Chapter III: Part 3

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.

An open is an interruption in the electric circuit such as a broken wire, etc.

Resistance is an obstruction in the electric circuit retarding the flow of current.

Series connection means that two or more units are connected in line with each other. Current enters one terminal, passes through the windings, out of the other terminal, and directly into the next unit, through its windings, and out to the opposite side of the line.

Parallel or multiple connection means that two or more units are wired in such a way that each makes a complete circuit of themselves. Current enters a unit, passing through its windings, and directly back to the line.

Shunt—A conductor joining two points in a circuit and designed to divert part of the current.

An electrical circuit carrying current can best be simply explained by considering an iron pipe through which water is flowing under pressure. The pipe represents the circuit, and water passing through it represents the current. The volume of water flowing represents the amperes, and the pressure of the water represents the volts. A leak which allows the water to escape represents a short circuit, and a valve in the pipe partially closed represents resistance.

ELECTRIC POT

The electrical equipment consists of four heaters, a dynamic thermometer, and a unit control panel. The passage of electric current through the windings inside the heaters generates heat which melts the metal in the crucible and raises it to the proper operating temperature, while the dynamic thermometer and the magnetic switch on the control panel operate to keep the metal at this predetermined temperature. These equipments are either 110 to 120 volts or 210 to 220 volts, direct current or alternating current.

The crucible heaters are the same for all voltages; they are connected in “series” for 200-volt to 250-volt circuits and in “parallel” for 100-volt to 125-volt circuits. They are immersed directly in the metal and partially surround the pump-well, heating the metal by direct contact. The heating element or resistor of these heaters is composed of resistant ribbon wound on strips of clear mica. Strips of mica entirely surround the resistor, completely insulating it from the metal parts of the pot. The resistors are protected by strong metal casings which surround them. They are not subject to wear and tear in normal service.

Heating the metal by direct contact from within the metal itself by these heaters, makes a very efficient equipment, as all of the heat generated is immediately transmitted to the metal exactly where it is required, and there is no loss of heat due to faulty conduction. The dynamic thermometer bulb being immersed in the metal adjacent to the heaters and the pump-well, permits of a very close temperature regulation.

As these heaters extend nearly the full height of the metal in the crucible and pass down through the top of the metal, there is no possibility of cracking a crucible. When the metal begins to heat, it is that portion in direct contact with the heaters which first becomes molten. Internal pressure is relieved by this melted pathway and the molten metal will flow to the top of the pot.

It is important that the pot never be filled with metal above the under side of the ring which is cast on the inside of the crucible. If the crucible is filled above this ring, metal may splash over into the heating insulating material and touch the electric terminals, grounding them.

The crucible heater must be entirely covered with metal at all times. If they are not, that portion that is exposed to the air will get very hot and continued exposure will burn them out, destroying them. They are not designed for operation in the air.

Do not pry around the units with a screwdriver or pound on them, if the metal envelope is punctured, molten metal will immediately enter, grounding the element and destroying the unit.

The temperature in the crucible is controlled by an adjustable dynamic thermometer mounted on the side of the pot, and which operates a switch in the control panel, turning the current on and off as needed. The bulb and tube of this thermometer contain mercury and the bulb is immersed in the metal in front of the well of the crucible. The tube is connected to a flattened hollow coiled spring tube. The mercury also passes through this air tight spring tube. On the free end of this coiled spring tube is fastened an insulated pin which operates the contact lever. The contact lever is suspended downward between two metal contact disks. These contact disks and the contact lever are connected to the main line through a magnetic switch mounted in the control panel. The thermometer only carries current long enough for the magnetic switch to connect and then the current is carried directly through the switch.

As the temperature of the metal rises the mercury in the bulb expands causing the coiled spring to uncoil slightly, driving the contact lever against the disk that shuts off the current, allowing the switch to fall open and disconnecting the circuit through the crucible heaters.

