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FORGING 



AMERICAN SCHOOL °f CORRESPONDENCE 

CHICAGO ILLINOIS 

T T U. S. A. 

2.15 





Class T' \ ; _ 
Book . h 5 ' 



Copyright N°. 



COPYRIGHT DEPOSIT. 



FORGING 



INSTRUCTION PAPER 



PREPARED BY 

John Lord Bacon 

Instructor in Forge Work 

Lewis Institute 

American Society of Mechanical Engineers 

Author of "Forge Practice" 



AMERICAN SCHOOL, OF CORRESPONDENCE 



ILLINOIS 
U.S.A. 




$ 



.* 



LIBRARY of CONGRESS 
Two Copies Received 

APR 23 1906 



BLASS 



OPY B. 



Copyright 1906 by 
American School of Correspondence 



Entered at Stationers' Hall, London 
All Rights Reserved 



FORGING. 



Forging in general treats of the hammering, working, or forming 
3f heated metals. 

The Materials upon which the work of forging or blacksmith- 
ing is done, are wrought iron and steel. As explained in "Metal- 
lurgy," wrought iron is an iron from which "the silicon phosphorus 
and most of the carbon has been removed." Steel usually con- 
tains some of the impurities that are characteristic of cast iron with 
the marked peculiarity of holding a varying percentage of carbon. 
Mild steels are so called on account of the small amount of carbon 
which they contain. As the percentage of carbon increases, it be- 
comes more difficult to weld the metal. Greater care must also be 
used in heating lest the metal be burned and its strength destroyed. 
Until recently all heavy forgings involving welding, were made of 
wrought iron, but now it is customary to make most forgings of mild 
steel, particularly large ones, although wrought iron is somewhat 
more satisfactory where a great amount of welding is required. 

These metals may be roughly divided into three general classes; 
although the. division line may not be sharply drawn between any 
two classes, the classes being Wrought Iron, Machine Steel and Tool 
Steel. The characteristics and method of manufacture of the three 
metals are described in "Metallurgy." A rough distinction such as 
a blacksmith would use is about as follows: Wrought Iron has a 
fibrous structure with stringy streaks of slag running lengthwise of 
the bar giving it a decided fibre, similar to wood. Machine Steel, 
more properly described as mild steel, or sometimes called soft steel, 
has much the same properties as wrought iron excepting that it lacks 
the fibre and is somewhat stronger. Tool Steel differs from the 
other two materials in the fact that by suddenly cooling from a high 
heat it may be made very hard, or hardens, as the technical term is. 
Wrought iron or machine steel are not hardened by the same treat- 
ment. Tool steel is practically the same thing as wrought iron or 



FORGING 



V., 



v.T". ; , y ': 7. ;;-,:. 




Fig. 1. 



machine steel with a small percentage of carbon added. In fact, 
either of the two metals may be turned into tool steel by the addition 
of carbon. This principle is used in case hardening. Norway iron 
or Swedish iron is a grade of very pure wrought iron containing little 

slag. It is more expensive 
than ordinary wrought 
iron.. Refined iron is a 
grade of wrought iron 
not as good as Norway 
iron but better than or- 
dinary iron. Norway 
iron costs about twice as 
much as machine steel, 
which is somewhat 
cheaper than wrought 
iron of almost any grade. Machine steel, made by both the open- 
hearth and Bessemer processes, is used for forging. 

EQUIPMENT. 

The equipment of the forge shop consists in general of a forge 
in which the metals are heated, an anvil for resting the metals on 
while hammering, and the 
various tools as described 
below for shaping and 
working. 

The Forge. While forges 
or fires are of many shapes 
and sizes the principles of 
their construction remain 
the same. An ordinary 
blacksmith forge is a fire- 
place in the bottom of 
which there is a tuyere for 
admitting a blast of air to 
blow the fire. Where the 




Fig. 2. 



air blast is furnished by a hand bellows, the pipe leading therefrom to 
the tuyere is open throughout. Where a power-driven blower furn- 
ishes the blast, there is a valve in the pipe for regulating the* same. 



FOKGING 



The usual form of tuyere consists of a single blast pipe, open- 
ing into the bottom of the fire pit. This may be a simple nozzle as 
in Fig. 1, with the blast regulated by a damper in the pipe; or, it 
may have a regulator at the mouth of the tuyere as shown. Some- 
times the tuyere has several openings, and is then in the form of a 




jSjaggBB^"^ 



Fig. 3. 



grate. Whatever its form, it should be possible to clean it from be- 
low, in order- that coal and clinkers falling into it may be removed. 
A modern type of forge is shown in Fig. 2. This is provided 
with a hood for carrying off the smoke. The pipe connected to the 
hood extends downward to an underground flue leading to an ex- 
haust fan which draws out the air. The blast pipe is also under- 



FORGING 



ground, and a small pipe leads upward to the tuyere, the amount of 
blast admitted to the fire being regulated by a slide in this pipe. 
This system of underground piping is known as the "Down Draft" 
system. 

In some shops no provision is made for carrying off the smoke, 
while in others hoods are placed above the forges and connected to 
overhead pipes, which may be either connected to an exhaust fan or 
led directly to the roof. The "Down Draft" system is the more mod- 
ern and generally the best. 

The Blast is furnished to the fires of a blacksmith shop by blowers 
of various kinds. For many years the ordinary bellows was used. 
This has been superseded by the fan blower which is now almost 
universally used, even for hand power. 

Such a fan blower is shown in Fig. 3. It is formed of a thin 
cast-iron shell in which there are a set of rapidly revolving blades. 
These blades set up a current of air which presses against the side 





of the shell and escapes through the tangential opening. The 
pressure of the blast used for an open blacksmith fire varies from 
about 2 to 7 ounces per square inch. The lower pressure is used 
for a light fire and light work. The higher pressure is suitable 
for heavy classes of work. 

Hammers. Several kinds of hammers are used in a forge shop. 
The commonest shape is the ball pene shown at A, Fig. 4. Other 
kinds are the straight pene and cross pene illustrated at B and C. 
A square faced hammer sometimes called a blacksmith's hammer, 
is shown at D. This is occasionally used on tool work. Com- 
monly a ball pene hammer of about a pound and a half weight is used. 



FORGING 



In the fitting of the handle to the head great care should be 
taken. Hammer handles are made elliptical in cross section. The 
major axis of this ellipse should exactly coincide with that of the 
eye of the head. The reason is that the hand naturally grasps the 
handle so that its major axis lies in the direction of the line of motion. 
Hence, unless the handle is properly fitted in this particular, there 
will be constant danger of striking a glancing blow. The handle 
should also stand at right angles to a center line drawn from the ball 
of the pene to the face. The eye in the head is usually so set that the 






weight on the face side is greater than that on the pene. The effect 
of this is to so balance the tool that heavier and more accurate blows 
can be struck than if the weight were evenly balanced on each side 
of the eye. 

Sledges are heavier hammers used by the blacksmith's helper 
and vary in weight from five to twenty pounds. The three common 
shapes are shown in Fig. 5; A, B, and C being cross pene, straight pene 
and double faced sledges respectively. A sledge for common work 
ordinarily weighs about 12 pounds. Sledge handles are generally 
about 30 to 36 inches long, depending on the nature of the work 
to be done. 

Anvils. Next to the hammer in importance is the anvil. This 
may be any block of metal upon which the piece to be shaped is laid. 
The anvil must be of such a weight that it can absorb the blows that 
are struck upon it without experiencing any perceptible motion 
in itself. 

The ordinary anvil, Fig. 6, has remained unchanged in form 
for many hundreds of years. As now made, the body a is of wrought 



6 FORGING 



iron to which a face of hardened steel is welded. From one end 
there projects the horn b, and the overhang of the body at the other 
end c, is called the tail. At the bottom there are four projections d, 
called the feet, which serve to increase the base upon which the anvil 
rests as well as to afford the means for clamping it down into position. 
In the tail there is a square and a circular hole. The former is 
called the hardie hole, the latter the spud hole. 

An anvil of this form serves for the execution of any work that 
may be desired. 

Anvils are also made with a body of cast iron, to which a face 
of steel is welded. 

The anvil should be placed upon the end of a heavy block of 
wood sunken into the ground to a depth of at least two feet, so that 
it may rest upon a firm but elastic foundation. As the anvil is sub- 




Fig. 6. 

jected to constant vibrations, by the nature of the work, it is necessary 
that it should be firmly fastened to the block. 

Anvils are classed and sold by weight. The weight is generally 
stamped on the side of the anvil. Three numbers are used. The 
first to the left shows the weight in cwt. of 112 pounds each. The 
middle number shows the additional quarters of cwt. and the right 
hand figure the number of odd pounds. For instance, an anvil 
marked 2-3-4 would weigh 2X112 + f of 112 + 4 lbs. =312 lbs. and 
would be known as about a 300-pound anvil. Anvils are sometimes 
made of special shapes, but the one here shown is the common one. 

Tongs. Next to the hammer and anvil in importance and 
usage are the tongs. They vary in size from those suitable for hold- 



FORGING 



ing the smallest wires to those capable of handling ingots and bars 
of many tons in weight. The jaws are also adapted to fit over the 
piece to be handled and are of a great variety of shapes. As the 




Fig. 7. 

requirements of each piece of work varies so much from that which 
precedes and follows it, it is customary for the blacksmith to dress 
his own tongs and adapt them, from time to time, to the work he 
has in hand. Comparatively few, therefore, of the various shapes 
of tongs found in shops are manufactured and for sale. A few of 
the general types and forms in common use are here given. 

A, Fig. 7, shows a pair of flat-jawed tongs, the commonest shape 
used. B is a pair of pick-up tongs used for holding work while tem- 
pering, and picking up pieces 
of hot metal. C is a common 
shape used for holding both 
square and round iron, the 
jaws being bent to fit the 
stock in each case. A modi- 
fication of this shape is also 
used for heavy steam hammer 
work. Tongs frequently have 
the jaws made in some special 
shape for a particular piece 
of work, the object always being to have the jaws grip the work as 
firmly as possible. 

Fitting Tongs. Tongs must be always carefully fitted to the work. 
Tongs which take hold of the work as shown in Fig. 8. should not 




Fig. 8. 



FORGING 



be used. The first pair shown have the jaws too close together, 
the second, too far apart. When properly fitted the jaws should 
touch the work throughout the entire length as shown in the lower 
sketch. To fit tongs the jaws are heated red hot, the piece to be held 





Fie;. 9. 



Fig. 10. 



placed between them, and the jaws hammered down until touching 
their entire length. Tongs which do not fit the work perfectly 
should never, under any circumstances, be used. When in use on 
all but the smallest work, a link is driven over the handles to grip the 
tongs in position as shown. 

Set Hammers and Flatters are used for smoothing off flat work 
when finishing. The set hammer, Fig. 9, is used for working up into 
corners and narrow places. The flatter, Fig. 10, is used on wide 

flat surfaces. The face of the 
set hammer used on light work 
is generally about lj inches 
square. That of the flatter 
about 2| inches square, although 
the sizes vary depending upon 
the kind of work. 

Swages, shown in Fig. 11, are 
used for finishing round and con- 
vex surfaces. The upper tool is 
known as the top swage and is 
provided with a handle. The 
lower one is the bottom swage and is held in place by a square 
stem or shank which extends downward and fits into the bardie 
hole of the anvil. Tools of this character should never be used 
on an anvil where they fit so tight that it is necessary to drive 
them into place. The swages shown here are used for round 




Fig. 11. 



Fig. 12. 



FORGING 



work. Swages are also made for octagonal, hexagonal and other 
shapes. 

Fullers, used for working grooves or hollows into shape, are also 
made top and bottom as shown in Fig. 12. The top fuller is for fin- 
ishing into round corners, around bosses, and on the inside of angles 
as illustrated later on. The fuller is also used to spread metal, 
when it is wished to work the metal only in one direction. The 
metal spreads at right angles to the working edge of the fuller. 

Swage Blocks, a common sort of which is shown in Fig. 13, 
are used for a variety of purposes mostly for taking the place of 




Fig. 13. 

bottom swages. These blocks are commonly made from cast iron 
and weigh about 150 pounds. 

Other Tools. The tools used commonly are calipers, a car- 
penter's two-foot steel square, dividers, a rule, shovel, tongs, ladle, 
poker and a straight bar for loosening the fire. In addition to the 
ordinary calipers, a blacksmith usually has a pair of double calipers 
similar to those shown in Fig. 14. With these, two dimensions may 
be used, one side being set for the thickness, and the other for the 
width, of the material. When several measurements are to be made 
particularly on large work, a strip of light stock about |-inch by 1 
inch wide is used. The different dimensions are laid off on this 
with chalk or soapstone. In use the strip is held against the work 
and used in the same manner as a rule. A light rod having a small 



10 



FORGING 



bent end, made by bending over about \ inch of stock at right angles, 
is also sometimes used, particularly when working under the steam 
hammer. The dimensions may be laid off from the inside of the 
hooked end. When in use the hooked end is pulled against the end 
of the material. Soap-stone crayon is ordinarily used for marking 
on iron. The marks do not burn off, but will not show at a red heat. 
Marks to show at a high heat must be made by nicking the corner 
of the bar with a chisel or by marking with the center punch. An- 
other common way of making measurements on hot material is to 
lay off the different distances on the side of the anvil with chalk, the 
dimensions being laid off from one corner or end. 

Fuel. The common fuel for small fires is "soft" or bituminous 
coal, coke for large fires and furnaces, and occasionally hard coal 

in small furnaces. The soft coal used 
is of a grade known as smithing coal. 
It should be very clean and free from 
impurities. A lump of good forge coal 
breaks easily with a crumbly looking 
fracture and the coal shows clean and 
bright on all faces. It will not break 
up into layers as "steaming" coal will, 
these seamy looking breaks being 
caused by the more or less earthy 
impurites. If forge coal splits and 
shows dull looking streaks or layers, it 
is poor coal. Good coal has little 
clinker and breaks easily. When 
used, the coal is dampened and kept 
wet before putting on the fire. It 
should be broken up fine before 
dampening, and not used in lumps. 
Fires. The fire must be carefully 
watched. It is very important that it 
should be in first class condition at all times for the work in hand. 
A certain depth of fire is always necessary. If the fire be too 
shallow, the cold blast will penetrate the fire in spots, making it 
impossible to heat the metal. There should be depth enough to 




JK 



Fig. 14. 



FORGING 11 



the fire to prevent this. For small work there should be at least 
three or four inches of fire below the metal that is heating. There 
should also be thickness enough of fire above the work being heated 
to prevent the metal from losing heat to the outside air. The fire 
should be kept as small as possible to heat the work properly. As a 
general rule the fire will follow the blast. If the fire is wanted larger 
it may be made so by loosening the edges of the fire by a bar, allowing 
the blast to come through around the sides, causing the fire to spread. 
When a small fire is wanted the damp coal should be packed down 
tightly around the sides and the center of the fire loosened up slightly. 
For light work a small round fire is used. For heavier heating the 
fire is started by placing a large block on top of the tuyere, on each 
side of which green coal is packed down hard in the shape of an 
oblong mound. The block is then removed and the fire started in 
the hole left. These mounds are left undisturbed and fresh fuel is 
added to the fire in the shape of coke which has either been previously 
made by loosely banking a quantity of green coal over the fire and 
partially burning it to coke, or is bought ready made. With a small 
fire the fuel is constantly added around the sides where it is turned 
into coke. This coke is raked into the center of the fire as wanted 
and more coal added around the sides and patted down to keep the 
fire in shape. 

Oxidizing and Reducing Fires. When too much blast is blown 
through the fire all the oxygen is not burned out of the air. This 
attacks the iron, forming a heavy coat of oxide, or scale, (the black 
scale which falls from heated iron). This sort of a fire is known as 
an oxidizing fire and should not be used when it is possible to avoid it. 
When just enough air is being admitted to keep the fire burning 
brightly and all of the oxygen is burned, the fire is in good condition 
for heating. Very little scale is formed and some of the scale already 
formed may even be turned back to iron. This sort of a fire is known 
as a reducing fire. In other words, when the fire is in condition to 
give oxygen to anything, it is an oxidizing fire. If in condition to 
take away oxygen, it is a reducing fire. 

Banking the Fire. The fire may be kept for some time by pla- 
cing a block of wood in the center and covering over with fresh coal. 

Stock. Material from which forgings are ordinarily made comes 



12 FOEGING 



to the forge shop in the shape of bars having uniform sections through- 
out; generally round, square, or rectangular in section, and varying 
from ^-inch thick to 18 inches square. Heavier sizes may be had to 
order. Bars are ordinarily 12 to 20 feet in length. Thin stuff, f of 
an inch or less in thickness, usually comes in strips of about 40 feet. 
This may be had from stock up to six or eight inches wide. Tool 
Steel also comes in bars generally about six or eight feet long. The 
ordinary sizes of tool steel stock are known as base sizes and the 
price is fixed on these base sizes. Stock of a larger or smaller size 
than the base sizes is generally charged for at an increase in price. 
Thus inch square tool steel, which is a base size, is worth in certain 
grades about 14 cents a pound. Steel of exactly the same grade and 
character, T ? 6 of an inch square, costs about 18 cents. 

WELDING. 

If a piece of steel or iron be heated, as the temperature is 
raised the metal becomes softer. Finally a heat is reached, called 
the welding heat, at which the metal is so soft that if two pieces 
similarly heated be placed in contact, they will stick. If the pieces 
so heated be placed together and hammered, they may be joined 
into one piece. This process is known as welding. The greatest 
difficulty in welding is to heat properly, which must be done evenly 
and cleanly. If the temperature is raised too high, the iron will 
burn, throwing off bright star-like sparks. If the temperature be 
too low, the pieces will not stick to each other. The proper heat can 
only be determined by experimenting, which may be easily done by 
doubling over a piece of scrap iron for two or three inches and weld- 
ing into a solid piece. 

