Linotype mechanism

by Alvin Garfield Swank; Raymond Means

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.