AMERICAN SCHOOL °f CORRESPONDENCE
T T U. S. A.
Class T' \ ; _
Book . h 5 '
John Lord Bacon
Instructor in Forge Work
American Society of Mechanical Engineers
Author of "Forge Practice"
AMERICAN SCHOOL, OF CORRESPONDENCE
LIBRARY of CONGRESS
Two Copies Received
APR 23 1906
Copyright 1906 by
American School of Correspondence
Entered at Stationers' Hall, London
All Rights Reserved
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
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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.
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
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
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.
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
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-
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"
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.
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
The ordinary anvil, Fig. 6, has remained unchanged in form
for many hundreds of years. As now made, the body a is of wrought
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-
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-
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
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
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
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
work. Swages are also made for octagonal, hexagonal and other
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
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
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
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
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.
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
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.
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
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.
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
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
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
For this work (finishing the edge of the scarf) as well as all
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
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
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
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-
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
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
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
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
scarfing being done by the pene end of the hammer. If necessary,
the ends of the pieces may be upset before scarfing. Care should
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.
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
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-
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
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
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.
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
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
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.
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.
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
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
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
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
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-
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
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
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
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
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
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.
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
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.
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,
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
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
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
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.
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
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
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
■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.
.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 =
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.
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
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
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-
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
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
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
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,
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.
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
' 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
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.
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.
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
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
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
volume of A a:
X 4 X o-tf
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
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"
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.
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
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.
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 .
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
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
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
WEIGHT OF FLAT ROLLED IRON.
Length, 12 inches.
2. 18' 2.29
7.65' 8.02 8.38
8.75J 9.17 9.58 10.00
10.94 11.46 11.S8 12.50
12.03,12. 60 13.17
15.31 16.04 16.77
18.59 19. 48120.36
19.69 20.63 21.56
20.78 21.78 22.76
21.87 22.93 23.96
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.
WEIGHTS OF ROUND AND SQUARE ROLLED IRON.
Length, 12 Inches.
£ fl a
°f ps » a
53 a*S °
.pf 3 v fl
V o fl o
y a a
r, HH -rH
ODr-j UJ fl
CO 0J <u
x 3 a
f 1 pjfe tb
rfd OJ d
03 c?S O
£fps v a
'53 o fl o
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-
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
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'
H 4 »
4 * H
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-
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.
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
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
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
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
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
The stock used when making small thin rings should be twice
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
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
Fig. 94. Fig. 95.
many forgings of the same general shape. The forging shown in
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
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
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-
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.
suited for nuts of different sizes
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
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
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
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
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.
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
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
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
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,
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,
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
the sounder forging.
The molder's trowel illustrated in Fig. 112
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
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-
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
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
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
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
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
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
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
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.
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.
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
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
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-
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
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
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
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
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.
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-
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
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
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
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
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.
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.
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-
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
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
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
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
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
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
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
momentary plunge tends to equalize the heat by cooling the thinner
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
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
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
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
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
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.
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
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.
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
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-
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.
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
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
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
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.
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.
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
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
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-
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
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
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.
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
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
•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,
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
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,
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-
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
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
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-
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
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
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
B Section XX'
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.
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
"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
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.
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,
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
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
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-
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
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
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.
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
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
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
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.
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
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.
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
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.
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
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-
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?
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
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.
i.tf. 23 lyt