Zero Clearance Jig Ensures Safe, Smooth Cuts
Recently, I was building a project that required cutting ¼″-wide grooves centered on the edge of some ¾″-thick frame pieces. I mounted a ¼″ dado blade in the table saw, and installed a dado blade insert. The only problem was the opening around the blade seemed huge. So big, in fact, I was concerned that the workpiece might actually tip down into the opening.
That led me to build an L-shaped accessory that attaches to the rip fence on the table saw (see Photo right). It creates a “zero-clearance” opening that provides support for the workpiece right up next to the dado blade. As a result, there’s no way for the piece to drop into the opening. And since the wood fibers are fully supported, tearout is virtually eliminated, which improves the quality of cut.
This accessory consists of two pieces: a base made of ¼″ hardboard and a plywood fence that are screwed together (Cross Section). A couple of screws secure the jig to the rip fence.
To form the zero-clearance opening, lower the dado blade and position the rip fence so the blade will cut through the base at the desired location. Then turn on the saw, and slowly raise the blade through the base. Additional openings can be made for cutting grooves in stock of different thickness.