'oK '^^^•'*/ V'*^\^^ %**T^.'V' ,. '^^^'*^' V cv ' ^^' ^<^ :. '*.o« :• '•^ ^^.v :m!i^. \/ z^^-, %/ •^^'o, -^z /% v^.^ oV^^^^iSk-. ^ov* :m^*-^ '^'-o^ ^ v»o^ \^ .^^"-_ V ^^-^^^ ^^^^ ,G^ V ♦T*^* A <^ '?• »* .G^ V ♦^7Vr«\A <^ 'o-»'i' ^V 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 INSTRCCTOB IN FOUNDRY PRACTICE, WORCESTER POLYTECHNIC INSTITUTE MEMBER, FOUNDRYMEN's ASSOCIATION ILLUSTRATED AMERICAN TECHNICAL SOCIETY CHICAGO 1920 T5 TjIo COPYRIGHT, 1916, 1918, 1920, BY A.MERICAN TECHNICAL SOCIETY COPYRIGHTED IN GREAT BRITAIN ALL RIGHTS RESERVED APR 23 1920 ©«'*S65687 INTRODUCTION nPHE making of a metal casting seems like a \ery 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 u})on 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, ha\'e partaken of the general mechanical de^•elopment 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 ])opular within the last few years. jNIalleable 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, have 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. 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 137 Facing mixtures 137 Packing 139 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 Ml S ja O o ^ .2 o M-; a :; Q O ( M s ;:; Pi t3 W "o ; < J3 I. Ck ^ i K • H G -" J 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 IMalleable 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 s}'stem 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 (1) loam work. Green-Sand Molding. The cheapest quickest method of form- ing the general run of castings is by green-sand molding. Drmp molding sand is rammed over the pattern, and suitable flasks are used for handling the mold. When the pattern is withdrawn the 2 FOUNDRY WORK mold is finished, and tlie metal 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 mider 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 exchides the use of sand and flasks. Selection of Method. No hard and fast ruk^s exist for the 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 JMlSCELLANEOrS 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 they grind against each other and pieces thus chipped off are carried by the rush of the current down into the rivers. Tumbled along by the rapid current of the upper river, the sand will finally be deposited where the stream flows more gently through the low land stretches FOUNDRY WORK TABLE I Proportions of Elements in Sands Elements (a) Silica SiO. Alumina (clay). . ..AI2O Iron oxide Fe20 Lime oxide CaO (b) Lime carbonate. . CaCO Magnesia MgO Soda Na20 Potash KoO Combined water. . . .H2O Organic matter Fire Sand (per cent) 98.04 1.40 .06 .20 ".16 14 Specific gravity 2.592 Degree of fineness i Molding Pands Iron Work Light (per cent) 82.21 9.48 4.25 '^68 .32 .09 .05 2.64 .28 2.652 85 Medium (per cent) 85.85 8.37 2.32 .50 .29 .81 .10 .03 1.08 .15 2.645 66 Heavy (per cent) 88.40 6.30 2.00 .78 '^50 .73 .04 2.630 46 Brass Light (per cent) 78.86 7.89 5.45 .50 1.46 1.18 .13 .09 3.80 .64 2.640 95 Core Sand (per cent) 85.50 2.65 .85 2'65 4.27 .04 .04 2.00 1.00 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 akmiina, 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 aaelyses shown in Table I, made by FOUNDRY WORK 5 W. G. Scott, give ail 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 finelv 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-mch sections. These will have less fine detail, so the sand may be coarser than in the previous case. The bond shoidd 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 offset by the larger size of the grain. This vent must be provided for because the metal will remain hot in the mold for a longer time and will cause gases to form during the whole of its cooling period. Heavy Sand. This grade of sand is used for the 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 timt 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 tlie sand which comes in contact with the melted metal. The object is to give a smooth surface to the casting. They accomj)lish this in two ways: (1) by filling in the pores between the sand, thus giving a smooth surface to the mok 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 puri)()se because jarbon 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, ^\ hich in the heavier classes of work forms the first layer of sand next the pattern. The use of the difl'erent facings will be clearly seen from the tabulation on page 8. Miscellaneous Materials Fire Clay. Fire clay comes from the same source tluit 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 slicked 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 ivash 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 parthig sand, and by far the most connnonly 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 puttmg 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 fiasks are used. Flasks consist of two or more such boxes. The lower box is called the drag or noicel, 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 work and the flasks are usually what are known as snap fiasks. They range in size from 9 by 12 inches to 18 by 20 inches. As is seen in Fig. 1, these flasks hmge 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. Many 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^^ ^^^ ^ rcgular^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 |-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) ; Matebial 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 2 3 1 1 1 2 1 2 2 Note. For each additional 6-inch deptli 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 36 inches, the thickness of crossbars should be 1^ 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 cast 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 A r S — rr- TU JJa. "iS^ ian ^r ^,j^ii ^- ::ii •ir-T^;7 nr o o 3 3 Trunion Handle ■ Cast •5teeL Doc 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 interchangeable 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 moldmg-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. ti. 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. INIolders' tools are designed for shaping and slir:king 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 mto 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 workmg up into a square corner, and the finishing trowels h and c (c) Fig. 10. Trowels Fig. 11. Slicks are iore for coping out and finishing along the curved edges of a patten. Trowels are measured by the width and length of blade. Vichs. Slicks are designated by the shape of the blade and the widtlpf the widest blade. In Fig. 11, a is a heart and leaf; 6 is a leaf an(V)oon; c is a heart and square; and c? is a spoon and bead. These ajin sizes of 1 inch to If inches. They are used for repairing and slictg small surfaces. Lift\. Fig. 12 shows lifters used to clean and finish the IG FOUNDRY WORK Fig. 13. (if) Square Comer Slicks Fig. 14. Floor Swab sizes from \- by lU-inch to 1- by 2U-mch; 6 is a bench lifter, the sizes of which vary from ^ inch to f inch wide. Corner Slicks. Fig. 13 shows at a and h 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 rf is a pipe slick madi 1 inch to 2 inches. This st\'le of tool is mainly used oniry sand and loam work. Swah. Swabs are ised to moisten the edges of the sand about a pattern b flask and to support the walls of the mold against the flow and pressure of the metal. The knack of ramming just right only I''ig. 19. Setting Gaggers ral i,r , ""'*""'^':^ P^-*'™ -d comparison of results. Hard rammmg closes up the vent, causing blowholes. Iron will not f- oe'' rT.t fl ^fr- ^"'* '"'""""« '^"^^ « -«^»k mold sur- the sand, leavng 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 nnsightly lump on the casting. The bottom parts of a mold, being under greater casting pressure, must be rammed somewhat harder than the upper portions. The joint also should be packed firmly, as it is exposed to more handling than any other part. Gaggcrs. 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. Chaplet.s 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 I)roject 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 support parts of cores which cannot be entirely secured by their prints w'liich are held in the sand of the mold. In Fig. 20 are shown the three prin- cipal forms of chaplets used, and how they are set in the mold; a is a stem ehaplet; 6 is a double-headed or stud chaplet; and c is a form of chaplet made up of strip metal. 22 FOUNDRY WORK 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 ])()ured. 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 Variuus 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 bbb 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 l)ottom 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 cover 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 Bedded in Floor 24 FOUNDRY WORK Gating. Gating is the term applied to the methods of forming openings and channels in the sand by which liquid metal may enter the mold cavity. The terms syriies and runners are also used in the same connection in some shops. Fimctiuns 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 shown at b, because the hot iron necessary for light work runs very fluid. The runner should not be more than | 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 w'hich 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 the gate opening is something that the molder must learn from experience. In arranging gates with regard to the shape of the pattern, the following points should be borne in mind: Place gates where Fig. 24. Skimming Gate 26 FOUNDRY WORK r) Fig. 25. Use of Gates the natural Iflow of the metal will tend to fill the mold quickly. Usually gate on the lighter sections of the casting. Select such points on the casting that the gates may be broken and ground off with least trouble — the greater the number of castings to be handled, the more important this point becomes. A study of the molding problems given will illus- \v> ,,^__^ trate this point. ^-^ Provide enough gates to fill all parts of \ / the mold with metal of uniform temperature. This depends upon the thickness of the work, as is illustrated in Fig. 25 by two molds having the same shape at the joints but of different thicknesses. In thin castings the metal tends to chill quickly, so it must be well distrib- . uted. In this illustration, a is a plate \ inch S thick, and should have several gates. |A piece having the same diameter but heavier, would run better from one gate as at h, while if a bush- ing of this diameter is required, the best results would be obtained by gating near the bottom, as in Fig. 22. For running work at the bottom as shown in Fig. 22, the gate piece h is separate from the run- ner, and is slicked into the mold after the pattern is drawn. The runner r should extend below the level of the gate to receive the force of the first fall of metal, which otherwise would tend to cut the sand of the gate. Shrinkage Heads. Melted metal shrinks as it cools, and this process begins from the moment the mold is filled. The surfaces next to the damp sand are the first to solidify, and they draw to themselves the more fluid metal from the interior. This process goes on until the whole casting has solidified. This shrinkage causes the grain in the middle to be coarse and sometimes even open or porous. The lower parts of a casting are under the pressure or weight Sinking of Casting w^'^''m. > '^. " •<>!-^ ;■-^;^';--'' ; ■ ; ^ >• ,-;•) .y/jfevv ?S^^/'S^ \ Ji— ^ »M i S^ % Np m ,-. ...