When heating wrought iron and mild steel, as the welding heat 
is reached, small particles of the metal are melted and blown upward 
from the fire by the blast. As these small particles come in contact 
with the air they burn and form small explosive sparks, like little 
white stars. Whenever these sparks are seen coming from the fire, 
it is a sure indication that the iron is burning. These sparks are 
sometimes used as a sort of an indication of the welding heat. The 
only sure way of determining the heat is by the appearance of the 
heated iron, which might be described as sort of creamy white. The 



FORGING 13 



welding heat is sometimes described as a white heat. This is not 
correct, as iron or steel is never raised to a white heat even when 
melted. This may be easily proved by comparing a piece of wrought 
iron at welding heat, with an ordinary arc lamp. When two pieces 
of metal are welded together there must be nothing between them. 
Heated iron or steel is always covered with scale (iron oxide). This 
scale, if allowed to stay on the surfaces to be joined, will prevent a 
good weld. It is necessary when welding, to heat the iron or steel to 
a high enough temperature to melt this scale and when the two pieces 
are put together, if the joint or scarf is properly made, most of this 
melted scale is easily forced from between the two pieces, leaving 
the clean surfaces of the metal in contact. This scale only melts at 
a very high heat, much higher than the heat at which it would be 
possible. to weld the iron could it be kept free from scale. 

Fluxes. These are used to- lower the melting point of the scale. 
The flux is sprinkled on the surfaces to be joined just before the 
metal reaches the welding heat. The metal is then put back into 
the fire, raised to the welding heat and the weld made as usual. The 
scale is acted upon by the flux and melts at a lower heat than when 
no flux is used. As the flux melts it spreads, or runs, over the hot 
metal and forms a sort of protective covering, which, by keeping out 
the air, prevents to a large extent, the formation of more scale. The 
flux in no way acts as a cement or glue to stick the pieces together, 
but merely helps to melt off the scale already formed, and prevents 
the formation of more. 

Sand and Borax. These substances are common fluxes. Sand 
may be used when welding wrought iron and machine steel; borax 
in place of sand for fine work and when welding tool steel. Borax 
is a better flux as it melts at a lower temperature than sand, and thus 
makes welding possible at a lower heat. Borax and salammoniac 
(ammonium-chloride) are sometimes mixed and used as a welding 
compound, or flux, the proportion being about four parts borax to 
one part salammoniac. This mixture is also a good flux for brazing. 
Borax contains a large amount of water which makes it boil and 
foam when melting and in this condition is very liable to drop away 
from the heating metal. If borax be heated red hot and allowed to 
cool, the water is driven off and the borax left in a glass like condition. 



14 



FORCING 



Borax treated this way and then powdered, is the best for welding, 
as it melts and sticks to the metal without any boiling. 

Welding Compounds are fluxes serving the same purpose as 
sand or borax. Some of the better ones use borax as a basis. Some 
of these compounds are first' class for their purpose and others are 
not as good, being simply intended as cheap substitutes for borax. 

Fagot Weld. This is made by simply placing two or more 
pieces on top of each other and welding them in a lump or slab. 
Scrap iron is worked up in this way by making a pile six or eight 
inches square and eighteen inches or two feet long on a board, such as 




Fig. 15. 

shown in Fig. 15. This pile is bound together with wires and placed 
in a furnace, fluxed with sand, and welded into a solid lump under a 
steam hammer. These lumps are afterwards worked out in bars 
or slabs by rolling or hammering. When a large piece is wanted, 
two or more of these bars are placed together and welded. 

Scarfing. For most welding the ends of the pieces to be joined 
must be so shaped that when welded they will make a smooth joint. 
This shaping of the ends is known as scarfing, and the shaped end 
is called a scarf. The scarfed ends should not fit tightly before 
welding, but should be so shaped that they touch in the center of the 
joint, leaving the sides somewhat open. In this way when the weld 
is made, the melted scale is forced from between the pieces. If the 
scarfs were made to touch on the edge of the joint, leaving the center 
hollow, the scale not having a chance to escape, would be held in the 
center of the joint, leaving a weak place, and making a bad weld. 



FORGING 



15 



Lap Weld. This is the common weld used for joining flat bars 
together. The ends to be welded are scarfed or shaped as shown 
in Fig. 16. In preparing, the ends of the pieces to be welded should 




Fig. 16. 

be first upset until they are considerably thicker than the rest of the 
bar. This is done to allow for the iron that burns off, or is lost by 
scaling, and also to allow for the hammering when welding the pieces 
together. To make a proper weld the joint should be well hammered, 
and as this reduces the size of the iron at that point, the pieces must 
be upset to allow for this reduction in size. For light work the scarf- 
ing may be done with a hand hammer. For heavy work a fuller and 
sledge should be used. After upsetting on light work, the end to be 





Fig. 17. 



Fig. 18. 



scarfed is roughly shaped with the pene end of the hammer as illus- 
trated in Fig. 17, the final finishing being done with the flat face of 
the hammer. 

For this work (finishing the edge of the scarf) as well as all 



16 



FORGING 



pointed work, the end of the bar should be brought to the extreme 
edge of the anvil in the manner indicated in Fig. 18. In this way a 
hard blow may be struck with the center of the face of the hammer 
without danger of striking the hammer on the anvil. For all ordinary 
lap welding the length of the scarf may be about 1^ times the thick- 
ness of the bar Thus on a bar 
^-inch thick, the scarf will be about 



Fig. 19. 



f of an inch long. The width of 
the end, Fig. 16, should be slightly 
less than the width of the bar. 
In welding the pieces together the 
the first piece held by the helper 
should be placed scarf side up on 

the anvil and the second piece laid on top, scarf side down, over- 
lapping them to about the amount shown in Fig. 19. As it is gen- 
erally somewhat difficult to lay the top piece directly in place, it 

should be steadied by resting lightly 
against the corner of the anvil and 
thus "steered" into place. 

Round Lap Weld. This is the 
weld used to join round bars end to 
end to form a continuous bar. All the 
precautions regarding the scarf, etc., 
used for making the lap weld should 
be taken with this as well. The gen- 
eral shape of the scarf is shown in 
Fig. 16. It will be noticed that the 
end is hammered to a sharp point. If 
the scarf be made with a flat or chisel- 
shaped end similar to the flat lap 
weld, the corners will project beyond 
the sides of the bar in welding and 
cause considerable trouble, as it will then be necessary to work 
entirely around the bar before the joint be closed down. With 
a pointed scarf the weld may be frequently made by hammering on 
two sides only. This is not so important when welding between 
swages. 




Fig. 20. 



FORGING 17 



Ring Round Stock. When a ring is made, the exact amount 
of stock may be cut, the ends upset and scarfed as though making a 
round lap weld, the stock bent into shape as shown in Fig. 20 and 
welded. The ends should be lapped sideways as shown. In this 
position a ring may be welded by simply laying it flat on the anvil, 
while if lapped the other way, B, one end in, the other out, it would 
be necessary to do the welding over the horn of the anvil. In all weld- 
the piece should be so lapped that the hammering may be done in 
ing the quickest and easiest manner. 

Allowance for Welding. In work of this character when the 
stock is cut to a certain length, allowance is sometimes made for loss 
due to welding. The exact amount is hard to determine, depending 
on how carefully the iron is heated and the number of heats required 
to make the weld. The only real loss which occurs in welding is 
the amount which* is burned off and lost in scale. Of course when 
preparing for the weld, the ends of the pieces are upset and the stock 
consequently shortened. The piece is still further shortened by 
overlapping the ends when making the weld, but as" all of this material 
is afterwards hammered back into shape no loss occurs. No rules 
can be given for the loss in welding, but as a rough guide on small 
work, a length of stock equal to from j to f the thickness of the bar 
will probably be about right for waste. Work of this kind should 
be watched very closely and the stock measured before and after 
welding in order to determine exactly how much stock is lost. 

Chain Links. The first step in mak- 
ing a chain link is to bend the stock into 
a "U" shape, care being taken to have 
the legs of the "U" exactly even in 
length. The scarf used is approximately Fig. 21. 

the pointed shape used for a round lap 

weld scarf. An easy method of scarfing is as follows: One end of 
the "U" shaped piece is laid on the anvil as indicated in Fig. 21. 
This is flattened by striking directly down with the flat face of the 
hammer, the piece being moved slightly to the left, as shown by the 
arrow, after each blow, until the end is reached. 

This operation leaves a series of little steps at the end of the 
piece and works it out in a more or less pointed shape as shown in 




FORGING 



A^> 




Fig. 22. 



Fig. 22 at A. The point should be finished by placing it over the 
horn of the anvil and touching up with a few light blows. After 
scarfing the other end of the "U" in the same manner the ends are 

overlapped as indicated at B and welded 
together. The second link is scarfed, 
spread open, and the first link inserted. 
It is then closed up again and welded. 
The third is joined on this, etc. When 
made on a commercial scale, light links 
are not always scarfed but sometimes 
simply hammered together and welded in 
one heat. This is not possible in ordi- 
nary work. 

Band Ring. A method of making a band ring from iron bent 
flat ways is illustrated in Fig. 23. Stock is cut to length, the ends 
upset and scarfed, using a regular 
flat weid scarf, and the ring bent 
into shape and welded; the welding 
being done over the horn of the 
anvil. The heating must be care- 
fully done or the outside lap will 
be burned before the inside is 
nearly hot enough to weld. 

Flat or Washer Ring. This is a ring made by bending flat 
iron edgeways. The ends of the stock are first upset but not scarfed, 
except for careful work, the ring bent into shape, and the corners 

trimmed off on radial lines as shown 
in Fiff. 24. The ends are then scarfed 
with a fuller or pene of a hammer 
and lapped over ready for welding 
as shown in Fig. 25. 

Butt Weld. When pieces are 
simply welded together end to end 
making a square joint through the 
weld, it is known as a butt weld. It is best when making a weld 
of this kind to round the ends slightly as illustrated in Fig. 26. The 
ends are heated and driven together and this round shape forces 




Fig. 23. 




Fig. 24. 



Fig. 25. 



FOKGING 



19 



out the scale and leaves a clean joint. As the pieces are driven 
together they are more or less upset at the joint, making a sort of 
a burr. This upset part should be worked down at a welding heat 
between swages. A butt weld is not as safe or as strong as a lap 
weld. Long pieces may be butt welded in the fire. This is done 





Fig. 26. 

by placing one piece in the fire, from each side of the forge. When 
the welding heat is reached the pieces are placed end to end, one 
piece "backed up" with a heavy weight, and the weld made by 
striking with a sledge hammer against the end of the other piece. 
Jump Weld. Another form of butt weld shown in Fig. 27 is 
a jump weld which however is a form which should be avoided as 
much as possible, as it is very liable to be weak. In making a weld 





Fig. 27. Fig. 28. 

of this kind the piece to be butted on the other should have its end 
upset in such a manner as to flare out and form sort of a flange, the 
wider the better. When the weld is made, this flange may be worked 
down with a fuller or set hammer, thus making a fairly strong weld. 
Split Weld for Thin Stock. Very thin stock is sometimes 
difficult to join with the ordinary lap weld for the reason that the 



20 



FORGING 



pieces lose their heat so rapidly that it is almost impossible to get 
them together on the anvil before they have cooled below the welding 
heat. This difficulty is somewhat overcome by shaping the ends 
as shown in Fig. 28. The ends are tapered to a blunt edge and split 
down the center for half an inch or so, depending upon the thickness 
of the stock. Half of each split edge is bent up, the other down, the 

pieces are driven tightly together and 
the split parts closed down on each 
other as shown in Fig. 28. The joint 
is then heated and welded. This is a 
weld sometimes used for welding 
spring steel, or tool steel. 

Cleft or Split Weld for Heavy 
Stock. Heavy stock is sometimes 
welded by using a scarf of the shape 
shown in Fig. 29. One piece is split 
and shaped into a "Y" while the other 
has its end brought to a blunt point. 
When properly shaped, the pieces are 
heated to the welding heat and driven 
together. The ends of the "Y" are 
then closed down over the other piece 
and the weld completed. A second 
heat is sometimes taken to do this. 
This weld is often used when joining 
tool steel to iron or machine steel. 
Sometimes the pieces are placed to- 
gether before taking the welding heat. 
Angle Weld. In all welding it 
should be remembered that the object of the scarfing is to so shape 
the pieces to be welded that they will fit together and form a 
smooth joint when properly hammered. Frequently there are sev- 
eral equally good methods of scarfing for the same sort of a weld, 
and it should be remembered that the method given here is not 
necessarily the only way in which that particular weld may be 
made. Fig. 30 shows one way of scarfing for a right angled weld 
made of flat iron. Both pieces are scarfed exactly alike, the 




Fig. 29. 



FORGING 



_ 



21 



scarfing being done by the pene end of the hammer. If necessary, 
the ends of the pieces may be upset before scarfing. Care should 





Fie. 30. 



Fig. 31. 



be used here as in other welds to see that the pieces touch first in the 
center of the scarf, otherwise a pocket will be formed which will 
retain the scale and spoil the weld. 

T=Weld. A method of scarfing for a T-weld is illustrated in 
Fig. 31. The stem A should be placed on the bar B, when welding, 
in about the position shown by the dotted line. 

T=Weld Round Stock. Two methods of scarfing for a T-weld 
made from round stock are shown in Fig. 32. The scarfs are formed 
mostly with the pene end of the hammer. The illustration will ex- 
plain itself. The stock should be well upset in either method. 

Welding Tool Steel. The general method of scarfing is the 
same in all welding but greater care must be used in heating when 
welding tool steel. The flux used for welding tool steel should be 
the salammoniac and borax mixture mentioned before. Spring 
steel or low carbon steel may be satisfactorily welded if care is used. 
To weld steel successfully the following precautions should be ob- 
served. Clean the fire of all cinders and ashes. Put sufficient coal 
upon the fire so that it will be unnecessary to add more coal while 
taking the welding heat. Upset both pieces near the end and scarf 
carefully. When possible, punch a hole and rivet the two pieces 
together. Heat the steel to a full red heat and sprinkle with borax. 
Replace in the fire and raise to the welding heat. Clean the scarfed 
surface and strike lightly at first, followed by heavier blows. The 
appearance of steel when at a welding heat is a pale straw color. 



22 



FORGING 



Always avoid a weld of high carbon steel alone, when possible. 

Steel may also be welded to wrought iron. This is done in the 

manufacturing of edged tools. The. body of the tool is of iron, to 

which a piece of steel is welded to form the cutting edge. This class 

of work is best done with a fire 
of anthracite coal, though coke, 
or charcoal may be used. The 
fire should be burning brightly 
when the heating is done. Lay 
the iron and steel on the coal un- 
til they are red hot. Then 
sprinkle the surfaces of both 
with the flux and let it vitrify. 
A convenient method of doing 
this is to have the powdered 
flux (borax preferred) in a pepper pot. As soon as the heat has 
changed the metals to a straw color lay them together and strike. 
A single blow of a drop hammer, or four or five with a light sledge 
will do the work. Be sure that these pieces are well covered with a 
flux before attempting to weld. 

CALCULATION OF STOCK FOR BENT SHAPES. 

It is always convenient and frequently necessary to know the exact 
amount of stock required to make a given piece of work. There are four 




Fig. 32. 



^01 



8" 



Fig 33. 



£ 




Fie. 34. 



general methods used for determining this. The first and most accurate 
method, if it can be used conveniently, is mathematical calculation. 
Taking as an example the bent piece illustrated in Fig. 33. If the out- 



FORGING 23 



sideofthisbe measured, it would seem as though 16 inches of stock were 
required. If the inside be measured, 14 inches would seem the prop- 
er amount. It has been found by experiment that if a piece of 
straight stock betaken and a line drawn on it through the, center, and 
this piece of stock then be. bent and the lengths of the inside, center, 
and outside lines be measured, the outside line will lengthen con- 
siderably as the piece is bent. The inside line will shorten 
correspondingly, while the center line will remain comparatively 
unaltered in length. This is universally true, and the proper length 
of stock required for making any bent shape may always be obtained 
by measuring the center line of the curve or bend. To return to 
the first example: In this case, if the center line of the stock be 
measured, 1\ inches will be the length for each leg, thus making a 
total of 15 inches of stock required to make that particular bend. 
This is a universal rule which should always be followed when meas- 
uring stock, to take the length of the center line. 

Circles. On circles and parts of circles the length of stock may 
be easily calculated. The circumference, or distance around a circle, 

is found by multiplying the diameter 

y^~~l JTx by 3} or, more accurately, 3. 1416. 

//V =] 7X ^ \ As an illustration, the stock necessary 

\ '\Jv^l | J 1 )\ to bend up the ring in Fig. 34, would 

t \ ^----| \'^ I be calculated as follows : The inside 

|_- r s • 1 " ~*- J diameter of the ring is six inches and 

Fig_ 35. the stock is one inch thick. This 

would make the diameter of the circle 
made by the center line, shown by C, which may be called the Cal- 
culating Diameter, seven inches, and the length of stock required 
would be 7X3-}- or 22 inches. 

Link. A combination of circle and straight lires is illustrated 
in Fig. 35. This link may be divided into two semicircles at the 
end, with two straight pieces at the sides. The outside diameter 
of the ends being two inches, would leave the straight sides each two 
inches long. The calculating diameter for the ends would be 1^ 
inches. The total length of stock then required for the ends would 
bel|X3}=4f or approximately 4-f^ inches. As each of the 
straight sides will take two inches of stock, the total length required 



24 



FOEGING 




would be 4" + 4-^-"=8f| inches With a slight allowance for 
welding, the amount cut should be 8f ". Another method of meas- 
uring stock is by using a measuring wheel such as is shown in Fig. 36. 
This is simply a light running wheel mounted on 
a handle with some sort of a pointer attacked. 
The wheel is sometimes made with a circum- 
ference of 24 inches and the rim graduated in 
inches and eights. To use it, the wheel is placed 
lightly in contact with the line or object which it 
is wished to measure, with the zero mark on the 
wheel corresponding to the point from which 
the measurement is started. The wheel is then 
pushed along the surface following the line to 
be measured, with just enough pressure to cause 
it to revolve. By counting the revolutions and 
parts of a revolution made by the wheel, the re- 
quired distance may be easily measured. 

