The offset should be nearly equal to the space between the teeth on the comb provided that the spaces between the teeth, and the thickness of the teeth are the same. Typically, a jig with 7/16" spaces between the teeth on the comb is designed for a 1/2" dovetail bit, and a 7/16" guide collar. This should give you a dovetail that is 1/2" wide on the bottom, and 3/8" wide at the top. The width of your cut in the center of the dovetail would therefore be 7/16" The vertical board should be offset toward the center of the jig 7/16" from the one that mounts horizontal in the jig. If you're aligning your boards on the left side of the jig, the vertical one should be offset to the right. Reverse if you're using the right side of your jig. I hope this helps. It made sense in my head when I started, (I promise)!!reds_21 said:mike
here is a question along the same lines of what you just mentioned, i have a dovetail jig as well but i am very unclear on how the correct set up should be. i realize that you need to off set one of the boards so the teeth will lock into place but how far do you offset them and which board do you move? the vertical board or the board that lays on top. what is the best way to make sure the wood is in the jig clamps perfectly, as in not at an angle but a true 90????? yo usee what im getting at???