As the temperature of the metal falls, the mercury in the bulb contracts allowing the coiled spring to force the contact lever against the disk that turns the current on by connecting the switch to the main line. The variation in the temperature is held within 15 degrees of the average working temperature.

The temperature control is normally set for a maximum of 550 degrees and a minimum of 535 degrees, that is, with normal operation the temperature of the metal will always be between these limits. This is found to give the best all around casting results for average metal. In case it is desired at any time to change the operating temperature, this can be done by turning adjusting screw right-handed for hotter metal, and left-handed for cooler metal. The head of this adjusting screw projects through the right-hand side of the dynamic thermometer cover.

Do not change the position of the control disks, unless badly pitted, as their relative distance is determined at the factory, and very seldom need to be changed.

A good thermometer should always be used when adjusting the screw for proper heat. Guessing will not get the proper results.

With ordinary work, and after the metal is at operating temperature, the current will be on and the crucible heaters generating heat about three minutes, then off and not generating heat about twelve minutes, and will repeat this cycle as long as snap switch is left in the “on” position.

THROAT AND MOUTHPIECE HEATERS

The mouth and throat heaters are clamped in close contact with the outside of the crucible throat to keep the metal at the operating temperature while being pumped from the crucible to the mold. The throat heater extends the full length of the pot throat and is held in close contact with it. The mouth heater is clamped tightly to the pot mouth. Both heaters are surrounded with heat insulating material and are held in close contact with the pot throat and mouth by a U-shaped clamp under the throat unit and a plate over the mouth unit, drawn tight by two nuts.

The mouth and throat heaters are always connected in “series,” one set being used for 100-volt to 125-volt and another set for 200-volt to 250-volt.

The heat for the throat and mouth units are controlled by a manually controlled rheostat moving from the left to the right, and fastened to the front of the control panel under and at the rear of the keyboard.

The rheostat is connected directly to the mouth and throat heater and is not controlled by the dynamic thermometer.

The crucible heaters are intended for heating the metal to the proper temperature, and the mouth and throat heaters are only intended to keep the metal at the proper temperature while being forced from the crucible to the mold.

If the voltage is irregular and remains too high for some time, or a speedy operator casts large slugs at a rapid rate continuously, the mouthpiece is apt to become heated and the slugs will have hollow backs. In this case it will be necessary to turn rheostat knob left-handed, but if the voltage remains low for some length of time, or a slow operator casts small slugs slowly, the mouthpiece may become cold and the slugs will have poor faces, in which case the rheostat knob should be turned right-handed.

When casting large slugs in rapid succession the mold is apt to become heated, but attempting to regulate the temperature of the metal in the crucible to overcome the heating of the mold will fail, because the electric pot is a heating unit only and will not cool the mold.

The control panel consists of a magnet switch mounted on a slate panel enclosed in a steel cabinet. The cabinet also has a suitable fuse cut-out and the switches which control both the pot and the electric motor (if used) and places all controls within easy reach of the operator. Connection is made between the pot proper, the dynamic thermometer, and the control panel by suitable wiring enclosed in a flexible conduit.

CARE OF ELECTRIC METAL POT

The contact points on the thermometer and the magnetic switch should be kept clean and free from corrosion. Use No. 00 sand-paper. (Never use emery cloth or paper.) Dirt and corrosion are electrical insulators, and if these contacts become dirty, electrical contact may not be made when the temperature reaches 550 degrees F.; the magnetic switch will not open and the crucible heaters will continue to increase the temperature of the metal until the fuses are blown; the dynamic thermometer permanently injured, or the heating units burned out. When the temperature reaches above 550 degrees, the metal is too hot, causing back squirts. When the metal has cooled, the contacts, owing to the dirt, will not operate, and the metal will continue to cool until it can not be used. The contact points should be cleaned about once each two weeks.