-. »^ 1 iH Fig. 27. Feeding Rod FOUNDRY WORK 27 h ^ h I f_ of all the metal above, and so resist these shrinkage strains. The top parts, however, require the. pressure of liquid metal in gates or risers to sustain them until they have hardened sufficiently to hold their shape, or they will sink as indicated by the section, Fig. 2G. Risers, mentioned in connection with securing clean metal, are also required on heavy pieces to prevent this distortion and to give sound metal. When used in this way they are called shrinkage heads or feeders. They should be 6 or 8 inches in diameter, so as to keep the iron liquid as long as possible, and should have a neck 2 or 3 inches in diameter, to a c a c e reduce the labor required to break them from the casting in cleaning. To prevent the metal in this neck from freez- ing, an iron feeding rod is inserted, as in Fig. 27, and is churned slowly up and down. This insures fluid metal reaching the interior. As the level in the feeder low- ers, hot metal should be added from a hand ladle. Pressure in Molds. The subject of the pres- sure of liquid iron men- tioned repeatedly in the foregoing pages, must be dealt with by the molder, in weighting his copes, strengthening flasks, securing cores, etc., and most frequently in connection with the first- of these. Natural Laws. Molten iron acts in accordance with the same natural laws that govern all liquids — as, for example, water (see Mechanics, Part II); iron, however, is 7.2 times heavier than water. The two laws applicable in foundry work are these: (1) Liquids always seek their own level; (2) pressure in liquids is exerted in every direction. a A c h d — a c TT I I I I I I |.4-!— K^ Fig. 2.S. Illustrating Pressure of Liquids in Molds 28 FOUNDRY WORK Pressure- Head Example. Applying the first law, if we have two columns of liquid iron connected at the bottom, they would just balance each other. For convenience we shall leave out of our calculations the upward pressure on the gates in the following examples, for in practical work they need seldom be taken into account. In A, Fig. 28, suppose these columns stand 6 inches above the joint hd, and that the column cd, has an area of 1 square inch. In B, suppose the area of the right-hand column cdef is 5 times the area of colunui cd. In both cases the level with top of runner a will })e maintained. The depth of the cavity below tiie joint hdf makes no difference in main- h' h" o^^ * — » I V f ^ 1 taining these levels. The weight of one cubic inch of iron, .26 l)ound, is taken as the basis of all calculations. Now if we close the column ed at d, as in C, it is clear that it would require the actual weight of that colmiin to balance the lifting pressure of the surface d, or 6X.26Xl = 1.56 pounds. And if the larger area dj is closed over, as in D, it takes 5 times this weight to resist the pressure exerted upon it by the runner, or GX. 26X5 = 7.8 pounds. If the pattern projected 2 inches into the cope, the height of the runner above the surface acting against the cope would be 4 inches, and the pressure to be overcome would be equal to the weight of ccjhe, or 4 X .26 X 5 = 5.2 pounds. The important factors, then, are: height of runner; and area of mold which presses against the cope. We can therefore state a rule: To calculate the upward pressure of molten iron, multiply the depth in inches hy the 'weight of one cubic inch of iron (.26), and multiply this product by the area in square inches upon which the pressure acts. Pressure-Distribution E.raniplc. Ajiplying the second law cited, the strains on sides and bottom of molds and upon cores is explained. 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 /iX.26. This also acts against the sides at ee. The pressure at h is h' X .26, and is exerted sidewise and downward. The pressure at c is Fx.26. This point, being half way between the levels a and h, 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 =121sq. in. Area of c (one side) = 99 sq. m. Area of four sides = 396 sq. in. Height of /i =6 in.; pressure head = 1.56 lb. per sq. in. Height of h' =15 in.; pressure head = 3.90 lb. per sq. in. Height of /i" = 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 = 270.27 lb. Total pressure on four sides = lOSl .08 lb. Total downward pressure on h = 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 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. Then Total lift on cope A is 8 X .26 X 1 13. 10 = 235.24 lb. The lift on cope B is 8 X. 26X34.56= 71.88 + (8+5) X. 26X78.54 = 265.46 Total lift on B =337.34 lb. 1 00 A -/2- _£0 , -/O- TZ 00 c' Fig. 30. Diagram Showing Difference in Pressure on Cope Duo 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 7 X. 26 = 1.82 lb. Pressure per square inch on b is 12x.26 = 3.121b. 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 5 X 12X 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. V < 1 I'J / a ^ Core , K r^sL t Fig,. 31. Diapram 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. Bloichohs. These come from gases becoming pocketed in the metal instead of passing off through the sand. This is due to hard ramming, 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 incoming 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 mold being so firm that it resists the natural shrinkage of the iron, causing the 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. When 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 bench work, and 4 to 8 inches on floor molds, depending upon the weight of the 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, slicks, 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. When it is irregular the drag joint must be coped out for e\'ery 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 ^. -„ „ . 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. I'se 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. 31. 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 5, 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 when this course is j:)roi)erly 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 o\er 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 tins 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 Coye. Set the cope on the drag and see that the hinges come at the same corner. Sift on a layer of sand about r| inches deep. Tuck firmly with the fingers about the lower end of the runner and around Fig. 35. Molding Sand with Rammer 34 FOUNDRY WORK Fig. 30. 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 with 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 are to be pickled. The mold should now be closed and the snap flask removed. Strengthening against Pressure. There are two methods used to strengthen these molds against the casting pressure. One is Fig. 37. Weiglit in Position 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 w^eight, 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 tj-pe 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 ao, but the partuig 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. Ram the drag, and roll it over, as described m 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 Wold finishing trowel or leaf and spoon. This process is called coping Old. 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 \vith 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 hito 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 rannning up the pattern. (Use, for example, the hand wheel Fig. iO. Angle of Joint J?- ^^s^^W'^^^^m^M^^'TT^W^^'Wrm b-'>^. -J? 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 oflF level with edges of drag bh, 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 I'ig. 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 sliop, irregularly shai)od work is often made in one piece. The n I older 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 better 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 oi\ 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 irreguhir 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 the flask is used 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 A, m /^attem on mo/d I>oarc/ Cut /n cope ^ Fig. 41. 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 a, 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 ware 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 tiiat 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 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. isn Fig. 47. Part Section of Moid Showing Use of Core-Lifting 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 off, and draw the cope pattern. Now, by 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 oi)posite sides of the cheek to support the sand, and crossbars in both drag and cope. These should be well wet with 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 about I4- Fig. 50 Casting of a NozzIp 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 w^ithin 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-mgot 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. Casting of Flask Section the flanges, portions of the top plate of the pattern arc left loose, as seen in Fig. 53. Pit. Dig the pit for the mold 10 inches larger on each side than the pattern, aiid about 6 inches deeper. Having screened some hard cinders through a No. 2 riddle, cover the bottom of the 44 FOUNDRY WORK These f^/eces Loose / I \ Fig. 53. Bedded-In Wi.rk 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 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. Remo\'e the pattern and with the fingers test the firmness of packing all over the mold. ^'ent these faces through to the cinder bed, and cover the vent holes with a |-lnch 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 until 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 _jr-" ■Runner Stick /Floor Line TIT Nails 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 Fig. 54. Section Showing Method of Molding cover these vent holes with facing sand, ram, and slick to finish; then cover with the loose pieces of the pattern. Coye. 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. FOUNDRY WORK 45 Lift the cope, repair, and face with graphite. Draw the patterPx with the crane and finish the mold. Connect the outer vent holes by a channel with the vent phig. From the end of each core print hbhh, 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 blockmg 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 support the actual weight of the metal, or it will boil. To uisure 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 A A on the top of these. By usmg a spirit level bb, 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 with 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'sm fTRICATE Smaller Cores (parts) Beach sand Fire sand Molding sand Sharp fire sand Strong loamy sand Flour Rosin Oil 10 1 8 2 15 15 1 2 15 5 2 1 Tempering means j 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 ])oured. 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 nuich ingenuity on the part of the core maker. For simple straight work a good sized vent wire is run through before the box is remoNcd. 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, lea\ing 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. C3. Sl'.ort 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. G4. 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-]\Iaking, 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 level 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. G4. Large Cylindrical Cores 54 FOUNDRY WORK motion. A vent channel is tlien scrapetl centrally on each half. Paste, made of flour and molasses ^Yate^, is applied around the edges and the two hahes 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 G-inch diam- eter and over, it is well to bind the halves at each end with a single wrap of small wire. Proper Seating. W' herever 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 \)\ato, the unevenness is Fig. 0.5. Bedding a Crooked Core overcome by sifting upon the plate a tliin 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, tlie 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. Co. 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 Re bif arcing. ]\Iention has been made of the use of wires for strengthening small cores. In making hirger ones, there is a greater weight of sand to cause strain in handling the core, and proportionately greater casting 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. 