The rubber bumper plugs are small “finger” like plugs that stick out of the cutting cylinder body and hold the sheet up against the anvil roll. The bumper plugs are held into the cylinder body by small pins that are inserted into the center hole of the bumper plug material. This expands the tube against the wall of the hole in the cutting cylinder body.
The bumper plug material is tan colored rubber tubing that needs to be cut into sections approximately 1-3/4″ (44.5mm) long.
Use a spray lubricant (like WD40) to spray the holes in the cutting cylinder. This makes the tubing easier to insert.
After the bumper plug tubing is pushed into the cutting cylinder body, there should be about ¾” (19mm) of tubing sticking out of the hole.
Insert a ¼” (6.4mm) in diameter pin into the center hole of the tubing.
Note: It is recommended that the pins be coated with oil so they slide into the tubing more easily.
Using a hammer pound the pin into the center of the tubing.
The pin being forced into the tubing will cause the tubing to expand and press against the cylinder. This expansion of material will hold the bumper plug in place.
Once the tubing is in place it must be cut so that it is the same height as the top of the knives, typically about 9/16” (14 mm).
A number of different techniques can be used to cut the tubing to the proper height.
Any piece of material such as steel or plastic can be used as a cutting guide. Cut the material to be used as a guide to the finished height of the bumper. Drill a 3/4”(19mm) diameter hole into the material.
Place the cutting guide over the bumper to be cut and cut the bumper to the finished height using a sharp razor knife.
A special tool having a spacer the height of the bumper plug and a razor cutting edge is available from Reichel & Drews.