intricate work, such as a modern Corliss cylinder, a skeleton pattern carrying the steam chests, etc., in accurate position is made, and in some very crooked work a pattern is furnished complete. As a rule, however, the loam molder must rely upon his own skill and ingenuity for the best method of constructing each detail of the work. Rigging* The equipment for the loam floor varies in different shops. In Fig. 119 are shown the essential features of an equipment for sweeping-up circular forms. Spindle. The spindle a should be large enough not to spring when being used, and long enough to conveniently clear the highest mold. A piece of 2-inch shafting is a handy size, for with it the sweeps may be made uniformly 1 inch less than the required diameter and placed snug to the spindle when set up, and the correct size of mold is ensured. This spindle should revolve smoothly in a step b. The step shown may be set at any convenient place on the floor. It has a long taper bearing, as shown in section A, capable of holding a 5-foot spindle without need of any top bearing. The three arms serve to FOUNDRY WORK 95 make the step set firmly, and upon them any phite may be readily leveled up. Where a tall spmdle is used, the spindle soeket is more shallow; the step may be cast without arms ami l)e bedded in the floor. The top of the spindle is steadied by the bracket c. This must carry a bearing box so designed that the spindle may be readily set in position or removed. And the bracket must swing back out of the way when any parts of the mold are to be handled by the crane. Sweeps. The sweeps are attached by means of the sweep arm d. The detail B shows one method of clamping the sweep arm to the spindle bj^ using a key. The arm is offset so that one face hangs in Fig. 119. Rig for Loam Work line with the center of the spindle. Bolting the face side of the sweep to this brings the working edge in a true radial ])lane. Sweeps are usually made from pine about 1| inches thick. The working edge is cut to the exact contour of the form to be swept, and then is beveled so that the edge actually sweeping the surface is on1>' about f inch. For very accurate work or when sweeps are to be much used, the edge is faced with thin strap iron to prevent wear. Plates. We have seen that the walls of green- and dry-sand molds are supported by sand packed into fhisks and that these flasks may be lifted, turned up sideways, or rolled completely over to suit 96 FOUNDRY WORK the convenience of the workman. The facing which forms the wall of a loam mold is supported by brickwork built upon flat plates of cast iron, and laid in a weak mortar of mud. From the nature of their construction, therefore, these molds must always be kept perpen- dicular when being handled. The parts may be raised, lowered, or moved in any direction horizontally, but they must not be tipped or rolled over. The plates are cast in open sand molds, as illustrated in Fig. 56. Two methods are employed to provide for handling them by the crane; Fig. 120. Laying-Up Loam Work either lugs are cast on the edges of the plates, as in C, D, and E, Fig. 119, or wrought staples are cast in the plates, as shown in B, Fig. 120, or in the crown plate of the main cylinder core. Fig. 123. Three typical plates for a loam job are shown in Fig. 119. C is the building plate; it should be at least 18 or 20 inches larger than the largest diameter of the casting to be made, and thick enough to support the weight of the entire mold without springing. D shows a cope ring; its inside diameter should clear the casting 2 inches on all sides. The face should be 8 to 12 inches wide, depending upon FOUNDRY WORK 97 the height of the mold. E shows a cover plate; its diameter equals the outside diameter of the brickwork on that part of the mold wliicli it covers. Here the loam facing is placed directly on the iron, and must be supported when the plate stands vertically or is turned com- pletely over as in C, Fig. 122. To hold the loam in this way, fingers or stickers are cast on these plates. This is accomplished by simply printing the end of a tapered stick into the bed of the open mold which ^^^^ Fig. 121. Steps in Sweeping Up Type Moid shapes the plates. These sticker plates are often used for a purpose similar to the core E, Fig. 110, and shape the outer face of a picked- out flange. This is illustrated in D, Fig. 122. Materials. Briclc. Common red brick is best for making loam molds. Figs. 120 to 12,1. It should be free from glaze and have a uniform texture, so that the pieces will break clean when it is necessary to fit them to the shape. An old 12-inch half-round file makes a handy tool for cutting these. Sometimes brick is molded 98 FOUNDRY WORK up from loam, and air-dried. It is much more fragile than red brick, and may be used in pockets, or where the shell of the casting is quite thin, and ordinary brick might resist the shrinkage strain to such an extent as to endanger cracking the casting. Mild. For laying up the brickwork, mud is used, loam facing being applied only to those surfaces wdiich come in actual contact ConsTractfon of /^olcf QT Nozzle-0- Fig. 122. Complete Typical Loam Mold with the iron. Mud is made from burnt loam or old floor sand, mixed with clay wash to the consistency of mortar. Facing. The composition of loam facing and slip have already been given under the description of making a barrel core. Cinders. Cinders are an important material in this work. Their size will depend upon their position in the mold. For working in between brick, the cinders should be crushed if necessary, put through a No. 4 sieve to remove smallest pieces, then passed through a No. 2 sieve to remove the larger pieces. FOUNDRY WORK 99 Principles of Work. Parts of Mold. Tlie names of the main parts of a loam mold difi'er somewhat from those ai)i)lie(l when molding m flasks. As will be seen from the section, Fig. 122, there are three main divisions in the mold: A, which corresponds to the drag in a three-part mold, is called the core. B, which corresponds to the cheek, is called the coiw in loam work. And C, which ser\es the same purpose as the cope of a green-sand mold, is spoken of as the cover in loam molding. When the central core is actually made a separate piece, as in Fig. 123, the lower part of the mold is called the bed ovjoundation. Fig. 123. Loam Mold for Marino Cylinder Laying-Vp. In laying-up a loam mold. Fig. 120, set the plate central with the spindle and a])i)r()ximately level. Then set the sweep and finish leveling the plate until repeated measure- ments at the four quarters of the circle show a uiiiforni sjjacc between the lower edge of the sweep and the surface of the i)late. For the building plate this measurement should be 5 inches; for a sticker plate the sweep should clear the sticker points by J to 1 inch according to the thickness of the casting. The hands are used in si)r(>ading nuid or loam ui)on the i)lales or brickwork when building the mold. The brick nuist always be set well apart, leaving a space at least the width of a finger between them. Fill in these spaces with fine cinders. The reason for this is 100 FOUNDRY WORK fourfold. It facilitates drying ; it provides good vent ; it gives or crushes sufficiently when the casting shrinks not to cause undue strain; and it reduces the labor in cleaning. In each course of brick the joints should lead as directly as possible away from the casting, but the joints should be broken between courses. These points are illus- trated in the sketch A, Fig. 120. As shown, the first two courses of the core are usually set edgewise. For the rest of the core and for the cope, the bricks are laid flat. These bricks run lengthwise around the circumference, with a course of headers about every four to six courses. Venting. Cinders between brick form the ordinary means of leading the vent from the loam facing. In confined places or pockets, as, for example, between the flange D and the main casting. Fig. 122, additional provision is made by laying long wisps of straw between the courses of brick. The service of the straw is similar to that of the hay rope of a barrel core. Jointing. The joint in loam work is made by a plate lifting away from a loam seat, or by two loam surfaces separating one from another. In forming the first of these the loam seat is swept up and allowed to partially set, then the surface is brushed with oil, and part- ing sand is thrown over it. The seat should then be soft enough to allow the iron plate to sink into it sufficiently to find a good bearing, while the oil and parting sand will prevent the loam facing from adhering to the underside of the plate. For the loam-to-loam joint, the same method is used, but the loam is allowed to set somewhat harder before building the joint against it. The angle of the main joint should be about 1 in 4 inches. To insure the different parts being put together for casting in exactly the same position in which they were built, a guide surface of loam is smoothed across the joint at three or four convenient points on the outside walls of the mold. These surfaces are each marked differently with the edge of the trowel, similar to the cut at C, Fig. 120. Drawback. To properly separate and finish some molds, it is necessary to lift away a portion of the mold before lifting the main part. Such a portion is called a drawback. The drawback is always built up in position against a pattern or sweep. With the cover plate, which on a smaller scale often serves the same purpose, as at FOUNDRY WORK 101 D, Fig. 122, a flat joint is made on the outer wall of the mold, but the cover plate is swept up separately. At S, Fig. 123, is shown a drawback which carries but a few courses of brick. It may be lifted away by lugs cast in the drawback plate with little danger of dis- placing its brickwork in handling. If the shape of the drawback renders it impracticable to handle it by the lower plate alone, the brickwork should be bound together by means of hook bolts which clamp on a top plate set sufficiently below the upper Joint to be entirely protected from the metal. This upper plate has staples cast in it by which the whole drawback may be lifted. At B, Fig. 120, the typical construction of such a piece is illustrated. The drawing shows one-half the length of the brickwork removed to bring out more clearly the rigging used. The upper end of the second lifting staple shows at a, with the loam cut neatly away to allow hooking into the staple. Where the main core lifts away or is to be covered with metal over its top, it must be bound together in a similar manner. This is illustrated in the mold for the marine-engine cylinder. Fig. 123, in which both of these conditions occur. ExamiJile of Internal Flange. If a casting has an internal flange requiring thickness of metal underneath the main core, the rigging will be altered to fit these conditions, as shown at D, Fig. 120. In this sketch a is a sticker plate and so will carry the loam necessary to face the bottom of the core. To this the small bearing plate h is securely bolted by the hook bolt c. This plate must set directly upon solid brickwork, as it carries the weight of the entire core. On this bearing plate are cast three studs which firmly support tlie sticker plate at the required height above the flange surface. The sticker plate carrying this print is filled with loam or dry sand and given a first baking, then swept to a finished surface before being inverted into position. Then the remainder of the core is built up on top and bound together, as in the previous example. Another way to form the bottom of this core is to sweep up a dummy flange d, in nuid. Set the bearing plate b, and work the loam in around the studs to form the short neck to the level of the top of the flange. Then spread over this flange | inch of loam and bed down onto this the sticker plate which has been previously filled with loam and dried, as is described below. Be sure that the studs on b bring up to a 102 FOUNDRY WORK firm bearing against tlie plate a, then clamp tight with hook bolts and proceed to sweep-up the body of the core. Bedding Cover Plate. In case a cover plate must be bedded down against a flat surface, as in the example just mentioned, or must take the impression of an irregular surface on the top of a mold or pattern, as illustrated in Fig. 123, the method to pursue is as follows: After casting, invert the plate and carefully lower it into position, and make sure that all fingers clear the surface by at least | or f inch. Now set the plate with the fingers up, fill in with loam enough to just clear their tops, leaving the proper openings for runners, risers, tie bolts, etc., and dry thoroughly in the oven. Upon removal from the oven, invert and try this loam cover again on the surface it must fit; scrape aw^ay any portions which project too much. Now hoist away the cover and coat the face with clay wash. Having previously prepared the surface of the pattern with oil and any loam joint with oil and parting sand, spread an even thickness of fresh loam all over and bed the plate down upon this. The cover plate, being still hot, will, by the aid of the clay wash, cause the thin layer of fresh loam to dry out and stick fast to the dry loam forming the body of the plate. Simple Mold. As an example of a simple loam mold let us consider the details of a large casting, having the shape of the frustrum of a cone, with a flange at the top and bottom and a flanged nozzle projecting from one side, such as the section clearly shown in Fig. 122. Foundation. Set the sweep, level up the building plate, and, building the brickwork as shown in A, Fig. 120, sweep the seat, joint, and bottom surface of flange, as shown at Ay Fig. 121. The lower flange may be formed by a wooden pattern furnished by the pattern maker, but it is more common to have the sweep made with the small board x, which may be removed. By doing this the exact shape of the flange may be swept up without changing the main sweep, as shown at B, Fig. 121. This dummy flange, as it is called, is swept- up from fairly stiff mud. Coi)e. The next step is to seat the cope ring and set the cope sweep, as shown at C, Fig. 121. This sweep shapes the mold for the outside of the casting, for the top flange, and for the top joint of the mold. Loam is thrown, a handful at a time, against the joint and FOUNDRY WORK 103 dummy flange, and the engaging faces of bricks are rubbed witli loam and pressed into position. When the top of the lower flange is reached in this way, the courses are laid-up for about 2 feet before the loam is spread upon their inner surface and struck off. This method is pursued until the mold is built to its full height. The projecting nozzle is formed by a wooden pattern ; this should be well oiled, and the brickwork and loam laid-up under it to support it at the proper level, as given by the center line on the pattern and corresponding line on the sweep. Such projections frequently must be supported in their exact position with reference to the main pattern by temporary wooden framework or skeleton work until the mold is built up under them. A finger y nailed to the top member of the cope sweep, shapes the guide surfaces on the outside of the mold wdiich are used to center the cover plate in closing the mold. A similar finger exactly the same distance from the spindle, is fastened to the sweep used to form the cover plate. After the finishing coat of slip has been swept on the surface of the cope, a joint surface about 4 inches wide is struck off flush with the outer face of the nozzle and that pattern is drawn out. Then the whole cope is lifted off and set on iron supports where it may be conveniently finished with black wash and slicks. It is then baked over night in the oven. Center Core. The dummy flange is now entirely removed from the first part swept, the core sweep is set, D, Fig. 121, and the center core is struck up. This core is then blackened, slicked oft', and baked. The cover plate is struck off with the stickers up, and baked so. This cover carries six 1-inch round holes through it, which will be just over the shell of the metal when the mold is closed. Five of them connect with the pouring basin and serve as runners, while the sixth serves as a riser. Closing. In assembling the mold for pouruig, the core is first set on a level bed of sand, the cope is accurately closed over it by the aid of the guide marks, and lastly the cover jjlate is closed in i)()siti()n. Now the whole mold is firmly clamped by blocking under the s])i(ler, from which wrought-iron loops or strings connect under the lugs of the building plate, as shown in Fig. 122. 