of any size. This eliminates the necessity for a special mouthpiece
for display, which was necessary with the older models.
Before replacing a screw mouthpiece be sure to thoroughly clean
the surface of the crucible and the back of the mouthpiece of all
dirt and dross. Place a thin coating of red lead and oil on the
back of the mouthpiece and place it in position. Tighten the screws
gradually, beginning at the ends and working toward the center.
METAL POT ADJUSTMENTS
There are two pot leg bushings which fit over the vise frame shaft
and project up into the fork of the pot leg. These support the metal
pot and hold it in position to lock up with the mold. The position of
the pot in relation to the mouthpiece is determined by four adjusting
screws in each pot leg and bearing against the bushings. These
screws permit the proper alignment of the mold and mouthpiece.
The holes in the mouthpiece, through which the metal passes to the
mold cell, should align with the smooth or constant side of the slug,
as this side of the mold always remains in the same position. When
using the mold liners for the different points of thickness of slugs,
the position of the mold cap changes. If the holes should align with
the rib side of a slug of large size, when changing to 6-point slug
the mold cap would cover the holes, thus shutting off the flow of
metal and causing an imperfect lockup or imperfect slugs.
The two screws at the top and bottom of each pot leg are for the
purpose of aligning the holes in the mouthpiece with the constant
side of the mold.
To make this adjustment, remove the mold and take it apart. Clean
thoroughly the mold and mold pocket. Leave the cap off and place the
constant part of the mold back in the pocket with a 30-em left-hand
liner and a constant right-hand liner in the mold. Remove the plunger
pin for safety. Turn the machine until the first elevator rests on
the vise cap. The mold should now be in front of the mouthpiece.
Raise the first elevator, holding it up with a piece of wood, one end
under the head of the slide and the other on the upper end of the
vise automatic stop rod. Close the vise. Unlock the mold cam lever,
move the mold disk forward by hand so the locking studs can enter
the bushings. Turn the machine by hand until the mouthpiece advances
against the mold. Release the two front adjusting screws a trifle so
the pot legs can move freely while making the adjustment. Release the
lock nuts and move the top and bottom screws until the bottom of the
holes in the mouthpiece are in line with the constant part of the
mold, and the two end holes are showing within the liners. Tighten
the lock nuts and the front adjusting screws after finishing the
adjustment.
A great amount of lockup trouble is caused by the mouthpiece on the
metal pot not locking up squarely against the mold, due to the front
and back pot leg screws being out of adjustment or the mouthpiece
being warped.
To adjust the pot legs so the mouthpiece will lock up squarely with
the mold, place the machine and the mold (without the cap) and the
30-em liners in the same position as when adjusting the height, but
have the mold cam lever connected to the mold slide. Leave a little
space between the mold and the mouthpiece. Place a piece of tissue
paper at each end of the mold between the mold and the mouthpiece.
Have the paper just inside the ends of the liners. Turn the machine
forward until the pump lever is ready to go down for the cast. Be
sure the plunger pin has been removed, to prevent accidentally
forcing the metal out of the pot.
If the left-hand paper should be tight and the right-hand paper
loose, loosen the front pot screw at the left and turn in on the
back screw. This will move the left end of the mouthpiece farther
back. Adjust with the front and back screws in this manner until both
papers are held tightly.
After completing the adjustment, replace the cap on the mold and turn
the machine to normal position.
Another method of testing the pot lockup is to let the machine
make the quarter revolution which brings the mold in front of the
mouthpiece. Disconnect the mold lever and pull the mold slide
forward. Apply a thin even coating of a mixture of red lead and oil,
or printers’ ink, to the back of the mold. Be sure to have the mold
clean. Hold out the mold disk driving pinion, so the disk will not
revolve, and let the machine run around without casting. The mixture
will transfer from the mold to the mouthpiece. If the mouthpiece is
touching only on one end of the mold it can be adjusted by the screws
in the sides of the pot legs. Adjust them to swing the crucible to
bring about a tight fit, repeating the above test until the transfer
is registering evenly the full length of the mouthpiece. After each
test wipe off the mouthpiece and mold, for any oil or too much red
lead or ink would give a false impression.
