Versatile, affordable, and easy to use, Don Browning’s Mortise Master makes spot-on mortises accessible to any woodworker. The jig is at its best making matching mortises for slip tenons. Layout is as simple as marking centerlines across the joint—the same way you would for a biscuit. Setup is easy, too. You start by clamping the jig’s two thick wood fences onto your workpiece and lining up your pencil mark with a scribed line. A thin lip along the inner edge of each fence sits on top of the workpiece and ensures the fences are level with each other.
The jig comes with a 1-in. bushing that you screw into your router’s baseplate. Once it’s on your router, you fit the bushing into the hole in the center of the jig’s ingenious polycarbonate slide plate, which is the heart of the system. With your plunge router riding on top of it, the plate slides back and forth on the jig, guided by little UHMW plastic blocks that attach to the slide plate in various positions and glide along metal T-tracks, making the mortising action smooth and precise. Those same tracks guide the two polycarbonate fences that act as stops, limiting the travel of the slide plate (and therefore the length of the mortise). The recommended upspiral carbide bit (supplied by you) should correspond to the width of the mortise. To rout a mortise, you set the depth on your router, fit the bushing into its hole in the slide plate, and hit the on-switch.
My big plunge router was very steady and easy to control on the thick fences and broad slide plate, and the upspiral bit ejected dust so well that I could rout an entire mortise without reaching for a vacuum hose to clear chips.
Once your workpieces are marked and the jig is set up, switching to a new workpiece and routing another mortise takes a few minutes at most. The jig can accommodate workpieces up to 3-1⁄2 in. thick, and rout mortises in a range of sizes.
—Asa Christiana is a woodworker in Portland, Ore.
Photos: Asa Christiana
From Fine Woodworking #291