104 FOUNDRY WORK The small core for the nozzle is now set, restmg on stud chaplets. The cover plate D is slid over the end of this core and thus holds it firmly in position. The casing is now placed around the mold and molding sand rammed in to support the bricks against the casting pressure. At the level of the nozzle core cinders are placed, and a pipe leads off to carry away the vent gases. The sand is rammed to about 12 inches over the cover plate and in it are cut the channels connecting the pouring basin and runners. A couple of bricks are set in the bottom of the basin to receive the first fall of metal from the ladle. Pouring. In pouring, the runners must be flooded at once and kept so until the mold is full. In heavy cylindrical castings it was formerly thought necessary to carry the shell of the casting some 6 inches higher than the top flange. This head served to collect all dirt and slag that perchance entered the mold with the iron, and it was cut off in the machine shop and returned to the foundry as scrap. With the increased knowl- edge of iron mixtures this head is now done away with in most instances. Where a large casting is to finish practically all over, and very clean metal is therefore necessary, overflow channels, connecting wdth pig beds, are often constructed in modern practice. Then, when pouring, the metal is not stopped until a certain per cent of it has been flowed entirely through the mold. This of course tends to wash out any dirt which may have gotten into the mold when pouring began. When the casting is cold, the casing and packing sand as well as the blocking under the spider are removed. Then the whole mold is carried to the cleaning shed where the bricks are removed and the casting cleaned. Intricate Mold. As an example of a complex piece of loam work, let us consider the molding of a modern marine-engine cylinder, as shown in section, Fig. 123. The example given is that of a double- ported low-pressure cylinder of a triple-expansion type. In this case a full wooden pattern should be built, with core boxes for the various dry-sand cores that enter into the construction of the mold. Foundation. The limits of this article prevent a detailed discus- sion of this subject; we will, therefore, confine ourselves mainly with FOUNDRY WORK 105 an explanation of the drawing, Fig. 123. The heavy building plate has a spindle opening somewhat to one side of its middle to be under the center of the cylinder. Upon this building plate the foundation of the mold is swept, carrying the seat for the cope ring, the bottom face of the flange, and the seat for the main cylinder core. The cope ring 1 is made wide enough on one side to carry that part of the mold forming the steam chest. The main c\linder core 2, the construction of which has already been explained, is next swept-up and lifted away, finished, and baked. Cajpe. Now the cope ring is seated, and the mold built and struck off for the bottom of the steam chest on a level with the bottom face of flange. Then the pattern may be set. Its position is accurately determined by the main cylinder print and the smaller prints of the steam chest which are bedded into the loam in accordance with measurements along a radial line marked off on the loam surface. With the pattern well oiled, the cope is built to the height of the upper flange of the cylinder; the entire back of the steam-chest core print being left open. The top of the steam chest is lifted off with the drawback 3, which joints at the middle of the upper steam nozzle, and carries that part of the mold to the level of the main cope joint. The two steam nozzles and the exhaust nozzle may be made with separate cores as explained in D, Fig. 122. By using the drawback, the entire top of the chest core print is left open for convenience in setting the chest and port cores. The top of the cylinder is jacketed, and through it pass the stufBng-box and manhole openings. The flanges of these two open- ings connect and in the pattern are left loose. The whole top surface is so irregular that it requires three levels of sticker plates to mold it, aside from two small cover plates over flanges. Covers. To the main cover 4 4 4 4 ^^'ith its various lengths of fingers, is bolted a crab 5 5 5 to carry the loam below the flanges of the stuffing box and manhole; and below this again are hung the dry-sand cores, 8 8 8, forming the jacketed part of the cylinder head. On top of the main co\'er is fastened a separate plate, 6, to shape the top of the upper steam inlet. And at 7 a \A:\\c w itii wrought-iron bars cast along its edge carries the loam back of the steam-chest flange. The small co\cr plates, 9 and 10, allow the flanges to be drawn for the parts which they mold. 106 FOUNDRY WORK The pattern is made in many parts so as to properly draw from the mold. When this has been done, all mold surfaces are carefully blackened and slicked before baking. Coring. W^hile the mold proper is being built, the dry-sand cores should be made up by the core makers, with the necessary rods, hangers, vent cinders, etc., as described under Core Making. The manhole core, 11, is made with a stop-off piece in the box to give the proper angle at the bottom of the core. It is hung to the cover and clears the main core by | inch. The stuffing-box core rests in a print in the main cylinder core, and is held by a taper print in the cover plate 10. The jacket cores are hung as shown. The openings made in the loam above the crab, to allow the hook bolts to be drawn up tight, are stopped off with green sand as previously described. The inlet cores 12 12, the exhaust core, 13, and the lightening cores, 14 14 ^4} are all bolted directly through the steam-chest core, 15, to horizon- tal bars which are long enough to bear against the sides of the mold at the back. The upper inlet core, 12, is kept from lifting under the pouring strain by being bolted to the body of the main cylinder core. Stud chaplets are also set between the inlet and exhaust cores to ensure correct thickness of metal at these points. Venting. The vent is taken off from the main cylinder core through the stuffing-box core at the top. Sometimes a small ladle- ful of metal is poured through this opening, when the piece is being poured, to ensure lighting these gases. The vent for the series of port cores is taken off by ramming a cinder bed up the entire back of the steam-chest core, allowing the gases to escape at the top. For safety, also, vents are taken from the bottom of the port and chest cores by the usual pipe vent. Pouring. The provision for pouring this mold requires especial attention. Notice the construction of the main basin, 16. The long runner 17, leading to the bottom gate, is left open on one side when the mold is built, so that it may be easily finished and kept free from dirt. Its open side is closed by cover cores when the mold is rammed up. Ten or twelve small gates like 18 are connected with the pouring basin, by semicircular channels, but are so placed that no metal shall fall on a core. With the basin arranged as shown, the FOUNDRY WORK 107 bottom part of the mold is first flooded with iron. When this has been done, the metal is poured in faster, so that hot iron is well distributed around the shell of the casting through the small top gates. Should the mold be poured at first from these top gates, the fall of the iron through the full height of the cylinder to the lower flange might result in cutting the loam on that surface. Molds of this size are usually rammed in a pit so as to bring the pouring basin conveniently near the floor. The portion above the floor level is, of course, rammed inside a casing, as described in the previous example. To guard against uneven cooling strains in this intricate casting, the clamping pressure on the mold is relieved when the metal has solidified, but the sand is not removed from around the brickw^ork for several days. This allows very gradual even cooling. It will be noticed that the piston does not work directly upon the inner walls of this type of cylinder. A separate hollow shell or lining is cast of strong tough iron. This has outside annular ribs at top and bottom and middle, which are turned to fit correspondingly pro- jecting ribs seen on the inside of the casting just under consideration. An air space is thus left between the lining and main casting which forms a jacket around the bore of the cylinder. a. O ^ « ^ O I '^ S Eu =■ FOUNDRY WORK PART II CASTING OPERATIONS MELTING General Characteristics. The subject of melting the metal which is to be poured into molds is one of the most important con- siderations in the foundry. It is also one which has received much attention in the last few years, the endeavor being to get away from the old rule-of-thumb methods and to arrive in the iron foundry at something near the precision in resulting metal that is already attained in the brass shops or the steel foundry. The heat for all melting is obtained from practically the same two chemical elements — carbon, and oxygen — carbon coming from the fuel, be it coal, coke, oil, or gas; and oxygen coming from the air of the blast. The design of the furnace, the kind of fuel used, and the applica- tion of the blast vary in accordance with the peculiar properties of the different metals and the degree of heat required to melt them. The melting of steel, copper alloys, and malleable cast iron will be dealt with under separate headings. We shall now consider only the melting of gray foundry irons. CUPOLA FURNACE Furnace Parts. Foundry iron is melted in direct contact with the fuel in a cupola furnace. The name was derived from the resem- blance of the furnace to the cupola formerly very common on the top of dwelling houses. Bottom. The cupola consists of a circular shell of boiler plate, lined with a double thickness of fire brick and resting on a square bedplate, with a central opening the size of the inside of the lining. This bottom is supported some 3| feet above a solid foundation, on four cast-iron legs. The bottom opening may be closed by cast-iron doors, which swing up into position, and are held so by an upright Fig. 124. Section Through Modern Cupola Furnace FOUNDRY WORK 111 iron bar placed centrally under them. These doors, protected by a sand bed, support the charge during the heat, and drop it out of the furnace when all the iron has been melted. The legs curve outward and the doors are hinged as far back as possible to protect them as much as can be from the heat of this "drop". Breast. At one side, level with the bottom, is the breast opening, at which place the fire is lighted, and in which the tap hole is formed for drawing off the melted metal. The spout, protected by a fire-sand mixture, projects in front of the breast and guides the metal into the ladles. Slag Hole. On cupolas over 36 inches inside of the lining, a slag hole is provided, which is similar to the tap hole, and is placed opposite the spout and about 2 inches lower than the main tuyeres. Fig. 124 shows a section through a modern cupola furnace, and needs but little further explanation. Lining. In lining the stack, the layer next the shell is usually made of boiler-arch brick about the size of regular fire brick. These are set on end, and should be fitted as tightly together as possible, and laid in a thin fire cement, made of very refractory fire clay and fine sharp silica sand. The object is to fill every crevice with a highly refractory material. Specially made curved fire brick can be purchased for the inside lining, although some foundrymen use tlie arch brick for this lining as well. The lining over the tuyeres is shaped to overhang them slightly, to prevent-melted slag dropping into them during the heat. The lining burns out quickest about 22 inches above the tuyeres, at what is practically the melting zone. The angle shelves riveted to the shell, as seen in the illustration, allow this section of the lining to be renewed without disturbing the rest of the stack. Tuyeres. The oblong air inlets, called tuyeres, are placed about 12 inches above the bed, and connect with an air-tight wind box which surrounds the outside of the stack near the base. The tuyeres direct the blast into the fuel, increasing the heat sufficiently to melt the charge. In the wind box, opposite each tuyere, is an air-tiulit sliding gate with a peephole, which allows the inciter to look directly into the furnace. In the larger cupolas a second set of tuyeres is arranged ahout 10 inches above the main ones. They are ustd, \\\\v\\ loim luats are 112 FOUNDRY WORK TABLE III Sizes of Cupola Furnaces Diameter Inside op Lining (inches) Cupola Height (feet) Charging Door Size (inches) Melting Capacity tPer Hour (tons) Per Heat (tons) 18 20 24 30 40 50 ,60 6 to 7 7 to 8 8 to 9 9 to 12 12 to 15 15 to 18 16 to 20 15 by 18 18 by 20 20 by 24 24 by 24 30 by 36 30 by 40 30 by 45 ito f i to 1 1 to 2 2 to 5 4 to 8 6 to 14 8 to 16 1 to 2 2 to 3 3 to 5 4 to 10 8 to 20 15 to 40 25 to 60 run off, to make up for loss of wind caused by the main tuyeres becoming partially