Scrolls and Irregular Shapes may be measured by either of two 
methods. The commoner way is to lay the scroll or shape off full 
size and measure the length by laying on this full sized drawing a 
string or thin piece of wire, causing the string or wire to follow the 
center line of the bent stock. The wire or string is then straightened 
and the length measured. This is about the easiest and best way of 
measuring work of this character. Another method which is more 
practical in the drafting room, consists of using a pair of dividers. 
The points of the dividers are set fairly close together and the center 
line is then stepped off and the number of steps counted. The same 
number of spaces are then laid off along a straight line and the length 
measured. 



Fig. 36. 



FORGING OPERATIONS. 

Shaping. After the metal has been heated it is shaped with the 
hammer. This shaping may consist of drawing, upsetting or 
bending. In drawing a bar of iron it is made longer and of a smaller 
diameter. Upsetting consists of shortening the bar with a corre- 
sponding increase of diameter. This work is usually done with a 
helper using a sledge hammer; the smith using a light hand hammer. 



FORGING 



25 




Fig. 37. 



They strike alternate blows. The helper must watch the point upon 
which the smith strikes and strike in the same place. Where two 
helpers are employed the smith strikes after each man. A blow on 
the anvil' by the smith is a signal to stop striking. 

Finishing. As the hammer usually marks the metal, it is 
customary to leave the metal a little full and finish by the use of 

flatters and swages. This 
applies to work that has 
been shaped under the 
sledge. Light work can be 
dressed smoothly, and the 
hammer can be made to ob- 
literate its own marks. 

Drawing Out. In draw- 
i n g out as well as in all 
other forging operations where heavy work is to be done, it is always 
best to heat the work to as high a temperature as the metal will stand 
without injury. Work can sometimes be drawn out much faster by 
working over the horn of the anvil than on the face, the reason being 
this: When a piece of work is hammered od the anvil face it flattens 
out and spreads nearly as much in width as it does in length, working 
it out longer and wider. As the piece is not wanted wider but merely 
longer, all the work spent 
in increasing the width of — £- 

the stock is wasted. If the 
hammering is done over the 
horn of the anvil as illus- 
trated in Fig. 37, the round- 
ed horn acts as a blunt wedge, forcing the metal lengthwise and thus 
utilizes almost the entire energy of a blow in stretching the metal 
in the desired direction. Fullers are also used to serve the same 
purpose and when working under the steam hammer a round bar 
sometimes takes the place of the fuller or horn of the anvil. 

Drawing Out and Pointing Round Stock. When drawing out 
or pointing round stock, it should always first be forged down square 
to the required size and then in as few blows as possible, rounded up. 
Fig. 38 illustrates, in a general way, the different steps in drawing 




Fig. 38. 



26 



FORGING 



down a round bar from a large to a smaller size, the first step being 
to hammer it down square as at B. This square shape is then made 
octagonal as at C and the octagon is finally rounded up as at D. If 
an attempt be made to hammer the bar by pounding it round and 

round without the preliminary 
squaring, the bar is very liable 
to split through the center, the 
action being a good deal as il- 
lustrated in Fig. 39, the effect 
of the blow coming as shown 
by the arrows A. The metal 
is squeezed together in this direction and forced apart in the di- 
rection at right angles as indicated by the arrows B. Then if the 
piece be slightly rolled for another blow, the sides will roll by 
each other, and cracks and splits will sooner or later develop, leaving 
the bar, if it should be sawed through the center, in a good deal the 
shape shown in Fig. 40. Particular care should be taken in making 
conical points as it is almost impossible to work stock down to a round 
point unless the point be first forged down to a square or pyramidal 
shape. 




Fig. 40. 




£L 




Fig. 41. 



Fie. 42. 



Truing Up Work. In drawing out it often happens that the 
bar becomes worked into an irregular or diamond shape, similar to 
the section shown in Fig. 41. To remedy this, and square up the 
bad corners, the bar should be laid across the anvil and worked 
much as shown in Fig. 42, the blows coming in the direction indicated 
by the arrow. Just as the hammer strikes the work it should be 
given a sort of sliding motion. No attempt should be made to square 
up a corner by striking squarely down upon the work. The hammer- 
ing should all be done in such a way as to force the metal back into 
the bar and away from the high corner. 



FORGING 



27 



Upsetting. When a piece is worked in such a way that its 
length is shortened and either or both its thickness and width in- 
creased, the piece is said to be upset and the operation is known as 
upsetting. There are several methods of upsetting, the one used 
depending largely upon the shape of the work. In short pieces the 

work is generally stood on end 
on the anvil, the hammering be- 
ing done directly down upon the 
upper end. The work should 
always be kept straight, and as 
soon as a bend or kink is started, 
it should be straightened out. 
When a long piece is to be up- 
set it is generally swung back 
and forth horizontally and the 
Fig. 43. upsetting done by ramming the 

end against the anvil. The effect 
of the blow has a decided influence upon the shape of the upset 
piece, as shown by the sketches of the two rivets in Fig. 43. Light 
blows affect the metal for a short distance only, as shown by the 
swelled out end, while the effect of heavier blows is felt jnore uni- 
formly throughout the entire length. 

When rivets are to be driven to fill holes tightly, the blows should 
be heavy, thus upsetting the rivet tightly into the holes. If a rivet 
is wanted to hold two pieces together in such a way that they may 
move, as for instance the rivet 
in a pair of tongs, the head 
should be formed with light 
blows, thus working only the 
end of the rivet. The part 
of the work which is heated to the highest temperature is the 
part which will be most upset, and when upsetting is wished at 
one point only, that point should be heated to the highest temperature, 
leaving the other parts of the bar as cold as possible. Upsetting long 
pieces is sometimes done by raising the piece and allowing it to drop 
on a heavy cast-iron plate set in the floor. These plates are known 
as upsetting plates. 



Fig. 44. 



FORGING 



Punching. Two kinds of punches are commonly used for 
making holes in hot metal; the straight hand punch used with a 
hand hammer and the one used for heavier stock, provided with a 
handle and used with a sledge hammer. Punches should of course 

be made of tool steel. For 
punching small holes in thin 
iron a hand punch is ordinar- 
ily used. This is a bar of 
round or octagonal steel, eight 
or ten inches in length, with 
the end forged down tapering 
•p io . 45 to the same shape, but slight- 

ly smaller than the hole to be 
punched. Such a punch for round holes is shown in Fig. 44. The 
end of the punch should be perfectly square across, not at all 
rounding. For heavier and faster work with a helper, a punch simi- 
lar to Fig. 45 is used, the striking being done with a sledge hammer. 
Fig. 46 illustrates the successive steps in punching a clean hole 
through a piece of hot iron. The work is first laid flat on the anvil 
and the punch driven about half way through as shown at A. This 
compresses the metal directly underneath the end of the punch and 





Fig. 46. 



raises a slight bulge on the opposite side of the bar. The piece is 
then turned over and the punch driven into the bar from this side 
(the hole being located by the bulge) while the bar is lying flat on 
the anvil. The punch should be driven about half of the way through, 
leaving the work as at C. The bar is then moved over the small 
round hole in the end of the anvil, or is placed on some object having 
a hole slightly larger than the hole to be punched, and the punch 



FORGING 



29 



driven clear through, driving out the small piece A and leaving the 
hole as shown at D. It would seem easier to drive the punch com- 
pletely through the work from one side. If this were done, however, 
the hole would be left as shown at E, one side would be rounded in, 
and the other side would be bulged out, while the hole would have 
a decided taper, being larger at the end from which the punching 
was done. If the piece be thick, after the hole is started, a little 
powdered coal is put in and the punching continued. The coal 
prevents the punch from sticking to some extent. 

Ring and Eye Bending. In 
making a ring or eye the first 
step is of course, to calculate the 
amount of stock required. In 
making ordinary rings four or 
five inches in diameter, the stock 
should be heated for about half its length. In starting the bend, the 
extreme end of the piece is first bent by placing the bar across the horn 
of the anvil and bending it down as illustrated in Fig. 47. The bar is 
then pushed ahead and bent down as it is fed forward. The blows 
should not come directly on top of the horn but fall outside of the point 
of support as illustrated. This bends the iron and does not hammer 
it out of shape. One-half of the circle is bent in this way, the stock 




Fig. 47. 



Fig. 48. 



^c 



/** 



2nd. 




^> 



4 th. 




Fig. 49. 

turned end for end, the other end heated, and the second half bent 
in the same way as the first, the bending being started from the 
end as before. 

Eye bending is done in a somewhat d'fTerent manner. Suppose 
it be required to bend up an eye as shown in Fig. 48. To calculate 
the amount of stock required: The diameter in this case to be used 



30 



FOEGING 



is two inches, and the amount of stock required 2 // X3}" = 6f", or 
practically 6f". This distance is laid off by making a chalk mark 
on the anvil 6f " from the end. The iron is heated and placed against 
the anvil with one end on the chalk mark and the other end extend- 
ing over the end of the anvil. The hand hammer is then held on the 
bar with one edge at the edge of the anvil, 
thus measuring off the required distance on 
the bar. Still holding the hammer on the 
bar the piece is laid across the anvil, with 
the edge of the hammer even with the edge 
of the anvil and the 6f inches extending over 
the edge or corner. This piece is then bent 
down into a right angle as shown in the first 
illustration of Fig. 49. The eye is bent in 
much the same manner as the ring, except 
that all the bending is done from one end, the successive steps 
being shown in the illustration. Small eyes are closed up in the 
manner shown in Fig. 50. 

Bend with Square Forged Corner. Brackets and other forg- 




Fig. 50. 





s 



A ---. 




Fig. 51. 



ings are frequently made with the outside corner square and sharp, 
as shown at C, Fig. 51. This may be done in either of two ways; by 
the first method the corner is bent from the size of stock required 
for the sides, being first bent to the shape of A. This corner is then 



FORGING 



31 



squared by upsetting the metal at the bend, the blows coming as 
shown by the arrows at B. The work should rest on the anvil face, 
and not over one corner, while being hammered. 

The second method is to use thicker stock and draw out the 
ends leaving a hump, shown at D, where the outside corner of the 




IE 



jsL. 



£ 



r/f" 



■'*/ 



-Fv 



£±- 



-*h- 



■*r 



Fig. 52. 

bend is to come. The dotted lines show the original shape of the 
bar; the solid lines the shape before bending. Sometimes stock is 
taken of the size used in the first method and upset to form the ridge, 
in place of drawing out the heavier stock. 

The first method is the one more commonly used on medium 
sized work. 

SIMPLE FORGING. 

Twisted Gate Hook. It should be understood that the descrip- 
tion given here will serve not only as a description of the particular 
piece in question but also as a general description of a variety of 



y 



G 



i 



D 



Fig. 53. 



Fig. 54. 



similarly shaped forgings. The methods used may be employed 
on other forgings of the same general shape. 

Fig. 52 shows a twisted gate hook. To start with, it is necessary 
to determine exactly what lengths the different parts of the hook will 
have after they are forged to dimensions, and before they are bent 
to shape. Before bending, the work is first drawn down to size as 



32 FOKGING 



is indicated. The bar is left square in the center for the central 
part, and each end is drawn to one-quarter inch round to form the 
hook and eye ends. The length of stock after being drawn out to 
\" round required to make the eye, is 2| inches. Allowing about 
one-quarter of an inch for the straight part before the eye is reached 
would make the total amount of stock required for the eye 2f inches. 
To obtain the amount of stock for the hook it is necessary to lay off 
the hook full size. If the drawing be full sized the measuring may 
be done directly on the drawing, but if not, a rough sketch having 
the proper dimensions should be laid off and the measuring done on 
that, the measuring of course being done along the dotted center 
line. This measuring is done by simply laying a string on the dotted 
line, then straightening out the string and measuring its length. In 
this way it will be found that 2| inches is required by the hook. The 
first step is then to forge the work into the shape shown in Fig. 52. 

Forming Shoulders. The shoulder 
where the round stock joins the square 
should be forged in the manner indicated 
in Fig. 53. The bar is laid across the 
anvil with the point where the shoulder 
is wished, lying directly on the corner of 
the anvil. The set hammer is then placed 
p io . g 5 on top of the work in such a way that the 

edge of the set hammer comes directly in 
line with the edge of the anvil. The set hammer is then driven into 
the work with a sledge hammer. The bar should be turned continu- 
ally or an uneven shoulder will be the result. If a shoulder is 
wanted on one side only, as illustrated in Fig. 54, it should be 
worked in as indicated there. That is, one side of the iron should lie 
' flat on the anvil face while the set hammer works down the metal next 
to the shoulder. 

After the two ends of the hook are drawn out, the eye and the 
hook are bent up into shape. The twist in the center of the hook 
may be made by using either two pairs of tongs or twisting in a vise. 
By the latter method a mark is first made on the vise in such a way that 
when the end of the hook is placed even with the mark, the edge of 
the vise will come at the end of the point where the twist is wanted. 




FORGING 



33 




A 



S£ 



I 



B 




Fig. 56. 



The hook should be heated and placed in the vise, the other end 
being grasped by a pair of tongs in such a way that the distance 
between the tongs and the vise is just equal in length to the twist. 
The twist is made by simply revolving the tongs around. In mak- 
ing a twist of this kind, no al- 
lowance need be made in 
length, as it practically has no 
effect on the length of the 
stock. 

Eye Bolts are made by two 
general methods, being either 
solid or welded. The solid 
eye bolt is. much the stronger. 
A solid eye bolt, or forged 
eye, as it is sometimes called, 
may be started in the general 
manner illustrated in Fig. 55. 
A nick is made on either 
side of a flat bar by using top and bottom fullers as illustrated. The 
end is then rounded up as shown in Fig. 56. Particular attention 
should be given to seeing that the eye is forged as nearly to a perfect 
circle as possible before any punching is done. The stock around 
the eye is rounded up over the horn of. the anvil, by swinging it back 
and forth as it is hammered. 
The hole when first punched is 
like B, but when finished should 
be like C. The other end of the 
bar is then drawn down to form 
the round shank. If a very long 
shank is wanted a short stub 
shank may be formed and a 
round bar of the proper size welded on. 

Welded eye bolts may be made in two different ways. The easier 
method produces an eye shaped as in Fig. 57. To make such a bolt, 
first scarf the end so that it will fit over the bend of the rod along- the 
dotted line a b. Bend the eye over the horn of the anvil. Finally bring to 
a welding heat and weld in accordance with instructions already given. 




Fig. 57. 



34 



FORGING 



An eye of better appearance, as shown in Fig. 58, is made as fol- 
lows : Upset the body of the metal as a seat for the scarf at the end, 





Fig. 58. 

shown at a, Fig. 58. Scarf the end of the bar and bend over the horn 
of the anvil into a true circle to fit the seat at a, and then weld as 
before. 

The length of metal required for an eye or ring is nearly equal 
to the length of the circumference of a circle whose diameter is equal 
to the mean diameter of the ring. Thus in 
Fig. 58 the length required for the eye will be 
approximately the length of the circle ab c b 
whose diameter is a c. 

Chain Hooks. These are made in a vari- 
ety of shapes and with solid or welded eyes, 
the general method of making the eyes being 
exactly as described before under "Eye Bolts". 
A common shape is shown in Fig. 59. The 
stock is forged into shape similar to Fig. 60 
before being bent. To determine the length A the drawing is meas- 
ured in the same way as described in making the gate hook. The 
weakest point in most hooks is the part lying between the lines marked 
a; re in Fig. 59. This part of the 
hook should be heavier and stronger 
than the other parts. When a strain 
is put on the hook, there is always 
a tendency to straighten out or to 
assume the shape shown by the dotted lines. When forging the 
hook into shape, the dimension B, Fig. 60, should be made such that 
the heaviest part of the hook comes in this weakest point. After the 
hook is entirely forged to size, it should be bent into shape. Hooks 



Fig. 59. 




Fie. 60. 



FORGING 



35 



are also made from round and square iron. When made for hook- 
ing over a link, and so shaped that the throat or opening is just 

large enough to slip easily over a 
link edgewise, but too narrow to 
slip off of this link down to the one 
which, of course, is turned at right 
angles, the hook is known as a grab 
hook. 

Hoisting Hooks. A widely ac- 
cepted shape for hooks of this char- 
acter used on cranes is shown on 
Fig. 61. The shape and formulae 
for the dimensions are given by Mr. 
Henry R. Town in his "Treatise on 
Cranes". T= Working load in tons 
of 2,000 lbs. A = Diameter of 
round stock, in inches, used to form 
the hook. The size of stock required for a hook to carry any par- 
ticular load is given below. The load for which the hook is designed 
is given in the upper line, the lower line gives the size of the stock to 
be used in making the hook. 




Fig. 61. 



T — llli 1 1 9 Q 

A _ _5_ 11 3 11 11 13 13 

^ — 8 T"6 4 J-TB" 1 4 X S 1 4 



4 5 6 8 10 



2 24- 2+ 21- 

w "4 -J 8 



3i 



The other dimensions of the hook are found by the following for- 
mulae, all of the dimensions being given in inches. 



D = .5 T + 1.25 


I = 1.33 A 


E = .64 T + 1.6 


J = 1.2 A 


F = .33 T + .85 


K = 1.13 A 


G = .75 D 


L = 1.05 A 


O = .363T + .66 


M = .5 A 


Q = .64 T + 1.6 


N = .85 B 


H = 1.08 A 


U = .S66A 



.16 



To illustrate the use of the table, suppose it be required to 
make a hook to raise a load of 500 lbs. or one-quarter of a ton. In 
the line marked "T" is found the load J. Directly below are figures 



3G 



FOKGING 



■f-J showing the size of stock to be used. The dimensions of the hook 
will be found as follows : 

. D = .5 Xi+ 1.25" = If". 

E = .64 X I + 1.6" = If' about. 



Etc. 



1 1 

l"6 



.915 or about f §-". 



