Foolproof fit, weather or not
For jigs that ride on a tablesaw fence, there's a fine line between smooth and sloppy. You want it to fit without side play, while still sliding smoothly along the fence. Throw seasonal wood movement into the equation and it may not work at all. But I've developed a simple solution for keeping those fence straddling jigs right on track.
When building the jig, make the spacer about 1⁄16 " wider than the fence. Then add 1⁄4 "x20 nylon screws along the outboard side of the jig. Drill a 3⁄16 " pilot hole for each; then use a 1⁄4 "x20 tap to thread the holes. (If you don't have a tap, use a new 1⁄4 "x20 steel machine screw to form the thread).
Use at least four screws arranged in vertical pairs at the front and rear of the saddle, taking care to avoid putting them in line with existing holes in the saw fence. Snug the jig to the fence by adjusting the nylon screws.
—John Cusimano, Lansdale, Pa.