choked by slag. The height of the tuyeres above the bed varies with the class of work to be poured. Where the metal is tapped and kept running continuously and is taken away by hand ladles, as in stove-plate work, the tuyeres are as low as 8 inches or 10 inches above the bed; while in shops where several tons of metal may be required to fill one mold, the tuyeres are as high as 18 inches above the bed. The height of the spout above the molding floor also varies in the same way; for hand-ladle work it may be but 18 inches above the floor, while a height of 5 or 6 feet may be required to serve the largest crane ladles. Charging. Several feet above the bottom, there is a door in the side of the stack, through which the stock is charged into the furnace. A platform or scaffold is constructed at a convenient level below the charging door, and all stock is charged into the cupola from this platform. It should be at least large enough to store the stock for the first two charges of fuel and iron. Table III, prepared by Dr. Edwin Kirk, gives the approximate height and size of charging door and the practical melting capacity of cupolas of different diameters. Blast. Fan Blower. Blast for the cupola is furnished by either a fan blower or a pressure blower. Fig. 125 shows a modern fan blower, of which the blast wheel is detailed at A. The high speed of the blades forces the air, by centrifugal action, away from the center of the shaft. The casing is so designed that the blades cut FOUNDRY WORK 113 TABLE IV Fan=Blower Performance Fan Diameter (inches) Speed (revolutions per minute) Wind Pressure (ounces per square inch) 18 24 36 48 4100 3750 2900 2600 5 6 10 14 off, as it were, at the top of the mam outlet, the air being thus forced through the blast pipe. The current of air is continually being drawn into the fan through the central opening around the shaft. Since air is very elastic, and the pressure in this case depends entirely upon the centrifugal action of the blades, should the tuyeres Fig. 125. Typical Fan Blower become clogged, the amount of air forced into tlie furnace will be reduced proportionately. On the other hand, it rccjuires less ])ow(T to operate the fan with reduced area of outlet tliau it does wlien the discharge is open free. An idea of the speeds at which blowers sliimld run iii.iy be obtained from Table IV. Pressure Bluicer. In the pressure blower shown in V\ii,. 12(), the action is positive, as will be seen from lhc sectional \ icw J, 114 FOUNDRY WORK Fig. 126. The wipers mesh into each other in such a way that they entrap a cjuantity of air and force it out of the opening. The full quantity of air is therefore forced through the tuyeres at all times. In such case, the power necessary to operate the blower increases as the tuyeres become choked, and the excessive force of the blast, due to choked tuyeres, is hard on the lining of the cupola. Gage. The cupola should have a blast gage attached to the wind box to measure the pressure of air which enters the tuyeres. The Fig. 126. Motor-Driven Pressure Blower pressure should be sufficient to force the air into the middle of the cupola to insure complete combustion. The unit of air pressure is 1 ounce. From 8 to 16 ounces is approximately the range usual in cupolas of from 48 inches to 70 inches diameter, inside lining. This pressure is measured by the displacement of water or mer- cury in a U-shaped tube. With both legs of the tube the same size, as in A, Fig. 127, the graduations represent the pressure of double that height of liquid. Such graduations would be as follows: FOUNDRY WORK 115 With a water gage, a difference in levels of 1.73 inches corre- sponds to 1 ounce wind pressure, so that the scale graduations per ounce would be spaced 1.735 ^^^ 55 7 . 1 . With mercury, a difference in levels of 0.127 inch corresponds to a pressure of 1 ounce so that the scale graduations would be spaced 0.127 _„_. 1 . — -— = . 0635 m. = — m. 2 lb As this last spacing would be too small for practical use, mercury gages, as at B, Fig. 127, are made with an increased area exposed to the blast pressure, and are graduated accordingly. Principles of Melting. Combus- tion cannot take place without oxy- gen, of which the air is the most abundant source of supply. For example, in the incandescent electric light, a strip of carbon is heated to a white heat, but it does not consume, or burn up, because all air has been exhausted from within the globe. In the cupola furnace, both coal and coke are used as fuel. They con- sist largely of carbon, and, after being lighted by the kindlings, are kept at a glowing red heat by the natural draft through the open tuyeres. The blast supplies the oxygen necessary for a melting heat. The quantity of air forced in by the blast cannot be entirely taken up by the layers of fuel immediately above the tuyeres ; thus, complete combustion does not take place until a distance of 18 to 23 inches above the tuyeres is reached. This is termed the melting zone. It is the aim of the melter to keep the top of his bed as nearly as possible at this level, so that the iron resting on it shall be exposed to this intense heat and melt rapidly. As the fuel of Fig. 127. Wind Gages 116 FOUNDRY WORK the bed burns away, this level tends to be lowered. But the iron on top of it melts and drops to the bottom of the cupola; and the subsequent charge of coke restores the level of the bed for the next charge of iron; and so on. Cupola Operation Running a Heat. The following routine must be pursued each time a heat is run off in the cupola : (1) Clear away the dump from the former heat. (2) Chip out the mside of the furnace with a special hand pick, removing the lumps of slag which collect about the lower part of the cupola walls, especially above the tuyeres. Where the slag coating is comparatively smooth, do not touch it, as that is the best coating possible for the lining. (3) Dauh up with a mixture of fire sand, held together with about 1 : 4 fire clay, and, wet with clay, wash to a consistency of thick mortar. Smear the surface to be repaired with clay wash; then, using the hands, plaster the daubing mixture into the broken spots in the lining, being careful to rub it in well, especially about the tuyeres. The top of the tuyeres should be kept slightly overhanging. The greater part of the daubing will be required from the bottom to the level of melting zone, about 22 inches above tuyeres. (4) S'wing up the bottom doors, and support them by a prop of gas pipe. (5) Build the bottom; first cover the doors with a 1-inch layer of gangway sand or fine cinders; then ram in burnt sand tempered about the same as for molds. This must be rammed evenly all over the bottom, and especially firm around the edges. The bottom should be made flat and level from side to side, with only a slight rise around the lining which should not extend more than 1 or 2 inches from the lining. The pitch varies with size of cupola; 1 inch to the foot will answer for cupolas of 24 inches to 30 inches diameter inside lining, while one-half that pitch will do for the larger furnaces. The cupola bottom should be able to vent so that it will dry out quickly, and not cause the metal to boil before the furnace is tapped. It should be strong enough to hold its surface diu-ing the heat, but to break and drop at once when the bottom is dropped. Too much pitch causes excess of pressure on the bott, making trouble in botting FOUNDRY WORK 117 up; with too little pitch the metal will not drain -well, causing a tendency to chill at the tap hole. A little daubing mixture should be worked into the sand bottom just inside the tap hole, to prevent breaking at this point when the tapping bar is forced through. (6) Lay the fire with shavings first, just inside the breast; then with fine kindling; then with enough large khidluig to make sure of lighting a layer of coke sufficient to form the bed. When the gases from the lower part of the bed burn up through, showing that the fuel is well lighted, level up the bed with the addition of a little more coke. (7) The first charge of iron should be put on now. Follow this with alternate charges of fuel and iron, to the level of charging door. (8) Form the tap hole; lay a bar of iron about | inch round in the spout, projecting in through the breast opening; fill in the breast around the bar with a strong loamy molding sand rammed hard. Recess this in well to leave the actual tap hole as short as possible. (9) Put on the blast when ready for the metal, and leave the tap hole open. Bott up when the metal begins to run freely — generally about 7 min-' utes after blast is on. Bott clay should be mixed with about | sawdust, to make it more fragile when tapping, and is made up in small balls, and shaped onto the end of the bott stick A, Fig. 128. (10) Tap when sufficient metal has collected to supply the first ladles. The tapping bar B, Fig. 128, has simply a round taper point; C is a gouge or spoon-shape, useful for trinuning sides of hole if the bott does not entirely free itself when tapped. (1 1) Drop the bottom, when all the iron has been melted and nui off. This is done by pulling away the bar that supports the bottom Fig. 128. Tapping Bars 118 FOUNDRY WORK TABLE V Foundry=Ladle Data Hand Ladle Bull Ladle Crane Ladle Geared Ladle Illustration Fig. 129 A Fig. 129 B, C Like C, with bail Fig. 130 Control Hand shank Single or double hand shank Bail with single or double hand shank Worm gear on heavy bail Capacity (pounds) 30 50 80 350 300 2,000 1,000 35,000 Weight (pounds) 15 16 35 100 115 350 1,900 7,000 Dimensions (inches) Top Side Bottom Inside Shell Lining Thick- ness Inside Shell Lining Thick- ness Inside Shell Lining Thick- ness Inside Shell Lining Thick- ness 7 to 8 3 4 9 to 15 U 14 to 26 If 20 to 75 2 to 4 7 to 8 1 2 9 to 15 i tof 14 to 26 f to 1 20 to 60 lto4| 6 to 7 |to| 8 to 13 1 to 1 12 to 23 1 to 3 18 to 66 lito doors. Throw water on the dump by bucket or hose, to deaden the heat, and leave it to cool off over night. Foundry Ladles. As the melted metal flows from the spout of the cupola, it is caught in ladles. The sizes of these are designated by the weight of metal they will hold; they vary from 30 pounds to 20 tons capacity. Table V, containing references to Figs. 129 and 130, give compact data regarding foundry ladles. The names of ladles relate to the method of carrying them. Hand ladles are made of cast iron or pressed steel. The larger ladles are built up of boiler plate. Cast iron is poured from the top of the ladle, which should therefore be provided w^ith lips. Lining. Ladles must be lined to protect them from burning through. ITp to 1-ton capacity, the cupola daubing mixture is used. The bowl is smeared with thick clay wash, and the clay pressed in hard wdth the hands, being rubbed smooth on the inside. The lining should be kept as thin as possible, f to f inch on hand ladles, 1 inch to 1^ inches on large ones; the bottom lining being from FOUNDRY WORK 119 one-third to one-half thicker than sides, as it receives the hrst fall of the incoming metal. The larger ladles are first lined with fire brick of thickness pro- portionate to their size, and then daubed on the inside with clay mixture similar to cupola lining. The lining must be well dried before use, to drive out moisture. In stove-plate and hardware shops, where most of the pouring is done with hand ladles, a special ladle drying stove similar to a shallow core oven is provided. A wood fire is built inside of the larger ladles to dry them out. To preserve a lining as long as possible, slight breaks are repaired daily. As with the cupola, the slag formed by the hot metal forms the best coating possible for the inside lining. Pouring. The first thing to be considered in connection with pouring is skimming off the slag which collects on top of the metal. This should be done on the larger ladles before leaving cupola, and again while metal is being poured. For this, a long iron rod is used, with blade shaped as in Z), Fig. 128. This is rested across the top of the ladle near the lip, and effectively holds the slag back; the long handle permits the skimmer to stand well back from the heat of the metal. On small ladles, skimmers are of course shorter, and the end is bent up more, for convenience, as the ladles will be much nearer the floor when pouring with them. Hand and bull ladles are shown in Fig. 129, while Fig. 130 shows a crane ladle. General Precautions. Much skill is required in pouring a mold. A molder must know the character of the work, and judge wlietlier it must be poured fast or slowly. In general, light work cannot be poured too fast. Heavier work is poured more slowly. Care must be exercised to keep the stream steady from the first, and not to spill into the mold, as this may cause cold-slnits or leave sliot iron in the castings. The runner basin must be kept full, for gates and runners are made with this express purpose in view, as has been stated previously. Fig. 129. Hand and Bull Ladlea 120 FOUNDRY WORK Metal must not be allowed to chill or freeze in the ladle, as this would destroy the lining when it came to removing the cold metal. Metal left in the ladles when the mold is full, must be poured back into a larger ladle or emptied into a convenient pig bed. These latter are built in a sand bed usually near the cupola; or stout cast-iron pig troughs or chills are provided. The chills should taper well on the inside, holding about 60 pounds each. Some are arranged to swing on trunnions for convenience in dumping. They should be smeared with a heavy oil and dusted with graphite, to prevent the metal »tick- Fig. 130. Crane Ladle ing in them. ' It is safer to heat these pig molds as well, so that no moisture will form and cause a kick or explosion when hot metal is first poured into them. Cupola Mixtures Requirements. By the term cupola mixture is meant the propor- tioning of the various pig irons and the scrap that make up cupola charges, with the object of obtaining definite physical and chemical properties in the resulting castings. The requirements of castings vary; and metal that would be good if run into thin stove plate, would be entirely too soft for heavy machine castings. Again, iron that might answer all requirements of a bed plate would not be strong and tough enough for steam-cylinder FOUNDRY WORK 121 work. The one in charge of this work, therefore, must so mix the different irons that his castings shall be soft enough to machine well if necessary, and at the same time be hard enough to stand the wear and tear of use. Precision Essential. Formerly the appearance of the fracture of a pig or of scrap was the sole guide in determining mixtures. Unques- tionably the fracture of iron indicates to the experienced eye much as to its physical properties, but this method of mixing has repeatedly proved misleading. Representative practice today