Depth Gauge


Setting bit height is either a hit-or-miss proposition based on eyeballing or a simple measuring task featuring a depth gauge jig. The latter approach is faster and more accurate. Plus, it saves aging knees by eliminating that awkward hunkering-down motion to reach bit level. With a depth gauge, you simply set the desired bit height and then raise the bit until it hits the bottom of the slide bar. With a piloted bit, make sure the slide clears the bearing and touches the cutter.

Built from multi-ply for strength and stability, this depth-gauge jig requires a short length of self-stick measuring tape with large numbers, a thumbscrew and a little piece of clear acrylic.

Lay out the depth-gauge body on some plywood. Drill the hole for the nickel 1/16-in. deeper than the T-slot using a 7/8-in. Forstner bit. Plow the T-slot with a T-slot router bit before shaping the body. The slide is a simple T-molding made by cutting two rabbets on the edge of a board and then ripping the molding free. Apply the self-stick tape rule at the bottom. Secure the acrylic plate with a couple of screws.

Zero the gauge by setting it on a flat surface, for example, your tablesaw. Let the slide drop to the table and lock. Score a line on the face of the acrylic over the 0-in. mark on the tape. Drill the holes slightly oversize in the acrylic plate to allow some minute adjustment, if necessary.

Leave a Reply