I = 1.33 A = 1.33 X 
When reducing the decimals the dimensions which have to do only 
with the bending of the hook, i.e., the opening, length, the length of 
point, etc., may be taken to the nearest 16th, but the dimensions 
through the body of the hook or stock should be reduced to the near- 
est 32nd on small hooks. The completed dimensions of the hook 
in question, 500 lbs. capacity, would be as follows: 
D = If" I = 

E = If" J = 

f =: H* k = 

G = 1" L = 

O = I " M = 

Q = 



H 



1 3// 

-U 

1 5// 

T6 

1" 

3// 
4 

1 3" 

1 4 

3// 

4 



2 9// 

3 2 

13// 



u = 



21// 
3 2 

2 3.// 
32 

11" 

32 

_9_// 
1 6 




Bolts. Bolts are made by two methods, the head being made 
by either upsetting or welding. The first method is more common 
on small bolts and machine made bolts. The welded head is more 
commonly used for heavy, hand forged bolts. The upset head is 

the stronger provided both are equally 
well made. The size of the bolt is 
always given as the diameter and 
length of shank or stem. Thus a bolt 
known as ¥ X 6", or \" bolt 6" long, 
would mean a bolt having a shank \" 
in diameter and 6" long from the 
under side of the head to the end of 
the stem, having the dimensions of the 
bolt shown in Fig. 62. The dimen- 
sions of the bolt heads are always the same for the same sized bolt ; 
and are determined from the diameter of the shank. The diameter 
of the head, shown at D, Fig. 62, is the distance across the head from 
flat side to flat side, and is known as the diameter across the flats. 




i. 



62. 



FORGING 



37 



The thickness of the head is taken, as shown at T. If S equals the 
diameter of the shank of the bolt, the dimensions of the head would 
be as follows: 

D = 14 X S + 1" 

T = S 
For a two-inch bolt the dimensions would be as follows: 
Diameter of head U X 2" + \" = 3|" 

The thickness of head would be equal to diameter of the shank, 
or 2". These dimensions are for rough or unfinished heads. Each 
dimension of a finished head is T \ of an inch less than the same 




Fig. 63. 

dimension of a rough head. Bolts generally have the top corners 
of the head rounded or chamfered off. This may be done with a 
hand hammer; or a cupping tool, which is simply a set hammer 
with the bottom face hollowed out into a cup shape, may be used. 
Upset Head Bolts. The general method of making bolts of 
this kind, when a single bolt is wanted, is described below. The method 
of upsetting is shown in Fig. 64. 

Where large quantities of bolts are to be made, the bars are 
heated in a furnace and headed by special machinery. Where the 
work is done by hand the tools are of the 
J 1 simplest character. The header consists of 
/ "H-n. a disc in which a hole has been drilled to 

correspond to the diameter of the bolt. A 
handle 12 or 15 inches in length is welded 
to the disc. Such a tool is shown in Fig. 
63. The hole should be about g- 1 ^ inch 
larger than the nominal size of iron. To 
make a bolt with this tool : First cut off the iron to the required length; 
then heat the end to be headed, to a dull straw color; strike the end with 
a hammer or against the anvil and upset it so that the portion intended 
for the formation of the head will not pass through the header. Then 
place the hole of the header over the square hole in the tail of the 




Fig. 64. 



38 



FORGING 



anvil and drop the cold end of the bolt through it. Strike the pro- 
jecting portion of the bar and upset it until the requisite thickness 
of head is obtained. This will probably leave a head of curved but 

irregular outline. Remove 
from the header and square 
the head thus upset, on the 
face of the anvil. This will 
probably thicken the head. 
Again drop the cold end 
through the header and 
strike the head until it is 
reduced to proper thick- 
ness. After which, again 
In doing this work, the 
The work will be facil- 




Fig. 65. 



square the edges on the face of the anvi 
smith will hold the header in his left hand, 
itated if a helper assists with a sledge hammer. 

There are a number of simple tools in use for clamping the 




Fig. 66. 

bar while it is being headed so as to avoid the preliminary upsetting. 
Welded Head Bo3ts are made by welding a ring of square iron 



FORGING 



39 



Fig. 67. 



around the end of the shank to form the head. The ring is generally 
bent up on the end of a bar as shown at A, Fig. 65, but not welded. 
This ring is cut off and placed on the end of the shank as shown at 
B. The joint in the ring should be left slightly open to allow for 
the expansion in welding. The ring is fastened to the end of the 
shank by striking it on one side and squeezing it against the shank. 
The bolt is put into the fire, heated to the welding heat, and the 

head welded up intothe re- 
quired shape. The ring should 
not be welded round at first, 
as it is difficult in this way to 
make a sound joint, there be- 
ing a much better chance of doing sound work by welding the head 
directly square or hexagonal as required. No attention need be 
paid to the joint in the ring as this will take care of itself. Con- 
siderable care must be used in taking the welding heat, as all the 
heat which reaches the joint must pass through the ring and there 
is a good chance of burning the ring before the shank reaches the 
welding heat if the heating is not done slowly and carefully. 

Tongs. Common flat jawed tongs, such as are used for hold- 
ing light work up to about three-quarters of an inch thick, may be 
made as follows: Stock should 
be about three-quarters of an 
inch square. The first step is to 
make a bend near the end simi- 
lar to A in Fig. 66. The bent 
stock is then laid across the an- 
vil in the position shown at C 
and the eye formed by striking 
down upon it with a sledge Fig. 68. 

hammer. A set hammer may 

be used for this work by placing the work flat side down on the top of 
the anvil and working down the stock for the eye, next to the shoulder, 
with the set hammer. To make the handle, enough stock may be taken 
and drawn out as shown at D and a complete handle forged in this 
way, or a small amount of stock may be taken and a short stub forged 
out. Enough round stock is then welded on to make the proper length 




40 



FOKGING 




of handle, as shown in Fig. 67. The jaw is tapered down as shown at 
E. The last step is to punch the hole for the rivet. It is always a good 
plan to slightly crease the inside face of the jaw with a fuller, as this in- 
sures the jaws gripping the work firmly with the edges, and not touch- 
ing it simply at one point in the center, as they sometimes do if this 

crease is not made. The 
tongs are then riveted to- 
gether, the riveting being 
done with the round end 
of the hammer; in this 
way a head is formed on 
the rivet without upset- 
ting the shank of the rivet 
very much where it passes through the hole. After riveting, the tongs 
will probably be stiff or hard to move. They may be loosened up 
by heating the eye part red hot and moving the handles forward and 
backward two or three times. They should then be firmly fitted 
to the work to be handled. 

Tongs for Round Stock may be made by the general method 
described above, the only difference being that after the jaws are 
shaped, and before riveting together, they should be rounded up as 
illustrated in Fig. 68, using a fuller and swage as shown. 

Light Tongs may be made from flat stock in the manner illus- 
trated in Fig. 69. A cut is made in a piece of flat stock, with a fuller, 



Fig. 69. 



A_ 



V 



^^ 



Fig. 70. 



near one end. This end is twisted over at right, angles as shown at B. 
Another cut is made on the opposite side, as at C, and the end drawn 
out as indicated by the dotted lines. The tongs are then finished 
in the usual way. Tongs of this character may be used for very 
light work and are easily made. 



FORGING 



41 



Pick=Up Tongs are made in much the same way as described 
above, the different steps being illustrated in Fig. 70. 

Bolt Tongs may be made from round stock, although square 
may be sometimes used to advantage. The first step is to bend the 
bar in the shape shown in Fig. 71. This may be done by the fuller 

at the edge of the anvil, shown at 
A, or on a swage block as at B. 
The jaw proper is rounded and fin- 
ished with a fuller and swage as 
shown in Fig. 72. The part be- 
tween the jaw proper and the eye 
may be worked down into shape by 
the fuller and set hammer. The 
finishing may be done as indicated 
in Fig. 73. The eye and handle are 
then flattened down and drawn out, 
the tongs are punched, riveted to- 
gether, finished, and fitted in the 
usual manner. 

' Ladles similar to the one shown 

in Fig. 74, may be made from two 

pieces welded together, one forming 

the handle, the other the bowl, 

or as sometimes is done, the handle may be riveted on. A piece 

of flat stock is first "laid out" as shown in Fig. 75. This is 






A B 

Fig. 72. Fig. 73. 

then cut out with a cold chisel and the handle welded on at the pro- 
jecting point. The bowl is formed by heating the stock to an even 
heat and placing it over a round hole in a swage block or other object. 



42 



FOKGING 




Fie. 74. 



This hole should be slightly smaller than the outside diameter of 

the piece to be worked. To round the bowl it is worked as indicated 

in Fig. 76, with the pene end of 
the hammer. The forming: 
should be done as much as possi- 
ble by working near the edge of 
the piece rather than in the cen- 
ter. After the bowl has been 
properly shaped the edges should 
be ground off smooth and the lips 

formed as shown in Fig. 77. This is done by placing the part from 

which the lip is made against one of the small grooves in the side of 

the swage block and driving in a piece of 

small round iron, thus hollowing out the lip. 

The stock draws in somewhat when be- 
ing rounded up. For the bowl of a ladle 

3^ in diameter, the stock when flat should 

have an outside diameter of about four 

inches, and be one-eighth of an inch thick. 

Machine steel should be used for making 

the bowl. If ordinary wrought iron is used 

the metal is almost sure to split. 




Fig. 75. 



CALCULATION OF STOCK FOR FORGED WORK. 

The calculations made previously for stock, were for stock which 
was simply bent into shape, the original section or size of the stock 
remaining unaltered. There is a large variety of work where the 
shape of the stock is considerably changed, and where it is essential 
to know the amount required to make a given forging. In doing 
this kind of work one rule must be remembered, i.e., that the volume 
of the stock remains unaltered although its shape may be changed. 
Take as an example the forging shown in Fig. 78, let us determine 
the amount of stock required to make the piece. 

The forging is made in the general manner shown in Fig. 79. 
A piece of stock should be taken large enough in section to make the 
block B, which will mean that it will be one inch wide and half an 
inch thick. The metal is worked by making the fuller cuts as shown 



FOEGING 



43 



in Fig. 79 and then drawing down the ends to the required size, it 
being, of course, necessary to know the amount of stock required for 
each end. 

For convenience in calculating, the forging will be divided into 




three parts, the rounded end A, the central rectangular block B, and 
the square end C. The stock used being 1" X i" the block B will 
of course require just two inches of stock. 
The end C would have a volume of Y X 2" 
X 3" = f of a cubic inch. The stock has a 
volume of, \" X 1" X I", = \ of a cubic 
inch for each inch of length. The number 
of inches of stock required for the end C 
would then be. f -r- \ or \\ inches. The 
end A is a round shaft or cylinder four 
inches long and ¥ in diameter. To find the volume of a cylinder, mul- 
tiply the square of the radius (h the diameter) by 3y and then multiply 
this result by the length of the 

A 




cylinder. This 
volume of A a: 



ill 



give 



the 



X 4 X o-tf 




Fig. 78. 



X 4= [} and the amount of 

stock required to make this 

piece would be \\ -r- \ = Ij-, which may be taken as If inches. 

There is, of course, some slight loss due to scaling in working the 



44 



FORGING 



iron, which must be allowed for. This is generally done by adding 
a slight amount to the minimum amount required in each case. 
The amount of stock required in this case would be about, 

Round shaft A If" 

Block B 2" 

Square shaft C If" 

Total 5f" 

When the forging is started, cuts, which are afterward opened 
up with a fuller, may be made as shown by the upper sketch in Fig. 79. 



X 



\r 



iz 



Fig. 79. 



In this particular case it is not absolutely necessary that exactly the 
proper amount of stock be taken, as it would be a very easy matter 

to take a little too much 



fS 



24' 



■tf--r 



Fig. 80. 



and trim off the surplus 
from the ends, after the 
forging was made. 

With the forging such as 
shown in Fig. 80, however, it is essential that the exact amount be 
used. This forging, which is the general shape of a connecting rod, 
would be started as shown in Fig. 



=3^ 



j\. 



=Cf 



— H— 



81, and it is quite important that 
the distance A be correct. The stock 
used should be 2" X 4". Each end 
will, of course, require just 6" of 
stock. The center part is a cyl- 
inder 2" in diameter and 24" long, the volume of which would be 
\" X 1" X 3| X 24" = 75f cubic inches, which may be taken as 
lh\ cubic inches. For each inch in length the 2" X 4" stock would 



Fig. 81 . 



FORGING 45 



have a volume of 4" X 2" X 1" = 8 cubic inches. Therefore it would 
require 75^ -f- 8 = 9 Y \" of stock, to form the central piece, conse- 
quently the distance between the cuts shown at A in Fig. 81 will 
be 9 T 7 ¥ V/ . To this might be added a slight allowance for loss in 
scaling. The total amount of stock required would be 6" + 6" + 
9 T V / = 21 T y. Any forging may generally be separated into simple 
parts of uniform shape as was done above. In this form the cal- 
culation may be easily made. 

Weight of Forging. To find the weight of any forging the vol- 
ume may first be found in cubic inches and this multiplied by .2779, 
the weight of wrought iron per cubic inch. If the forging be made 
of steel, the figures .2936 should be used in place of .2779. This 
gives the weight in pounds. Below is given the weight of wrought 
iron, cast iron and steel both in pounds per cubic inch and per cubic 
foot. 

Cast Iron 450 per cu. ft. .2604 per cu. inch. 

Wrought Iron 480 " " " .2779 " .'■'■ " 

Steel 490 " " " .2936 " " " 

Suppose it were required to find the weight of the forging shown 
in Fig. 78. A has a volume of ^ cubic inch, C f cubic inch 
and B 1 cubic inch, making a total of 2 || cubic inches. If the 
forging were made of wrought iron it would weigh 2 4-f X .2779 = 
.7 lbs. The forging in Fig. 80 has a total volume of 171 f cubic 
inches and would weigh, if made of wrought iron, 47.64 lbs. 

A much easier way to calculate weights is to use tables such as 
given on pages 46 and 47. The first table gives the weights per foot of 
flat iron bars. In the second table is given the weights for each foot 
of length of round and square bars. 

When using the table on page 46 to ascertain the weight of any 
size of flat iron per foot of length, look in the first column at the left 
for the thickness. Then follow out in a horizontal line to the column 
giving the width. The number given will be the weight in pounds 
of cne foot of the desired size. 

To use the table for calculating weights, the procedure would be as 
follows: 

Taking Fig. 80 as an example, each end is 2" X 4" and 6" long 
and the two ends would be equal, as far as weight is concerned, to a bar 



46 



FORGING 



WEIGHT OF FLAT ROLLED IRON. 
Length, 12 inches. 



ta 

00 

J4 






















WIDTHS. 


















3 


i 

i 


5 
g 


s 


* 


1 


Is 


U 


11 


1* 


1 % 


n 


U 


2 


2J 


2} 2| 


2i 


2§ 


23 


21 3 


g 


•208 


.260 


.313 


.365 .417 


.469 [.521 


.573 .625 


.677 


.729 


.781 


.833 


.885 .938 


.989 1.04 


1.09 1.15 


1.20 1.25 


1 


.416 


.521 


.625 


.729 


.833 


.93811.04 


1.15 1.25 


1.35 


1.46 


1.56 


1.67 


1.77 


1.88 


1.98 


2.08 


2. 18' 2.29 


2.39 


2.50 


f 


.62 1 


.781 


.938 


1.09 


1.25 


1.41 1.56 


1.72 1.88 


2.03 


2.19 


2.35 


2.50 


2.65 


281 


2.97 


3.13 


3.28' 3.44 


3.59 


3.75 




.833 


1.04 


1.25 


1.46 


1.67 


1.88 


2.08 


2.29 2.50 


2.71 


2.92 


3.13 


3.33 


3.54 


3.75 


3.96 


4.17 


4.37 4.58 


4.79 


5.00 


| 




1.30 


1.56 


1.82 


2.08 


2.35 


2.60 


2.86'3.13 


3. 39 


3.65 


3.91 


4.17 


4.43 


4.69 


4.95 


5.21 


5.47i 5.73 


5.99 


6.25 


| 






1.88 


2.19 


2.50 


2.81 


3.13 


3.44 3.75 


1.06 


4.38 


4.69 


5.00 


5.31 


5.63 


5.94 


6.25 


6.56 6.88 


7.19 


7.50 


I 








2.55 


2.92 


3.2S 


3.65 


4.014. 38 


1.71 


5.10 


5.46 


5.83 


6.19 


6.57 


6.92 


7.29 


7.65' 8.02 8.38 


8.75 


1 










3.33 


3.75 


4.17 


4.58 5.00 


5.42 


5.83 


6.25 


6.67 


7.08 


7.50 


7.91 


8.33 


8.75J 9.17 9.58 10.00 


Is 












1.22 


4.69 


5.155.63 


6.09 


6.56 


7.03 


7.50 


7.97 


8.44 


8.90 


9.38 


9.84 10.3ri0.78ill.25 


ji 














5.21 


5.73 6.25 


6.77 


7.29 


7.81 


8.33 


8.85 


9.38 


9.89 


10.42 


10.94 11.46 11.S8 12.50 


lg 
















6.30 6.88 


7.45 


8.02 


8.59 


9.17 


9.74 


10.32 


10.88 


11.46 


12.03,12. 60 13.17 


13.75 




















7.50 


8.12 


8.75 


9.37 


10.00 


10.62 


i:..25 


11.87 


12.50 


13.12 13.75il4.37 


15.00 


11 




















8.80 


9.45 


10.14 


10.83 


11.51 


12.19 


12.86 


13.54 


14.22 14.E0J15.57 


16.25 


1| 






















10.21 


10.94 


11.67 


12.40 


13.13 


13.85 


14.58 


15.31 16.04 16.77 


17.50 


11 
























11.72 


12.50 


13.28 


14.06 


14.84 


15.63 


16.41 17.19J17.97 


18.75 


2 


























13.33 


14.16 


15.00 


15.83 


16.67 


17.50 18.33,19.16 


20.00 


2! 




