recognizes chemical analysis of the various irons as most essential to the proper mixing. Many firms now buy their pig iron and many other allied supplies by specification; and the chemical analysis of the iron must show that its various metalloids come within certain limited per cents. To understand, then, these modern methods, we must consider the subject of the chemistry of iron. Affecting Elements. By the chemical definition, an element is a form of matter which cannot be decomposed, or, in other words, cannot be broken up into other forms by any means known to science. Iron is such an element; but absolutely pure iron is of no com- mercial value; it is only when it is combined with impurities — or, as we must recognize them, other chemical elements — that mankind is interested in it. In the forms of iron with which we are dealing — pig iron, and cast iron — five elements are considered as affecting their pliysical properties. These elements are carbon, silicon, sulphur, phosphorus, and manganese. Carbon. Carbon is the most important and most abundant of all the chemical elements. It forms the principal part of many substances in daily use about us, such as coal, coke, lead pencils, graphite facings, etc. In its relation to iron, carbon is peculiar in that it occurs in iron in two forms. One is in a chemical combination forming a hard substance with a fine grain, of which tool steel is the purest type. The other is simply a mechanical mixture forming minute facets of free carbon interposed between the crystals of the combined form. It softens cast iron, but weakens it by causing larger crystals to form. In drawing the finger across a freshly cut surface or fracture of cast 122 FOUNDRY WORK iron, some of this free carbon may be rubbed off, and shows as dirt on the finger. We shall use the term graphite in referring to this form of free carbon, and the term combined carbon in referring to the element in its combined state. Silicon. Silicon, of itself, is a hardening element in cast iron, but on account of its marked influence upon carbon formations, it is usually considered a softener. During the cooling process, silicon retards the formation of combined carbon, thus increasing the forma- tion of graphite in proportion to the increase of silicon. At the same time, through its own influence on iron, it preserves the fine character of the grain, and so maintains the strength of the cast- ing. In other words, within certain limits, the addition of silicon softens castings without impairing their strength. It makes iron run more fluid, and reduces shrinkage. Silicon varies in castings from 1.50 to 2.50 per cent. Sulphur. Sulphur is the most injurious element in iron. It makes castings hard, red-short, and tends to the formation of blow- holes. At the melting temperature, iron absorbs sulphur from the fuel — a decided reason why foundry coke should be as free as possible from this element. Sulphur in castings should not exceed 0.07 per cent. Phosphorus. Phosphorus tends to make iron run very fluid when melted. It is a hardener. For machine castings it should not exceed 1 per cent. Manganese. Manganese strengthens, and, of itself, hardens iron. Chemists are beginning to consider its proportions more care- fully, in the belief that under certain conditions it acts as does silicon, softening the castings while retaining their strength. It is usual to keep it below 0.50 per cent. Factors of Quality. The strength of a casting and the finish which it is capable of taking are largely dependent upon its having a fine even grain. We have seen that the porportions between the com- bined carbon, the graphite, and the silicon have decided influence upon this condition. But the rate of cooling must also be taken into account. A thin casting cools rapidly, tends to increase the combined carbon, and, without the influence of silicon, would be hard and brittle. In a heavy casting, the metal stays liquid longer, more graphite is thrown of^, and the casting is naturally softer. There- FOUNDRY WORK 123 fore light work requires a larger proportion of silicon to counteract the effect of the rapid cooling than does larger work. Chemical Analysis. Modern practice makes daily analysis for the two carbons, for the silicon, and the sulphur, occasionally testing for the other elements to see that they are kept within their safe limits. Silicon, however, is used as the guide for regulating mixtures. ProportioTis of Silicon. The following shows good proportions of silicon for different classes of work : Casting Steam cylinders Medium heavy work (^-inch to 2-inch thickness) Light work (less than |-inch thickness) Silicon (per cent) 1.70 2.00 2.50 A more complete analysis of results to be aimed for is : Casting Elements (per cent) [Silicon Phosphorus Sulphur Manganese Automobile cylinders Corliss engine cylinders (IJ- to l|-inch thickness) 2.25 1.20 to 1.70 1.0 below 0.1 0.075 below 0.095 0.5 0.5 To calculate for any result, we must first know the analysis of the irons to be used in making the charge. We shall consider silicon as the guide. In keeping track of results, the proportion of silicon in the local scrap of an establishment can be accurately estimated. With miscellaneous machinery scrap, this is more difficult; the following, however, are safe estimates: Casting Silicon (per cent) Small thin scrap Large scrap ranges 2.0 to2.4 1.50 to 2.0 Method. The analysis of pig iron is made from drillings taken from a fresh fracture. Between the very fine grain about the chilled sides of the pig and the very coarse grain in the cfiitcr, a\erage-sized 124 FOUNDRY WORK crystals will be noticed in the fracture. It is h( re that the drillings for analysis should be made, as indicated in Fig. 131. About a |-inch flat drill is best to use, as it cuts a more uniform chip from the varying grades of pig than does a twist drill. To determine the analysis of a carload lot of pig iron, the following method is employed: Select ten pigs which will represent an average of the close, medium, and coarse-grained iron in the car. These pigs should be broken, and drillings taken from the fresh fracture. The drillings from these ten fractures are thoroughly mixed together, and about 2 ounces by weight, or a large tablespoonful by meas- ure, is sufficient for the chemical analysis. The result is taken as the average analysis of the carload. The smaller foundries who do not employ a chemist can get a good work- ing analysis of their iron from the fur- nace from which it is bought. Or, in many cases, sample drillings are sent to a practicing chemist. Usual Silicon and Sulphur. The proportions of silicon and sulphur contained in the ordinary grades of pig iron are approximately as follows : Fig. 131. Section of Pig Drilled for Analysis Grade of Pig Silicon (per cent) Sulphur (per cent) Ferrosilicon Silvery No. 1 foundry No. 2 foundry No. 3 foundry 7 to 12 3 to 5 2.50 to 2.90 1.95 to 2.40 1.40 to 1.90 0.03 0.03 0.03 0.04 0.05 Calculation of Mixture. When we have the analysis of our iron, we can proceed to calculate the mixture, bearing in mind that some of the silicon will be burned out of the iron during the heat. From 0.15 to 0.25 per cent is a fair estimate for this loss in cupolas ranging in size from 36 inches to 72 inches inside lining. This loss must be deducted from the final estimate. Illustratiw Examples. It is proposed to make a mixture for miscellaneous machinery castings which require about 2 per cent FOUNDRY WORK 125 of silicon, and we wish to use one-half scrap and three other irons, whose silicon contents are as follows: Grade of Iron Silicon (per cent) Silvery No. 1 foundry No. 2 foundry No. 3 foundry Scrap 4 2.65 2.22 1.75 2.00 The student should bear in mind that per cent means too or .01. To multiply a whole number by per cent, set the decimal point two places to the left in the percentage; thus 35 per cent of 5,000 = .35X5, 000 = 1,750. In multiplying per cent by per cent, set decimal points in the percentages one place to the left before multiplying, and the result is expressed as per cent; thus 25% of 35% = 2.5X3.5 = 8.75 per cent. Then we may have the following proportions of silicon, using the above irons: (B) (C) (D) 25% X2.65% =0.6625% 20% X2.22% = 0.4440% 5% X 1.75% = 0.0875% 50% X2.00% = 1.0000% (A) No. 1 No. 2 No. 3 Scrap Total silicon content Deduct for loss in heat = 2.194 % = 0.20 % Estimated silicon in result = 1.994 % Or, with No. 2 and silvery irons, we may have: (A) (B) (C) (D) No. 2 45%X2.22% =0.999 % Silvery 5%X4.00%=0.200 % Scrap 50% X2.00% = 1.000 % Total silicon content =2.199 % Deduct for loss in heat =0.17 % Estimated silicon in result =2.029 % In these examples, column (A) is the kind of iron; (B), per cent of this iron used in charge; (C), per cent of silicon in single grade of iron; (D), per cent of silicon to whole charge as supplied by each grade. One or more per cents in column {B) are usually 126 FOUNDRY WORK decided upon before beginning calculations, and then the others are varied until the desired silicon content is obtained. With this as a guide, it is a simple matter to find the actual weight for each grade, to make up any size of charge. For example, we wish to put 5,000 pounds on the bed and 3,000 pounds on other charges. Then, using the first mixture and the ratio 5:3 between the bed and the other charges, we have : From column (5) Bed Other charges No. 1 25% X 5,000 = 1,250 lb. 750 1b. No. 2 20%X5,000 = l,000 1b. 6001b. No. 3 5%X5,000= 2501b. 1501b. Scrap 50% X 5,000 = 2,500 lb. 1,5001b. Total iron 5,000 lb. 3,000 lb. Fuel. Both anthracite coal and foundry coke are used in the cupola. Coal, owing to its density, carries a heavier load than coke, but it requires greater blast pressure and does not melt as fast as coke. Foundry Coke. Coke, for foundry use, should be what is known as "72-hour" coke, as free as possible from dust and cinders. Coke is made up of a sponge-like coke structure which is almost pure fixed carbon, and an open cellular structure, which makes it especially valuable as a furnace fuel because it is so readily penetrated by the blast. A representative analysis of a strong 72-hour coke is as follows: Item Proportion (per cent) Moisture Volatile matter Fixed carbon Sulphur Ash 0.49 ^ 1.31 87.46 0.72 10.02 Cellular structure Coke structure 50.04 49.96 Heat units per pound 12,937 B.t.u. Specific gravity 1.89 Proportions of Charge. The proportions of the bed fuel, the first charge of iron, and the subsequent charges of fuel and iron vary FOUNDRY WORK 127 greatlj^ with the size and design of the cupola, the grade of fuel used, and the method of charging. To determine the right amount of fuel for the bed, the most practical thing to do is to cut and try, <'S])('cially with a new equipment. For 36- to 48-inch cupolas, averaging 22 inches above the tuyeres for the melting zone, with a 10-ounce blast to start, the best way to proceed is to chalk off this distance inside the cupola before daubing up. Then, from a ^-inch rod of iron, bend a shape like Fig. 132. The distance a equals the distance from the mark inside the cupola to about 4 inches above the bottom of the charging door. \Yhen the coke is well lighted, before charging the iron, level off the bed accord- ing to this gage. The safe practice is to have the bed too high. If the bed is too high, it is indicated by slow but hot metal; if the l^ed is too low, the metal is dull. After the first heat, the height may be adjusted until proper melting is obtained; then try always to work to the same height. The weight and character of the ^. _, „ ,^ * Fig. 132. Bed Gage coke charged on the bed should be carefully noted. The first charge of metal should be in the pro- portions of 2 pounds of metal to 1 of fuel; all others in the ratio of 10 of metal to 1 of fuel. Intermediate charges of coke should be just sufficient to preserve the upper level of the bed. The layer is usuall}^ about 6 inches thick; its weight should be carefully taken. The action of the furnace must be carefully watched, with the object of making it melt the iron charged as rapidly as possible and of bringing it down white hot. Also, the ratio of iron to fuel should be reduced as low as may be, without sacrificing either of these other objects. Supplementary Operations Sand Mixing. When a mold is poured, the intense heat of the iron burns out those properties in the sand which give it its bond, making it necessary that a certain ])r(i])()rti()u of new sand shall be mixed with the heap sand and used as facing, as has been exjjhuned in earlier paragraphs. The facing sand should be mixed ^** r-^ •"«*" Fig. 109. Oven Charged Fig. 170. Ash Pit. and Firing Doors air-tight. After this has been accomplished, the pots are placed in the oven either by a hand or by a power charging machine, as illustrated in Fig. 167. FOUNDRY WORK 165 Oven. The annealing oven is quite simple. The principle involved is the introduction of heat from some convenient point and its distribution in a uniform manner, and the introduction of as Fig, 171. Final Sorting of Castings Fig. 172. Shipping Room little air as possible. The combustion space should be no larger than necessary, the draft regulation perfect, and the bottom of the oven underlaid by a series of flues which allow the gases to circulate 166 FOUNDRY WORK before escaping into the stack, so there may be as little loss of heat as possible. Oil, gas, or coal may be used for fuel as best adapted to the locality. Fig. 168 shows the interior of an oven, while Fig. 169 shows the boxes in place. Fig. 170 is a side view of an oven showing the firing doors and the ash pits. Having placed the full number of "#:.r3?„ .- --■■--\ V"--"- '*' -V ««.-«"■ :^".,-=--=.