60. Heavy bars aahb 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 wlic^n 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 Fig. 67. Sections Showing Use of Cast- IroQ 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, 4» 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 the core. This is illustrated in the pipe core shown in Fig. 68. Tlie 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 6 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 '^.Wli^''|y ' !^^ ^' ^M».^ | , | |^^^^ | ^ ^ .V»,^l5 » ^j■V^ ■ .»l| | Wi.^ | | Fig. 69. Core Machine 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 within 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 fnll 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 ty])ical 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 ' =■-'-'' ^3^ B' , / A J . ■^ ■ ' " WWJtX< — Fig. 70. Bolt-Hole Core Fig. 71. Caliper.^ 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- ]\Iakmg. 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 sm.all 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 on m /f/r \/enf v-^/^ni\j)ii/^/Tm7ma<INING (inches! Cupola Height (feet) Charging Door Size (inches) Melting Capacity ,Per 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 bv 20 20 bv 24 24 by 24 30 bv 36 30 by 40 30 by 45 Ho 5 h to 1 1 to 2 2 to 5 4 to 8 6 to 14 8 to 16 f 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 m 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 s])out 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 o' 5 or G 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 i)ractical 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 main outlet, the air beinji 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 the furnace will be reduced proportionately. On the other hand, it requires less power to operate the fan with reduced area of outlet th.an it does when the discharge is open free. An idea of the speeds at which blowers should run may be obtained from Table l\. Pressure Blower. In the })ressure blower shown in Fig. 126, the action is positive, as will be seen from the sectional view A, 114 FOUNDRY WORK Fig. 126. The wipers mesh into each other in such a way that they entrap a quantity 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 i)rossure of air which enters the tuyeres. The Fig. 12G. Motor-Driven Pressure Blower I)ressure 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 1.785 ^^, 55 7 . 1 . — r — = .8do =— - = — -m.— -- in. 2 ()4 8 04 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 . 2 16 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 o])cn 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 /O 9 \—8 7 I — 6 5 4 o — 7 O 3x /4 '— 10 '- e 4 Fig. 127. Wind Gages 116 FOUNDRY WORK tlie 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; aad so on. Cupola Operation Running a Heat. The following routine must be pursued each time a heat is run ott' in the cupola : (1) Clear away the dump from the former heat. (2) Chip out the inside 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) Daub tip 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 tlie surface to be rej)aircd 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, es])ecially about the tuyeres. The top of the tuyeres should be kc])t slightly overhanging. The greater part of the daubing will be required from the l^ottom to the level of melting zone, about 22 inches above tuyeres. (4) Suing 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 nnist 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 indies 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 during 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 hotting 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 kindHng; then with enough large kindling 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 \i\ 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, aud shaped onto the end of the bott stick .1 , 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 trimming sides of hole if the bott does not entirely free itself when tapped. (11) Drop the bottom, when all the iron has been melted and run off. This is done by pulling away the bar that supports the bottom Fig. 128. Tapping Bara 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 Itof 14 to 26 f tol 20 to 60 lto4| 6 to 7 h tof 8 to 13 f to 1 12 to 23 1 to 3 18 to 66 iHo 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 Y, containing references to Figs. 1 29 and 1 30, 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 with lips. Lining. Ladles must be lined to protect them from burning through. Up to 1-ton capacity, the cupola daubing mixture is used. The bowl is smeared with thick clay wash, and the clay pressed in hard with 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 first 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 V, ^.^^ ^.^^ Hand and BuII Ladk. 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 couNcnience, 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 whether 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-shuts or lea\e shot 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. 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 stick- 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 ctipola 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. IVIany 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 whicli we are dealing — pig iron, and cast iron — five elements are considered as affecting their physical 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. Sul2)hir. 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. P'or 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 stag's liquid longer, more graphite is thrown off, 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. Proportions of Silicon. The following shows good proportions of silicon for different classes of work : Casting Steam cylinders Medium heavy work (i-inch to 2-in(',h thickness) Light work (less than i-inch thickness) Silicon (per cent) 1.70 2.0() 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 ^ 1^-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: Ca,sting Silicon (per cent) Small thin scrap Large scrap ranges 2.0 to 2.4 1.50to2,0 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 center, average-sized 124 FOUNDRY WORK crystals will be noticed in the fracture. It is here that the drillings for analysis should be made, as indicated in Fig. 131. About a f-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 tlie 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. i;u. .s.iioii .,f rig Drilled 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: 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. AN'hen 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. Illustrative 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 to 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% = 2.5 X 3.5 = 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% X 2.22% =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% X 4.00% =0.200 % Scrap 50% X2.00% = 1.000 % Total silicon content =2.199 % Deduct for loss in heat =0.17 % Estimated sihcon 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. P^or 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 (B) Bed Other charges No. 1 25% X 5,000 = 1,250 lb. 750 1b. No. 2 20% X 5,000 = 1,000 lb. 600 1b. No. 3 5%X5,000= 250 1b. 1501b. Scrap 50%X5,000 = 2,500 1b. 1,500 1b. Total iron 5,000 lb. 3,000 lb. Fuel. Both anthracite coal and foundry coke are used in the cupola. Coal, owhig 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 greatly 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, especially 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. When the coke is well lighted, before charging the iron, lo\el 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 bed 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 i)()nnds 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 usually about G 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 Mi.xing. "When a mold is poured, the intense heat of the iron burns out those jjroperties in the sand which give it its bond, making it necessary that a certain proportion of new sand shall be mixed with the heap sand and used as facing, as has been explained in earlier paragraphs. The facing sand should be mixed daily for the moklers by one or more of the laborers, at a place convenient to the storage sheds 128 FOUNDRY WORK and molding floors. A hard smooth floor of clay or of iron plates is a great advantage. The proportions of the different sands are measured by the shovelful, bucketful, or barrowful, and the sands are spread over each other in flat layers, sufficient water being sprinkled on to temper the pile. The sand then is cut through once with the shovel, is put through a No. 2 sieve, all lumps being broken up, and the refuse thrown Fig. 133. Rotary Sieve out is put through a No. 4 sieve, and finally is thrown in a pile ready for use. When this work is done by hand, the ordinary screen sieve com- monly employed by masons is used for the riddling, and a round foundry riddle for the final sifting. To reduce the labor of this, the riddle is slid back and forth on a pair of parallel bars supported conveniently above the storage pile. Mixing Machines. The two classes of labor-saving machines used in mixing facings, core sand, etc., are those which mix by FOUNDRY WORK 129 riddling; and those which mix by a combined breaking and stirring action. There are many varieties on the market, the illustrations shown being typical. The rotary sieve shown in Fig. 133 is made with wire screen on the revolving sides, and is driven by belt or connected motor. Sand shoveled into the central opening is sifted in a pile on the floor, or directly into a barrow. The rub- ber hammer on top auto- matically raps each face of the sieve as it re- volves, knocking the meshes free of sand. Fig. 134 shows one of the latest labor savers in this line. Here a foundry riddle is supported in a metal ring attached to the i)iston of the machine. It is made to vibrate rapidly by means of com- Fig. 134. Sand Shaker Fig. 135. Pulley-Driven Centrifugal Mixer pressed air or steam. These shakiTS are made with portable tripod, as shown; they are also made stationary or are fastened on a post 130 FOUNDRY WORK by means of a swivel joint, to be swung over a wheelbarrow or over a molding machine, and out of the way again when not in use. Fig. 135 shows a centrifugal mixer. Inside of the umbrella casing, a horizontal plate about 12 inches in diameter and carrying a number of vertical steel pins about G inches long is fastened to the top of a short upright shaft driven by a belt running inside of the casing shown at the base of the machine. The machine runs about 1,500 revolutions per minute; and sand shoveled into the hopper is very evenly broken up by the pins and thrown against the steel hood, breaking and shattering any lumps of clay or loam and making a Fig. 136. Facing Grinder very uniform mixture. The hopper may easily be removed to clean the plate. The machine is used for the final mixing. Fig. 136 shows a foundry grinder or facing mill. It is the type of mill used for mixing loam. Either the pan or the rollers are attached to the driving shaft and made to revolve, crushing and mixing whate\er is shoveled into the pan. Frequently, a stout blade, something like a plowshare, is fixed between the rollers, and prevents the mixture caking to the bottom of the pan. The faces of the rolls are of very hard or of chilled cast iron to withstand wear. When the loam mixture is sufficient!