The hole in the hollow tube connecting the bulb and the flattened coil spring of the dynamic thermometer is very small and care must be taken that the tube is not injured when feeding metal to the pot, or that no sharp bends are made in it, as it will close the hole and interfere with the proper working of the thermometer.

Occasionally some of the parts such as the heaters, thermometer, or the wiring inside the pot may become damaged and will have to be replaced. In ordering the new parts for replacements, be sure to specify the voltage being used and the serial number of the pot. This number plate can be found on top of the pot cover.

It is seldom that both crucible heaters will be burned out at the same time, so if your pot is a 100 to 125-volt equipment, and one of the crucible heaters tests open or grounded, and must be removed and replaced, the metal in the crucible may be heated by the crucible heater that is in good condition; but if your pot is 200 to 250-volt equipment, and one of the crucible heaters must be replaced, it will be necessary to melt the metal in the crucible with a blow torch before either crucible heater can be removed. It is not necessary to remove the metal from the pot. Merely keep the metal agitated while melting it with the blow torch.

Frequently a heating unit is burned out by a little metal splashing on the terminals, causing a gradual short circuit. This trouble can be eliminated by wrapping the heater terminals with asbestos tape.

When cleaning the contact points on the dynamic thermometer, it is necessary to remove the cover by taking out the two long flat head screws. This cover should be examined for small particles of metal before replacing.

To remove and replace a damaged wire in the pot, fasten another wire securely to one end of it, grasp the other end with a pair of pliers and pull. The new wire will be pulled in as the old one is removed.

Rubber covered wire or slow burning wire is not satisfactory. A special wire with a special grade of insulation should be used.

If it becomes necessary to remove the dynamic thermometer, heat the metal in the crucible to operating temperature and then turn the main switch off. Disconnect the thermometer wiring and dip out the metal to below the level of the thermometer bulb. Take off the pot cover and remove the two screws fastening the thermometer case to the bracket. Grasp the case with the hand and the bulb with a pair of pliers and raise up and out. Be very careful at all times not to damage or break the bulb or hollow wire which contain the mercury; to do so will cause trouble in regulating the heat.

Replace the thermometer while the crucible is hot. See that the bulb does not project out from the casting so as to interfere with the insertion of ingots of cold metal. Press the tube firmly but carefully into place over the edge of the crucible, being careful not to injure it. Fasten the case to the bracket and reconnect the wiring and put on the cover.

All the pot adjustments on the electric pot are the same as on a gas pot.

CURRENT CONSUMPTION

The maximum current consumption is 1,500 watts and the minimum 325 watts, the average consumption throughout a day’s work is approximately 600 watts or .6 kilo-watts. The cost of current varies widely in different localities, but you may find the cost of operating your pot by multiplying the number of hours by the cost of current per kilowatt hour and then by .6. The result will be the cost in cents. For instance, operating a pot nine hours with current costing six cents per kilowatt hour would cost thirty-two and four-tenths cents—9 x 6 x .6 equals 32.4 cents.

FUSES

The main line fuses, which protect the entire system from overloads, when blown, should be replaced by other fuses of the same rating.

The fuse for the mouth and throat heater circuit is for the purpose of protecting this circuit from accidents, and should always be replaced by another fuse of the same rating. This replacing of the fuses by others of the same rating is very important. On a 200 to 250-volt circuit, the main line fuses should be 10 amperes. The mouth and throat fuse, which is located in the control box above the magnetic switch, should be 3 amperes. On a 100 to 125-volt circuit the main line fuses should be 20 amperes. The throat and mouth fuse should be 5 amperes. Fuses of a greater amperage than those mentioned may cause the units to burn out or cause a fire hazard.

MOLDS

The various models of machines placed on the market today have a flexibility that requires a variety of molds to take care of the varying lengths and thicknesses of slugs. The molds are adjustable and are all removable from the mold disk should the occasion require. The molds are all constructed along the same general line, with a base and movable cap. The caps in all molds are held in place by two guides, pinned on each end of the base of the mold, and projecting into grooves in the cap.

