Which type of joint shown on page 4 you should use depends on several factors. The vast majority of fingerjointing for mouldings, door and window parts, and general recovery of short pieces is done using a reversible joint. A single head with one thick cutter per bolt could be used to cut both sides of a reversible joint, however, production fingerjointing usually requires both a left and a right head.

The end match, or male-female joint, is a less common joint, but is used in cases where the fingerjointed stock will be moulded or shaped on both sides as in the case of fingerjointed chair backs. Two separate heads would be required for an end match joint, since one head would have thick cutters on both the bottom and the top of the stack, and the other head would have all thin cutters.

The re-saw joint utilizes a thick center cutter to leave a thick shoulder to allow for splitting the stock into two thinner pieces.

The number of cutters that will be required to cut a particular thickness of material can usually be calculated in the following manner. Please refer to the chart on page 5 for cutter specifications.

Balance of the fingerjoint head is extremely critical to a good fingerjoint. Even a very slight amount of imbalance or improper setup may produce a joint that will fail. All cutter stacks should be assembled so that they will keep the head in dynamic balance during operation. The best way to ensure cutterhead balance is to weigh each stack of cutters, and then install stacks that weigh the same across from each other. If there is more than one tenth of a gram difference between stacks that will be installed across from each other, the heavier stack should be lightened by grinding material off the flat area on the back of the cutter.

Balance of cutter bolts is just as important as the cutter balance. If you are replacing bolts or reassembling a cutterhead, bolts that are straight across from each other must be balanced to within one tenth of a gram. Be certain to use care when pressing bolts in or removing them from the head. Always use an arbor press, and be sure that both the bolts and the head are completely free from dirt or debris. Bolts that are worn or scored must be replaced.

The set up fixture is perhaps one of the most important tools for guaranteeing a good joint. Once the fixture is mounted securely in a vise, carefully slide the cutterhead onto the arbor. Note that there are three locating holes for the "L" pin. Locate the "L" pin into the side hole that will hold the cutters away from the locating post. (The center hole should not be used for loosening or tightening the nuts.)

Loosen the nut, and relocate the "L" pin to the center hole. Rotate each cutter in that stack up to the locating post so that all cutters are flush with the post. You may want to check with a feeler gage no more than .002 thick to be sure that all cutters are rotated completely to the post. Snug the nut up by hand, and continue the same procedure until all stacks have been re-set to the post and hand tightened. Never use a wrench to loosen or tighten the nuts with the "L" pin in the center hole.

After the cutters have been relocated away from the post (by placing the "L" pin in one of the side holes) use a torque wrench, and begin to tighten the bolts in a diagonal or alternating pattern. Torque each stack in 50 foot pound increments until you have attained 250 foot pounds. On WKW laminated beam fingerjoint heads equipped with 1-1/8" diameter bolts, torque to 450 foot pounds.

WKW also offers 6- 8- and 10-post set up fixtures. Call for information.