}' ground, it must be shoveled from the pan, FOUNDRY WORK 131 and delivered to the iiiolders or stored temporarily. It will set if stored too long. Tliis is the type of mill used in the steel fomidries, for grinding the facing materials. The various sands are dumped into the pan at one side, and, when ground sufficiently, are shoveled directly from the pan into a centrifugal mixer. This prepares them for use. Cleaning Castings. After a casting has solidified in the mold, the flash should be removed, leaving the casting in the sand. For light bench work and snap-flask work, the mold is lifted bodily and the sand dumped on the pile; the bottom boards are piled in one place, and the cases are piled in another ready for the next day's work. As the molds are dumped, the castings are removed from the sand and piled at the edge of the gangway. When all castings have been removed from the sand, the gates are broken and thrown in a pile by themsehes. When cold enough to handle, the castings are removed to the cleaning room, and the gates and sprues are sent to the scrap pile. With heavier floor work, the clamps are removed as soon as the casting has set ; the flash is rapped with a sledge hammer and is stripped off the mold, leaving the castings to cool gradually in the sand. Sometimes a sharp blow is given on top of the runner while it is still red; this breaks it off before the flask is shaken out. At a red heat, cast iron is very weak and can easily be broken, Tumbling. The most effective way to clean small castings is in a rattling barrel. Fig. 137 shows a modern set of dustless barrels. The shell of the barrel is -|-inch boiler plate riveted to cast-iron heads, with a door arranged to be entirely removed for packing and dumping. The bearings are hollow, and from one end the dust is drawn off through a galvanized-iron pipe. This pipe connects with an air-tight wooden chamber, as shown in Fig. 138, varying in size with the number of barrels connected with it. In this chamber hang a number of cloth-covered screens. An exhaust fan is connected to Fig. 137. Dustles.s Tumbling Barrel 132 FOUNDRY WORK this chamber at the opposite end from the inlet pipe. When the fan is in operation, a strong current of air is drawn through the barrels and through the chamber. The dust, entering the chamber, settles on the screens, so that but little dust escai)es to the outside air. When necessary, the exhaust is stopped, and, by means of a crank on the outside of the dust chamber, the screens are shaken and the dust drops off, when it can be removed through a trap into an ash can or wheelbarrow. The driving shaft carrying the pinion re- volves all the time, and any barrel may be thrown over into gear or drawn out of gear by the opera- tion of a hand lever. The barrels should run about 25 revolutions per minute. P^ach barrel should be packed as full as possible with several shovelfuls of gates, shot iron, or hard- ened stars thrown in with the castings. The clean- ing is accomplished in from 20 minutes to half an hour by the scouring action of castings, scrap, etc., rubbing against each other. Castings up to 50 or 100 pounds can be rattled, but only those of a similar character as to design or weight should be packed in together, otherwise the lighter castings will be broken by the heavier. When removed from the barrel, the work should show a smooth clean surface of an even gray color. From the rattlers, castings go to the grinding room, where pro- jecting gates or other slight roughness is removed on the emery wheel. Heavy castings are cleaned by hand, by pickling, or by sand- blasting. Fig. 138. Dust Collector for Tumbling Barrel FOUNDRY WORK 133 Fig. 139. Steel Bristle Brush Hand-Cleaning. When cleaning by hand, the worst of the sand is rapped off by light hammering, the remainder scraped off with old files and with steel-wire brushes such as that shown in Fig. 139. Some shops rub off finally with broken pieces of coarse emery wheel. Risers and fins are removed with cold chisels. The pneumatic chisel, shown in Fig. 140, is used as a timesaver. Where work is light enough to handle, small fins are removed by emery wheels; medium coarse wheels will cut faster on cast iron than fine ones, and will hold their shape better. It is when castings must be cleaned by hand, that the value of a good facing dust shows itself. With the proper facing, the sand parts readily from the casting leaving a fine-looking smooth surface. With poor facings, on the other hand, the iron burns into the sand, making it hard to clean, and leaves a rough surface on the work. Pickling. Pickling is a method of cleaning re- sorted to where there is much machining to be done on a casting. The work is placed in a pile on a suit- able platform, and dilute sulphuric acid is thrown over it during one day, frequently enough to keep it well wet. The platform should be arranged to drain the acid back into the vat. Acid is diluted from 1 : 8 to 1 : 10. After about 12 hours' bath with acid, the castings are washed clean with hot water. The acid acts on the hard skin of oxide of iron which forms when the iron strikes the damp sand, and it eats through this skin to Fig. 140. Pneumatic; Chi.sel for Cutting Risers and Fins 134 FOUNDRY WORK the iron itself. The washhig water should be hot enough to warm the castings sufficiently for them to dry rapidly without rusting. The acid must be thoroughly washed off, or it will continue to eat Fig. 141. Saiul-Blast Arrangement into the iron and cause a white powder — sulphate of iron — to form on the surface. An excellent arrangement for a pickling department is to have the trough arranged on skids which allow it to be rocked endwise. FOUNDRY WORK 135 This drains into the pickling vat when acid is being thrown on, and into the gutter when the castings are being washed. Sheet lead is the best protective covering for small pickling troughs, but it is expensive and not durable enough to stand for heavy work. Sand-BIasting. For castings of such shape and size that they cannot well be rattled, but are too small to be cleaned by hand, the sand blast has been used to advantage in many shops. Fig. 141 gives an idea of the arrangement of the cleaning stall. Castings are placed on the wooden grating. By means of corn- Fig. 142. Core Rod Struightencr pressed air a sharp silica sand is forced through a strong rubber hose and is directed against the castings by a hardened-steel nozzle. The operator wears a helmet supplied with fresh air by an air hose, to protect his eyes and lungs from the clouds of fine dust. An exhaust hood is arranged also to take off as much of the dust as possible. The manual labor of this method is practically reduced to noth- ing, aside from handling the castings. The system, however, requires the installation of a rather considerable equipment, which has debarred its use in many foundries. 136 FOUNDRY WORK Re-Use of Core Bods. In removing cores, the bars become very much bent. In such shape they were formerly scrai)])ed, or refitted to suit new cores with a hammer and block of iron. Fig. 142 shows a very practical power machine which delivers the bars perfectly straight. The machine consists of a pair of rolls, with different sizes of grooves turned in them, which pull a rod through a flaring mouthpiece and deliver it through a corresponding eye on the opposite side. The machines are made in different sizes, and take rods from |-inch to |-inch diameter. STEEL WORK Present Development. This class of work has developed within the last few years, and, beginning with the heavier parts of marine and engine construction, it is now crowding the field of drop forgings. Steel castings are malleable, and are very much stronger than iron ones. The principles of molding involved are similar to those in other classes of molding, but practice is varied to meet special conditions. Processes. The art of making steel castings may be divided into three heads: (1) preparation and melting of the metal; (2) making and pouring the molds; (3) heat-treatment of finished castings. As the first and third heads come more properly under other depart- ments, we shall here simply outline these processes, dealing in detail with the second heading only. Characteristics of Metal. This branch of foundry work has developed to a great extent since the early nineties. The metal is similar in mixture, method of melting, and physical properties to the steel which is poured into ingot molds for forging purposes. The graphitic carbon is entirely burned out; the strength of the metal is therefore very much greater than that of cast iron. Combined carbon, manganese, and silicon are the elements depended upon for this strength; sulphur and phosphorus are kept very low. A typical analysis shows these elements in the following proportions : Carbon Manganese Silicon Sulphur Phosphorus 0.27% 0.857o 0.35% 0.0207o 0.025% Owing to the purity of this form of iron, about 50 per cent more heat is required to melt it than is necessary in the case of pig iron — or about 3,300 degrees Fahrenheit. When melted, the metal runs FOUNDRY WORK 137 much more sluggishly than cast iron, and, on account of the absence of graphitic carbon, it does not expand at the moment of solidifying, and therefore does not take as sharp an impression. To insure as perfect an impression as possible, the molds are constructed with a good head of metal in the risers, and they are poured under pressure. The shrinkage is double that of iron; the risers are made very large, and are placed directly on the casting to insure feeding well. Great care must be exercised that neither mold faces nor cores bind during || cooling, as such binding ""''^''"""" """" tV4-A might cause a flaw. Shrinkage. When two surfaces meet at right angles, the corner re- mains hot longest, and the sides shrmk away, tending to cause a fracture at a, Fig. 143. To overcome this, thin webs are cut by the molder about every 4 inches or inches — shown at b. These cool first, and hold the adjacent sides in position, preventing them from pulling away from each other. The internal strain due to this cooling is relieved by the annealing. After the casting is annealed, the webs are cut away. Fig. 143. Shrinkage Webs STEEL MOLDS Facing Mixtures. To with.stan(l the high heat, pure silica sand is used as the basis of the facing mixtures for steel molds. Pure quartz or silica rock is quarried, and reduced to sand form through a series of rock crushers. At the foundry the necessary bond is given by the addition of fire clay and molasses water. These are thor- oughly mixed with the sand in a facing mill and mixer, Figs. 135 and 136. A typical mixture is as follows: 1 barrow silica sand 3 pails powdered fire clay Temper with molasses water Where quartz sand is very expensive, the following mixtures, 1, II, III, or I\', will reduce the cost. The old crucibles and fire brick should be crushed separately in the mill before mixing. 