The base of the mold is screwed firmly to the disk, and the two liners are held in place by the cap and the pressure from three screws which project through the rim of the mold disk. The cap and base being held parallel by the guides.

To change the mold from one size of body or length of slug it is only necessary to loosen the three screws, remove the liners and insert the ones desired. Do not pry the cap upward with a screwdriver inserted in the casting range of the mold cell. When tightening the screws in the rim of the disk, bring them just to a firm bearing. There is danger of cracking the rim if the screws are too tight.

THE UNIVERSAL ADJUSTABLE

The universal adjustable mold is the one most generally used. By removing the liners and substituting others, slugs of any length from 5 to 30 picas and from 5 to 14 points in body may be cast. All standard molds will cast 30-pica slugs.

The right-hand, or constant liner, is marked for thickness only. It is not necessary to change this liner unless the slug thickness is changed.

The left-hand liner is marked for thickness and length. The number stamped for the length, subtracted from 30, gives the length of slug which will be cast. For example, if a 13-em slug is wanted, use liner number 17, which allows the opening in the mold to be the required length. When ordering liners for these molds, always specify thickness and length of slug to be cast; also specify U. A. mold.

THE RECESSED

In order to cast light-weight slugs and for quick cooling, the recessed mold is made. This mold will cast slugs with cavities, or recesses. The base of this mold is the same as the universal adjustable. The lower surface of the cap has rectangular projections and grooves. The molten metal is forced into these grooves and forms the supporting ribs beneath the type face. The rectangles form the recesses. The weight of the slug is reduced about one-third. A more solid slug is formed because there is less air to be displaced from the mold. There is less metal in the mold cell, therefore it cools more rapidly than the regular universal adjustable. These molds require special left-hand liners and are adjustable for body size from 10- to 14-point and all measures from 8 to 30 picas, except the half-em measures. For these restricted measures a special mold is required and will only be made on special order. In ordering liners for a recessed mold you must be careful to specify “recessed mold” and the length in ems required. These molds can be applied to any model of machine, but must never be used for any size below 10-point.

DISPLAY AND HEADLETTER

The special display and headletter mold is similar to a recessed mold, but to accommodate the increased size of faces, the recesses are deeper. This mold has practically the same restrictions as to length of slug as the recessed mold. One-letter matrices with the character for raised position must be used on this mold. The filling piece under the first elevator jaws must be used when using the mold. Matrices can not be sent in on the duplex rails of the assembling elevator.

Each display mold has a body range of 5 points only, so the entire range of bodies from 15 to 36 points would require four of these molds as follows: The range of one is 15 to 19 points, that is, any width of liner from 15 to 19 points can be used on this mold; the range of the second would be 20 to 24 points, the third would be 26 to 30 points, the fourth, 32 to 36 points. The range of the molds are always marked on the cap so no mistake can be made.

In ordering liners for the display and headletter molds, care must be taken to specify the range marked on the cap.

These molds are limited as to length of measure the same as the recessed molds.

ADVERTISING

The advertising figure mold differs from the universal adjustable only in the mold cap. The cap is constructed with an extra thick lip against which the overhang in the matrices are cast. This permits of casting large characters, which will lap over one or more adjacent slugs. The grooves in the cap are ground parallel. With this mold slugs from 5- to 12-point can be cast, but not above 12-point at any time. This mold can also be used for casting headletter type, by letting the letter overhang the slug. Place a blank slug underneath the overhanging letters to support them.

When using the advertising figure equipment, display figures or characters can be cast at any desired point in the line of text matter, the characters or figures casting on the first slug against the lip of the mold, thus overhanging one or more other slugs when assembled.

In determining how large a figure may be cast on any size of slug from 5- to 12-point, bear in mind that not over eleven points of the figure may be cast against the lip of the mold cap.