If the mouthpiece touches at both ends and not in the center or in
the center and not on the ends, it indicates that the mouthpiece is
warped and the above adjustments would not be satisfactory.
When the mouthpiece is warped or high, it is necessary to take
out the high spots with a fine file or an oil stone. Take off a
very little of the surface at a time and repeat the tests with the
red lead until a proper lockup is secured all the way across the
mouthpiece.
After fitting up a mouthpiece in this manner, the vents should be cut
to their original depth.
After making the pot adjustments, test the mold slide adjustment to
make sure that it brings the face of the mold to within .010 of an
inch from the face of the matrices. See that the pot lever has the
1/16 of an inch play needed during lockup.
Be sure the washers on the pot lever shaft are so placed that the
sides of the lever do not bear on the cams.
POT LEVER
The pot lever is located directly back of the metal pot and, through
cam No. 8 and the pot cam roller, gives the pot its forward and
backward action. There is a cushion spring on the pot lever eyebolt
that connects the lower end of the pot lever to the pot jacket. This
spring gives the lockup of the pot and mold and takes up all excess
motion of the lever during the lockup.
There is a short piece of pipe pinned to the eyebolt inside of the
spring, which prevents having too much tension on the spring. The nut
on the front is the adjusting nut. This nut has a washer next to the
spring, to keep the spring from being forced over the head of the
nut. This nut should be tight against the pipe. With the end of the
rear nut against the pipe on the bolt, there should be 1/16 of an
inch from the back of the pot lever to the head of the nut when the
machine is in casting position. This 1/16 of an inch adjustment gives
the correct lockup to the pot and also prevents breaking the lever by
too much pressure.
The pot lever spring should be examined frequently, as back squirts
will be caused by a spring which is broken or worn. This trouble is
caused by not giving pressure enough to the mouthpiece when it is
being locked against the mold for the cast.
A lever spring weak, worn, or out of adjustment will also cause an
uneven height of the matrices, due to the lack of pressure during the
cast.
When it is necessary to remove a pot lever spring, pull the pot
forward by hand, place a support beneath the pot jacket to hold the
pot lever roll off the cam. Remove the pot balancing spring, take off
the rear nut on the eyebolt and push back on the lever. The spring
can then be removed.
The roller in the pot lever has nine anti-friction roller bearings.
These rollers should frequently be examined for wear, and if found
worn should be renewed, because a set of worn anti-friction rollers
will also cause an imperfect lockup. When renewing these rollers, put
in all nine new ones. If a roller is worn or broken, or the bearing
pin or pot lever roller worn, there will be play between the lever
and cam, which will prevent a tight lockup.
To take out the pot lever: Pull the pot forward by hand, place a
support beneath the pot jacket, remove the balancing spring, loosen
the screw in the upper shaft bearing, and pull the shaft out. On the
upper shaft bearing on each side of the pot lever, are washers of
varying thickness. These washers are for the purpose of adjusting the
pot lever sidewise so it will not bind on the main cams. When taking
out this shaft be careful that the washers are not lost or mixed.
Take out the wing pin that holds the eyebolt to the pot jacket. Place
the lever on the bench and take out roller bearings by releasing
the set screw and pulling out the roller pin. Before replacing the
bearings, in the lower roller, coat them with vaseline or hard
grease. By placing a small piece of an old keyboard rubber roll in
the hole, so the bearings fit around it, they will be held in place
until the pin is slipped through. The pin will force the rubber out.
Fastened to the back of the pot lever, at the right-hand side, is the
pot return cam shoe. As the main cams revolve, the pot return cam,
fastened to cam No. 9, comes in contact with the shoe, pulling the
pot away from the mold after the slug has been cast.
REMOVING A POT
To remove a pot from a machine: Remove the plunger, dip as much metal
out of the pot as possible. Lower the first elevator to the vise cap,
and let vise down to second position. Remove the mold slide. Take
off the pot leg caps. Loosen the front adjusting screws in the pot
legs. Loosen the nut on the pot lever eyebolt, to release the spring
tension. Take out the pot lever shaft, and remove the pot lever. Take
off the mold disk shield and pump stop bracket. The pot can then be
lifted out by placing a rope through the supports on the jacket for
the pot lever shaft, so that the pot can be raised up while it is
being guided out of the machine by taking hold of the bottom of the
pot legs.