138 FOUNDRY WORK Vor facing wash, these mixtures are '!;r()un(l very fine, and tliinned with molasses water. Core sand for steel work is practically the same mixture as the mold facing. For thin metal a somewhat less refractory natural sand may be added to reduce the cost of the mixture. For small round or fiat cores, ^V piirt rosin, with silica sand, tempered with molasses water, makes a good core. It should, however, be thoroughly burnt. For core-icash mix- ture, use 3 parts silica flour; 1 part Ceylon graphite; molasses water. Flasks. Flasks for steel work are built of cast iron. Fig. 4, Part I. Full-length crossbars are bolted in the cope, 6 inches to 8 inches on centers, depending on the size of the flask. Short crossbars are fastened between these as needed, say 12 inches to IG inches on centers, as seen in Fig. 144. Oblong bolt holes 4 inches on centers are cast in the sides of the flask and in all crossbars. Slots to correspond are cast in flanges of bars, so that they may be readily removed or shifted when fitting the cope to the pattern. Fig. 144. Short. Crossbar FOUNDRY WORK 139 The holes for pins should be drilled to template in all flasks of the same size, so that copes and drags may be interchanged. Flask pins are slipped through the holes temporarily when the flask is being closed or opened. On large work the cope is bolted to the drag while being rammed. The bottom plate is of cast iron, and is clamped to the flange of the drag with short clamps and steel wedges. The same tools are used for packing and finishing the mold as those described in connection with iron molding. Flasks of from 18 inches to 48 inches in length have two handles bolted on the ends to lift them with. Larger flasks ha\e trunnions, rockers, or U-shaped handles cast on the sides. Fig. 14.5. Small Fla.sk for Steel Molds Fig. 145 shows type of convenient small flask built up of channel and angle iron, size 14 by 20 to 24 by 48 inches. Packing. In packing the mold, place the pattern on the board and cover with 1 1 to 3 inches of facing, depending on the size of the job. Tuck well with the fingers. The facing is used as prepared by the mixer, not sifted. Set the drag on the board, shovel in heap sand, and ram the mold somewhat harder than for iron. Strike off, and seat the bottom plate, fastening it firmly to the flange of drag with clamps or bolts. When this is done, roll the mold over, and remove the moldboard. Press with the fingers all over the joint surface, especially around the pattern, to make sure of firm packing. If soft places arft 140 FOUNDRY WORK found, they should be tucked in with facing sand. When needed repairs are made, slick the joint all over. Use burnt core sand for making the parting. Try on the cope and adjust bars to fit the pattern. Clay-wash the cope before packing. Put on necessary facing over the joint and the pattern. Set the gate on the joint, but place risers directly on the pattern. Set the necessary gaggers, shovel in heap sand, and Riser \flunr er r r Cope . -V ti , 1 '•y I — k TZ '^ /ron Rods CD p ^ Ea •t^ ^i \ Gate Drag \ ^ ... C o yer Core ^^ ] ''y>^yr///}/y>^//y/y///>//;'///}y'/y>y>///^/////>/>/////^/y///^y/A Fig. 146. Section Through Steel Mold ram the cope. A'ent well, lift the cope, moisten the edges, and draw the pattern. In finishing the mold, nails are used freely, about 1^ to 2 inches apart, driven in till the heads are flush with the surface of the sand. This is to pre\'ent the cutting of the surface by the rush of hot metal when the mold is poured. It is at this stage that the thin webs previously mentioned, are cut into the corner fillets where needed. The whole surface of the mold must be smoothly slicked over with the trowel and convenient slicks. When this is done, paint on the facing wash with a very flexible long-bristled brush. FOUNDRY WORK 141 Fig. 146 shows the section of a mold for a shrouded pinion, and illustrates the points above mentioned. The runner is lead in at the bottom by use of a cover core, as described in Dry-Sand Molding. INIolds for steel should be more than dried; they should be thoroughly baked to drive off every particle of moisture. This prevents the sieel boiling in the mold and causing imperfections in the casting. Where but little machine work is to be done on small work up to Ij inches thick, the molds may be made up in wooden flasks and poured green. For this class of work, only pure quartz sand and fire clay are used, tempered with molasses water. These may be made up and poured on the same day. Cores. Cores for steel molds are made up in boxes similar to those used in the iron foundry. Although using special sands, the cores are strengthened with iron rods, vented with cinders, and provided with convenient hangers for lifting, as described in previous paragraphs. Where cores must be made in halves, one set of half-cores may be made and baked. The other half is then made and rolled over directly on the baked half. Fire-clay wash is used to cement the joint. This method allows the joint between the halves of a core to be nicely slicked down. Steel cores must be more collapsible than those for iron, on account of the excessive shrinkage of the metal. This is provided for in the mixture of the sand used, and by thoroughly baking the core to reduce the effect of the binding materials to a minimum. STEEL CASTINGS Running a Heat. Open- Hearth Melting. The melting of steel is a science by itself, and cannot be dealt with adequately in an article of this character. Only a very brief description of the process is given. The main feature is the difference in application of heat. INIetal is melted in what is termed the open-hearth furnace, a sectional plan of which is shown in Fig. 147. The charge of scrap steel and pig iron is placed on the central hearth. Heat is obtained by producer gas supplied with air blast. Both gas and air are heated in one set of regenerators before entering the combustion chamber. The flame 142 FOUNDRY WORK plays on top of the charge, and the waste gases pass off through the other regenerator section of the furnace, heating up its brick- work. The direction of the gases is changed about every 20 minutes. The regenerator is practically a tunnel about 15 feet long, filled with brickwork built up as shown in Fig. 148. About 4 heats a day are run from the furnaces. Samples of the bath are analyzed at intervals during the heat. Guided by these analyses the proper proportions of ores, fluxes, 58 I I- Regenerators Regenerators Fig. 147. Section through Open-Hearth Furnace with Regenerators and pig are added to the ])ath to give it the right composition, a typical analysis of which has been given. Pouring. When the bath is in proper condition, the entire charge, be it 5 tons or 40 tons, is drawn off into a ladle previously heated by a special gas burner. This ladle is lifted by the crane and carried to the pouring floor. In order to secure the soundest metal free from pent gases or slag, all steel for casting purposes is tapped from the bottom of the ladle. The stopper is carried by a stiff round bar encased in fire-clay tubing. This passes through the liquid metal, as in Fig. 149, and may be raised or lowered by an arm attached to a rack-and-pinion mech- anism bolted to the outer shell of the ladle and operated by means of a large hand wheel. The ladle is swung into position with the tap FOUNDRY WORK 143 hole directly over the pouring head. Four men hold the ladle steady with long iron rods. The metal thus enters the mold under the head of presi^ure of all the steel above JL H ^Ti — Fig. 14S. _D. XT u XT How Brick Is Set in Regenerators it in the ladle. When all the steel is drawn from the ladle, the latter is swung on its side near the furnaces, the stopper is removed, and all the slag possible is racked out. The ladles Duist be repaired after each heat, often to the extent of replac- ing one-half of the thin fire-brick lining. The casing of the stopper will last for but one heat, as the rod is sure to get bent out of shape. The rods are repaired by a black- smith before recasing them. Setting Up Molds. Set- ting up is usually done by a different set of men from those employed to make the molds. For convenience in pour- ing, rinuicr boxes, such as shown in Fig. 150, and which serve simply as funnel-shaped mouths to the runners, are rammed \\\) in small round sheet-metal boxes, using a wooden pattern to form the hole. These are baked in the oven. When the molds are properly dried, they should be removed from the oven, placed on the pouring floor, and have the dust blown out with compressed air. Now set the cores, close the molds, and clamp along joint flanges. Set runner boxes over the nniners, and tvick heap sand around to prevent leakage. In pouring, a mold is filled only to the level of Fig. 149. Section of Steel Ladle Fig. 150. Runner Box for Steel Mold 144 FOUNDRY WORK the top of the risers. The metal drains from the runner box, thus allowing it to be used more than once. Cleaning Castings. Steel castings do not run as smoothly as cast-iron ones, but they have this advantage, that, if they show only slight surface defects, the metal may be peened over with a hammer to improve appearance. The intense heat makes the metal burn into the sand greatly, so that cleanhig is much more difficult, and the sand often must be almost cut from the castings by means of long cold chisels, struck with sledges. Pneumatic hammers are used to a large extent in cleaning and in removing fins and slight projections. Where shrinkage webs show, they must be cut out. Steel does not break off as does cast iron. The heavy gates and risers must be Fig. 151. Cutting Off Riser removed by metal saws, as shown in Fig. 151, or by drilling a number of 1-inch holes side by side through the base of the riser and then breaking it off. The castings are generally annealed before the risers are cut off. Annealing. In all steel castings of any size, cooling strains will develop on account of the shrinkage, and these should be relieved by annealing. In suitable trench-like ovens, the steel is heated to a dull redness. This allows the grain to assume normal conditions. The heating is usually done with a wood fire. Overheating renders the grain coarse, and weakens the casting. As indicated by the following figures, proper heat-treatment materially increases strength and toughness, and the work which is properly annealed is not only actually stronger, but being tougher, will stand more hard usage. FOUNDRY WORK 145 Conditions Tensile Strength ;lb. per.sq.in.) Elongation (per cent) Reduction OF Area (per cent) Raw Annealed Improperly annealed 80,360 81,767 79,421 13.31 27.6 14.3 16.2 40.4 17.8 MALLEABLE PRACTICE Development. It is believed that early attempts to soften hard castings by reheating them, and the collection anfl ])iiblication of the results of these operations in 1722, by Reaumur, which led to the taking out of patents on the process by Lucas in 1804, comprised the early history of the malleable-iron industry Seth Boyden of Newark, New Jersey, produced the first m;d- leable iron in America. It is recorded that in 1828, The Franklin Institute of Philadelphia, Pennsylvania, awarded him a premium for the best specimens of annealed cast iron. These were mainly harness trimmings. Before 1890, the secrets of the process of malleableizing were closely guarded, which accounts for its slow growth, but since then great advances have been made both in quality and tomiage, due to a better knowledge of the princ-iples involved. As the industry now stands it is farthest advanced in the Ui^ited States. It is estimated that for the year 1907 the output for all Europe was but 50,000 tons as compared with a production of 980,000 tons in America for the same year. It is rather surprising that, while there is more skill required to produce malleables — and there are several extra operations — the price is so little in a(hance of that for gray iron. This is accounted for in part by the large number of castings ordered from a given pattern. Comparative Characteristics of Metal. An idea of the value of this material is best obtained by a comparison of its properties with those of similar substances. Thus, gray-iron castings range from those nearly black in fracture, to white, with all degrees of softness up to glass hardness. They may be strong or weak and still serve their puri)ose. The desirable characteristics of the gray-iron casting is its extreme resistance to compression. Where great shock is to be cared for, great massiveness is required. 