CARBOLITE

There is an adjustable mold used on some machines which is made of carbolite steel. This mold is harder than the regular U. A. mold and will not warp easily. However, it heats up quicker, retains the heat longer and will not work very satisfactorily for large slugs or where a large amount of metal is used. The regular U. A. liners are used on this mold.

36-EM ADJUSTABLE

The universal adjustable molds for 36-em machines will cast any measure from 30- to 36-ems inclusive, from 5- to 14-point body. If a measure shorter than 30 ems is desired a regular 30-em mold must be used.

In order to change liners on a 36-em mold it is necessary to take the mold from the mold disk, as the liners fit around three sides of the post, and can not be changed in the regular way.

It is possible to remove the 36-em mold from the disk and substitute a 30-em mold. A filling piece is required to take up the difference between the 30-em and the 36-em mold.

MOLD WIPERS

There are two felt wipers which are designed to keep the face and back of the mold clean. A small amount of a mixture of cup grease and graphite rubbed into the back wiper will keep the base of the mold clean. For the front mold wiper, keep the felt well saturated with graphite. Do not use oil or grease on the front wiper, or it will be transferred onto the matrices and into the magazine. A good plan is to soak the felt with gasoline and rub the graphite in. When the felt becomes worn, new ones should be applied. When applying new felt, put graphite between the layers. Be careful that the felt does not become worn to the extent that the steel part of the wipers will be allowed to rub against the mold.

MOLD HINTS

If the mold cap guides become bent they will throw the mold cap out of alignment with the constant side of the mold. The guides can be straightened by removing the mold from the disk. Place a straight-edge across the mold and cap to determine how the guides are bent. They may be tapped with a hammer and a piece of brass rule to spring them back in position. Care should be used in this operation and if bent very much, the mold should be shipped to the nearest agency for repairs. A mold with bent guides or a warped cap will cause back squirts and to remedy these, the mold must be repaired. Mold cap guides can be renewed by driving out the small pin that holds them in place in the base of the mold and fitting in new ones.

If a mold has become warped by overheating, it can be shipped to the nearest agency to be ground. If the mold is ground on the back, the slug will be less than type high, according to the amount taken off in the grinding. The liners must be ground as well as the mold. Always be very careful of the mold so this will not be necessary.

The bottom of the mold sometimes becomes tinned. This will not permit the mold and mouthpiece to lock up properly. The trouble can be remedied by removing the mold from the disk and placing it on the bench. Put a small amount of metal polish on a block of hard wood. Rub the wood back and forth the entire length of the bottom of the mold, with an even pressure. As the metal polish contains an abrasive, the mold, cap, and liners should be kept together, so that the casting edge of the mold will not be rounded. Be careful of the molds as they are one of the most important parts of the machine and will run indefinitely if handled intelligently.

Take the mold apart and clean the base and the cap with the polish. Place each part in a vise so it will be held solid while cleaning. After using the polish, clean with gasoline.

When metal gets into a mold cap screw in the disk after a squirt, do not hammer the metal with a screwdriver. To do so merely drives the metal tighter in the threads of the hole. Gouge the metal out with a knife a little at a time.

Do not remove the mold keeper from the mold. The mold keeper is for the purpose of holding the lugs of the matrices in alignment. If it is removed and not replaced properly, it will interfere with the proper alignment of every line set.

Keep the face of the mold clean and free from metal which has a tendency to accumulate during the day while the mold is being used. A clean face of the mold will greatly facilitate the press make-ready. Metal on the mold causes high and low letters on the slug.

REMOVING AND REPLACING MOLD

To remove a mold from the disk, loosen the three screws in the rim of the disk, take out the four screws which hold the mold to the disk and lift the mold out of the pocket, being very careful not to drop it.

In replacing a mold in the disk, be sure that all seating surfaces of the mold and disk are clean and free of all metal, so the mold will align with the trimming knives and mold knife. Then bring the four front screws to a light bearing. Next tighten the three cap screws in the disk, the center one first. Then tighten the four front screws tight.

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