15.05 


15.94 


16.81 


17.71 


18.59 19. 48120.36 


21.25 


2} 






























16.88 


17 80 


18.75 


19.69 20.63 21.56 


22.50 


2 B 
































18.80 


19.79 


20.78 21.78 22.76 


23.75 


2\ 


































20 83 


21.87 22.93 23.96 


25.00 


2J 




































22.97 24.07,25.16 


26.25 


2J 




































125.21 26.35 


27.50 


21 




































27.55 


28.75 


3 




































1 


30.00 



2" X 4" and 1 ft. long. From the table it will be seen that a bar 2" X 2" 
weighs 13.33 lbs. and a bar 2" X 4", being twice as thick would weigh 
twice that, or 26.66 lbs. A bar two inches in diameter weighs 10.47 
lbs. per foot and as the central part of the forging is 2 ft. long, it will 
weigh 20.94 lbs., making the total weight of the forging 47.6 lbs. 
Finish. Many forgings are machined or "finished" after leaving 
the forge shop. The drawings are always made to represent the 
finished work and therefore give the finished dimensions, and it is 
necessary when this finishing is to be done, to make allowance for it 
when making the forging, that all parts which have to be finished or 
"machined" may be left with extra metal to be removed in finishing. 
The parts required to be finished are generally marked on the drawing. 
Sometimes the finished surfaces have the word "finished" marked 
on them. Sometimes the finishing is shown simply by the symbol f , 
as used in Fig. 82, showing that the shafts and pin only of the crank 
are to be finished. When all surfaces of a piece are to be finished 
the words -finish all over are sometimes marked on the drawing. 



FORGING 



47 



WEIGHTS OF ROUND AND SQUARE ROLLED IRON. 
Length, 12 Inches. 



2 U.S 

£ fl a 



c3 

o^ o 

■5,3 feoi 
°f ps » a 

53 a*S ° 



.013 
.052 
.117 
.208 
.326 
.469 
.638 
.833 
1.055 
1.302 
1.576 
1.875 
2.201 
2.552 
2.930 
3.333 
3.763 
4.219 
4.701 
5.208 
5.742 
6.302 
6.888 
7.500 
8.138 
8.802 
9.492 
10.21 
10.95 
11.72 
12.51 
13.33 
14.18 
15.05 
15.95 
16.88 
17.83 
18.80 
19.80 
20.83 
21.89 
22.97 



.pf 3 v fl 
V o fl o 
t>tfOJ 



.010 
.041 
.092 
.164 
.256 
.368 
.501 
.654 
.828 
1.023 
1.237 
1.473 
1.728 
2.004 
2.301 
2.618 
2.955 
3.313 
3.692 
4.091 
4.510 
4.950 
5.410 
5.890 
6.392 
6.913 
7.455 
8.018 
8.601 
9.204 
9.828 
10.47 
11.14 
11.82 
12.53 
13.25 
14.00 
14.77 
15.55 
16.36 
17.19 
18.04 



y a a 

OlSH 

r, HH -rH 



oCQo 

ODr-j UJ fl 



24.08 

25.21 

26.37 

27.55 

28.76 

30.00 

31.26 

32.55 

33.87 

35.21 

36.58 

37.97 

39.39 

40.83 

42.30 

43.80 

45.33 

46.88 

48.45 

50.05 

51.68 

53.33 

55.01 

56.72 

58.45 

60.21 

61.99 

63.80 

65.64 

67.50 

69.39 

71.30 

73.24 

75.21 

77.20 

79.22 

81.26 

83.33 

85.43 

87.55 

89.70 

91.88 



'Sqflo 



18.91 

19.80 

20.71 

21.64 

22.59 

23.56 

24.55 

25.57 

26.60 

27.65 

28.73 

29.82 

30.94 

32.07 

33.23 

34.40 

35.60 

36.82 

38.05 

39.31 

40.59 

41.89 

43.21 

44.55 

45.91 

47.29 

48.69 

50.11 

51.55 

53.01 

54.50 

56.00 

57.52 

59.07 

60.63 

62.22 

63.82 

65.45 

67.10 

68.76 

70.45 

72.16 

73.89 



CO 0J <u 

x 3 a 
|5.2 



H[Ot> 


cm o 


?„3^ so 


f 1 pjfe tb 


rfd OJ d 
03 c?S O 


£fps v a 
'53 o fl o 


gcflOi-3 


^tfOi-J 


96.30 


75.64 


98.55 


77.40 


100.8 


79.19 


103.1 


81.00 


105.5 


82.83 


107.8 


84.69 


110.2 


86.56 


112.6 


88.45 


115.1 


90.36 


117.5 


92.29 


120.0 


94.25 


125.1 


98.22 


130.2 


102.3 


135.5 


106.4 


140.8 


110.6 


146.3 


114.9 


151.9 


119.3 


157.6 


123.7 


163.3 


128.3 


169.2 


132.9 


175.2 


137.6 


181.3 


142.4 


187.5 


147.3 


193.8 


152.2 


200.2 


157.2 


206.7 


162.4 


213.3 


167.6 


226.9 


178.2 


240.8 


189.2 


255.2 


200.4 


270.0 


212. 1 


285.2 


224.0 


300.8 


236.3 


316.9 


248.9 


333.3 


261.8 


350.2 


275. 1 


367.5 


288.6 


385.2 


302.5 


403.3 


316.8 


421.9 


331.3 


440.8 


346.2 


460.2 


361.4 


480. 


377. 



The allowance for finishing on small forgings is generally about 
T \ " on each surface. Thus, if a block were wanted to finish 4" X2"X 
1" and T y were allowed for finishing, the dimensions of the forging 
would be 41" X 2|" X li". On a forging like Fig. 80, about \" allow- 
ance would be made for finishing, if it were called for. Thus the 
diameter of the central shaft would be 2\", the thickness of the ends 
2\", etc. s On larger work \" is sometimes allowed for machining. 
The amount of finish allowed depends to a large extent on the way 
the forging is to be finished. When hand finishing is done, that is, 
filing or scraping, j 1 / or even ^/ is enough; when all of the finish- 



48 



FORGING 



ing is done in a lathe or other machine, more material should be left. 

When a forging calls for finish, in calculating the amount of 

stock, or weight, the dimensions taken should not be the actual ones 




Fig. 82. 

shown by the drawing, but these dimensions with the proper allow- 
ance made for finish. 

Crank Shafts. There are several methods of forging crank shafts. 
The more commonly used is the commercial method, as described 
.in detail below. When forgings were mostly made of wrought iron, the 





■ ■ of' 


T 


H 4 » 




[- 


potxxxnq 

| ( 

H— s"-*> 

! ; 






u 4- 






4 * H 






* 



Fig. 83. 

cranks were welded up of several pieces. One piece was used for 
each of the shafts, one piece for each cheek or side, and another piece 
for the crank pin. Cranks are sometimes bent up out of round stock, 
but this method is only used on small work. The common method 
now employed where machine steel is used, is to forge the crank from 
one solid piece of material. The stock is taken large enough to shape 



s!'A*~ 4"— *J/§ U- 




Fig. 84. 




the largest part of the crank without any upsetting. If a crank be 
required similar to Fig. 82, the size of stock to be used should be H" 
by 4" in section. 



FOKGING 



49 




Fie. 85. 



When the forging leaves the shop, it will be left in a shape similar 
to the shape shown by the solid lines in Fig. S3, the dimensions shown 
here allowing for the necessary finishing. The crank itself would be 
left in a solid block, the throat being afterwards cut out as indicated 
by the dotted lines. A line of holes is first drilled as shown, and the 
block of metal to be taken out is removed by making two slits with 

a cold saw and the block then 
knocked out with a sledge hammer. 
It is possible to form this throat by 
chopping out the surplus metal 
with a hot chisel in the forge shop, 
but on small cranks in particular, 
such as here shown, it is generally 
cheaper in a well equipped shop to 
use the first method. 

The first step is of course to 
calculate the amount of stock re- 
quired. The long end would contain 
10.13 cubic inches. As each inch of stock contains 6 cubic inches, 
it would require 1.7" of stock to form this end provided there was 
no waste from scale. Waste does take place, however, and must 
be allowed for, so about 2" of stock should be taken. The short 
end contains 5.22 cubic inches and would require .87" of stock, with- 
out allowance for scale. About 1\" should be taken. The total 
stock then required would be 7-|". 

The first step is to make the cuts, and spread the ends as shown 
in Fig. 84. These ends may then be forged 
down with a sledge hammer as illustrated 
or may be worked out under the steam 
hammer, the finishing up against the 
shoulders being done as illustrated in Fig. 
85. The shaft may be rounded down and 
finished between swages. Care must be 
taken to see that the cuts are properly 
spread before drawing out the ends. If the 
cuts are left without spreading, the metal will act somewhat after 
the manner shown in Fig. 86. The top part of the bar, as it is 



1 v 


*\* "" 






I 


/ 



Fig. 86. 



50 



FORGING 



worked down, will fold over and leave a crack or cold shut as illus- 
trated. When the metal starts to act in this way the fault should 
be corrected by trimming off the overlapping corner along the dot- 
ted line shown in the upper sketch. 

Multiple=Throw Cranks. When a crank shaft has more than one 



Fig. 87. 



crank or crank pin, it is spoken of as a multiple-throw crank. A 
double-throw crank is a crank shaft with two cranks. A three throw 
or triple throw, one with three cranks, etc. As a general rule mul- 
tiple-throw cranks are forged flat, i.e., the cranks are all forged in 




Fig. 88. 

line with each other. The shafts and pins are then rough turned 
and the cranks are heated and twisted into shape. The forging for 
the double-throw crank shown in Fig. 87 would first be made in the 
general shape shown in Fig. 88. The parts shown by the dotted lines 

would then be cut out with a drill 
and saw as described above, and 
the shafts and pins rough turned, 
i.e., turned round, but left as large 
as possible. The forging is then 
returned to the forge shop where it 
is heated and the cranks twisted to the desired angle. When twist- 
ing, the crank would be gripped just to the right of the point marked 
A. This may be done with a vise, or wrench if the crank is small, or 




FORGING 



51 



it may be held under the steam hammer. The twisting may be done 
with a wrench similar to Fig. 89 which 
may be easily made by bending up a U 
of flat stock and welding on a handle. 

A Three-Throw Crank without any 
intermediate bearings is shown in Fig. 
90. The rough forging for this is shown 
in Fig. 91. The extra metal is removed 
as indicated by the dotted lines and the 
twisting done as described before. 

Weldless Rings. Rings and eyes 
forged solid without any welds may be 
made in the general manner described 
below. As an example, suppose it be 
required to make a ring such as illus- 
trated in Fig. 92. A flat bar is first 
forged rounding on the ends, punched 
and split as shown, this split is opened 
out and the ring hammered into shape. 
It is necessary, of course, to calculate 
the amount of stock required. This 
may be done as follows: The first step 
is to determine the area of the ring, 
which is done by taking the area of the 
outside circle, and subtracting from it the 
area of the inside circle. 

Area of outside circle 12.57 

" " inside " 7.07 



sq. m. 



rinff 



5.50 




The stock used when making small thin rings should be twice 




52 



FORGING 





Fig. 92. 



the width of the side of the ring to which is added at least one-quarter 
of an inch. When the bar is split the stock is more or less deformed 
and when worked back into shape is slightly thinned. Although no 
stock is lost by the hammering, an allowance 
must be made for the thinning and stretching 
and it is necessary to make the stock slightly 
wider on this account, as noted above. Allow- 
ing V' for hammering, and taking stock 1\" wide, 
the amount of stock required would be 5.5 -r- 1.5, 
equal to 3.66". Allowing a small amount for loss 
by scale, etc., 3f \" of stock should be taken. In 
making this calculation, the thickness of the stock 
is not taken into consideration, as the thickness of 
the finished ring is the same as the stock. 
This general method is used on a large variety of work, particularly 
where rings are to be made of tool steel and should be made without 
a weld. 

Another method of making weldless rings, under the steam ham- 
mer, is illustrated in Fig. 93. The 
proper amount of stock is first forged 
into a disk, a hole is punched into this 
disk and a mandril inserted. A U- 
shaped rest is then placed on the anvil 
of the steam, hammer and the mandril 
laid on this. The ring is turned on 
the mandril and forged into shape. 
Larger and larger mandrils are sub- 
stituted as the hole in the ring increases in size. 

Lever with Boss. The following description will serve for 







Fie. 93. 




Fig. 94. Fig. 95. 

many forgings of the same general shape. The forging shown in 



FORGING 



53 



Fig. 94 will be taken as an example. There are two general ways 
of making work of this character. One is to take stock of the proper 
size for the lever and weld on a chunk for the boss. The other is to 
take stock large enough to form the boss and draw out either the entire 



Ks-^h 




Fig. 96. 
lever, or a short stub, to which the lever is welded. The work may be 
started for the first method by doubling over the end of the stock as 
illustrated in Fig. 95. This is welded up and rounded by the same 
general method as afterwards described for the other boss. The 





Fig. 97. 
second method of shaping is illustrated in Fig. 96. The stock in 
this case would be two inches square. The fuller cut is first made 
as illustrated at A. The end is then drawn out into the shape shown at 
B. In drawing out the stock, if the metal be allowed to flatten down 
into shape like C, a "cold-shut" will be formed close to the boss, as the 
corner at X will overlap and work into the metal, making a crack in 
the work. The proper way to draw out the stock is shown at D. 
The square piece left for the boss is rounded up over the cor- 



54 



FORGING 



<7^ 



§ 



Fie. 98. 



^ 



^- 



^ 



ner of the anvil as shown in Fig. 97. Sometimes to make the work 
easier to get at, the end is bent back out of the way and straight 3ned 
after the forging is completed. The boss may be 
smoothed up by using a set hammer or swage in 
the manner indicated. 

Knuckles. One example of a very numerous 
class of forgings is shown in Fig. 98. This is the 
shape used for what are known as marine ends 
of connecting rods, knuckle joints on valve rods, and various other 
places. A common method employed to 
make such a forging is shown in Fig. 99. 
Two fuller cuts are first made as indicated 
at A and the part for the shaft of the forging 
drawn out. The thick end is then punched 
and split, as indicated at B. This split end 
is opened up and forged out in the manner 
indicated in Fig. 100, if the work is done on 
the anvil. Fig. 101 illustrates the method 
of working out under the steam hammer, 
the end being first flattened as indicated 
and then gradually tipped up to the position 
shown by the dotted lines. When drawn 
to size, the ends are flattened out straight 
across and the finishing done around the 
shank with a fuller as indicated in Fig. 102. 
The forging is then bent into a U-shaped Fi S- "• 

loop of approximately the shape of the finished knuckle. A bar of 
iron the same dimension as the inside of the 
finished knuckle is inserted between the sides 
of the loop, and the sides closed down flat as 
shown in Fig. 103. Fig. 104 shows other forg- 
ings which may be shaped by this same general 
method. Trim E, Fig. 99, to the dotted line. 
Wrenches. A simple tool that is fre- 
quently called for is the S wrench. This 
wrench is usually made with a gap at each end 
It is shown complete in Fig. 105. 





Fig. 100. 
suited for nuts of different sizes 



FORGING 



55 



The jaws at the end should be parallel with each other. A line drawn 
from one jaw to the other should make an angle of 30 degrees with the 
center line of each. There are two ways in which such a wrench can 




Fig. 101. 

be forged. One is to forge the jaws separately and then weld to 
the handle. In the other the jaws are cut from a solid piece of metal 
and the iron between is then drawn down to the proper size for the 
handle. The latter is preferable, since it avoids all welds. To 
make the wrench by the second process, select a piece of steel large 




e 




U 




^&5S 



•47 



Fig. 102 Fig. 103. 

enough to form the head. Fuller it down back of the head as shown 
in A, Fig. 106, at a a. Round the end and punch the hole b. Next 
treat the other end m the same way and draw out the intermediate 
metal giving the form shown at B. Now cut out the holes b b securing 



56 



FOKGING 



the form shown at C. It now remains to bend the heads to the prop- 
er angle and give the desired curve to the shank. In forging such 



«=(C 



5i 



iittttth 



qj 



o 





Fig. 104. 
a wrench the outer edges should be slightly rounded so that they 
will not cut the hand. The inside of the jaws should be perfectly 
square with sharp edges. This finish can be best obtained by filing. 




Fig. 105. 
Socket Wrenches are made in several ways. The easiest way 
in "hurry up" work is the method illustrated in Fig. 107. A stub 
is forged to the same size and shape as the finished hole is to be, and 



FORGING 



57 



a ring, bent up of thin flat iron, welded round this stub. When finish- 
ing the socket, a nut or bolt head of the same size that the wrench is 
intended to fit, should be placed in the hole and the socket finished 






Fig. 106. 

over this, between swages. A better way of making wrenches of 
this kind is to make a forging having the same dimensions as the fin- 
ished wrench with the socket end left solid. The socket end is then 




Fig. 107. 

drilled to a depth slightly greater than the socket is wanted. The 
diameter of the drilled hole should be as shown in Fig. 108, equal 
to the shortest diameter of the finished hole. After drilling, the socket 
end is heated and a punch, of the same shape as the finished hole, 



58 



FORGING 



driven into it. The end of the punch should be square across and 
the corners sharp. As the punch is driven in, it will shave off some 
of the metal around the corners of the hole and force it to the bottom, 





Fig. 108. 

thus making it necessary to have the drilled hole slightly deeper than 
the finished socket. 

