KNIFE WIPER
Reading edition
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.
The brass wiper is held to the bar with two flat head screws, and the constant passing of the wiper over the face of the sharp knives soon wears the wiper so it will break off. A new wiper must be applied or the shavings will hang to the slugs.
Never have the wiper bearing too hard on the face of the knife as the constant rubbing up and down will dull the trimming edge of the knives and wear the wiper in a short time.
Keep the knife wiper in good working condition all the time and save proofreader’s marks.
Do not forget that the knife wiper is operated by the first elevator slide. Therefore anything that prevents the free action of the wiper will interfere with the movement of the first elevator.