146 FOUNDRY WORK The steel casting has the highest strength of any cast metal: it may be deformed considerably without danger, and is cheaper than a corresponding forging. The malleable casting is the connecting link between the two above mentioned. It is stronger than the gray casting but not as strong as cast steel. It can be bent or twisted considerably without breaking, and approaches gray iron in compressive strength; but its most valuable characteristic is resistance to shock. This property is best illustrated by the car coupler, a large number of drop tests having shown the value of the malleable coupler as compared with one of cast steel. TESTING Methods. There are two general ways for testing malleable cast iron: (!) l)y so-called shop tests; and (2) by laboratory tests of bars cast from every heat and annealed with the castings. SJiop Tests. The usual shop tests consist of bending occasional castings, as well as of twisting the longer pieces, and also of the making and breaking of test wedges. These wedges are about 6 inches long and 1 inch square for 3 inches of their total length, then tapering down in thickness to nothing for the last 3 inches, but keeping the full inch width; this gi\es thick iron as well as thin on the same piece. When the test wedges come from the annealing, they should be broken on an anvil by striking them with short light blows, the object being to see how much the thin end of the wedge can be bent before the piece breaks, after which, by holding the two parts together and observing the bend, a very fair idea of the quality of the castings these wedges represent, may be had. Laboratory Tests. The regulation test bars are rectangular in form and are of two sizes: the 1-inch square bar to represent castings 2 inch thick and over; while a 1- by |-inch section bar cares for the lighter castings. The following specifications adopted by the American Society for Testing ]\Iaterials form the only official standard in existence. Specifications for Malleable Cast Iron Process of Manufacture. Malleable-iron castings may be made by the open-hearth, air-furnace, or cupola process. Cupola iron, however, is not recommended for heavy or important castings. FOUNDRY WORK 147 Chemical Properties. Castings for which physical requirements are specified shall not contain over 0.06 per cent of sulphur or over 0.225 per cent of phosphorus. Physical Properties. (1) Standard Test Bar. This bar shall be 1 inch square and 14 inches long, cast without chills and left perfectly free in the mold. Three bars shall be c;ist in one mold, heavy risers insuring sound bars. Where the full heat goes into the castings, which are subject to specifica- tion, one mold shali bo poured 2 minutes after tapping into the first ladle, and another mold shall be poured from the last iron of the heat. Molds shall be suitably stamped to insure identification of the bars, the bars being annealed with the castings. Where only a partial heat is required for the work in hand, one mold shall be cast from the first ladle used and another after the required iron has been tapped. (2) Of the three test bars from the two molds required for each heat, one shall be tested for tensile strength and elongation, the other for transverse strength and deflection. The other remaining bar is reserved for either tensile or transverse test, in case of failure of the other two bars to come up to require- ments. The halves of the bars broken transversely may also be used for the tensile test. (3) Failure to reach the required limit for the tensile test with elongation, as also for the transverse test with deflection, on the part of at least one test, rejects the castings from that heat. (4) Tensile Test. The tensile strength of a standard test bar for casting under si)ecification shall not be less than 40,(X)0 pounds i)er square inch. The elongation measured in 2 inches shall not be less than 2| per cent. (5) Transverse Test. The transverse strength of a standard test bar on supports 12 inches apart, pressure being applied at the center, shall not be less than 3,000 pounds with deflection at least ^ inch. Test Lugs. Castings of special design or special importance may be provided with suitable test lugs at the option of the inspector. At his request, at least one of these lugs shall be left on the casting for his inspection. Annealing. (1) Malleable castings shall neither be over- nor under- annealed. They must have received their full heat in the oven at least 60 hours after reaching that temperature. (2) The saggers shall not be dumped until the contents shall be at least black hot. Finish. Castings shall be true to ))at(ern, free from blemishes, scale, or shrinkage cracks. A variation of ro i'K'h per foot shall Ix^ jMM-niissihle. Found- ers shall not be held responsible for defects due to irn^gular cross-sections and unevenly distributed metal. Inspection. The inspector representing the purchaser shall have all reasonable facilities given him by the founder to satisfy him that the finished material is furnished in accordance with these specifications. All tests and inspections shall be made prior to shipment. In general it may be said it is not necessary to have a metal very high in tensile strength but rather one which has high transverse strength and good deflection. This means a soft ductile metal which 148 FOUNDRY WORK adjusts itself to conditions more readily than a stiff strong product, for it is very hard to jjroduce a strong and at the same time soft material, especially in the foundry making only the lighter grades of castings. PRODUCTION PROCESSES Preparing Molds Patterns. One of the most important departments of the malleable works is the pattern shop. INIalleable castings are com- paratively light when considered in connection with general gray- iron practice and many times are ordered in enormous quantities from the same pattern. Every refinement in pattern-making for light castings is found in this branch of the foundry industry. When developing a new article, the pattern-maker nuist practically Ive in the foundry. As trial castings are made he nuist measure them up with the pattern and make changes as found necessary; he must try them out again both before and after annealing, and with iron from difl'erent parts of the heat, and thus bring out new points calculated to help the molder and to lessen difficulties from shrinkage. It is tlie rule never to start an order for a quantity until the pattern has been tried out, the hard castings have been broken for evidence of shrinkage, and everyone has been satisfied it is safe to proceed. Construction Difficulties. The terms shrinkage and contraction, as applied to malleable castings, should be clearly understood before any further mention is made of this subject. While shrinkage in gray-iron practice is often considered as the shortening of a casting in cooling, in malleable practice shrinkage means the tearing apart of the particles of iron in the interior of a larger section, close to a small one, leaving a spongy mass which is weak and very dangerous to the life of a casting. Contraction being sim})ly reduction in size while the casting is cooling, amounts roughly to 4- inch per foot in the hard, i.e., before annealing. During the annealing, about half of this is recovered, so that the net result is about the same as in gray- iron practice. It should be plain, however, that this big contraction causes the tearing as above mentioned when there are heavy sections which remain in a molten state a little longer than do adjoining light sections, unless liquid iron can be fed in. Where this is impos- FOUNDRY WORK 149 sible, the use of chills must be resorted to and fillets made much larger. In gating patterns it is to be remembered that A\hite iron chills easily and must be poured rapidly. To a certain extent, this limits the number of pieces that may be run successfully, unless the gates be made so large there would be danger of dirty casthigs. The run- ners should be large and the sprues heavy, the idea being to get a large amount of metal in front of the gate for the individual casting. The use of the match plate is largely resorted to also, as being well adapted to this class of work. Fig. 152 shows a group of three of the gated patterns in daily use in the Arcade Mal- leable Iron Foundry, Worcester, Massachu- setts. In Fig. 153 there are shown 84 small thumb nuts on one gate ; also 18 hinge patterns mounted on a match plate. Molding Methods. But little diti'erence from ordinary gray-iron meth- ods, occurs in molding practice other than in gating and in pouring. Since white iron melts at a somewhat lower temperature, there is less danger of sand burning into the casting, so less attention is paid to facing sand. A large per cent of the work is made in the snap flask on xh^ bench, as illustrated in Fig. 154. From the fact that nearly all work is in quantity, here is where molding machines may be used to great advantage. As these are explained elsewhere, no more need be said except that care should be exercised m the selection of t}-pes Fig. 1.52. Giitud I'at terns 150 FOUNDRY WORK Fig. lo3. Typical Gated Pattern and Match Plate- Fig. 154. Molds in Position for Pouring FOUNDRY WORK 151 Fig. 155. View of Molding Floor, Fig. 154, Taken from Opposite End of Plant r"'^ Fig. 156. Sand-Mixing Machine Courtesy of Standard Sand and Machine Company, Cleveland, Ohio 152 FOUNDRY WORK best suited to local conditions. Fig. 155 is a view from the opposite end of the same foundry floor. Flasks. While much of the work is handled in snap flasks, it is not unusual to find metal flasks closely conforming to the shape of the pattern, thereby greatly reducing the amount of sand to be handled, with a corresponding reduction in cost of production. Cores. Practically all castings are cored and the problem is to produce a sufficient number of cores that there may be no delay for the molder. As there is no important difference in the preparation of cores — the same sand and binders being used — the large number required warrants the introduction of modern sand-handling and mixing machinery to a somewhat greater extent than in gray iron. Fig. 157. Mixing Paddles of Standard Sand-Mixing Machine The batch mixer alone proves of great value by the reduction of binder required due to its more even distribution; oftentimes this amounts to nearly 100 per cent. The t;ype of batch mixer shown in Fig. 156 is made by the Standard Sand and Machine Company, Cleveland, Ohio. Fig. 157 is a view of the mixing paddles. Melting Metal Methods of Melting. Under this head the several methods in use will be described, which are as follows: (1) crucible; (2) cupola; (3) air-furnace; and (4) open-hearth. Crucible Melting. The quality of metal produced by this method is without doubt of the best. Being melted out of contact of the fuel, there is no danger of absorbing impurities therefrom, but the small amount of metal available at one time limits the production to. only the smaller work. Partly for this reason, the excessive cost of FOUNDRY WORK 153 production does not admit of competition with other methods which, while hicking somewhat in qiiahty, yet meet actual requirements. Fig. 158. Air Furnace with Bath at End Remote from the Bridge A more detailed description of melting in the crucible is given in the subsequent section on Brass ]\Ielting. Fig. l')9. Longitudinal Section of Air Furnace witli Bath Immediately bohind the Bridge Cupola Melting. As in gray iron, the cupola offers the most economical method of melting iron, not only in cost of installation 154 FOUNDRY WORK and saving of fuel, but in ease of manipulation as well. It has some disadvantages ■which restrict its use, the greatest being the inferior quality of metal produced, which is caused by the contact of metal with the fuel, and also the danger of burned iron which in turn makes sluggish iron, with the result that castings are likely to show pin- holes. There is also greater difficulty in annealing — usually it requires 200 or 300 degrees Fahrenheit higher temperature. This method may be safely used only when the property of bending, rather than strength, is rec^uired. Pipe fittings form a large part of the pro- duction of the cupola method. However, it makes a convenient melting medium for the production of anealing boxes. Fig. 160. Sectioa of Roof of Air Furnace Air-Furnace Melting. The number of furnaces of this type far exceeds all others. In the issue of the Foundry Magazine for Feb- ruary, 1910, the ninnl)cr of the different types of furnaces engaged in the production of malleable in America was given as follows: air furnaces, 369; cupolas, 42; open-hearth furnaces, 21. Figs. 158 and 159 show two general types of air furnace. In the furnace represented in Fig. 159 the bath is immediately behind- the bridge, while that shown in Fig. 158 has its bath at the end, remote from the bridge. Fuel is placed on the gate through the charging door 7), which is of cast iron lined with fire brick. The hearth // is where the metal is placed when charged. E is the stack through which the gases FOUNDRY WORK 155 finally escape. B is the bath where the molten metal collects and at its lowest point the tapping hole is located. The metal is charged by Fig. 161. Complete Installatiou of Air Furnace removing a part of the roof as shown at 0, a section of which is shown in Fig. 160. Peepholes are shown