^: I Fig. 173. Recording Pyrometer Courtesy of The Bristol Company, Waterbury, Connecticut boxes in the oven, the front is closed and the ovens are fired. As before stated this operation requires from 6 to 10 days from the time the fire is started until the oven has cooled sufficiently to allow the removal of the boxes. As the boxes are withdrawn from the oven and are taken to the floor of the annealing room, they are suspended from an overhead trolley, or by a crane, and the castings are removed by striking the FOUNDRY WORK 167 boxes several sharp blows with a medium-weight sledge hammer, the castings and scale falling upon the floor. The castings are now picked from the scale and it will be noted that there is some tendency for the scale to adhere to them. This may be removed by the ordinary rolling barrels, after which any gates or fins remaining should be ground off. The amount of labor required for this oper- ation depends upon how^ carefully the gates were moved while castings were in the hard. After a final inspection, the castings should be ready for shipment. Figs. 171 and 172 show the castings being sorted out and ready for shipment in the shipping room. Pyrometer. The use of the pyrometer in connection with the annealing furnace is almost obligatory. Fig. 173 shows a standard type of recording pyrometer. The pyrometer equipment is often placed in the office of the head executive of a local plant; it is pos- sible for him to plug into any two of his battery of annealing furnaces at any time during the day. Also, in the morning, there is recorded a true record of temperatures for the night before. As no operator knows whether his furnace is under observation or not, this system has the tendency to keep the men at all times alert. Finishing. The amount of finish given the castings varies with local conditions and class of castings produced. There are some classes of work where, by the use of leather scraps in the soft-rolling room, the work is so carefully cleaned and polished that the castings may be tinned or nickeled and sometimes gold- or silver-plated, making very beautiful work in which great strength is combined with cheapness of production. BRASS WORK ALLOYS Distinctions. Cast iron, cast steel, and malleable iron, which we have previously considered, are three forms of the same metal — iron. The difference in their physical characteristics is due solely to a variation in the proportions of certain elements or metaloids combined with the iron. The metals to be dealt with in this section arc termed aUoijs — that is, mixtures of two or more separate metals. The common alloys in use in the foundry, for casting various machine parts, are 168 FOUNDRY WORK made from combinations of copper, tin, and zinc, and are called brass, or bronze. Brass and Bronze. Although the term brass is held by some authorities to cover any of these combinations, the general classifica- tion accepts brass as an alloy of copper and zinc, and bronze as an alloy of copper and tin. In some sections the latter is spoken of as composition. Bronze has been used by man in all ages. Centuries before' the Christian Era the Egyptians employed it for making coin, armor, and weapons, as well as household utensils, and statuettes of their gods. Analyses of many of these ancient relics show the composition to be almost identical with the bronzes of the present day. Brass also was in use before the time of Christ, but unquestionably bronze was of earlier origin. Metals. A short discussion of the separate metals will help in understanding the properties of their allocs. Copper. Copper has a red color; it is hard, ductile, and very tough. It melts at about 2000 degrees F. ; but it is difficult to make castings of the pure metal. Copper does not rust as does iron, and is one of the best conductors of heat and electricity. For this reason it is largely used in sheet form as a sheathing metal, and in the form of wire or rods for electrical transmission. Casting copper is put on the market in ingots of special form weighing from 18 to 25 pounds each. Tin. Tin is a white lustrous metal, very malleable, but lacking tenacity. It may be reduced extremely thin by rolling, as is shown by tin foil. It melts at 450 degrees F. When a bar of tin is bent it will give a crackling sound known as the cry, which at once dis- tinguishes it from other metals such as solder, lead, etc., which have similar external appearance. It is put on the market in pigs weighing about 30 pounds and also in bars of about 1 pound each. Its cost is approximately 1| times that of copper and 5 times as much as zinc. Tin may be cast unalloyed, and is sometimes used to run pattern letters or small duplicate patterns cast in zinc chill molds. The addition of | to | by weight of lead gives a cheaper metal, however, and one that will run equally well. Tin mixed with copper gives greater fluidity, lower melting point, and greater strength, changing the color from red to bright FOUNDRY WORK 169 yellow. Serviceable alloys may contain as high as 20 per cent of tin. This gives a metal of golden yellow color, very hard, tough, and difficult to work. With larger percentages of tin the color shades to gray, the metal is hard, brittle, and has little strength, and has no value for engineering purposes. Zinc. Zinc has a bluish white color; it is hard, but weak and brittle. The fracture shows very large crystals of characteristic shape. It melts at about 700 degrees F,, and shrinks but little in cooling. For this reason it may be used to cast directly for small metal patterns to form chills from which soft-metal castings may be made for duplicating these patterns. If exposed to the air at high temperatures, zinc will volatilize, that is, turn to a gas and burn. It burns with a bluish flame, and throws off clouds of dense white smoke. For this reason great care must be used to keep the air away from it as much as possible when being melted or mixed in an alloy, for, aside from the loss of metal, an oxide is formed in the mixture which impairs the quality of the alloy. Zinc is known Jn commerce under two names: when rolled into sheets it is called zinc; when in ingot form for casting, it is called spelter. These ingots are flat, approximately. 8 by 1 by 17 inches, and weigh about 30 pounds. In this form they may be easil}^ broken in small pieces for convenience in charging. Zinc may be added to copper in a very wide range of proportions, the alloy increasing in hardness and losing ductility with the increase in the proportion of zinc. The color changes from the red of the cop- per to a full yellow when j zinc is used. Further additions of zinc change the color to red, yellow, violet, and gray. The alloys are serviceable up to 40 or 50 per cent of zinc. When zinc is mixed with melted metal, considerable reaction or boiling takes place, which tends to make a more thorough mixture and to drive impurities to the surface. For this reason a small pro- portion of zinc — 2 or 3 per cent — is often stirred into bronze mixtures after the pot is drawn. Lead. Lead has a bluish white color, and considerable luster when freshly cut. It is malleable, soft, and tough, but very weak. It melts at about 600 degrees F. Lead is not used by itself as an alloy with copper. A vcr>- small proportion may be added to the standard mixture for brass or bronze. 170 FOUNDRY WORK TABLE VI Proportions of Mixtures Copper Tin Zinc Lead Use /per \ Vcent J (ounce) \ cent/ (ounce) /per \ Vcent / (ounce) /perN \ cent/ (ounce) Gun metal — for bearings; very tough hard mix- ture 83 16 12 2^ 2.5 1 2 2,5 \ 2 Steam or valve metal — cuts freely; very tough; resists corrosion 85 16 7 li 5 3 4 3 1 2 Composition metal — for general use on small machine parts 90 16 5 1 5 1 2 Art bronze — rich color; runs fluid at compara- tively low heat 90 16 6 1 2 1 2 1 1 4 Common yellow brass — for general run of ma- chine castings 66.5 16 33.5 8 Brass — to machine easier than the above; for same purposes 66 16 33 8 1 1 2 Antifriction metal — f o r journal boxes 1.8 1 64.7 32 33.35 16 1 1 2 Mixture — for small pat- terns; runs well; shrinks little 66 2 34 1 It will cause them to run more fluidly in pouring, and be softer for machining. For this reason, lead is added to bearing mixtures to advantage. But it tends to deaden the color and reduce the conduc- tivity of the metal for electrical purposes. Mixtures. General Proportions. The percentages given in Table VI are for convenience in comparison and for figuring large heats. The beginner, however, will generally melt but 1 or 2 pigs of copper at one time. These he will weigh first, and then figure the other portions of his mixture from this weight. In this case a formula given in pounds and ounces is much simpler. Variation. From what has been said, it is understood that it is possible to vary these mixtures to meet special conditions. To harden or toughen an alloy, increase the tin ; to soften it, reduce the tin. The same is true with zinc, but it will require larger proportion- ate changes in this metal to effect similar results in the alloy. Phosphorus. Phosphorus is not a metal, but is a very active chemical element manufactured from bone ash. It has such an FOUNDRY WORK TABLE VII Phosphor=Bronze Mixtures 171 Element Proportions of Alloy Hard Tough ;per cent) (pounds) (per cent) (pounds) Copper Tin Phosphorus Phosphor tin 87.5 12.25 0.25 81 3 4 1 5 90. 9.75 .25 9 1 '2 i Total 100. 10 100. 10 affinity for the oxygen of the air, that in its pure state it must be kept under water, because the shghtest scratch would cause it to burn fiercely. It forms the principal substance used in making the heads of matches. As a rule it is never used in the foundry in its pure state. For the production of phosphor-bronze castings there are several combined forms of phosphorus on the market. The most convenient of these is known as phosphor tin, which is metallic tin carrying various fixed percentages of phosphorus, of which 5 per cent is one very common proportion. Knowing the amount of phosphorus carried by the tin, the exact proportion for the entire alloy may be readily calculated. This element should not be used in alloys containing zinc or lead. Phosphorus acts as a flux, combining with any oxidized or burned impurities in the bath of metal and driving them to the top. It tends to make the tin crystalline in form, in which condition it unites more firmly with the copper. It apparently unites chemically with copper, making that metal harder. The proportion of phosphorus should not exceed 0.75 per cent, while 0.25 to 0.40 per cent are safer proportions. Two typical mixtures, one using 5 per cent phosphor tin, are given in Table VII. PRODUCTION Molding Materials. Natural molding sands are used for brass work. They are usually finer than sands used in iron work, because 172 FOUNDRY WORK brass parts are generally small and often have fine detail which must be brought out very sharply in the mold. For this reason, also, the sands should have more alumina or bond than iron sands. This increase of bond is possible because the metals entering the mold are not as hot as iron would be, and therefore do not require as much vent, but they have a greater tendency to cut the mold. Fig. 174. A — Flask for Brass; iS — Screw Clamp For the general run of work the whole heap is kept in good con- dition by the frequent addition of new sand, but on large work a facing mixture is used similar to that of the iron foundry. Burnt sand, powdered charcoal, and partainol are all good parting materials; the last two are best on small work, as they make a cleaner joint. Since they make a good facing for the mold, they are not blown off of the patterns. ptw«»»a\Biii!i:iiiii ii iiiiiiiiiiiiiiiiiiiiiiiiiiiiiii :!iii!i!ii3iiii!;: llilililliMliiililililiiyiiii^iftiiiiililiy iliiil i iiiii ii ii a i lM ^ Fig. 175. Spill Trough Equipment. Tools. The brass molder uses practically the same kind of tools, such as shovels, sieves, rammers, and molder's tools generally, as already have been described. Flasks. Snap flasks may be used, but the pins, hinges, and catches must be kept in careful adjustment so that the parts of the mold shall register perfectly. The same is true of the larger bo>' flasks for floor work. FOUNDRY WORK 173 The most tj'pical brass flasks are of cast iron with accurately fitting round steel pins, as seen in Fig. 174 at A. They have holes on the joint at one end of tlie flask so that the mold may be set upright when pouring. This gives a decided additional pouring pressure with a minimum thickness of sand over the castings. Boards without cleats support the sand in the flask, and the whole is clamped, before setting on end, by means of some form of double-screw clamp similar to the illustration B, in Fig. 174. Fig. 176. Drying Stove Spill Trough. Great care is taken in the brass shop to save all the shot and spilled metal possible. To this end, when the molds are to be poured on end, they are leaned against a cast-iron spill trough such as shown in Fig. 175. There should be a 1-inch layer of sand over the bottom of this tray. The crucible is held over it when pouring the molds, thus making it possible to conveniently catch, any metal that is spilled. Drying Stove. For thin work the face of the molds are skin- dried to drive off the moisture before the metal enters the mold. Drying stoves, similar to that shown in Fig. 17G, are used for this purpose. When the mold is finished, the two halves are carefully 174 FOUNDRY WORK sprayed with a weak molasses water, and the flask is set on end on the wide platform with the face of the mold next to the stove. When sufficiently dry, the mold is closed and poured at once. Principles of Work. Size of Heat. Brass work deals, as a rule, with smaller quantities in every way than does iron work. The patterns are generally smaller, and the brass molder takes particular pride in making all his joints so neat that hardly a fin shows on his castings. The matter of catching the shot metal has been mentioned. Up to the time of the introduction of the oil-melting furnace, it was customary to heat a pot of metal for each molder. These heats were comparatively small, so that the molder would make up possibly 6 or 8 molds, then draw his pot and pour them, running in this way several heats in a day. Using the furnace, several heats are run each day, but a much larger quantity of metal is melted at each heat, so that the work of several molders is poured with exactly the same metal. Molds. A mold for brass should be rammed about the same as for iron. On name plates and thin work, after the initial facing of sifted sand has been properly tucked with the fingers, the fiask is filled heaping full of sand. Then by the aid of a rope hanging down from the ceiling, the molder springs up on top of the flask and packs the mold with his feet, the weight of his body giving the right degree of firmness to the sand. Stove-plate molders often pack their flasks in the same way. The main differences between making up molds for brass and those for iron are due to the three following causes: brass melts at a lower heat; it does not run as fluid as iron; it has about double the shrinkage of iron. For these reasons the sand may be somewhat less porous and still vent sufficiently, if risers are placed to allow for the escape of the air. On bench work the vent wire is not used. The runners for brass should be larger than for iron, and the gates, instead of being broad and shallow, should be more semicircular in section. Poi^ring molds on end gives the pressure necessary to force a more slug^i. h metal to take a sharp impression, and the heavy runners shown in the following examples serve to feed the casting as it shrinks. Forms of skimming gates, as explained in an earlier section, are used to good advantage when the work is of a very particular nature. FOUNDRY WORK 175 Cores for brass work are made up as previously described. To give a smoother surface on the small cores, about 3- molding sand is often mixed in with the beach sand of the stock mixture. Examples of Work. To illustrate more clearly some of the typical methods of brass work, let our first example be a thin flat plate with decoration in low relief on one side. Place the pattern face down, a little below the center of flask. Sift on facing through a No. 16 sieve, then tuck, fill, and pack, as previously described. Roll over and make a joint. Now cut a half section of the main runners and risers, but do not connect them with the mold at this stage. Dust on parting material from a bag, and ram the other half of the flask just hard enough to stand handling. Runner (Riser - zaBUA fmi^" '^ ■ {}\ ' V' ■ \ L f « J, " / -I I . ■■■■I ^ "- >—• r ' ' H i' A B Fig. 177. A— Mold for Thin Plate; fi— Mold for Heavy Plate Separate the flask; spray the face of the mold with weak molasses water, and dust on it from a bag some finely powdered pumice stone, or any fine strong sand, and over this a little parting dust. Now replace this half over the pattern, and re-ram to the required firm- ness, and again separate and this time draw the pattern. The impression of the runners and risers cut in the first half of the mold show as ridges on the second half packed, and serve as guides for cutting the runners to a full round section. 