When it comes to shop-made guides for portable circular saws, there are two important criteria: The first is that the guide tracks the saw accurately. The second is that the edge of the guide aligns perfectly with the blade so that no offset needs to be calculated when setting up a cut. For tracking purposes, my 3⁄4"-thick guide includes a 3⁄4"-wide, 3⁄8"-deep slot, which guides a wooden runner that screws to my saw base. (When affixing the runner, make sure it’s perfectly parallel to the blade.) I made the base oversized initially and then trimmed it to final width with the saw running in its slot. That aligned the edge of the guide with the blade for easy positioning against a cutline. I made the track about 54" long so it generously spans a 4 × 8' sheet of plywood crosswise.
The real trick here, though, is that this guide does not require clamps to hold its position. Instead, I attached a sheet of rubber “nonslip padding” to the underside of the base, keeping it back from the edges 1⁄4" or so. The padding–designed to hold workpieces in place for routing, sanding, and other maneuvers–is simply stapled in a few places along its perimeter. It holds the guide in place remarkably well with no slippage whatsoever that could compromise cut accuracy.
—Russ Svendsen, Olean, New York
