Tech Talk
What are "Shaper Collars"?
Writing an article about Shaper Collars in the Nineties' may seem about as topical as an article on using a Telex, but the fact is there are still many of them in use in medium and small shops; as well many large production factories have them for running samples, prototypes or short run profiles. The problem with Shaper Collars is that they are a dangerous tool and too often their set-up and operation are treated with complacency. I have recently witnessed and heard about some examples of careless use of Collars that were particularly surprising in that, although the people involved had years of experience using them, the Collars and their set up methods were unsafe.
There are basically two types of Shaper Collars on the market (see Fig. 1). The standard Collar has V- shaped grooves that match the angle of the knife edges that seat in them. The other version are known as Lock-edge or Safety Collars. The have worm screws set in one collar that lock the knives in position and allow for fine adjustment of the knives in the head. The knives (see Fig. 2) for these collars have notches on one beveled edge that match the pitch of the worm screws. Neither of these heads are stupid-Proof, but the Lock-edge Collars have some real advantages over the Standard head. If you have a set of the standard ones the grooves must be kept clean and free of any debris or pitch build-up. The V notches should be checked regularly for any nicks or worn surfaces. The knives must seat firmly and uniformly in the grooves, without any point pressure. If the grooves are worn or rounded, the contact area will be reduced and uneven, and the knives may be able to move, even when tightened. If there is this type of wear in your heads, discard them. The same is true of the Lock-edge style, but with these, the screws must also be checked regularly. They must be secured properly by the roll pin that holds them in place and the screws themselves must rotate smoothly and be free of burrs or debris.Shaper collars use two identical knives at a time. The knives should be made from the same material. Not necessarily the same bar of steel, but the same dimensions - width, length and thickness. Use only steel made for these Collars. Any type of substitution may not have the correct bevel, and ruin your heads, or worse, injure someone. Never run these Collars with one profiled knife and one "balancer". This seems quite obvious, but I have seen it done. The knives must be long enough so that the part that is in the head is more than 50% longer than the diameter of the head. For example, if the head is 3 inches in Diameter, the knives should be at least 2 inches, plus the profile length, long. The profiled portion of the knife needs to be as close to the collar as possible. Never set the knives up to stick out farther than they have to.Lock-edge knives are only for Lock-edge Collars. They are not safe in Standard collars, and similarly, never try to put standard beveled knives in a Lock-edge Collar. Shaper Collars usually include bolts of various lengths to pull and secure the top and bottom Collars together. When you are setting up a set of knives these screws should be lightly tightened after the collars are on the spindle and the knives are in place. Then do the fine adjustment by turning the worm screws, so that both knives are on equal cutting circles. When they are adjusted, lightly tighten the Spindle nut and then tighten the two bolts that hold the two collars together. Check the knives, visually, once more to make sure they are seated properly, and on the same swing circle, and then tighten the spindle nut. Do not try to turn the adjusting worm screws unless the spindle nut and the two bolts have been loosened off.All Shaper Collars have the correct rotation clearly marked on the top Collar. This is the only direction they can be run. Standard reducing bushings can not be used in Shaper Collars, as the bushings could move on the shaft and create a very dangerous situation. If it is necessary to reduce the bore use T-shaped bushings (see Fig. 3) that can't move once the spindle nut is tightened.Using Solid cutters on a shaper requires attention and care, but Shaper Collars require that much more, because you literally have to assemble it on the machine and there is a lot more to be aware of. by: Doug Reid, President, B.C. Saw