'Tonnect the gates in four places, as shown in A, Fig. 177. Skin-dry an^ mold and it is ready to close and pour. Dusting fine sand on the face of the mold, then reprinting, as it is termed, ensures a very smooth, perfect mold face. Where the mold is not skin-dried, flour is dusted over the face, allowed to st;ind 17G FOUNDRY WORK TABLE VIII Crucible Sizes r Number Measurements Outside Capacity Weight OP Water Holding Capacity (Liquid Measure) Height Diameter Top Bilge Bottom (gallon) (quart) (pint) (inches) (inches) (inches) (inches) (pounds) . 2 u If li 0000 3 21 2i 51 If 6 1 61 5i 6i 31 2.08 12 2 8 6f 9i 5 4.16 30 1 1 1 11 81 6i 11.5 1 60 3 14 lOf 111 8 25 1 90 4 151 m 121 9 33.3 300 12 2 22 161 171 12i 104. for a short time, and then blown oflf. This makes a good facing. Cutting the heavy runner over the top of the thin plate ensures a sufficient supply of clean hot metal to the gates under a large enough pressure to force the metal into every detail of the mold before it has time to chill. In B, Fig. 177, is shown the difference in construction of the gate when a heavier piece is cast with the flask setting horizontally. The gate proper is cut in the drag, but a good feeding head is cut out of the cope side to keep the metal in the riser liquid until the casting has solidified. Dwplication. For duplicating w^ork, the sand match, oil match, or follow board are used, the same as for iron work. Fig. 178 shows a typical set of castings run from the end and made from gated patterns set in an oil match. Steady pins are placed on the gates to facilitate a clean lift. Melting. Characteristics. All alloy metals, and especially zinc and tin, burn if exposed to the air while melting. To prevent this Fig. 178. Duplicated Gated Work FOUNDRY WORK 177 burning the brass melter endeavors to so control the draft in his furnace that all oxygen entering the gates combines with the fuel, and that the gases which may reach the metal shall contain no free oxygen. For this reason, the ordinary brass furnace is a natural- draft furnace, although a forced draft is often connected below the grates to make combustion independent of atmospheric conditions. The metal does not come in direct contact with the fuel, but is contained in fire-clay pots called crucibles, which are bedded in the fire. Hard coal or coke is used for fuel. These cruci- bles, Fig. 179, A, are manufactured from a very refra(;tory fire-clay mixture, and are strong and tough, even at a high temperature. They are lifted in and out of the furnace by the tongs shown at B, Fig. 179. For the larger sizes a crane is used for hoisting the pot. Crucibles are classed by number, as seen in Table VIII. New crucibles should always be annealed before using, that is, brought very slowly to a low red heat. Natural-Draft Furnace. Furnaces of this type are usually called brass furnaces, and may be bought on the market made up in single com- plete units. Fig. 180 illustrates one of a battery of several furnaces connecting with a common flue. The top is on a level with the molding floor. The sketch shows clearly the principles of construction. A cast-iron bottom plate A, with a circular opening, carries a shell of boiler plate lined with fire brick. The diameter inside the lining should be 6 inches larger than the crucible to be used. A top plate, with a similar opening, binds the whole together. On one side, below the top, the opening B, w^hich may be formed by a cast-iron box, connects with the flue or stack. Two heavy ribs cast on the bottom plate rest on a pair of rails as shown, and these rails are supported by suitable piers of brickwork about 2 feet high, so that ashes may be conveniently removed when the furnace is diunped. - B n Fig. 179. Crucible and Tongs 178 FOUNDRY WORK In the space made by the ribs, between the bottom plate and the rails, the grate bars C are set. These bars are loose and may be pulled out when it is desired to dump the fire for the day. Operation. Before starting the fire in preparing to run off a heat, a good plan is to use a half fire brick on which to rest the crucible, or the bottom of a worn-out crucible cut off to the height of 4 inches or 5 inches may be turned upside down and used for this purpose. Sufficient time and special care should be exercised in placing the metal in a crucible. It is more or less dangerous to jam in the charges, so particular care should be taken to see that they are placed Fig. 180. Natural-Draft Furnace in the crucible loosely. Graphite is the crucible's principal ingre- dient; the only expansion possible to a crucible comes from its clay body, hence, if the charges are wedged in a crucible and jammed to fit tight, their expansion, which is much greater than the expansion of the crucible, cracks the latter before the melting point is reached. The crucible should be kept covered, especially for brass. In melting brass, melt down the copper first, then the scrap. When this is melted, charge the zinc and stir well before lifting the pot. Allow the mixture to come to the proper heat again, then pull the pot, skim off the dross, and stir in the lead if any is called for, just before pouring. In bronze the same method is pursued, but both the FOUNDRY WORK 179 tin and zinc are stirred in after the pot is drawn. In mixing in the zinc in brass, care must be taken to plunge it well under the surface Fig. 181. Section through Oil Furnace of the copper with long handled pick-up tongs, and to hold the piece down with the stirring bar until it has melted. Where a large casting requires more metal than can be melted in a single crucible, several furnaces must be used and the contents of their various crucibles assembled into one large pouring ladle just before pouring. Fig. 182. General Views of Oil Furnace Gas or Oil Furnace. With the development of natural-gas and crude-oil burners for commercial heating, several good furnaces have been designed in which a large quantity of metal can be melted at 180 FOUNDRY WORK one time. Fig. 181 shows a furnace of this character in section. This type has tandem melting chambers with burners at the end, which may be used separately or both together. The waste gases from the Fig. 183. Sprue Trimmer Courtesy of Toledo Machine and Tool Company, Toledo, Ohio bath of liquid metal are used to heat up a fresh cnarge in the other chamber. The metal is charged and poured from the openings at the top of the furnace. Each chamber may be revolved separately, to FOUNDRY WORK 181 Fig. 1S4. Dipping Basket empty tlie furnace when the charge is melted. Fig. 182 shows the general arrangement of the oil feed pump and blower for these melting furnaces. The flame plan's directly on to the metal. The oil pressure should remain constant at about 5 pounds per sc[uare inch. But the air pressure is regulated to vary the intensity of the heat as desired. The pouring ladle must be well heated before us"ng. This is done with a special gas burner, or, when crucibles are used, they are often heated by means of a small fire in an ordinary furnace. Different sizes of furnaces are built to melt from 250 to 2000 pounds of metal at a heat. Twelve or fourteen heats a day can be run. The saving is approximately 50 per cent in time, and is also very considerable in expense, over ordinary crucible furnaces of equal capacity. Cleaning. When the castings are taken from the sand they should be rapped smartly to free all loose sand, then, if machining is to be done on them, they should be plunged, while hot, into water. This softens the castings. This method is used also to blow out cores from small w^ork. Since brass does not burn into the sand as much as iron, the small castings in many shops are brushed clean, before being cut from the gates, by means of a circular scratch brush mounted on a spindle sim- ilar to a polishing wheel. A sprue-trimmer, shown in Fig. 183, is part of the equipment of a brass foundry. These machines are made to operate by foot as shown, or by power. With them the castings are cut neatly and quickly from the runners. Pickling. A good method of cleaning brass and bronze is by pickling. JMake a mixture of 2 parts common nitric acid and 1 part Fig. 185. Maenotic Separator 182 FOUNDRY WORK sulphuric acid, in a stone jar. Place the piece to be cleaned in a stone dipping basket, Fig. 184, and dip once into the acid, then wash off in clean water, and dry in sawdust. Chip Separation. In many cases, brass chips and filings are turned back to the foundry to be remelted. The smallest portions of steel or iron in these would prevent their being used in this way, as they make extremely hard spots in the castings. Fig. 185 shows a magnetic separator which effectively removes all steel and iron chips. The brass chips and sweepings from the machine shop are placed in the hopper of this machine. They are caused to be spread out on one side of a slowly revolving brass covered drum. Inside of this brass shell are strong magnets which hold to their surfaces the steel and iron chips, while the brass chips drop off into a tote box. A stiff brush at the back of the cylinder removes the iron chips, and they drop into a separate box. SHOP MANAGEMENT PLANT ARRANGEMENT Governing Factors. The success of a foundry depends upon the ability of its managers to promptly turn out castings which meet the requirements demanded of them, at the lowest possible cost commensurate with the quality of the work. In this article we wish to direct the attention of students to some features in the way of equipment and management which aid in accomplishing these results. The most important processes in the foundry are the following : melting metal, making molds, and pouring them. Much of the work necessary in preparing for these processes consists in handling heavy materials such as coke, iron, sand, etc. To reduce this handling to its lowest limits, as to distances, number of re-handlings, and methods of conveyance, are problems to be considered in the plan of the shop as a whole. TYPICAL FOUNDRY General Plan. To briefly illustrate some of the points to be brought out, let us consider the plan of the shop shown in Fig. 186, and its sectional elevation shown in Fig. 187, FOUNDRY WORK 183 Building. The building is of steel construction, and the columns supporting the roof trusses serve also to carry the tracks for the overhead traveling cranes. The outer walls should be filled in with some good weather- resisting material, of which there is nothing better than brick. These walls should be of good height and have a sufficient window area to supply light well in toward the middle of the shop. Ventilation. The method of heating and ventilatmg best adapted for a foundry is the indirect fan system. One or more large Upper Level Storage Coke Bins Pig /ron Yard Fig. 186. Typical Plan of Foundry fans, situated generally toward the ends of the shop, draw fresh air in through a compact system of steam coils, and, by means of over- head piping, deliver it to all portions of the shop. The impure gases are carried off through ventilators in the clearstory at the top of the roof. Floor. The fioor of the foundry should consist of molding sand, the depth of the sand floor varying with the class of work to be done. If the natural soil of the grounds is open and porous, a thickness of 3 or 4 inches of clay, well rolled down, should be put in underneath 184 FOUNDRY WORK the sand floor. This will help greatly in keeping the molding floor in good condition, as it prevents the moisture draining out of the sand. Shop Office. The foundry office should be located at such a point that the foreman can command a view of the whole shop. It should be convenient to the different departments and at the same time be protected as far as possible from dust. The office room, shown in Fig. 186 at A, is built on the outside of the main building, but has a large bay window which projects a few feet into the shop from which all corners of the foundry can be seen. Pattern Room. A space B, having suitable low tables and shelv- ing, is reserved near the office for the temporary storing of patterns in daily use. This brings them directly under the attention of the foreman and his assistants who can readily check the patterns as they come in and quickly find those requiring prompt attention. Fig. 187. Tj'pical Elevation of Foundry Cupolas. At C are shown the cupolas, directly opposite the foreman's office, and so situated that all of the molding floors may be served as quickly as possible without interfering one with the other. In large foundries there are two or more cupolas, to admit of different mixtures being melted simultaneously. Often a compara- tively small cupola is installed near the floor for light work for the service of that floor alone. The blowers should be placed near the cupolas, avoiding long connecting wind pipes. The application of electric motors removes the necessity of concentrating the power at one point in the shop. Molding Divisions. Heavy Work. The main bay of the foundry is devoted to the heaviest work and is served by at least two overhead cranes. FOUNDRY WORK 185 The heavy green-sand castings are made at one end so that the flasks for this work may be stored in yards near by and be brought in through the door D. These molds are made up farthest from the cleaning shed, because only the castings themselves need be trans- ferred there. The flasks and rigging for the dry-sand and loam molds should be brought in through the opposite door E. The loam work, as a rule, is the most bulky to handle and should be nearest the cleaning p" /y/ Moulding Machines Fig. 188. Automatic Sand Mixer sheds so that it need not be carried across the other