SLUG TROUBLES
An imperfect face on slugs could be caused by any of the following:
Holes in the mouthpiece not inside the slug line, holes in the
mouthpiece closed, or partly so; vents in the mouthpiece filled up,
or insufficient ventage; dross in the throat of the pot back of the
mouthpiece, mold cell rough inside, due to being damaged; mold cell
dirty or oily, inferior metal, holes from the pot to the well stopped
up, plunger not clearing the well holes, plunger or pot well dirty,
governor not working properly, temperature of the metal not adapted
to the size of slug being cast, cold metal. Too large a hole in the
mouthpiece will give a small slug an imperfect face.
When the slug is cold, the body of the slug may be solid and have
a stringy or flaky appearance, and the face may be imperfect, some
of the letters being poorly cast or blurred. The base of the slug
usually will be good.
When the slug is too hot the face is good, but the body is hollow and
spongy and the slug is light. It is imperfectly formed, due to the
heat of the metal.
A bright bottom on a slug shows that the mold knife has trimmed a
thin layer of metal from the bottom of the slug, due to an imperfect
lockup, the excess metal running over the bottom of the mold. If
the mouthpiece makes a perfect contact with the mold at the moment
of casting, there will be no excess metal and the slug will show a
clean bottom.
An imperfect lockup can be caused by any of the following: Cold
metal due to low gas pressure, dirty burners, gas burning in mixer,
improper packing around the mouthpiece, or improperly packed metal
pot; hot metal, too much metal in the pot, dirty plunger or well,
air vents cut too deep, air vents cut too high above holes, dull
mold knife, pot cam lever roller or bearing pin worn, pot lever not
working freely on the lever shaft, due to gum or lack of oil; metal
on the bottom of the mold, mold knife out of adjustment, mold disk
guide out of adjustment, leaky mouthpiece, warped mold, pot lever
spring weak or broken, accumulation of metal back of the mold disk,
mold cap guides bent, loose stay bolt, loose adjusting screws on pot
legs.
GASOLINE BURNER
There are three methods commonly used to heat a metal pot: Gasoline
burner, gas burner, and electric heater.
The gasoline burner in most cases is undesirable on account of cost,
time, and fire hazard; but through the lack of electrical current or
gas it must sometimes be used.
There is a burner designed for either gasoline or kerosene by the
Linotype Company. This burner will give complete combustion in
burning either gasoline or kerosene. It has no threaded joints
and, therefore, no joints to leak. It is equipped with a positive
mouthpiece burner and control. This burner can be taken apart for
cleaning without removing any screws. The fuel is forced to the
burner from a pressure tank. With this improved mouthpiece burner
control, the burner may be adjusted for a slug of any size. The best
results can be obtained from a gasoline or kerosene burner by keeping
it clean.
GAS BURNERS
The gas burner used to heat the metal pot is made up of three
sections. The largest burner heats the main part of the pot. Another
pipe leads up to heat the throat, and a small burner heats the
mouthpiece. The pot and throat burners are held near the pot by a
rod which passes through the pot jacket and under the pot burner. The
mouthpiece burner is held in place by a support and a screw which
extends into the pot jacket.
The gas enters the burners through the pot gas burner cocks. The gas
cock that feeds the pot burner has a larger inlet hole than those of
the throat or the mouthpiece burners, because more gas is required
for the pot burner. The inlet holes must be kept open and free from
soot and metal, but should never be drilled larger at any time.
Should you find a burner tip that has been drilled, a new tip should
be applied by driving out the old tip and inserting a new one.
As the gas leaves the gas cock it passes through the air mixer. The
air mixer is open on the bottom side and allows a flow of air to mix
with the gas. Unless the gas is mixed with the proper amount of air
it will not make sufficient heat under the pot. Do not at any time
allow the gas to burn in the mixer. Sometimes when lighting the gas
or when the pressure is low the flame may light in the mixer. It
should then be turned out and relighted, holding a flame near the
burner. Should the gas be allowed to burn in the mixer the heat will
be lost before it reaches the burner; and furthermore, the burner
will soon become clogged with soot.
From the mixer, the gas passes upward into the pot burner. The pot
burner consists of a circular shaped chamber which is covered with
a flat plate. The top rim of the chamber is notched, which allows
the gas to flow out around the top plate, forming a very hot flame.