Ladle Shank. The ladle shank shown in Fig. 109 may be made 
in several ways. The ring may be welded up of flat stock and a 
round handle welded on with a T-weld. Or square stock may be 
taken, worked out and split as shown in Fig. 110, these split ends 

being afterwards welded to make 
the ring. Another method of mak- 
ing without any welds at all would 
be to split the stock as indicated 
in Fig. Ill and work out in the 
same way that a weldless ring is 
made. The latter method would 
take more time but would make 




Fie;. 109. 



the sounder forging. 
The molder's trowel illustrated in Fig. 112 



Molder's Trowel. 

is a sample of a large class of forgings, having a wide, thin face with 
a comparatively small thin stem forged at one end. The stock used 
for the trowel would be about \" X V. This is thick enough to 
allow for the formation of a ridge at R. Fig. 113 shows the general 



FOEGING 



59 



method employed. Two nicks are first made with fullers as illus- 
trated at A and the stem drawn down, roughly, to size. This stem 
is then bent up at right angles and forged to a square corner as illus- 




Fig. 110. 

trated at B, in the same general manner as the square corner of a 
bracket is formed. When flattening out the blade in order to leave 
the ridge shown at R, Fig. 112, the work should be held as shown at 

C, Fig. 113. Here the handle 

=1 



is held pointing downward and 
against the side of the anvil. 
By striking down on the work 
and covering the part directly 
over the edge of the anvil with 
the blows, all the metal on the 
anvil will be flattened down. 
By swinging the piece around 
into a reversed position, the other edge of the blade is then thinned 
down. This leaves the small triangle shown by the dotted lines 




Fig. in. 



60 



FOKGING 



un worked and forms the ridge shown at R. The same result could 
be obtained by placing the work flat on the anvil face and using a 
set hammer. 

TOOL STEEL WORK. 

Tool Steel. Although not strictly true technically, for ordinary 
purposes tool steel may be considered simply a combination of iron 
and carbon. The more common grade contains perhaps 1 per cent 




Fig. 112. 

of carbon. Machine steel and wrought iron do not contain this 
element carbon to any great extent. If a piece of wrought iron or 
machine steel be heated red hot and suddenly cooled, the metal re- 
mains practically as it was before heating, but if a piece of tool steel 
be subjected to this treatment, it becomes very hard and brittle. By 
a modification of this heating and cooling, almost any degree of hard- 
ness may be imparted to the steel. When tool steel is heated red hot 

and then suddenly cool- 
ed, becoming very hard, 
the process is known as 
Hardening. For more 
detailed explanations of 
hardening, tempering, 
etc., the student is re- 
ferred to "Tool Making", 
as merely general state- 
ments and explanations 
will be given here. If two pieces of tool steel be heated, one to a 
comparatively high heat and one to a lower heat and the two pieces 
suddenly cooled in water, if the ends be then snapped off, a decided 
difference will be noticed in the fractures. The piece cooled from the 




Fig. 11 



FOEGING 61 

higher temperature will have a very coarse grain, while that cooled 
from the lower temperature will have a finer grain. Two things are 
fixed when hardening a piece of tool steel — hardness and grain. 
The hardness depends upon the rapidity with which the steel is 
cooled. The more rapid the cooling, the harder the steel. The 
grain depends upon the heat from which the steel is cooled. There 
is only one heat from which the steel may be cooled and have the 
proper grain. This heat is known as the hardening heat. A piece 
of steel when cooled from this hardening heat has an extremely fine 
silky looking grain and is left very hard and brittle. 

Hardening. .The hardening heat varies with the amount of 
carbon the steel contains, the greater the percentage of carbon, the 
lower the hardening heat. 

To determine the hardening heat, a bar \" or f" square is heated 
to a good red heat on one end, and cooled in cold water. This end 
is then tested, if too hard to file it has been hardened, and the heat 
from which it was cooled was either the proper hardening heat or 
some higher heat. If the end can be filed it was cooled from some 
heat below the hardening heat. If the end proves to be soft it should 
be rehardened by cooling from a higher heat, if hard it should be 
broken off and the fracture examined. If the grain of the broken 
end is very fine the steel is properly hardened, if coarse, it was heated 
too hot and the end should be rehardened at a lower heat. The ex- 
periment should be repeated until the operator is able to give the steel 
a very fine grain every time. Any variation either above or below 
the hardening heat will make the grain coarse. A temperature lower 
than the critical heat will not make the steel as coarse in structure 
as a temperature correspondingly higher, but there will be some 
difference. 

Hardening Baths. Various baths are used for cooling steel 
when hardening, on account of the different rates at which they cool 
the heated metal. An oil bath is used when the steel is wanted tougher 
and not excessively hard, as the oil cools the steel slower than water. 
Brine or an acid bath are used when the steel is wanted very hard, as 
they absorb heat more rapidly than water. For excessively hard 
work mercury, or quicksilver, is sometimes used, as it absorbs the 
heat very rapidly. 



62 FORGING 



General Laws of Hardening. The two simple general facts of 
hardening that must be remembered areas follows: First, the heat 
from which the steel is cooled determines the grain ; secondly, the rapid- 
ity of cooling determines the hardness, everything else being equal, 
the more rapid the cooling, the harder the steel. 

Annealing. When steel is annealed it is softened. This is done 
by cooling the steel very slowly from the hardening heat, the cooling 
being done as slowly as possible. This cooling in some cases takes 
several days. As noted under hardening, the rapidity of cooling 
determines the final hardness of the steel and if the steel be cooled very 
slowly it will be left very soft; while if cooled rapidly, it will be left 
hard. This difference in the time taken to cool the steel is the only 
difference between hardening and annealing. Both should be done 
from the same heat. The details of various methods of annealing 
are described in "Tool Making". 

Tempering. Tools which are simply hardened as described 
above are, with few exceptions, too brittle for use and it is necessary 
to reduce the brittleness. This process is known as tempering. 
Tools are always left as hard as it is possible to leave them and still 
have them tough enough for the work for which they are intended. 
In reducing the brittleness of the steel, some of the hardness is of 
necessity taken out and tempering is therefore sometimes spoken of 
as a reduction of the hardness, but it is in reality, merely a reduction 
of the brittleness. After a tool or piece of steel has been hardened, 
some of the brittleness is taken out by a slight reheating to a low tem- 
perature. These temperatures vary from 200° F., to about 650° F. 
These temperatures are determined in various ways. The simplest 
and perhaps the most commonly used, is to polish the steel after it 
has been hardened and then reheat the part to be tempered until the 
surface shows a certain color. 

If any bright piece of iron or steel be heated, when a temperature 
of about 400° F is reached, the surface will turn pale yellow. As the 
temperature is increased this yellow grows darker until at about 500° F 
it is a decided brown. When 600° F is reached, a deep blue color shows 
on the surface. These colors are produced by a thin scale which is 
formed on the surface of the steel and are no indication whatever of 
hardness, merely showing to what heat steel or iron has been raised. 



FORGING 63 



Tempered tools may be divided into two general classes: First, 
those which have one edge only tempered; second, those which 
are tempered throughout. To the first class belong most lathe tools, 
cold chisels, etc. To the second class, taps, dies, milling cutters, etc. 
When tempering tools of the first class, considerably more of the tool 
is heated than is wanted hardened. The cutting edge is then hard- 
ened by cooling in water. The tool is then taken from the water, the 
hardened edge polished, and reheated by allowing the heat to "come 
down" from the body of the tool, which is still quite hot. Tools of 
the second class are first hardened by being heated to a uniform hard- 
ening heat and then cooled completely. The tool is then polished 
and the temper drawn by placing the steel either over the fire or on a 
piece of metal which has previously been heated red hot. It is ab- 
solutely essential that the steel should be heated to a uniform tem- 
perature when hardened. The parts to be hardened should show 
no difference whatever in color when being heated. If points or 
corners of tools are allowed to come to the hardening temperature 
before the body of the tool is hot, these overheated corners are almost 
sure to crack off. Absolute uniformity in heating to the proper hard- 
ening heat is necessary to insure success in hardening operations. 

Lead Bath. To insure uniformity in heating, various methods 
are used, and when the work is done on a large scale the heating 
is generally done in a furnace fired with gas. Another common 
method is to heat the steel in a bath of red hot lead. The lead is heated 
in a pot or crucible, to the hardening heat of the steel. The top of 
the lead is covered with powdered charcoal or coal to prevent the 
formation of the slag or dross on top. When steel is heated in lead 
it must be perfectly clean, dry, and free from rust. 

TOOL FORGING AND TEMPERING. 

Forging Heat. Before attempting any work with tool steel, a 
piece of scrap steel is to be experimented with, heated and hardened 
several times at various heats until the manipulator is sure of the 
effect of the various hearts upon the grain of the steel. The steel 
should also be experimented with to determine just how high a heat 
it will stand. When heavy forging is to be done, i. e., when the first 
rough shaping is done upon a tool, a comparatively high heat should 



64 



FORGING 



be used. The steel should be forged at about what might be called 
a good yellow heat. The lighter hammering, when finishing, should 
be done at a lower heat, about the hardening heat. Very little, if any, 
hammering should be done below the hardening heat. If the grain 



D 




D 



n 



Fig. 114. 

of the steel has heen raised by too high a heat, it can generally be quite 
decidedly reduced by a little hammering at some heat above the hard- 
ening temperature. 

Cold Chisels. The stock should be heated to a good yellow 
heat and forged into shape and finished as smoothly as possible. 
When properly forged, the end or cutting edge will bulge 
out as shown in Fig. 114. It is a good plan to simply 
nick this end across at the point where the finished 
edge is to come and then after the chisel has been tem- 
pered, this nicked end may be broken off and the grain 
examined. Whenever possible, it is a good plan to 
leave an end of this sort on a tool that may be broken 
off after the tempering is done. When hardening, a 
chisel should be heated red hot about as far back from 
the cutting edge as the point A, Fig. 115. Care must 
be taken to heat slowly enough to keep the part being 
heated at a uniform temperature throughout. If the 
point becomes overheated, it should not be dipped in 
water to cool off, but allowed to cool in the air to below 
the hardening heat and then reheated more carefully. 
When properly heated, the end should be hardened by 
dipping in cold water to the point B. As soon as the end 
is cold, the chisel should be withdrawn from the water 
and the end polished bright by rubbing with a piece of emery 
paper. The part of the chisel from A to B will still be red hot 



B 



-A 



Fig. 115. 



FOKGING 



65 



and the heat from this part will gradually reheat the hardened point. 
As this cold part is reheated, the polished surface will change color 
showing at first yellow, then brown, and at last purple. As soon as 
the purple (almost blue color) reaches the nick at the end, the chisel 




Fig. 116. 

should be completely cooled. The waste end may now be snapped 
off and the grain examined. If the grain is too coarse the tool should 
be rehardened at a lower temperature, while if the metal is too soft, 
and the end bends without breaking, it should be rehardened at a 
higher temperature. 

Cape Chisel. This is a chisel used for cutting grooves, key 
seats, etc. The end A should be wider than the rest of the blade back 




Fig. 117. 

to B, Fig. 116. The chisel is started by thinning down B with two 
fullers, or over the horn of the anvil as shown at A, Fig. 117. The 
end is then drawn out and finished with a hammer or flatter in the 
manner illustrated at B. A cape chisel is given the same temper as 
a cold chisel. 



66 



FORGING 



Square and Round Nose Chisels. These two chisels, the ends 
of which are shown in Fig. 118, are forged and tempered in practically 
the same way as the ordinary cape chisel, the only difference being in 
the shape of the ends. Round nose cape chisels are sometimes used 
for centering drills and are then known as centering chisels. 

Lathe Tools. The same general forms of lathe tools are used 
in nearly all shops, but the shapes are altered somewhat to suit in- 
dividual tastes. 

Right Hand and Left Hand Tools. Many lathe tools are made 

in pairs and are called right 
and left hand tools. If a 
tool is made in such a way 
that the cutting edge comes 
toward the left hand as the 
tool is held in position in 
the lathe, it is known as a 
right hand tool, i. e., a tool 
which begins a cut at the 
right hand end of the piece 
and moves from right to left is known as a right hand tool. The one 
commencing at the left hand end and cutting toward the right would 
be known as a left hand tool. The general shape of right and left 
hand tools for the same use is generally the same excepting that 
the cutting edges are on opposite sides. 

Clearance. When making all lathe tools, care must be taken to 




Fig. 118. 




Section 
A B 



Fig. 119. 

see that they have proper clearance, i. e., the cutting edge must pro- 
ject beyond or outside of the other parts of the tool. In other words, 
the sides of the tool must be undercut or slant downwards and back- 
wards away from the cutting edge. This is illustrated in the section 
A B of Fig. 119, where the lower edge of the tool is made considerably 



FORGING 



67 



thinner than the upper edge, in order to give the proper clearance. 
Round Nose and Thread Tools. These tools are practically 
alike excepting for a slight difference in the way the ends are ground. 
The general shape is shown in Fig. 119. When hardening, the tools 
should be heated about as far as 
the line A, Fig. 120, and cooled 
up to the line B. The temper is 
then drawn in the same general 
way as described for tempering 
of cold chisels excepting that 
when a light yellow color shows 
at the cutting edge the tool is 
cooled for the second time. All 
lathe tools are given practically 
the same temper. Sometimes 
tools are left much harder. In 




Fig. 120. 



one quite well known plant the tools are simply reheated until the 
water evaporates from the cutting end, indicating a reheating to a 
temperature of about 200°F. 

Cutting off Tools are forged with the blade either on one side or 
in the center of the stock. The easier way to make them is to forge 
the blade with one side flush with the side of the tool. Such a tool is 
shown in Fig. 121. The cutting edge, A, the extreme tip of the blade, 
should be wider than any other part of the thinned end, B. In other 
words, this edge should have clearance in all directions as indicated 

in the drawing. The clear- 
ance angle at the end of the 
tool as shown in the sketch, is 
about correct for lathe tools. 
For heavier tools for the 
planer, the angle should be 
as shown by the line X X. 
When hardening, the end of 
the tool should be heated to about point C C and cooled to about 
the line D D, and the temper drawn as described for the round 
nose tool. Tools may be forged in the general way shown in 
Fig. 122. The tool is started by making a fuller cut as shown 




68 



FORGING 



at A. After roughly shaping, the end is trimmed off with a hot 
chisel along the dotted line at C. Great care must be taken to 
see that the blade of the tool has proper clearance in all directions. 




Anvil 



Fig. 122. 



When a tool is wanted with a blade forged in the center, it should be 
first started by using two fullers instead of one, then making two 
cuts, one on each side of the stock, in place of the single cut shown at A. 




Fig. 123. 

Boring Tool. The general shape of this tool is shown in Fig. 123. 

The length of the thin end depends upon the depth of the hole in 

which the tool is to be used and as a general rule should be made as 

short and thick as possible, in 
order to avoid springing. The 
tool may be started in the same 
general way as the cutting off 
tool, the fuller cut being made on 
the edge of the stock instead of 
on the side. The cutting edge 

of the tool is at the end of the small "nose," and this "nose" is 

the only part which should be tempered. 

Diamond Points. These tools are made in a variety of modifica- 




Fig. 124. 



FOKGTNG 



69 



tions of the shape shown in Fig. 124. There are various methods 
used for shaping them, one of which is illustrated in Fig. 125. The 
shape is started as indicated at A. After the nick has been made as 
shown, the end of the tool is shaped as shown by the dotted lines, the 
blows coming in the direction of the arrow. Further shaping is done 
as indicated at B. To square up the end of the nose of the tool, it is 
worked backward and forward as indicated at C. The tool is finished 
by trimming off the end to the proper angle with a hot chisel and touch- 
ing it up with a set hammer When hardened it should be dipped 
about as shown at D. 

Side Tools or side finishing tools as they are sometimes called, 
are generally made in about the shape shown at F, Fig. 126. The tool 




Fig. 125. 

may be started by making a fuller cut as shown at A. The end x is then 
drawn out with a fuller into the shape B. After smoothing up with 
a set hammer the blade is trued into shape along the dotted lines at C. 
The tool is finished by giving the proper "offset" to the top edge of 
the blade. This is done by placing the tool flat side down with the 
blade extending over, and the end of the blade next the shank about Y 
beyond, the outside edge of the anvil. A set hammer is placed on the 
blade close up to the shoulder and slightly tipped, so that the face of 



70 



FORGING 



the hammer touches the thin edge of the blade only, as illustrated at D. 
One or two light blows with the sledge will give the necessary offset 
and after touching up the blade, the tool is ready for tempering. 
When heating for hardening, the tool should be placed in the fire with 




Fig. 126. 

the cutting edge up. In this way it is more easy to avoid overheating 
the edge. The hardening should be done by dipping the tool in 
water as illustrated at E, only the small part A being left above the 
surface. The tool is taken from the water, quickly rubbed bright 



nnxo 




n 




Fig. 127. 



Fig. 128. 



on the flat side, and the temper drawn until the cutting edge shows a 
light yellow. The same color should show the entire length of the 
cutting edge. If the color shows darker at one end, it indicates that 
that end of the blade was not cooled enough and the tool should be 



FOKGING 



71 



rehardened, this time dipping the tool in such a way as to bring that 
end of the blade which was too soft before, deeper in the water. 

Centering Tool. The centering tool shown in Fig. 127 is used 
for starting holes on face-plate and chuck work. The end may be 
shaped by making a fuller cut and then flattening out the metal, 
trimming the cutting edge to shape with the hot chisel. 

Forming Tools for Turret Lathes are sometimes forged up in the 
same general shape as above and tempered like other lathe tools. 

Finishing Tool. This tool, Fig. 128, may be started either with 
a fuller cut or in the same way as the diamond point. The end is 
then flattened out and shaped with a set hammer as shown in Fig. 129. 
This generally leaves the end bent out too nearly straight, but it may 
be easily bent back into shape as 
indicated at B. This bending 
will probably leave the point 
something like C. A few blows 
of the hammer at the point indi- 
cated by the arrow will give the 
tool the shape as at D. The cut- 
ting edge should be tempered 
the same as other lathe tools. 
For planer and shaper tools of 
this shape, the end should be 
more nearly at right angles to 
the edge of the tool, making an 
angle of about six or eight de- 
grees less than the perpendicular. 
In other words, the tool should have less end rake. 

Flat Drills need no particular description as to forging and shap- 
ing. The size of the drill is determined by the width of the flat end , this 
being the same size as the hole the drill is intended to bore. If this 
dimension were one inch, the drill would be known as a one-inch drill. 
The drill should be made somewhat softer than lathe tools, the temper 
being drawn until a light brown shows at the cutting edge. 

