Before setting the trimming knives, make sure that the mold is properly seated in the mold disk and that there is no metal between the liners and the mold.
When the trimming knives become dull it is practically impossible to set them to trim accurately. Even when they are set nearly accurate, they will hold the adjustment only a short time.
Dull knives also cause trouble by making it difficult to eject the slug. This will often cause the clutch to slip.
When a long slug measures thicker or thinner at the ends than in the center, it is usually due to dull knives, but may be caused by the knives being forced in a twist or strain by the adjusting screws or some foreign substance behind the knives.
KNIFE WIPER
The knife wiper is a very important part of the Linotype. Its function is to wipe the burrs or slug trimmings from the face of the parallel knives after a slug is ejected. If the knife wiper is not working, the face of the line of type will have an accumulation of shavings from the previous line on it.
The knife wiper in use on all machines of very recent manufacture is operated by a small roller, fastened to a bracket on the first elevator slide, which comes in contact with a lever connected to the knife wiper bar. When the elevator goes from normal to the lower, or casting, position, the knife wiper bar is forced upward. On the upper end of the knife wiper bar is a small brass wiper which is forced upward with the bar. This wiper rubs against the trimming knives, cleaning them of the metal shavings which may have lodged from the previous slug trimmed.
There are no adjustments on this type of wiper, except to have the brass lightly touching the knives.
Old Style Knife Wiper
There are quite a number of the old style knife wipers still in use. This knife wiper is operated by a latch rod on the first elevator lever. This rod comes in contact with a latch on the knife wiper bar, on its downward stroke, and pushes the bar upward by coming in contact with the bottom of wiper bar on the upward stroke of the first elevator lever. The wiper bar should be free to move up and down in the guides, moving the brass wiper lightly over the face of the trimming knives. On the upper part of the wiper bar are two pins which prevent the bar from going too far below the knives and too high above them. A flat spring riding over the top of the bar holds it to the bottom of the guide so the brass wiper can operate properly.