at PPP, which are for observation. Fig. 162. View Showing Method of Firing Air Furnace The iron is charged on the hearth so as to leave openings between the pieces, and the molten metal should be skimmed from time to 156 FOUNDRY WORK time so that it may receive the direct action of the burning gases passing over it. Fig. 161 shows a type of air furnace complete. Fig. 162 is a view of the opposite side wdth a melter in the act of firing. Fig. 163 shows the slag hole, and the slag just skimmed off. The air furnace requires greater skill to operate than does the cupola, and the fuel ratio is higher, but, if of good ciuality and lig. u> .giu properly fired, is not excessive and should average about 3 of metal to 1 of fuel. Oj^en- Hearth Melting. It is said the open-hearth installation represents the highest type of melting ^•et devised, but the high first cost, combined with frequent and hea\y repairs and skill required to operate, confine its use to the largest plants, and as long as the trade is satisfied with the quality of the product of the more easily operated air furnace, it is quite doubtful if the open hearth will be generally adopted. The description of the open-hearth furnace which has been given in Steel-Casting Practice may be referred to. Iron Mixture. Without the proper mixture of iron no furnace will produce satisfactory iron, hence the importance of using the greatest care in this part of malleable practice. FOUNDRY WORK 157 That the reader may clearly understand the basic principles involved, it is necessary first to discuss the various materials entering into the mixture. These include pig iron, sprues, faulty castings, annealed scrap, steel scrap, and ferro-alloys. Good Compositio7i. As all the materials have a bearing on the finished casting and should only be used as they affect this, it is at this time well to give an analysis for good malleable castings, which is as follows : Element Proportion (per cent) Silicon Carbon Sulphur Manganese Phosphorus 0.75 to 1.25 3.00 0.04 (extreme) 0.60 (extreme) 0.20 (extreme) There is considerable latitude allowed due to the class of work to be produced. ]\Iakers of heavy castings exclusively may specify their silicon from 0.75 to 1.50 per cent, while for very light work silicon from 1.25 to 2.00 per cent may be the rule. Total carbon shoud never run below 2.75 per cent in the hard, i.e., before the annealing. ]\Ianganese should average about 0.40, not much lower, and ne\er above 0.60. Sulphur should always be as low as possible, 0.07 per cent l)eing the high limit in the casting, hence the necessity for choosing irons for the mixture which will insure this. Phos- phorus below 0.225 per cent is desired. Pig Iron. Formerly it was thought that only charcoal pig was suitable for malleable practice, but today, owing to improved blast- furnace practice, coke irons which are known to the trade as coke vialleable give first-rate results and are used to a considerable extent, yet it is seldom that the writer has heard of a mixture that did not include one or more of the well-known brands of charcoal iron known to the trade as Mabel, Briar Hill, Hinckley, and FJla. It is generally conceded that a mixture containing several brands of iron, or at least two or three grades of the same brand, produces better castings. Scrap. The next problem which presents itself is the dispo- sition of gates, sprues, and discards, which are daily accumulated in the works, and the per cent of which varies with the class of work 158 -FOUNDRY WORK produced, running as high as 60 per cent in the Hghtest work or not exceeding 25 per cent for very heavy castings. From this it will be seen that it is quite likely to be a varying element. The practice of taking the silicon content for every heat before castings go into the annealing operation gi\es opportunity for fairly exact calcu- lations. Corrections may be made in the mixtures as may be found necessary, otherwise, should there be an accumulation of such material, it would soon become an unknown quantity and so be a source of annoyance as well as of loss to the management. The annealed scrap offers more difficulties owing to the effect which e\en small amounts lune on the quality of the product. Quite frequently there is no attemi)t to use this in the regular mixture but rather to utilize it in the production of annealing pots of which more will be said later. The use of steel scrap in malleable mixtures is proving beneficial although the amount is at present limited to something like 10 per cent. This material should not be charged with the regular mixture, but should be introduced into the bath of molten metal so that it may be quickly covered by the protecting slag, for the steel must not be allowed to burn as this would seriously injure the quality of the castings. It is also possible to use small amounts of gray-iron scrap, though it is seldom necessary to do so, and usually 5 per cent is the limit. FerrosUicon. This material is carried in stock, either as a 0.50 or 0.75 per cent alloy for use in the ladle, or as a 14 to 20 per cent pig for use in the furnace. In choosing metals for the heat it first is necessary to ascertain the silicon content desired in the castings, and then to select such amounts of the different brands of pig iron at hand as are required to bring about the desired result, first making careful calculation of the amount of scrap to be cared for and its effect on the mixture as regards its silicon content. The previous section on ]Melting may be referred to regarding gray-iron mixture. In conclusion, it would be well for the reader to clearly under- stand that it requires greater skill to produce malleables, and for this reason a well-equipped laboratory and a good metallurgist are almost necessities where high quality is the order of the day. FOUNDRY WORK 159 Malleable Casting Variation from Qray=Iron Practice. The furnace having been duly charged for the day's melt with the desired mixture of metal, we will now consider the casting operation which differs only from gray- iron practice in that the metal contains a larger per cent of carbon in the combined form, melts at a lower temperature, and also cools more quickly in the ladle, and for this reason must be handled more rapidly. The hand ladles are of somewhat smaller capacity, usually about 25 pounds, as compared with 40 to 60 pounds in gray-iron practice. Carrying. This lighter burden allows the molder greater free- dom in his movements. It is common practice to see the molder catching-in to the stream of molten metal and running to his floor that the molds may receive the benefit of the hottest metal possible. While this is possible in malleable-iron work, with the larger ladles of gray-iron practice, this would not only be exhausting, but highly dangerous as well. It must be remembered that the majority of work is light and that the floor space required for the setting-up of sufficient molds to pour, say, a 30-ton heat, is considerable, and even with the furnace located as it should be in the center of the works, there must be long carries. These are in part overcome by the installation of some overhead trolley system using 500-pound ladles; and where the nature of the work permits— i.e., it is not too light — this method is of course preferable. Cooling. As there is great danger of the castings developing cracks if exposed to the air while still red hot, it is far better practice to let them remain in the sand until they are at least black hot when they may be safely shaken out: the exception being some special work, as brake wheels, for example, in which there are developed great casting strains. In this case it is found best to shake out while still red hot and quickly place them in a so-called reheating oven which is already fired very hot. This furnace, after being fully charged with the day's output of this special work, is closed and the fire allowed to die out over night, when the castings will be found to be partly annealed, though not in a malleable sense. This treatment is found of considerable value in certain classes of work which otherwise might be hard to save. IGO FOUNDRY WORK Cleaning Castings. The castings having become cool so that they may be readily handled, a rough separation of castings and gates should be undertaken and the cores removed as far as possible, after which the castings should be inspected and all missruns or otherwise defective castings removed. The discards along, with the gates and sprues should then be tumbled to remove the sand scale before being returned for remelting, otherwise it would form an excessive slag and require a larger amount of fuel to remelt. i H A * ''' / J fcr"^'''' Fig. 164. Modern Exhaust Tumbling Barrel Hard' Rolling. After this rough sorting the castings are ready for the hard-rolling room which contains a series of tumbling barrels, all of which should be equipped with an exhaust system, or else the dust created in this department will become the bane of the plant. Fig. 164 shows an installation of modern exhaust tumbling barrels. The castings should be rolled only long enough for the removal of the sand scale, usually accomplished in from 20 to 30 minutes. Some classes of work may be so delicate that it would be impossible to clean them in this manner without too great a loss from breakage, and in such cases the acid bath may be resorted to, or perhaps the FOUNDRY WORK 161 sand blast which is fast superseding other methods of cleaning all classes of castings. Fig. 165 shows a New Haven sand-blast tumbling barrel which is well adapted to this work. After this hard-rolling process the castings are removed to the trimming room w'here the gates and fins remaining may be easily removed with a hammer, thus saving much time in the grinding room after the annealing. Annealing. We now arrive at one of the most important depart- ments of the plant. No matter how carefully all previous operations may have been conducted, all will have been in vain sliould any Fig. 105. Sand-Blast Tumbling Barrel neglect creep into this part of the practice, for it is here that the \cvy nature of the casting is changed from its hard and brittle state showing a white fracture, to the so-called black-heart malleable, the fracture showing a steely rim with a black velvety core. This change is brought about by gradually bringing the tem- perature in the annealing ovens up to about 1600 degrees Fahren- heit, and by maintaining that temperature from 3 to 4 days, after which the fire is allowed to slowly die down ; this whole process requires from 8 to 10 days. There have been attempts made to shorten this 162 FOUNDRY WORK decrees, thereby reducng the total period of the process to about 6 TiL' nWi Packing AiiHoalinK Hoxos Fig. 107. Hand Chargmg Truck days; but this has been clone at the expense of qualitv, and the best results are obtained by the former method the f'lr"''"' f ^^fV- After inspection in the trimn.ing room, the castmgs are brought to the annealing room which has L floor FOUNDRY WORK 163 space divided into two parts — the packing floor, and the ovens. There are usually two rows of o\ens, one on each side of the build- ing, and the clear space between is used for ])acking the pots and also for dumping them after the annealing. The floor of this is made of 1-inch iron plates. The annealing boxes, or laggers, may be either square or round, or perhaps more generally oblong, and are first cast 1 inch thick. These pots are piled three or four high — the first one is placed on an iron stool — all joints being luted up with mud made by adding water to the burnt sand from the rolling room with perhaps the Kig. 108. niterior View of Annealing Oven addition of a little fire clay. The scale used for packing is cinder squeezed from muck balls where wrought iron is made. It was formerly the practice to spread this scale upon the floor and sprinkle it daily with a solution of sal ammoniac to rust it, but later-day practice has proven this unnecessary. As the castings come into the annealing room the operator places a pot on the stool, shtn-els in some scale, carefully placing in a layer of castings in such manner that none comes in contact with the sides of the pot or no two castings touch each other, then" more scale and more castings are added until the pot is filled, as shown in Fig. 166. On this another pot is placed and duly packed, this to 164 FOUNDRY WORK be continued until the pots are piled as high as desired, after which ail joints are sealed with mud making the whole pile more or less 1 IK. U,\). t)\. n ( h i-ig. 1(11. Ash Fir and Iinng Door 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 P^ig. 173. Recording Pyrometer Courtesy of The Bristol Company, Waterbury, ConnecticxU 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 medmm-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 wdiile 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 w^ork 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 are termed alloys — 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. I 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 alloys. 