Springs are generally tempered in oil. The spring is heated to 
a uniform hardening heat and hardened by cooling in oil. The tem- 
per is drawn by holding the spring, still covered with oil, over the 




72 



FORGING 



flame of the forge, and heating until the oil burns over the entire 
spring. If the spring is not uniform in section throughout, it is gen- 
erally advisable, while heating it, to plunge every few seconds into 
the oil bath, taking it out instantly and continuing the heating. This 




Fig. 130. 
momentary plunge tends to equalize the heat by cooling the thinner 
parts. 

Lard oil or fish oil are generally used as mineral oil is too uncertain 
in composition. The above method of tempering is known as blazing 
off, the blazing point of the oil being used to indicate the temperature 
in place of the color of the scale. The same results could be obtained 
by polishing the spring and heating until it turned blue. 

Hammers. When making a ham- 
mer the stock should be taken large 
enough to make the largest part of 
the hammer without any upsetting. 
As a general rule the hammer is forg- 
ed on the end of a bar and finished as completely as possible before 
cutting off. 

Riveting Hammer. About the easiest hammer to shape is the 
riveting hammer shown at D, Fig. 4. This hammer, as well as all 
other hammers, is started by first punching the hole for the eye as 
shown at A, Fig. 130. When the eye is punched the stock is generally 
bulged out sideways and in order to hold the shape of the eye while 




Seer ion 
A. B. 



FORGING 



73 



flattening down this bulge, a drift pin such as shown in Fig. 131 is 
used. This pin is made larger in the center and tapering at both 
ends. The center or larger part of the pin has the same shape as the 
finished eye of the hammer. This pin is driven into the punched hole 
and the sides of the eye forged into shape as illustrated at B, Fig. 130. 
After the eye has been properly shaped, the next step is to shape down 
the tapering pene leaving the work, after a nick has been made around 
the bar where the face of the hammer will come, as shown at C. The 
end of the hammer toward the face is then slightly tapered in the man- 
ner indicated at D. After the hammer has been as nearly as possible 
finished, it is cut from the bar and the face trued up. For tempering, 
the whole hammer is heated to an even hardening heat. The hammer 
is then grasped by placing one jaw of the tongs through the eye. 
Both ends are tempered, this being done 
by hardeneng first one end and then the 
other. The small end is first hardened 
by dipping in the water as shown at 
Fig. 132. As soon as this end is cooled 
the position of the hammer is instantly 
reversed and the face end hardened. 
"While the large end is in the water the 
smaller end is polished and the temper 
color watched for. When a dark brown 
scale appears on the small end the ham- 
mer is again reversed bringing the large end uppermost and the 
pene in the water. The face end is then polished and the temper 
drawn. If the large end is properly hardened before the temper 
color appears on the small end, the hammer may be taken complete- 
ly out of the water, the large end polished, and the colors watched for 
on both ends at once. As soon as one end shows the proper color 
it is promptly dipped in water, the other end following as soon as 
the color appears there, but under no circumstances should the eye 
be cooled while still red hot. For some special work hammer faces 
should be left harder, but for ordinary use the temper as given 
above, is very satisfactory. 

Ball Pene Hammer. The general method of making this ham- 
mer is illustrated in Fig. 133. After punching the hole, the hammer 




Fig. 132. 



14: 



FOKGING 



is roughed out by using the fullers as shown at A and B. The ball 
end is then rounded up, the octagonal parts shaped with the fullers 
and the hammer cut from the bar, ground and tempered. Ball 




Fig. 133. 

pene hammers may be made with a steam hammer in practically 

the same way as described above, excepting that round bars of 

steel should be substituted for 
the fullers. 

Blacksmith's Tools such as 
cold chisels, hot chisels, set ham- 
mers and flatters are made in 
much the same way as hammers. 
The wide face of the flatters may 
be upset by using a block such as 
is shown in Fig. 134. The heated 
end of the tool is dropped into 
the hole in the block and the face 

upset into the wide shallow opening. Swages may also be worked up 

in this way. 




Fie. 134. 



FORGING 75 



Self=hardening Steel is used to a large extent in modern practice 
for lathe tools, much being used in the shape of small square steel 
held in special holders. Such a tool is illustrated in Fig. 135. Self- 
hardening steel, as its name indicates, is almost self-hardening 
in nature, generally the only treatment that is required to harden the 
steel being; to heat it red hot and allow it to cool. Sometimes the 
steel is cooled in an air blast or is dipped in oil. It is not necessary 
to "draw the temper". The self-hardening quality of steel is given 
to it by the addition of Chromium, Molybdenyum, Tungsten, or one 
of that group of elements, in addition to the carbon which ordinary 
tool steel contains. Self-hardening steel is comparatively expensive, 
costing from 40 cents and upwards per pound, some of the more 
'expensive grades. costing $1.00 or so. When in use, self-hardening 
steel will stand a much higher cutting speed than the ordinary so- 
called carbon steel. For this reason it is much more economical to use, 
although its first cost is higher. Self-hardening steel cannot be cut 
with a cold chisel and must be 
either cut hot or nicked with an 
emery wheel and snapped off. 
Great care must be used in forg- 
ing it, as the range of temperature 
through which it may be forged p. 135 

is comparatively slight, running 

from a good red heat to a yellow heat. Some grades of self-hard- 
ening steel may be annealed by heating the steel to a high heat in 
the center of a good fire and allowing the fire and the steel to cool 
off together. Steel which has been annealed in this way may be 
hardened by heating to the hardening heat and cooling in oil. 

Taylor=White Process. This method of treating special grades 
of self-hardening steel was discovered some years ago by the men 
after whom it is named. It was found that if a piece of self-hardening 
steel be heated to a very high temperature (about the welding heat) 
and then suddenly cooled to about a low red heat, the steel would 
be in a condition to stand very much harder usage and take a much 
heavier cut. Steel treated in this way seemed to have the cutting 
edge of the tools almost burned or melted off and considerable grind- 
ing was necessary to bring them into shape. When put in use the 




76 



FORGING 



edges would almost immediately be slightly rounded or crumble off, 
but after this slight breaking down of the cutting edge, the steel would 
stand up under excessively trying conditions of high speed and heavy 
cut. Tools of this character were of very little, or no, use for fine 
finishing , but were of great value for heavy and roughing cuts. 

HEAVY FORGING. 

Steam Hammer. An ordinary form of steam hammer is shown 

in Fig. 136. Its essential parts are an inverted steam cylinder, to 

whose piston rod the hammer head is attached, and the frame for 

carrying the whole. The hammer is raised by admitting steam 




Fig. 136. 

beneath the piston. The blow is dealt by exhausting the steam from 
beneath the piston and admitting it above the same. The head is 
thus accelerated by gravity and the pressure of steam above the piston. 
The valve gear is so arranged that the intensity of the blow may be 
varied by changing the amount of steam admitted to the piston on its 
downward stroke. The steam admitted below on the same stroke 
forms a cushion for the absorption ~>f the momentum of the head. 
In this way the lightest of taps and the heaviest of blows can be deliv- 



FORGING 



77 



ered by the same hammer. These hammers are also made in a great 
variety of sizes. Steam hammers are rated by the weight of the falling 
parts, i. e., the piston rod, ram or head, and hammer die. A hammer 
in which these parts weigh 400 lbs. would be called a 400 lb. hammer. 
Steam hammers are made in two distinct parts: the frame, carrying 
the hammer or ram, and the anvil, on which the hammer strikes. 



ft 



a 




Fig. 137. 

The frame is carried on a heavy foundation, and the heavy anvil, 
which is generally made of cast iron and fitted with a die block of 
tool steel, rests upon a heavier foundation of timber or masonry cap- 
ped with a timber. The object of these separate foundations is to 
allow the anvil to give slightly under a blow without disturbing the 
frame. On very light power hammers the anvil and frame are some- 
times made together. 

Hammer Dies. The dies, as most commonly used with a steam 




Fig. 138. • Fig. 139. 

hammer, have flat faces. The best ones are made of tool steel. These 
dies may be made of tool steel and left unhardened, then when the 
dies become battered out of shape from use, they may be trued up 
and refaced without going to the trouble of annealing and hardening. 
Dies of gray cast iron and cast iron with a chilled face are also quite 
commonly used. Ordinary gray cast iron is used, particularly when 



78 



FOKGING 



special shaped dies are employed for welding and light bending. 
Tongs for steam hammer work should always carefully be fitted 
and should grip the stock firmly on at least three sides. A quite com- 
mon shape for tongs for heavy work is shown in Fig. 137. To hold 
the tongs securely on the work and to make it easier to handle them, 
a link is sometimes used of the shape shown. This is driven firmly 




Fig. 140. 



Fig. 141. 



over the handles of the tongs and the projecting ends are used as 
handles for turning the work. 

Hammer Chisels. The common shape for hot chisels for use 
under the steam hammer is given in Fig. 138. The handle and blade 
are sometimes made from one piece of tool steel. Sometimes the 
blade is made of tool steel and an iron handle welded on as shown in 
the sketch. The handle next to the blade should be flattened out 
to form sort of a spring which permits a little give when using the 



B 



Fig. 142. 

chisel. The edge of the chisel should be left square across and not 
rounding. The proper shape is shown at A, Fig. 139. Sometimes 
for special work the edge may be slightly beveled as at B or C. For 
cutting or nicking bars cold, a chisel similar in shape to Fig. 140 is 
sometimes used. This is made very flat and stumpy to resist the 
crushing effect of heavy blows. For cutting into corners a chisel 
similar in shape to Fig. 141 is sometimes used. For bent or irregular 
work the chisel may be formed accordingly. For cutting off hot stock 
the method used is about as illustrated in Fig. 142, i. e., the work is 
cut nearly through as shown at A. The bar is then turned over and 
a thin strip of steel with square corners placed on top as shown at B. 



FORGING 



79 



A quick heavy blow of the hammer drives this steel bar through the 
work and carries away the thin fin shown, leaving both of the cut ends 
clean and smooth. 

Tools. The tools used for steam hammer work are generally 
very simple. Swages for finishing work up to three. or four inches 
in diameter are commonly made in the shape shown in Fig. 143. 




Fig. 143. 

The handle is made in the shape of a spring and may be either made 
in one piece with the blocks and drawn out as shown at C, or may be 
inserted as shown at B. This sort of a tool is known as a spring tool. 
Another sort of swage sometimes used, is illustrated in Fig. 144, the 




Fig. 144. 

top swage at A, the bottom swage at B. This sort of a swage is used 
on a die block which has a square hole cut in its face similar to the 
hardy hole in an anvil. The short horn X, of the swage, fits into this 
hole, the other two projections coming over the side of the anvil block. 
Tapering and Fullering Tool. The faces of the anvil and ham- 
mer dies are flat and parallel and it is, of course, impossible to finish 



80 



FORGING 



tapering work smooth between the bare dies. This work may be done 
by using a tool similar to Fig. 145. Its method of use is shown in Fig. 
146, the roughing being done with the round side down and the finish- 




Fig. 145. 

ing with the flat side. Fullers used for ordinary hand forgings are 
seldom employed in steam hammer work. Round bars are used in 
their place in the manner illustrated in Fig. 147. If a nick is wanted 
on one side only, simply one round bar is used. Care must always 
be taken to be sure that the work is in the proper position before 




Roughing 



Finishing 



Fig. 146. 



\ / 



striking a heavy blow with the hammer. To do this the hammer 

should be brought down lightly on the work thus bringing the piece 

to a flat "bearing" for the first blow. 

Squaring up Work. It frequently 
happens that work is knocked lop- 
sided under the hammer, being 
worked up into some such shape 
as shown at A, Fig. 148. To cor- 
rect this and bring the work up 
square, the bar should be put under 
the hammer and there knocked in- 
to shape B and then rolled in the 

direction indicated by the arrow until shaped as at C when it may 

then be worked down square and finished like D. 

Crank Shafts. The crank shaft shown in Figs. 82 and 83 is quite 




Fie. 147. 



FORGING 



81 



/? 



B 



D 



OOD 

Fig. 148. 



a common example of steam hammer work. The stock is first worked 

as illustrated in Fig. 149, the cuts being on each side of the crank cheek. 

A special tool is used for this as illustrated. When the cuts are very 
deep, they should first be made with a hot 
chisel and then opened up with this spread- 
ing tool. With light cuts, however, both 
operations may be done with a spreading 
tool at the same time. Care must be taken, 

when flattening out the ends, io prevent any of the material from 

doubling over and forming a "cold shut". After the ends are 

hammered out, the corners next 

to the cheeks may be squared by I 

using a block as shown in Fig. 85. 
Connecting Rod : Drawing 

out between the shoulders. The 

forging illustrated in Fig. 80, 

while hardly the exact propor- 
tions of the connecting rod, is 

near enough the proper shape to 

give a good example of this 

kind of forging. The work is 

first started by making two cuts 

as illustrated in Fig. 150. The 

metal between the two cuts is 

then drawn out by using two 

steel blocks as shown in Fig. 151 

until the metal is stretched long 

enough to allow the corners of 

the square ends to clear the edges of the hammer dies, when the 

work is done directly upon the bare die. 

MISCELLANEOUS PROCESSES. 

Shrinking. When iron is heated it expands and upon being 
cooled it contracts to about its original size. This property is utilized 
in doing what is known as shrinking. Fig. 152 shows a collar shrunk 
on a shaft. The collar and shaft are made separate, the hole through 
the collar being slightly less in diameter than the outside diameter of 




Fig. 149. 



82 



FORGING 



the shaft. The collar is then heated red hot and the heat causes the 
collar to expand, making the hole larger in diameter than the shaft. 
The collar, while still hot, is then placed on the shaft in proper position, 
and cooled as quickly as possible by pouring water on it. As the collar 



^v 



3 



^^ 



ZI 




Fig. 150. 



Fig. 151. 



•is cooled it contracts and squeezes, or locks, itself firmly in position. 
This principle of shrinking is used to a large extent where a firm, tight 
fit is wanted, the only objection being that it is rather difficult to take 
a piece off after it has once been shrunk into place. 

Brazing. When two pieces of iron or steel are welded together, 




Fig. 152. 

they are joined by making the pieces so hot that the particles of one 
piece will stick to those of the other, no medium being used to join 
them. In brazing, however, the brass acts in joining two pieces of 
metal together in somewhat the same manner that glue does in joining 
two pieces of wood. Briefly the process is as follows: The surfaces 



FORGING 



83 



to be joined are cleaned, held together by a suitable clamp, heated to 
the temperature of melting brass, flux added, and the brass melted 
into the joint. The brass used is generally in the shape of "spelter". 
This is a finely granulated brass which melts at a comparatively low 
temperature. "Spelter" comes in several grades designated by hard, 




Brass 
Wire, 




Fig. 153. 

soft, etc., the harder spelters melting at higher heat but making a 
stronger joint. Brass wire or strips of rolled brass are sometimes 
used in place of spelter, brass wire in particular being very convenient 
in many places. A simple example of a brazed joint is shown in Fig. 
153, where a flange is brazed to the end of a small pipe. It is not 
necessary in this case to use any clamps as the pieces will hold them- 
selves together. The joint between the 
two should be made roughly. If a tight 
joint be used there will be no chance for 
the brass to run in. The joint should fit 
in spots but not all around. Before put- 
ting the two pieces together, the surfaces 
to be joined should be cleaned free from 
loose dirt and scale. When ready for 
brazing the joint is smeared with a flux 
(one part salammoniac, six or eight parts 
borax) which may be added dry or put on 

in the form of a paste mixed with water. The joint is then heated 
and the spelter mixed with flux sprinkled on and melted into place. 
Brass wire could be used in place of the spelter in the manner 
indicated, the wire being bent into a ring and laid round the joint 
as shown. Ordinary borax may be used as a flux, although not 
as good as the mixture used above. The heat should be gradu- 




Fig. 154. 



84 



FOKGING 




ally raised until the brass melts and runs all around and into the 
joint, when the piece should be lifted from the fire and thoroughly 
cleaned by scraping off the melted borax and scale. It is neces 

sary to remove the borax, 
as it leaves a hard glassy 
scale which is particularly 
disagreeable if any filing 
or finishing has to be done 
to the joint. This scale 
may be loosened by plung- 
ing the work while still red 
Fig. 155. hot, into cold water. Al- 

most any metal that will 
stand the heat, may be brazed. Great care must be used in braz- 
ing cast iron to have the surfaces in contact properly cleaned to 
start with, and then properly 
protected from the oxidizing 
influences of the air and fire 
while being heated. 

Annealing Copper and 
Brass may be done by heat- 
ing the metals to a red heat 
and then cooling suddenly in 
cold water. When copper or. 
brass is hammered to any ex- 
tent, it becomes hard and 
springy and if it has to be 
further worked, it must be an- 
nealed or softened, otherwise 
it is almost sure to split. 

Bending Cast Iron. It is 
sometimes necessary to 
straighten a casting which h s 
become warped or twisted. 
Cast iron may be twisted or 

bent to quite an extent if worked cautiously. The bending may 
generally be done at about the ordinary hardening heat of tool 




Fig. 156. 



FORGING 



85 



steel and should be done by a steadily applied pressure, not by 
blows. There is more danger of breaking the work by working it at 
too high a heat than by working at too low. As an example of how 
iron may be twisted, a bar of gray cast iron one inch square and a foot 
long may be twisted through about 90°, before it will break. 

Case=Hardening. The essential difference between machine 
steel and tool steel is the amount of carbon that they contain. If car- 
bon be added to machine steel it will be turned into tool steel. Some- 
times articles are wanted very hard on the surface to resist wear and 
at the same time very tough to withstand shocks. If the piece be 
made of tool steel in order to be hard 
enough, it will be too brittle, and if made 
of machine steel in order to be tough enough, 
will be too soft. To overcome this diffi- 
culty the parts are made of machine steel 
and then the outside is carbonized or con- 
verted into tool steel to a slight depth, and 
this outside coating of tool steel then hard- 
ened. The process is known as case-harden- 
ing. The method used generally consists of 
heating the machine steel red hot in contact 
with something very rich in carbon, gener- 
ally ground bone. The surface of the 
machine steel takes up or absorbs the car- 
bon and is converted into tool steel. For 
more detailed information the reader is referred to "Tool Making". 