floors. ' Both dry-sand and loam floors are convenient to the large ovens ¥ . Core Shoj). The core shop is situated in the side bay at G, to make it convenient to swing the large cores on to the buggies to be run into the large ovens. A jib crane near the corner of tlicse o\ens makes the men working on such cores independent of the traveling crane. The ovens for small cores are built along the side of the large ovens and utilize the same stoke hole, ash pit, and stack. Light Work. Distributed through the side bays also are the medium-work floor II, the light-work floor /, and the mokling- machine floor J. This ensures a supply of good light necessary to the smaller details of this class of work. 186 FOUNDRY WORK Machines. The molding machines are placed on that side of the shop near the sand storage sheds, to allow for handling the sand by means of belt conveyors with hoppers above the machines, an illustration of which is shown in Fig. 188. The sand-mixing space is in the side bay near the cupolas at K, and is furnished with power from independent motors or from a jack shaft leading from the blower room. This position affords direct access to the sand bins. The raw material after being mixed and tempered is delivered by barrow or sand car direct to the] various floors. The mix- ers might be installed in one of the storage vaults across the roadway. Materials. Unloading. The quickest means of unloading either wagon or carload lots of material is by dumping, where the material can be so handled. One of two things is necessary to accomplish this: either the storage bins must be placed in a basement under- neath the roadbed; or the roadway must be run up an incline over the top of the bins. The former method is more frequently met with in the crowded condition of the large cities, but the latter is preferable because less time is consumed in running material up an incline in large quantities than is required to hoist small quantities more frequently from a basement. Storage. At L and L' , Figs. 186 and 187, are shown the storage yards for pig iron and coke; these are on a level with the charging platform of the cupola, C and C , and the materials can be loaded on cars and pushed directly to the charging door. In some modern shops these push cars are built so that their load may be dumped as a whole into the cupola. The storage for core-oven fuel, sands, and clay, is shown at MM, in bins built underneath the tracks and on a level with the foundry floor. These bins should be arranged to open on top, with a chute under the track and a trap at the side, so that coal or sand may either be dumped or shoveled directly into them. Handling Systems. Tracks. In the largest shops a standard- gage track should run directly through the main foundry, and there should be also similar tracks through the roadway next the cupola bay for convenience in removing the dump. The track over the storage bins has been mentioned. Two methods of transferring material between departments within the shop, aside from the cranes, are the overhead-trolley FOUNDRY WORK 187 system, Fig. 189, and the narrow-gage industrial railway. The former is of advantage in manufacturing plants where the loads to be transferred are nearly uniform in weight and frequency of hand- ling. This system leaves gangways smooth and free from obstruc- tions. For general work, however, the industrial railways are more frequently installed. These serve all floors to deliver flasks, sand, or iron, and to remove castings. Cranes. Of the many styles of overhead traveling cranes that are on the market, those using electricity as the motive power are undoubtedly the most serviceable. The cranes in the main foundry in- dicated at 0', Fig. 187, should have two hoisting drums on the carriage; one for such light work as handling flasks, rigging, and patterns; the other for the heavy work on the large ladles and castings. Small jib cranes fur- nished with a 2- to 4-ton air or electric hoist placed on the side of a man's floor make it possible for the molder and helper to han- dle work of considerable size by themselves, and prevent loss of time from waiting for the overhead crane. The method of distributing the melted metal varies with the class of work made. In shops doing general jobbing work, the ladles for pouring the largest work are carried from the cupola directly by the overhead cranes. Bay Floor. For serving the floors in the bays one of the systems mentioned above is generally used. The metal is conveyed to the floor in a large ladle and from this smaller ones are filled and carried by hand or by a small crane to the molds. Cleaning Department. The cleaning department should be situated at one end of the shop near E, Fig. 186, or in a shed extension Fig. 189. Overhead Track and Trolley 188 FOUNDRY WORK to the foundry proper. It requires space to pile the castings as they are brought from the floors with sufficient room for the men to begin work on these piles. As a rule, the smaller castings are first collected and put through the tumbling barrels, then the medium work is cleaned by hand or by sand blast; this leaves room for work around the largest pieces. As soon as castings are cleaned they are weighed and shipped to the customer, store house, or to the department which does the next operation upon them. PERFORMANCE LABOR Division. The division of labor in a foundry is briefly as follows : Superintendent. The superintendent is responsible for the operation of the foundry as a whole. He hires the men and oversees the purchase of materials and supplies, having under him clerks who keep track of the details of this work. Some of the things to which he gives personal attention are: In consultation with his foreman he gives personal attention to the receipt of the most important patterns; decides how they shall be molded; on what floor and with what mixture they shall be poured. He devises ways and means of increas- ing the productiveness of his shop. Foreman. The foreman or his assistants must be in the shop a sufficient time before work begins for the day to see that each molder has work laid out for him, and must keep the men supplied with work through the day. He estimates the amount of the charge for the day and directs the melter as to mixtures. It is the duty of the foreman and his assistants to give directions to the apprentice boys and to see that these directions are carried out to the best of the boys' ability. Molders. The molders should give their entire time to making up molds. On floor work they are usually given a helper who carries flasks, cores, chaplets, etc., and does the heavier work when handling the sand. When the molds are poured and his flasks stripped off the molder is through for the day. Laborers. Most modern shops employ a night gang of laborers to put the shop in proper shape for the molders to start their special work immediately when the whistle blows in the morning. These men remove the castings from the sand and transfer them to the FOUNDRY WORK 1S9 cleaning shed. They pick out all bars and gaggers used in the molds and stow them in place. They temper and cut the sand and dig any pits necessary for bedding in work. SAFETY FIRST Accident Prevention. While it may be an impossibility to wholly prevent accidents in and about the foundry, much has been accom- plished in that line. Mechanical safeguards are now in pretty general use in modern foundries. It is only the out-of-date shop which is conspicuous for neglect in providing them. Personal Factor. Only some of the more important items regard- ing safety are called to the reader's attention, and perhaps the most important one of all is to teach the workman to think safety first. As an example, in a foundry employing 850 men there were, during a period of 6 months, 57 accidents involving loss of time. Not one of these was due to the lack of mechanical safeguards; all were results of carelessness on the part of the injured, or of negligence by their fellow workmen. Clothing. A large percentage of accidents in the foundry are in the nature of burns from hot metal, and again by far the greater part of these are below the knee. This shows the practical necessity for a legging of some material which would resist the hot metal. All employes in the foundry who come in contact in any manner with the work of pouring, or of shaking out flasks after pouring, when the hot sand may be just as dangerous as the molten metal, should be compelled to wear the foundry or congress shoe. Shop Equipment. There should be frequent inspection of all foundry rigging, such as crane hooks, chains, and ladle shanks, also great care should be used under the cupola and tapping spout, as any excess of moisture, were molten metal to be spilled upon it, would cause explosions and probably seriously injure someone. In the cleaning room, protection for the eyes from flying chips of metal is important; so, also, are guards over grinding wheels which should be equipped with an efficient exhaust to care for dust. While there are many more things which miglit be mentioned regarding safety, as applied to foundry practice, those already men- tioned should be sufficient to cause the student to think safety, to put his thoughts in practice and to teach others to do likewise. 190 FOUNDRY WORK PHYSICAL RESULTS Checking. The methods of mixing iron by analysis have been previously dealt with, but these mixtures must be checked by physi- cal tests on the resulting castings. Two systems of checking are now in more or less general use throughout the United States. Keep's Mechanical Analysis. A very complete system of regu- lating mixtures, termed by the inventor Mechanical Analysis has been devised by W. J. Keep, of Detroit, Michigan, who has had long experience in this subject. In Fig. 190, A shows a follow board arranged with patterns and yokes. The test bars are | inch square and 12 inches long. They are cast in green sand with their ends chilled against the faces of the cast-iron yokes, shown in the cut. Three molds should be cast each heat, and the test bars allowed to cool in the molds. Silicon and Shrinkage. The analysis is based on the fact that silicon is the most important variable chemical element in cast iron. Fig. 190. A — -Keep's Test-Bar Pattern; B — Measuring Shrinkage and that shrinkage in castings is inversely proportionate to the silicon in the mixture. The first test, as shown at B, Fig. 190, is to replace each bar in the same yoke in which it was cast and by means of a specially graduated taper scale to ascertain accurately the amount of shrinkage. The shrinkage of the bars when the castings prove satisfactory, should be considered the standard for that class of work for that shop. If at any time the shrinkage is greater than the standard, increase the silicon by using more soft pig; if it is less, decrease silicon by using more scrap or cheaper iron. Chilled Depth. The depth of chill on the castings is measured after chipping off a piece from the end of the bar. Transverse Strength. The third test is to obtain the transverse strength of each bar. This is done on a special testing machine FOUNDRY WORK 191 4 ~ which gives a graphical record of the deflection and the ultimate breaking load. These dead loads will vary with different mixtures approximately from 340 to 500 pounds. Deductions. Quoting from Mr. Keep's circular: With high shrinkage and high strength of a §-inch square test bar, heavy castings will be strong but small castings may be brittle. With low shrinkage and high strength, large castings will be weak and small castings will be strong. With uniform shrinkage, an increase in the strength of a ^-inch square test bar will increase the strength of all castings proportionately. Arbitration=Bar Tests. The other form of tests was devised by a committee of the American Foundrymen's Association, and is recommended in the Proposed Standard Specifications for Gray-Iron Castings by the American Society for ~i ^ i Testing Materials. Test Bar. The test bar specified is 1| inches in diameter and 15 inches long, and is known as the arbitration bar. The tensile test is not recommended, but, if called for, a special threaded test piece is turned down from the arbitration bar, and has a test section 0.8 inch in diameter and 1 inch between shoulders. The transverse test is made with supports 12 inches apart. Fig. 191 shows a sketch of the patterns for these bars. Tv/o bars are rammed in a flask and poured on end. The small prints on the two bar patterns project into the cope and are connected by one pouring basin. A special green-sand mixture is specified for x_^/__ making these molds; the molds are to be baked before pouring, and the bars allowed to remain in the sand until cold. Specifications. Table IX shows the specified requirements; in this connection castings are distinguished as follows: Unless furnace iron is specified, all gray castings are understood to be made by the cupola process. Light castings are those having any section less than i inch. Heavy castings have no section less than 2 inches. Medium castings are those not included in the above. Fig. 191. Pat- tern for .\rbi- tratioa Bur 192 FOUNDRY WORK TABLE IX Arbitration=Bar Standards Gr.'^de of Castings Chemical Pbop- EKTIES Physical, Properties Sulphur Content High Limit (per cent) Transverse Test* Minimum Load (lb.) Tensile Strength Low Limit (lb. per eq. in.) Light Medium Heavy 0.08 0.10 0.12 2500 2900 3300 18,000 21,000 24,000 PRACTICAL DATA Using Percentage (1) To find the percentage of any number when the rate per cent is given : Multiply the number by the rate per cent and set the decimal point two places to the left. Example: Find 7.5 per cent of 35. 35x7.5 = 262.5; decimal point moved two places to the left gives Ans. 2.625 (2) To find what rate per cent one number is of another: Add two ciphers to the percentage and divide by the number on which the percentage is reckoned. Example: What per cent of 75 tons is 9 tons? 900-7-75 = 12. Ans. 12 per cent (3) To find a number when the rate per cent and the percentage are known: Add two ciphers to the percentage and divide by the rate per cent. Example: If 68 pounds is 15 per cent of the entire charge, how many pounds in the total charge? Ans. 6800 ^ 15 = 453.33 pounds (4) To find what number is a certain per cent more or less than a given number: (a) When the given number is more than the required number, add two ciphers to the number and divide by 100 plus the rate per cent. Example: 465 is 35 per cent more than what number? Ans. 46500^(100+35)135 = 344.4 ih) When the given number is less than the required number add two ciphers to the number and divide by 100 minus the rate per cent. *In no case, shall the deflection be under 0.10 of an inch. FOUNDRY WORK 193 Storage Data Square Box Measure Size (inches) 1 Capacity 24 X16 X28 16 Xl6fX 8 Six Six 4 4 X 4iX 4 1 barrel 1 bushel 1 gallon 1 quart Molding Material Weights Material Amount (cu. ft.) Weight (ton) River sand Pit sand Stiff clay 21 22 28 1 1 1 Example. 