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 sheatliing 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 11 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, tongh, 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 \\ill \olatilize, that is, turn to a g;is 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 in commerce under two names: when rolled into sheets it is called zbic; 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 easily 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 | 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 unpurities to tlie surface. For this reason a small ])ro- 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 copp(T. A very small proportion may be added to the standard mixture for brass or bronze. 170 FOUNDRY WORK TABLE VI Proportions of Mixtures Use Copper Tin Zi NC Lead /per \ Voent / ; ounce) \ cent / founcej / per \ \cent y (ounce) / per \ V cent J Counce) Gun metal — for bearings; very tough hard mix- ture 83 16 12 -'2 2.5 1 '2 2.5 .1 2 Steam or valve metal — cuts freely; very tough; resists corrosion So 16 7 u 5 3 4 3 h 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 3 1 5 1 i 1 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 l.S 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. Phosyhorus. Phosphorus is not a metal, but is a very active chemical element manufactured from bone ash. It has such ap FOUNDRY WORK 171 TABLE VII Phosphor=Bronze Mixtures 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 90. 9.75 .25 9 1 2 Total 100. 10 100. 10 affinity for the oxygen of the air, that in its pure state it must be kept under water, because tlie sHghtest scratch wouhl 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 pliosphorus on the market. The most convenient of these is known as pho.s-phor 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, coml)ining 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 VIl. 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; B — 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. 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 box flasks for floor work. FOUNDRY WORK 173 The most t^-pical brass flasks are of cast iron with accurately fitting round steel pins, as seen in Fig. 174 at ^. They have holes on' the joint at one end of the 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 Sj)ill 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 Store. 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. 176, 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 flask 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. Pouring molds on end gives the pressure necessary to force a more sluggish 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 | 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 i s) If ■'•,." I' » ^ n ». -■ , ' it \ /' " TXT A B Fig. 177. .4— Mold for Thiu Plate; fl— 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. Connect the gates in four places, as shown in A, Fig. 177. Skin-dry the 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 stand 176 FOUNDRY WORK TABLE Vm Crucible Sizes Number Measurements Outside Capacity Weight OF Water Holding Capacity (Liquid Measure) Height Diameter Top Bilge Bottom (gallon) (quart) (pint) (inches) (inches) (inches) (inches) (pounds) 2 U If u 0000 3 1 2f 21 5i If 6 1 6^ 1 5i 3f 2.08 12 2 8 i 61 61 9i 5 4.16 30 1 1 1 11 1 81 6^ 11.5 60 3 ■ 14 ! 101 111 8 25 90 4 2~ 151 1 lU 12^ 9 33.3 300 12 22 16i 17^ 121 104. for a short time, and then blown off. 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 uiultT a large enough pressure to force the metal into every detail of the mold before it has time to cliili. 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. Duplication. For duplicating work, 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 refractory 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 tjpe 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 G 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, which 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 dumped. /? 179. Crucible and Tongs 178 FOUNDRY WORK 111 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. N'alural-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 zmc 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 pkmge it well under the surface Fig. 181. Section through Oil P^urnace 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. /^e/f/ny /'urnoce •^ w S H b IS a bi H H u. H a ••; BS s S « S s K S s K g Q < 6 < 6 < < < a i 0.0123 .3926 10 78.54 31.41 30 706.86 94.24 65 3318.3 204.2 1 0.0491 .7854 h 86.59 32.98 31 754 . 76 97.38 66 3421.2 207.3 f 0.1104 1.178 11 95.03 34.55 32 804.24 100.5 67 3525 . 6 210,4 0,1963 1.570 \ 103.86 36.12 33 855.30 103.6 68 3631.6 213,6 J 0.3007 1.963 12 113.09 37.69 34 907.92 106.8 69 3739.2 216,7 f 0.4417 2.356 5 122.71 39.27 35 962.11 109.9 70 3848.4 219 9 0.6013 2.748 13^ 132.73 40.85 36 1017.8 113.0 71 3959.2 223 l' 0.7S54 3.141 2 143.13 42.41 37 1075.2 116.2 72 4071.5 226.1 ■ 0.9940 3.534 14 153.93 43.98 38 1134.1 119.3 73 4185,3 229,3 1 1.227 3.927 i 165.13 45.55 39 1194.5 122.5 74 4300,8 232 4 ? 1.484 4.319 15 176.71 47.12 40 1256.6 125.6 75 4417,8 235 6 J 1.767 4.713 i 188.69 48.69 41 1320.2 128.8 76 4536 4 238 7 « 2.078 5.105 16 201.06 50.26 42 1385.4 131.9 77 4656 241,9 5 2.405 5.497 i 213.82 51.83 43 1452.2 135.0 78 4778,3 245,0 1 2.761 5.890 17 226.98 53.40 44 1520.5 138.2 79 4901,6 248,1 2 3.141 6.283 i 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 254.4 } 4.908 7.854 i 268.80 58.11 47 1734.9 147.6 82 5281,0 257 . 6 \ 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 J 8.295 10.21 20 314.16 62.83 50 1963.5 157.0 85 5674,5 267.0 a 9.621 10.99 i 330.06 64.40 51 2042.8 160.2 86 5808,8 270.1 3 11.044 11.78 21 346.36 65.97 52 2123.7 163.3 87 5944,6 273.3 4 12.566 12.56 h 363.05 67.54 53 2206.1 166.5 88 6082,1 276.4 J 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 55 2375.8 172.7 90 6361,7 282.7 5 23 . 758 17.27 23 415.47 72.25 56 2463.0 175.9 91 6503,8 285.8 6 28.274 18.84 i 433.73 73.82 57 2551.7 179.0 92 6647 6 289.0 i 33.183 20.42 24 452.39 75 39 58 2642.0 182.2 93 6792 9 292.1 7 38.484 21.99 i 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 8 50.265 25.13 26 530.93 81.68 61 2922 4 191.6 96 72,38.2 301.5 J 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 X0.1666 Weight of flat iron per foot = Width X thickness X 3.333 = 5 pounds for each 5 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. I'in 1() 10.4 Zinc Weight of brass pattern X .9 = weight of iron casting, approximately. FOUNDRY WORK 195 Specific Gravities and Weights of Metals Specific Gravitv Weight per Material 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 lirass, 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 Go d, 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 [yellow 435 Bright iron becomes < P!j^q 500 550 Igray 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 *Froin late scientific investigations. INDEX INDEX PAGE 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 I'l molding process 1 ' 4 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 HI Bronze 168 specific gravity and weight of 195 2 INDEX PAGE c Carbon . 1. 12i, 136 Cast-iron analysis jqq Casting operations jOg brass work ^ _ _ __ _ 167 malleable practice I45 melting gray iron IO9 steelwork 136 Centrifugal sand mixer I29 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 maUeable-iron work, in 160 steel work, in I44 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 57 Core ovens ^ 48 Core plates 48 racks for .- 50 Core sand 6, 46 mixtvn-es 51 Core work 2 46 barrel 92 for brass molding 175 dry-sand 46 general equipment for 48 green-sand 39, 62 for malleable-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 malleable-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 flat-joint „-. 32 floor-bedding pit L-_ 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 ^ 1 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 ^ Flaslcs for 9 brass molding 172 malleabhviron molding ^^- 152 steel molding 138 Flat joint 32 Floor bedding . 23, 42 Foremen, duties of 188 Foundry, typical 182 cleaning department 187 4 INDEX PAGE Foundry, typical (continued) core shop 185 cranes 187 cupolas 184 floor plan 183 heaA^^-molding division ' 185 light-molding division 185 molding machines 186 pattern room :. 184 shop office 184 storage of materials 186 tracks 186 typo 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 Gils furnace for brass melting 179 Gated patterns for duplicate castings 67 Gating 24 Graphite foundry facing 7 Gray iron 109 Green-sand corea __ 39, 62 Green-sand molding 1 principles of 18 typical problems in 31 H Hard-rolling of castings IGO Heat, running a H^ for brass work 174 for malleable casting 159 for steel casting. - 141 I Iron 109 specific gravity and weight of 195 temperature indications 196 J Jointing ^2 loam molds 10" INDEX 5 FAOB K Keep's mechanical analysis of cast iron 190 chilled depth :. 190 deductions by 191 siUcon and shrinkage 190 transverse strength 190 Labor, shop management of foundry 188 foremen 188 laborers 188 moldera 188 superintendent 188 Laborers, duties of foundry 188 Ladles for 118 brass work 177 malleable-iron work 159 steelwork - 142 Laying up loam mold " , 99 Lead 169 melting temperature 196 specific gravity and weight of 195 Lifters 15 Lifting ring, core 40 Lining HI cupola-furnace HI 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 1^^^> 196 cleaning 160 finishing 167 melting, methods of 152 metal characteristics 145 method of casting 159 methods of testing 146 mixture for 156 molding 1^^ patterns for !■*" specifications for 14^ 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 J 9 Molders, duties of -_ 188 Molding machines 67 Molding practice 1 brass 1 167 divisions of iron molding 1 general molding equipment 3 maUeable-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, 13G, 170 PickUng 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 jarorjolt 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 PAGE 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 i 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 Shp 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 Squeezer machine (continued) automatic g6 power type 75 Steel 137 annealing castings of I44 casting, running a heat for 141 cleaning castings of . I44 cores in molding 1 141 facings for, mold I37 flasks for molding 138 molds for, setting up I43 packing process in molding I39 specific gravity and weight of 195 temperatui'e, 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 mixtvu^es 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 Tumbling castings 131 Tuyeres HI V V«nt rods 1(5 Ventilation systems in typical foundry 183 Venting ^ 22 dry-sand cores 47 loam molds 100, 106 W Warping 31 Wliitc iron in malleable practice 149 Z Zinc 169 melting temperature ._ .^ 196 341 90 \»o >" v^ <3, *r7o' aO-' lV.^ o V .^ .^^-^^.^ *•' C * J .0 ''^ -,,1- «,. 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