Pipe Bending. A piece of pipe when bent always has a tendency 
to collapse and if this collapsing can be prevented by keeping the 
sides of the pipe from spreading, a pipe may be successfully bent into 
almost any shape. One way of doing this would be to bend the pipe 
between two flat plates as shown in Fig. 154, the plates being the 
same distance apart as the outside diameter of the pipe. In bending 
large pipe, the sides are sometimes prevented from bulging by working 
in with a flatter. Where a single piece is to be bent, it may be done by 
heating the pipe and inserting one end in one of the holes in a swage 
block as shown in Fig. 155, the pipe being then bent by bearing down 
on the free end. As soon as a slight bend is made it is generally 




iB 



Fig. 157. 



86 



FORGING 



necessary to lay the pipe flat on" the anvil and work down the bulge 
with a flatter. Where many pieces are to be bent, a grooved "jig" 
such as shown in Fig. 156 is sometimes used. The jig is of such a 
shape that the pipe is completely surrounded where it is being bent, 
thus not having any opportunity to collapse or bulge. Pipe is some- 




Fig. 158. 

times filled full of sand for bending. This helps to some extent. 
Care must be taken to see that the pipe is full and that the ends are 
solidly plugged. For bending thin copper tubing, it may be filled 
with melted rosin. This gives very satisfactory results for this char- 
acter of work. After bending, the rosin is removed by simply heating 
the pipe. 

Duplicate Work. Where several pieces are to be exactly alike 
in a shop that is not equipped for special work, it is sometimes 

practical to use a "jig" for performing 

the operations. For simple bending the 

"jig" may consist of a set of cast-iron 

blocks. Fig. 157 illustrates a simple bend 

with the block used for doing the work. 

The work is done as shown at B. The 

piece to be bent is placed, as shown by 

the dotted lines, with the bending block 

on top. The bending is done by one or 

two strokes of the steam hammer. For 

convenience in handling, the bending blocks are sometimes held by a 

spring handle as shown in Fig. 158. The blocks in this case are 

for bending the hooks shown at A. The handle is simply a piece of 




Fig. 159. 



FOKGING 



87 



Y round iron with the ends screwed into the cast-iron blocks and held 
firmly by the lock nuts shown. This makes a cheap arrangement for 
a variety of work, as the same handles may be used on various sets of 





|X 

,v,-k 

i \ 


> 1 




■& 




© 


r* 


y 



B Section XX' 

Fig. 160. 

blocks. Where a great number of pieces are to be made, these blocks 
or bending dies may be made of such a shape that they can be keyed 
on the steam hammer in place of the regular flat dies. 

Die Forging. Pieces are sometimes shaped between formed steel 
dies where many are to be made exactly alike. An example of this 
sort of work is the eye bolt, Fig. 159. 
Round stock is used and is first shaped 
like A, Fig. 160. The shaping is done 
in the dies shown at B, which are sim- 
ply two small blocks of tool steel fast- 
ened together with a spring handle, 
the inside faces of the blocks being 
formed to shape the piece as shown. 
The end of the bar is heated, placed 
between the die blocks and hammered 
until it takes the required shape, be- 
ing turned through about 90° be- 
tween each two blows of the steam 
hammer, and the hammering continued until the die faces just touch. 




Fig. 161. 



FORGING 



For the second step the ball is flattened to about the thickness of the 
finished eye and the hole punched under the steam hammer with an 
ordinary punch, leaving the work as shown at C. The final shaping 
is done with the finishing die D. This die is so shaped that when the 
two parts are together, the hole left is exactly the shape of the finished 
forging. In the first die it will be noticed that the holes do not con- 
form exactly to the desired shape of the forging, being, instead of semi- 




^ 




:■:■■.■:-■■ 




Fig. 162. Fig. 163. 

circular, considerably rounded off at the edges. This is shown more 
clearly in Fig. 1G1 at A, where the dotted lines show the shape of the 
forging, the solid lines the shape of the die. The object of the above 
is this: If the hole is semicircular in section, the stock, being larger 
than the smaller parts of the hole, after a blow will be left like B, the 
metal being forced out between the flat faces of the die and forming 
fins. When the bar is turned these fins are worked back and make a 



FORGING 



89 



"cold shut". When the hole is a modified semicircle the stock will 
be formed like C, and may be turned and worked without danger of 
"cold shuts". Dies for this kind of work are sometimes made of 
cast iron.' When made of tool steel it is sometimes possible to shape 
them hot. A "master" forging is first make of tool steel to exactly the 
shape of the required forging. The blocks for the dies are then forged 
with flat faces. These blocks are fastened to the handle and then 




Fig. 164. 

heated red hot. The master forging is then placed between the dies 
and the dies hammered doWn tight over the forging. This leaves a 
cavity just the shape for the required forging. 

MANUFACTURING. 

The manufacturing shop differs very essentially from the jobbing 
shop. In the latter shop very few forgings are made at the same 
time exactly alike, while in manufacturing, each forging is generally 
duplicated a large number of times and special machines are used for 
doing the work. 

Drop Forges are used for quickly forming complicated shapes 
out of wrought iron or steel. They consist, as the name indicates, 



90 FORGING 



of a head that may be "dropped" from any desired height upon the 
piece to be shaped. The head of the drop and the anvil are in the 
form of dies. As they come together the metal is forced to flow so as 
to fill the interstices and thus take on the form desired. In drop 
forging the metal must be heated to a high temperature so as to be in a 
soft and plastic condition. 

A common type of drop hammer used for this kind of work is 
is shown in Fig. 162. The hammer in this case is fastened to a board 
and is raised by the friction rollers at the top of the frame being 
pressed against the board. When the hammer reaches the top of the 
frame it is dropped by releasing the rollers from the board. This may 




Fig. 165. 

be done automatically or by a foot treadle. Drop hammers are also 
built in the same general way as steam hammers. Dies for drop 
forging generally consist of a roughing or breaking-down die where 
the rough stock is first given approximately the desired shape and a 
smoothing die when tb<3 finishing is done. These dies have in their 
faces, holes of the same shape as the required forging. 

Power Hammers. Another tool which is used to quite a large 
extent in manufacturing as well as in the jobbing shop is the power 
hammer. This is made in several different types and is used where a 
quick, rapid blow is wanted. These hammers are run by belts. Two 
general types are shown in Figs. 163 and 164. The first is known as a 



FORGING 



91 



justice hammer. The second is a Bradley. Shaped dies are fre- 
quently used on these hammers. 

Bulldozer. This is a tool used for bending and consists of a 
heavy cast-iron bed with a block or bolster at one end, and a moving 
head which slides back and forth on the bed. A common type is 
shown in Fig. 165. Heavy dies are clamped against the bolster and 
on the moving head, of such a shape and in such a way that when the 
moving head is nearest the bol- 
ster, the shape left between the 
two dies is exactly the shape to 
which it is desired to bend the 
stock. In operation, the moving 
head slides back and forth on the 
bed. The bar to be bent is heated 
and placed between the dies when 
the head is farthest from the bolster. 
A clutch is then thrown in and the 
head moves forward to the bolster, 
bending the iron as it goes. 

Presses serve the same purpose 
as drop hammers. They do the work 
more slowly, however. The class 
of work is, in some respects, the 
same. The principal difference lies 
in peculiarities of shape that re- 
quire different time intervals for the 
flow of the metal. Where the 

shape is such that the metal must move slowly in order to acquire its 
new shape or fill the die, the press should be used. 

Flanging Press. A particular type of forging press is the flanging 
press. This is used more particularly in boiler work and is generally 
a heavy hydraulic press. The flanging is done by placing the heated 
metal on the bed of the press and closing the dies together by hydrau- 
lic pressure. 

Cranes. Where heavy work is to be handled, it is necessary to 
have some means of conveying the work from one part of the shop to 
another. This is done by means of cranes of two general types. The 




Fig. 166. 



92 



FORGING 



traveling crane and jib crane. The former type runs on an over- 
head track from one end of the shop to the other, generally. The 
latter type is used more commonly for handling work under the ham- 
mers, and is merely an arm or boom swinging around a post and having 
a suitable arrangement for raising and lowering the work. When 
handling heavy work, whenever possible, it is suspended from the 
crane by its center, in such a way that it nearly balances. The 




Fig. 167. 

suspending is generally done by means of an endless chain such as 
illustrated in Fig. 166, and in this way it may be easily rolled and 
swung from side to side. For ease in handling large forgings, a bar, 
or handle is sometimes welded on. This is known as a porter bar. 
Furnaces. In nearly all manufacturing work and in large work in 
the jobbing shop, the heating is done in furnaces. The heat is gener- 
ally supplied by either hard coal, coke or oil, coke being more com- 
monly employed in jobbing shops. Sometimes ordinary coal is used. 
A furnace used for heating small work for manufacturing is shown 
in Fig. 167. This may be used with either ordinary coal or coke. 



FORGING 



93 



Gas Furnaces are used when an even heat is wanted, particularly 
for hardening and tempering. For manufacturing work the furnaces 
are sometimes fixed to do the heating automatically. The pieces to 
be hardened are carried through the furnace on an endless chain 
which moves at a speed so timed that the pieces have just time enough 




Fig. 168. 
to be heated to the right temperature as they pass through the furnace. 
Such a furnace is shown in Fig. 168. A simple gas furnace for all 
around work is shown in Fig. 169. 

Reverberatory Furnaces. A reverberatory or air furnace is 
a furnace in which ore, metal or other material is exposed to the 
action of flame, but not to the contact of burning fuel. The flame 
passes over a bridge and then downward upon the material spread 
upon the hearth. Such furnaces are extensively used in shops where 
heavy work is being executed. They are also used for melting iron 
or other metals. For this purpose, however, they are not economical 
since they require about twice as much fuel as that used in the cupola 
for the production of good hot iron. To be effective the flame must 



94 



FORGING 



be made to reverberate from the low roof of the furnace down upon 
the hearth and work. The form of the roof and the velocity of the 
currents determines the hottest part of the furnace. 

A common form of reverberatory furnace is shown in Fig. 170. 
The whole is lined with fire brick from the top of the grates to the 
top of the stack. The fuel is burned in a fire box separated from the 

heating portion of the furnace by a 
low bridge wall D. Access to the 
grate is obtained by suitable doors 
both above and below. When in 
service, both doors are tightly closed 
and a strong forced draft is admit- 
ted to the ash pit. Beyond the 
bridge wall is the furnace proper. 
This usually consists of a low cham- 
ber with a level floor. Like the fire 
box it is completely lined with a 
thick wall of fire brick. Access is 
obtained to this chamber through a 
vertically sliding door. These doors 
are also lined with fire brick and 
are usually suspended from chains. 
These pass over pulleys, and have 
counter balancing weights at the 
other end. 

The operation of the furnace 
is exceedingly simple. After the 
fuel has been charged upon the grates, the ash pit and furnace doors 
are closed; the material to be heated is put upon the floor of the cham- 
ber; the doors are closed and the draft admitted to the ash pit. The 
thick walls which surround the furnace prevent radiation of its heat. 
The fire brick are, therefore, heated to incandescence and the hot 
gases sweep through the chamber. The flow of the gases is usually 
checked by a choke damper on top of the stack. 

The outer form of these furnaces is usually rectangular. The 
brick walls are tied together by stay rods to prevent bulging and 
the corners are protected by angle irons. 




Fig. 169. 



FORGING 



95 



The selection of the fuel is an important matter in the operation 
of these furnaces. Experiments have been made with almost every 
kind of fuel. That now universally used is a soft bituminous coal 
that will' not cake. 

Steam or power hammers are always used in connection with 
these furnaces. The work is too large and heavy for manipulation 
by hand hammers. 

An ordinary class of work done with them is the welding of 
slabs from small pieces of scrap. To do this a rough pine board 
about 12 inches wide and from 15 to 18 inches long is used. On it 




Fig. 170. 

is neatly piled about 200 pounds of small scrap pieces. This material 
is then bound to the boards by wires, and the whole is placed upon 
the hearth of the furnace. It is allowed to remain until the whole 
mass is at a welding heat. When in this condition, the plastic surfaces 
of the pieces serve to stick them together, so that the whole mass can 
be handled as a single unit by the tongs. The board, of course, burns 
away, leaving the metal on the hearth. The metal is then lifted out 
and placed under the steam hammer. A few light blows serve to do 
the welding. After this heavier blows are struck and the mass is 
hammered into any shape that may be desired. Usually this first 
hammering gives it the form of a slab. Slabs thus made are cut up 
and again welded to form the metal for the final shape. 

In the piling of the metal upon the board or shingle, as it is 
called, great care should be exercised. Iron and steel should net 
be piled together. Rusty metal should be cleaned before being put 
in the pile. Large air spaces between the pieces should be avoided. 



96 FOKGING 



The whole mass should be packed together as compactly as possible. 

Bolt Headers are really upsetting machines that form the heads 
of bolts upon straight rods. Owing to the rapidity with which they 
do their work, they are invariably used for manufacturing bolts in 
quantities. 

Miscellaneous Suggestions. In doing work in the blacksmith 
shop it must be constantly remembered that the work is larger at the 
time it is being manipulated than it will be when cool. Allowance 
must, therefore, always be made for shrinkage. As the pattern maker 
allows for the contraction of the molten metal to the cold casting, so 
the blacksmith must allow for the contraction of the hot iron or steel 
to the cold forging. 

The temperatures of iron at the several colors, are as follows: 

Lowest red visible in dark 878° F. 

Lowest red visible in daylight 887° F. 

Dull red 1100° F. 

Full red 1370° F. 

Light red, scaling heat 1550° F. 

Orange 1650° F. 

Light orange 1725° F. 

Yellow 1825° F. 

Light yellow. . 1950° F. 

This table is based on temperatures given by Messrs. Taylor and White, 
Transactions Am. Soc. of Mech. Engs., Vol. XXI. 

From the above it will be seen that the temperature at which 
forgings are finished under the hammer, should be at about 900° 
Fahr. When these same forgings are cold their temperature will be 
from 60° to 70° Fahr. There is, therefore, a difference of at least 
840° between the working and the finished temperature. The expan- 
sion of iron may be taken to average about .00000662 of its length 
for each increase of one degree Fahrenheit in its temperature. If a 
bar of machine steel exactly 2 feet long when cold, be heated red 
hot and measured, it will be found to have increased nearly \" in 
length. Taking the temperature of the red heat as 1370° F., and 
that of the cold bar as 70° F., the increase in length would be 1300X 
.00000662 X 24 ( length in inches ) = .206". This expansion must be 
allowed for when measuring forgings red hot. 



EXAMINATION PAPER 



FORGING. 



Read carefully : Place your name and full address at the head of the 
paper. Any cheap, light paper like the sample previously sent you may be 
used. Do not crowd your work, but arrange it neatly and legibly. Do not 
copy the ansivers from the Instruction Paper; use your own words, so that 
we may be sure that you understand the subject. 



1. Make a sketch and show all dimensions of a hoisting hook 
for a load of 2,000 lbs. 

2. What is the essential difference between tool steel and 
wrought iron? 

3. What is shrinking? 

4. What three materials are commonly used in forge work? 

5. Give two methods of measuring the amount of stock re- 
quired to make a scroll. 

6. How much would the crank shaft shown in Fig. 82 weigh, 
before any machine work was done on it, if \" be allowed for finish 
on all surfaces where called for? 

7. How is a lead bath used, and what is the advantage in tem- 
pering? 

8. What length of stock, \" in diameter, is required to make 
a ring 3" inside diameter? No allowance for welding. 

9. What is meant by the term "allowance for finish"? 

10. What is annealing? 

11. How does brazing differ from welding? 

12. What is the tuyere? 

13. If two plates are to be riveted together as tightly as possible, 
should heavy or light blows be used? 

14. Wliat is meant by "the hardening heat?" 

15. Make a sketch showing what dimensions the forging shown 
in Fig. 78 would have if \" finish were allowed all over. 

16. Of what does welding consist? 

17. What precautions must be taken when forging a round bar 
to a point? 



FORGING 



18. Three pieces of tool steel are heated to the hardening heat; 
the first is cooled in water, the second in oil, and the third is allowed 
to cool in the air. What will be the relative hardness? Why? 

19. How are tongs fitted to work? 

20. Make a sketch and show all dimensions of a hexagonal 
head bolt f" x 8". 

21. How is the final hardness of steel affected by the rate of 
cooling? 

22. If a tap is broken off in a piece of work, the work is wanted 
in a hurry, and it is necessary to anneal the piece, how can the anneal- 
ing be done? 

23. What is brazing? 

24. How much would an anvil marked 3—2—10 weigh? 

25. Why are scarfs used in welding? 

26. Why are springs hardened and tempered in oil? 

27. Why is borax a better flux than sand? 

28. What are the characteristics of a good forge coal? 

29. What determines the size of the grain in hardened steel? 

30. What is the down draft system? 

31. What is meant by scarfing? 

32. What is meant by clearance on lathe tools? 
33.. What is a flux, and why is it used in welding? 

34. How are steam hammers rated? 

35. Why should the ends of pieces to be welded, be upset? 

36. (a) What do you understand to be meant by an oxidizing 
fire? (b) What do you understand to be meant by a reducing fire ? 

37. In making an S wrench, which is preferable; to forge the 
jaws separately and then weld on the handle, or to cut the jaws 
from a solid piece of metal and draw down the material between 
them to the proper size for the handle ? 

38. Explain the method of making a ladle shank in such a way 
that no welds are necessary in its construction. 

39. Describe with sketches the so-called commercial method 
of forging a crank shaft. 

After completing the work, add and sign the following statement: 

I hereby certify that the above work is entirely my own. 

(Signed) 



i.tf. 23 lyt