This straightedge helps you rout and rip accurately
Make a smarter straightedge by gluing a 2" wide strip of 1⁄2 "-thick stock to an equally long piece of 1⁄4 " plywood or tempered hardboard. Both pieces should be a few inches longer than your longest cuts, and the 1⁄4 " piece should be wider than the distance from your saw's blade (or router's straight bit) to the edge of the tool's base. When the glue dries, rip or rout the 1⁄4 " stock as shown above. Now, you can align this just-cut edge with your layout mark to know where the cut will start.
—Roger Boulet, Winnipeg, Manitoba