The flame from the burner should be of a bluish appearance. A dirty
burner will cause a yellow flame. There is very little heat in a
yellow flame, and when the burner shows a yellow flame, it usually
indicates a dirty burner or a fire in the mixer. A very important
part of the burner is the top plate. When this plate becomes warped
or badly burned it should be replaced with a new one.
Two pipes lead out from the front end of the pot burner to carry
a flame up under the crucible throat. These pipes are fed through
the front gas cock. The gas passes through a separate chamber in
the front side of the pot burner. It is very essential that these
burners are working properly as they keep the metal hot in the throat
of the crucible.
The mouthpiece burner consists of a small pipe into which holes
have been drilled to allow the gas to escape. This burner extends
underneath the mouth of the crucible the full length of the
mouthpiece. There are two extra holes on the right-hand end to give
a little more flow of gas at that point. The holes should never be
reamed out larger, but should be kept clean and free from soot or
metal. Metal sometimes gets through the holes and partly fills the
pipe. This retards the free flow of gas and causes loss of heat to
the mouthpiece.
Good slugs from a machine are to a great extent dependent on good,
clean burners. Only experience on various machines will enable one
to tell just how much flame to carry in each burner on a machine.
The governor should regulate the pot and throat burners, when once
adjusted. However, it is better for the operator to regulate the
mouthpiece burner with the gas cock, according to the size of the
slug being cast.
GAS POT HINTS
Keep gas tips clean and round. A blue flame is the heating flame.
Watch the mouthpiece burner. Clean out metal and dross which forms
there due to metal dripping from the mouthpiece.
If the mouthpiece burner does not give a long, blue flame after
cleaning, procure a new mouthpiece burner and replace the old one.
A yellow flame indicates too little air in the mixture. This can be
caused from too large a hole in the gas tip, air inlet partly closed,
dirty burners, or gas burning in the mixer. Sometimes the hole in the
tip of the gas cock is too large. The hole can be paned with a small
hammer and reamed out with a small broach to the proper size.
The pot burner top plate is fastened by four stove bolts. These bolts
become charred and brittle from the heat, and the nuts will be very
hard to start. Have a few of these bolts on hand when changing the
plates, because the plate must fit tightly to the burner to obtain
the best results.
Good slugs can not be produced with dirty burners. Keep them clean.
It is better to spend ten or fifteen minutes cleaning the burners
than to lose an hour trying to regulate the temperature of the metal.
TO REMOVE THE GAS BURNERS
Disconnect the hose on the older styles or the gas pipe union on
the newer styles. Separate the mouthpiece burner from the crucible
at the sleeve. (This operation is not necessary on the thermostat
connections.) Pull out the rod which holds the burners in place and
lift them out.
To remove the mouthpiece burner, take out the screw which holds the
support to the jacket of the pot, slip the connecting sleeve back,
and pull the burner to the left.
PRESSURE GOVERNOR
The pressure governor is used to control the flow of gas to the
machine and to keep it at an even pressure. The governor is placed on
the main gas line so the gas must pass through it before flowing to
the machine. It is not necessary to have a pressure governor on each
machine, for where there is more than one machine, a governor large
enough to supply any amount may be secured.
The gas enters through a valve in the bottom of the governor and
passes up into the supply chamber. From the supply chamber the gas
flows out to the machine burner. The pressure in the supply chamber
is regulated by an inverted cup float. The lower rim of the float is
immersed in mercury, which causes the cup to float and also acts as
a seal to prevent the gas escaping through the top of the governor.
Weights are placed on top of the float to counterbalance the gas
pressure. Fastened to the float is a rod which passes through the gas
chamber. This rod connects to and operates the valve in the inlet
opening. When the gas pressure is increased it raises the float by
its pressure. When the float raises, it at the same time raises the
valve in the intake, which decreases the opening through which the
gas enters. Should the pressure in the main fall off, the float
sinks deeper into the mercury, and the opening in the valve is
opened, permitting a greater flow of gas. Thus the pressure in the
gas chamber is held uniform, because the greater the pressure on the
float, the smaller the opening for the gas to enter.
