Ditzy setup: what the
manual won't tell you
Fine Woodworking, April 2003

Fine Woodworking (www.finewoodworking.com) wrote about the difficulties of setting up most dovetail jigs. This review is © 1993 Fine Woodworking.

The owner's manual for your dovetail fixture will cover the details of setting up, but there are some important points that it probably won't mention.

The precise depth of cut, which determines joint tightness, seldom is exactly what the manual calls for. My Sears manual says to set the cutting depth to exactly 17/32 in., a measurement that requires a machinist's combination square and a thick magnifying lens for people over 40. But setting my carbide dovetail bit by this rule produces too loose a joint. A slightly deeper cut tightens the joint. The owner's manual will get you in the ball park, but you'll have to discover the setting that's right for your bit, router and template (see the photo at left).

Another thing the owner's manual won't explain is what's too tight a joint and what's too loose. What I've learned is that glue takes up space, and a joint that I have to tap together dry, I"ll have to bang together during glue-up. You should be able to push the dry joint together by hand without recourse to your mallet.

The manual describes how to control socket depth, but it probably won't discuss the correct depth. If you've cut your drawer fronts to fit snugly in their openings, then you want he pins on the drawer sides to lie about 1/64 in. below the tops of their sockets. This condition lets you beltsand the endgrain edges of the front and back flush with the sides and provides just enough clearance between the sides of the drawer and the opening. If you do this right, the side-to-side fit should require no further fiddling.

No manual will admit that setting up and adjusting both router and fixture is tedious and time-wasting. It can take a half-hour to go through the steps: install the guide bushing in your router, chuck and adjust the bit, make a trial cut, fine-tune the depth of cut, try again. At last you've got it. But next time, you'll have to go through the whole ditzy routine again.

About six years ago, I got fed up with setting up, so I went out and bought myself a new plunge router. This meant I could dedicate my old Sears router to dovetails, and since then, I haven't had to remove the bushing or adjust the bit.