526 is 23 per cent less than what number? Ans. 52600^ (100-23) = 52600^77 = 683.116 Mensuration Circumference of a circle Area of a square or rectangle Area of a triangle Area of a circle Convex surface of a cylinder Convex surface of a sphere Contents of a rectangular solid ■■ Contents of a cylinder Contents of a sphere One side of square having same area as given circle = diameter X 3. 1416 = base side X height = base X 2 X perpendicular height = diameter squared X .7854 = circumference X height = circumference X diameter = area of base X height = area of base circle X height = cube of diameter X. 5236 ("diameter X. 8862 = \ or [circumference X .2821 Conversion Factors X 0.08333 X 0.00695 X 0.00058 X 0.004329 X1728 X 27 Inches Square inches Cubic inches Cubic inches Cubic feet Cubic yards U. S. gallons of water X 8 . 33 U. S. gallons of water X 231.00 Pounds of water X 27 . 72 Ounces of water X 1 • 735 = feet = sq. feet = cu. feet = U. S. gallons = cu. inches = cu. feet = pounds = cu. inches = cii. inches = cu. inches 194 FOUNDRY WORK Circular Areas and Circumferences H P -0 K <1 K En S P « H W a < H H 2; (a K » b S P s K m % ■< Q K < z a W S u « u < z « S K 6 1 0.0123 .3926 10 78.54 31.41 30 706.86 94.24 65 3318.3 204.2 1 0.0491 .7854 i 86.59 32.98 31 754.76 97.38 66 3421.2 207.3 1 0.1104 1.178 11 95.03 34.55 32 804.24 100.5 67 3525.6 210.4 2 0.1963 1.570 i 103.86 36.12 33 855.30 103.6 68 3631.6 213.6 1 0.3067 1.963 12 113.09 37.69 34 907.92 106.8 69 3739.2 216.7 i 0.4417 2.356 i 122.71 39.27 35 962.11 109.9 70 3848.4 219.9 1 0.6013 2.748 13 132.73 40.85 36 1017.8 113.0 71 3959.2 223.0 1 0.7854 3.141 1 143.13 42.41 37 1075.2 116.2 72 4071.5 226.1 i 0.9940 3.534 14^ 153.93 43.98 38 1134.1 119.3 73 4185.3 229.3 1 1.227 3.927 2 165.13 45.55 39 1194.5 122.5 74 4300.8 232.4 1 1.484 4.319 15^ 176.71 47.12 40 1256.6 125.6 75 4417.8 235.6 i 1.767 4.713 2 188.69 48.69 41 1320.2 128.8 76 4536.4 238.7 1 2.078 5.105 16 201.06 50.26 42 1385.4 131.9 77 4656.0 241.9 1 2.405 5.497 i 213.82 51.83 43 1452.2 135.0 78 4778.3 245.0 2.761 5.890 17 226.98 53.40 44 1520.5 138.2 79 4901.6 248.1 2 3.141 6.283 1 240.52 54.97 45 1590.4 141.3 80 5026.5 251.3 1 3.976 7.068 18' 254.46 56.54 46 1661.9 144.5 81 5153.0 254.4 1 4.908 7.854 1 268.80 58.11 47 1734.9 147.6 82 5281.0 257.6 i 5.939 8.639 19' 283.52 59.69 48 1809.5 150.7 83 5410.6 260.7 3* 7.068 9.424 i 298.64 61.26 49 1885.7 153.9 84 5541.7 263.8 i 8.295 10.21 20 314.16 62.83 50 1963.5 157.0 85 5674.5 267.0 i 9.621 10.99 § 330.06 64.40 51 2042.8 160.2 86 5808.8 270.1 a 11.044 11.78 21 346.36 65.97 52 2123.7 163.3 87 5944.6 273.3 4 12.566 12.56 2 363.05 67.54 53 2206.1 166.5 88 6082.1 276.4 1 15.904 14.13 22 380.13 69.11 54 2290.2 169.6 89 6221.1 270.6 5' 19.635 15.70 i 397.60 70.68 65 2375.8 172.7 90 6361.7 282.7 1 23.758 17.27 23' 415.47 72.25 56 2463.0 175.9 91 6503.8 285.8 e' 28.274 18.84 i 433.73 73.82 57 2551.7 179.0 92 6647.6 289.0 1 33.183 20.42 24 452.39 75.39 58 2642.0 182.2 93 6792.9 292.1 7' 38.484 21.99 1 471.43 76.96 59 2733.9 185.3 94 6939.7 295.3 i 44.178 23.56 25' 490.87 78.54 60 2827.4 188.4 95 7088.2 298.4 s 50.265 25.13 26 530.93 81.68 61 2922.4 191.6 96 7238.2 301.5 i 56.745 26.70 27 572.55 84.82 62 3019.0 194.7 97 7389.8 304.7 9 63.617 28.27 28 615.75 87.96 63 3117.2 197.9 98 7542.9 307.8 i 70.882 29.84 29 660.52 91.10 64 3216.9 201.0 99 7697.7 311.0 Weight Calculation Weight of round iron per foot = Diameter (quarter inches) squared X 0.1666 Weight of flat iron per foot = Width X thickness X 3 .333 " " =5 pounds for each | inch in thickness = Diameter squared X 10.7 (approximate) = Bar diameter (quarter inches) squared X 2000 To compute weight of metal from weight of pattern, with no allowance for cores or runners, multiply as follows: Weight of plates per sq. ft. Weight of chain Safe load (pounds) for chain Multiplication Factors White Pine Mahogany Result 16.7 10.7 Cast iron 18 12.2 Brass 23 15. Lead 15 9. Tin 16 10.4 Zinc Weight of brass pattern X . 9 = weight of iron casting, approximately. FOUNDRY WORK 195 Specific Gravities and Weights of Metals Material Specikic Gravitv Weight per Cubic Inch (pounds) Water, at 39.1° F. 1. .036 Aluminum 2.6 .094 Antimony, cast 6 . 64 to 6 . 74 6.7 .237 Bismuth 9.74 .352 Brass, cast 7 . 8 to 8.4 8.1 .30 Bronze- 8 . 4 to 8.6 8.5 .305 Copper, cast 8 . 6 to 8.8 8.7 .32 Gold, pure, 24 carat 19.25 .70 Iron, cast 6 . 9 to 7.4 7.21 .263 Iron, wrought 7 . 6 to 7.9 7.77 .281 Lead 11.4 .41 Mercury, at 60° F. 13.58 .49 Platinum 21 . to 22 . 21.5 .775 Silver 10.5 .386 Steel, average 7.8 .283 Spelter or zinc 6 . 8 to 7.2 7. .26 Tin, cast 7.2 to 7.5 7.35 .262 Pressure In Molds Depth Pounds Depth Pounds Depth Pounds (ft.) (in.) (per sq. in.) (ft.) (in.) (per sq. in.) (ft.) (in.) (per sq. in.) 1 .26 19 4.94 3 6 10.92 2 .52 20 5.20 4 12.48 3 .78 21 5.46 4 6 14.04 4 1.04 22 5.72 5 15.60 5 1.30 23 5.98 5 6 17.16 6 1.56 2 00 6.24 6 18.72 7 1.82 25 6.50 6 6 20.28 8 2.08 26 6.76 7 21.84 9 2.34 27 7.02 7 6 23.40 10 2.60 28 7.28 8 24.96 11 2.86 29 7.54 8 6 26.52 1 00 3.12 2 6 7.80 9 28.08 13 3.38 31 8.06 9 6 29.64 14 3.64 32 8.32 10 31.20 15 3.90 33 8.58 10 6 32.76 16 4.16 34 8.84 11 34.32 17 4.42 35 9.10 11 6 35.88 1 6 4.68 3 00 9.36 12 37.44 To find the total lifting pressure on the cope, multiply the pressure per square inch at a given depth below the pouring basin by the area (square inches) of the surface acted against. The result is in pounds. 196 FOUNDRY WORK Temperatures* Heat Connection (Degrees Fahrenheit) Core ovens 250 to 450 fyellow 435 Bright iron becomes | f^^^^^ 500 550 [gray 750 Tin melts 445 Mercury boils 660 Lead melts 612 Zinc melts 775 Silver melts 1775 Copper melts 1885 Gold melts 1900 ^a dark room, just visible 950 Iron bar red in ■ ordinary office 1075 daylight, open air 1450 Cast iron melts ■ white gray 2075 2230 Steel melts 2750 Annealing malleable iron 1600 to 1750 *From late scientific investigations. INDEX BMDEX FAGB A Air furnace for melting malleable iron 154 Alloys, brass and bronze 167 Analysis of cast iron 190 arbitration bar 191 Keep's mechanical 190 Analysis of cupola mixtures, chemical 123 Annealing malleable-iron castings 161 oven for 165 Annealing steel castings 144 Arbitration-bar tests of cast iron 191 specifications for 191 test bar in 191 Arbors for core work 56, 63 B Balanced cores 60 Barrel cores, making 92 Batch sand mixer 152 Binders, core 9, 47, 51 Blast 112 fan-blower 112 gage for 114 pressure-blower 113 Blowholes... 22,31 Bottom doors, cupola-furnace 109 Brass 167 chip separation 182 cleaning castings of 181 heats, size of 174 melting 176 molding equipment 172 molding materials 171 molding process 174 pattern weight 194 specific gravity and weight 195 work, examples of 175 Brass work 167 alloys in 167 production processes in 171 Breast, cupola-furnace 111 Bronze 168 specific gravity and weight of 195 2 " INDEX PAGE c Carbon 121, 136 Cast-iron analysis : 190 Casting operations 109 brass work 167 malleable practice 145 melting gray iron 109 steel work 136 Centrifugal sand mixer 129 Chaplets 21 setting 60 Charcoal foundry facing 7 Charging door, cupola-furnace 112 Cheek 9 Clamps 17 Clay wash 8 Cleaning castings, methods of 131 malleable-iron work, in 160 steel work, in 144 Coke, foundry 126 Cold-shuts 31 Cope 9 flat joint, for 33 floor bedding, in 44 loam molding, in 99, 102, 105 pressure head on 28 Coping out 35 Copper ' 168 specific gravity and weight 195 temperature, melting 196 Core-making machines 67 Core ovens 48 Core plates 48 racks for 50 Core sand 6, 46 mixtm-es 51 Core work 2, 46 barrel 92 for brass molding 175 dry-sand 46 general equipment for 48 green-sand 39, 62 for maUeable-iron molding 152 setting cores in 58 for steel molding 141 Core-rod straightening machine 134 Cover core 90 Cover plates in loam molding 95, 105 Crucible maUeable-iron melting 152 INDEX 3 PAGE Cupola furnace ^ 109 mixtures for 120 operation of 116 parts of 109 Cupola malleable-iron melting 153 Cutting and tempering sand 19 D Drag 9 fiat-joint 32 floor-bedding pit 43 Draw sticks 17 Drawback 100 Drying stove for brass molds 173 Dry -sand cores 46 equipment for making 48 methods of making 53 materials for 46 setting of 58 use of 51 Dry-sand molding 2, 89 Duplicating of castings, multiple 66 brass 176 gated-pattern method 67 jolt ramming machine 79 machine molding 67 malleable-iron 148 permanent match 67 roller ramming machine 86 roll-over machine 73, 77 squeezer machine 71, 75, 86 stripping-plate machine 68 F Facings 6 dry-sand core 47, 51 for steel molding 137 Ferrosilicon in malleable iron 158 Fire clay 7 Fire sand 5 Flasks for --- 9 brass molding 172 malleable-iron molding , 152 steel molding 138 Flat joint 32 Floor bedding 23,42 Foremen, duties of 188 Foundi'y, typical 182 cleaning department 187 4 INDEX PAGE Foundry, typical (continued) core shop 185 cranes 187 cupolas ^ 184 floor plan 183 heavy-molding division 185 light-molding division 185 molding machines 186 pattern room 184 shop office 184 storage of materials 186 tracks 186 type of building 183 unloading of materials 186 ventilation 183 Foundry work 1-196 casting operations 109 molding practice . 1 practical data 192 shop management 182 Free sands 6 G Gaggers 21 Gas furnace for brass melting 179 Gated patterns for duplicate castings 67 Gating 1 J 24 Graphite foundry facing 7 Gray iron ^ 109 Green-sand cores 39, 62 Green-sand molding 1 principles of 18 typical problems in — 31 H Hard-rolling of castings. 160 Heat, running a 116 for brass work 174 for malleable casting 159 for steel casting 141 I Iron 109 specific gravity and weight of 195 | temperature indications 196 Jointing 32 loam molds _ -- 100 INDEX 5 PAQE K Keep's mechanical analysis of cast iron 190 chilled depth 190 deductions by 191 siUcon and shrinkage 190 transverse strength 190 L Labor, shop management of foundry 188 foremen 188 laborers 188 molders 188 superintendent 188 Laborers, duties of foundry 188 Ladles for 118 brass work 177 malleable-iron work 159 steel work 142 Laying up loam mold 99 Lead 169 melting temperature 196 specific gravity and weight of 195 Lifters --- 15 Lifting ring, core : --_ 40 Lining 111 cupola-furnace 111 foundry-ladle 118 Loam mixtures 92 Loam molding 2, 94 example of complex cylinder 104 example of simple 102 materials for 97 principles of 99 rigging for 94 M Malleable cast iron. 145 annealing 161, 196 cleaning 160 finishing 167 melting, methods of 152 metal characteristics 145 method of casting 159 methods of testing 146 mixtm-e for 156 molding 148 patterns for 148 specifications for 146 6 INDEX PAGE Malleable practice 145 development of 145 production processes 148 Manganese 122, 136 Match, sand 36 permanent oil 67 Materials, molding- 3 brick for loam molding 97 cinders 98 facings 6, 98 miscellaneous 7 mud for loam molding 98 sands 3, 171 Melting 109 brass 176 malleable-iron 152 principles of iron 115 steel : 141 supplementary operations in iron 127 Mixing machines, sand 128 Mixing of sand 127 Mixtures, cupola-furnace 120 calculation of . 124 chemical analysis of 123 elements in 121 fuel in 126 proportions of charge in 126 Mold board 9 Molders, duties of 188 Molding machines Z 67 Molding practice ^ 1 brass 167 divisions of iron molding 1 general molding equipment 3 malleable-iron 145 processes 18 steel 137, 143 N Natural-draft furnace for brass work 177 Nowel or drag 9 O Open sand molding 45 Open-hearth malleable-iron melting 156 Open-hearth steel, casting 141 P Packing steel molds 139 Parting dusts '- 8 INDEX 7 PAGE Patterns for malleable castings 148 Phosphor bronze 171 phosphor tin in 171 Phosphorus 122, 136, 170 Pickling castings 133 of brass and bronze 181 Pig iron in malleable work 157 Pouring 119 brass 174 loam molds 104, 106 malleable iron 159 short 31 steel 142 venting action during 23 Practical data 192 circular areas and circumferences 194 conversion factors 193 mensuration 193 percentage, examples of using 192 pressure in molds 195 specific gravities and weights 195 square box measure 193 temperatures 196 weight of metal and patterns 194 weights, molding material 193 Pressure in molds 27, 195 pressure distribution examples 28 pressure-head examples 28 Pyrometer for annealing furnace 167 R Ramming 20 Ramming machine 79 jar or jolt 79 roller 86 Rammers 13 core work, for 48 Rapping plate 17 Rattler or tumbling barrel 131 Reinforcement, core 47, 55 Risers 22 Roll-over machine - 73 power type - 77 Rotary sieve 129 Runners 24 S Safety-first factors 189 clothing 189 personal 189 8 INDEX PAGB Safety-first factors (continued) shop equipment 189 Sand shaker 129 Sand-blasting 135 Sands, molding 3 core sand ■_. 6, 46 elements in 4 fire sand 5 for brass work 171 for malleable iron work ^ 149 for steel work 137 free sands 6 grades of 5 green-sand mixture 18 volume per ton 193 Scabs 31 Scrap iron in malleable work ^ 157 Sea-coal foundry facing 7 Setting cores 58 Shop management 182 governing factors in 182 labor 188 of typical foundry 182 physical results 190 safety first in 189 Shovel 12 Shrinkage cracks 31 Shrinkage heads or feeders 26 Shrinkage in malleable casting 148 Shrinkage in steel work 137 Sieve, riddle or foundry 13, 129 Sifting 19 Silicon 122, 136 Skimming gate 24 Slag hole, cupola-furnace 111 Slicks 15 corner 16 Slip or skinning loam 94 Snap flask 9 Spill trough for brass pouring 173 Spindle for loam mold sweeping 94 Split-pattern molds 38 core lifting ring 40 green-sand core 39 loose-piece 39 three-part 41 Spraying can for core work ^-- 48 Sprues . 24 Squeezer machine 71 INDEX 9 PAGE Squeezor machine (continued) automatic 86 power type 75 Steel 137 annealing castings of 144 casting, running a heat for 141 cleaning castings of 144 cores in molding 141 facings for, mold 137 flasks for molding 138 molds for, setting up 143 packing process in molding 139 specific gravity and weight of 195 temperature, melting 196 Steel work 136 casting 141 molding 137 Stripping-plate machine 68 Sulphur 122, 136 Superintendent, duties of 188 Swabs 16 Sweeping 95 cores 56 Swells 31 T Tables alloys, proportions of mixtures in 170 arbitration-bar standards for cast iron 192 crucible sizes 176 cupola-furnace sizes 112 fan-blower performance 113 flasks, sizes of wooden 11 ladle data, foundry- 118 phosphor-bronze mixtures 171 sands, proportions of elements in 4 Tapping 117 Tempering 19 cores, dry-sand 47 Testing cast iron 191 malleable 146 Three-part mold 41 Tin - - --- 168 specific gravity and weight of 195 temperature, melting 196 Tools, hand-molding ■ 9 for finishing 14 for brass work 172 Trowels 15, 48 10 INDEX PAOE Tumbling castings 131 Tuyeres 111 V Vent rods 16 Ventilation systems in typical foundry 183 Venting 22 dry-sand cores , 47 loam molds 100, 106 W Warping 31 White iron in malleable practice 149 Z Zinc 169 melting temperature 196 341 90 / ^^^-^^^-^ 'O , i - .- ■^ A*- \^ . t ♦ ^^^9"^'