To regulate the pressure, place weights on the float until sufficient
gas flows to the burners to give a good flame.
MERCURY GAS GOVERNOR
In a governor of this style, the gas from the main line passes
through the upper pipe, down through the internal tube, and escapes
between the end of this tube and a column of mercury in the mercury
tube, passing up behind the internal tube, and out through the lower
pipe to the burners.
To prepare the governor for use, remove the adjusting rod and pour
in mercury until it rises in the mercury tube almost to the lower
end of the internal tube, which can be seen through the glass disk
at the side of the governor. When the metal in the pot reaches the
proper temperature, the surface of the mercury stands at the lower
end of the internal tube, but a notch in the side of this tube above
the mercury permits a flow of gas sufficient to prevent shutting the
gas entirely off underneath the pot. When the temperature falls, the
mercury in the holder and column will be cooled, and its surface
lowered in the tube. This will allow an increased flow of gas to the
burner until the temperature of the pot is raised to the proper point.
The regulation of the governor is effected by moving the adjusting
rod in or out. If the temperature in the pot is too high and the
mercury fails to close the tube, the adjusting rod must be moved in
until the mercury raises in the tube. If the temperature in the pot
is too low, the mercury closes the tube before the proper temperature
is reached in the pot. Thus the rod must be moved out until the
mercury is lowered from the top of the tube to the proper extent.
THERMOSTAT GAS GOVERNOR
The supply of gas at the burners is controlled by the expansion and
contraction of rods immersed in the molten metal in the crucible at
the left-hand side of the metal pot. These rods are of a special
alloy, which is extremely sensitive to variations of heat. No mercury
is used, so that the governor is not affected by the pressure of the
gas at any time.
The principle upon which the thermostat is built, is the difference
in expansion of two metals under heat.
The part of the thermostat which is immersed in the metal is made of
cast iron and has a hole or pocket in which the rod of composition
metal sets. The upper end pushes against a hinged lever; the other
end of this lever operates a valve plunger. The expansion of the
thermostat rod being greater than cast iron, raises the valve lever,
which forces down the valve plunger, seating the plunger nearer the
valve seat. This cuts down the flow of gas to the burners. The rod
contracts as the metal cools, and allows the valve spring to open the
valve.
Underneath the valve rod cap and encircling the valve rod, is a
spiral spring which raises the valve rod as the expansion rod
contracts, which opens the gas inlet, and also keeps the expansion
rod pushed to the bottom of the pocket.
In the lower end of the valve is a hole to prevent the burner going
out if valve is entirely closed. This hole must not be enlarged.
The valve adjusting screw is slotted and has a setscrew inserted
through the valve lever to keep the adjusting screw from turning.
Between the head of the adjusting screw and under part of the lever
is a spring which forces the head of adjusting screw against the cap
of the valve. When tightening up on the adjusting nut the spring
closes, releasing some of the pressure on the valve, permitting more
gas to pass the valve. By loosening the adjusting nut the spring
expands, forcing the valve down, cutting down the flow of gas to the
burners.
To adjust thermostat, if metal is not hot enough, raise the adjusting
screw by turning the adjusting nut farther down; if the metal is too
hot, unscrew adjusting nut, allowing the adjusting screw to force the
valve farther down.
The screw in the top of the expansion rod is for the purpose of
making the rod longer, should occasion require. Do not change this
screw unless necessary.
There are two sets of rods and valves on the regular equipment. One
set regulates the gas to the pot burners and the other regulates
the gas to the mouthpiece burner. Experience has shown that it is
impractical to regulate the mouthpiece from the crucible, so cut off
this part of the regulation and use a gas burner cock.
ELECTRIC POT DEFINITIONS
The circuit is that part of the equipment such as copper wires,
resistance wires, switches, etc., which is intended to carry electric
current. They are all insulated from the frame of the pot.
The current is the electricity passing through the equipment.
Amperes is the volume of current passing through.
Volts is the strength or pressure of the current.
A watt is the product of the volts multiplied by the amperes.
A kilowatt is 1,000 watts.
A kilowatt hour is one kilowatt of current used for one hour.
A ground is a bare part of the electric circuit accidentally touching
the frame of the pot.
A short circuit is one or more grounds which will allow the current
to take a shorter path.