The wedge style knife block is the old style quick-change block and is held to the vise in the same manner as the universal block. The left-hand knife is mounted and adjusted the same as with the universal block. The right-hand knife is held to the block by two shoulder screws which pass through the two friction springs and washers from the front of the block. This assembly holds the knife tight against the block, but permits the two strong springs to force the knife against the wedge.
The wedge is operated by a small hand lever and is graduated from 5 to 12 points, inclusive. By pulling the lever up or down the wedge moves and the knife follows the wedge.
Knife, Right Hand, Spring Plate
There is a steel plate assembled in the right side of the knife block which keeps the slugs upright as they travel through the knife block into the chase. This plate is called the knife spring plate and is held in place by two lugs at the back of the plate extending into the base of the right-hand knife. It is forced toward the left by a flat bronze spring, called the spring plate spring. There should be just enough tension on this spring to force the plate up against the outgoing slug with an even pressure so the slug will be held upright as it is being pushed into the chase by the ejector blade. The flat spring is so shaped that the ends fit behind rivet heads, to hold the plate in place. If the spring becomes bent so it will not stay behind the rivets, the lugs will work out of their seat and the gate will obstruct the passageway of the slug. This will oftentimes smash the face of the slugs.
Facts and Suggestions About Trimming Knives
The right-hand knife must be adjusted so that its edge is exactly parallel with the left-hand knife in order to make the slug of equal thickness throughout its entire length. The faces of the two knives separate slightly toward the front of the machine, which allows the slug to pass freely forward from the cutting edges. The right-hand knife must be shaped so there is a cutting edge of about 1/64 of an inch on the side that stands next to the slug. By having this edge the “gouging” of the knife into the slug is prevented, and slugs are trimmed to equal thickness at the top and bottom. This cutting edge must never be more than 1/64 of an inch.
Always remember that the knives can be set to trim the slugs perfectly from one point-size to another with accuracy, but it requires patience, as the knives must be adjusted to a thousandth part of an inch.
Keep the knife block and the knives clean. The seat of the knives should also be clean. It will be impossible to get an accurate adjustment if dirt or gum interferes with the movement of the knives.
The trimming knives should have exceedingly sharp or thin edges to work satisfactorily. If the knives become very dull or the cutting edge rounded or nicked, they should be taken off the machine and reground. Send them to the nearest agency as they are equipped with grinders and other fixtures to do this regrinding and maintain the correct angles and shape of the knives. Always send both the right-hand and left-hand knives, as they should be reground in pairs, and the cutting edges should exactly match each other in order to obtain good results.
Use a full measure slug when adjusting the trimming knives. Cast a full line of capital letters on the slug and hold the matrices for recast. Measure the slug on the ribs at the top and near the bottom. The slug should measure the same at the top edge and near the bottom if the knife which trims the smooth side is correctly set. The slug should measure the same at the top edge of both ends if the knife which trims the rib side of the slug is correctly set.