When I first saw a self-clamping straightedge guide in a catalog, it seemed like a gimmick. That all changed when I used a straightedge guide for the first time. The guide clamps in place quickly and securely. And the perfectly straight, smooth edge makes it a breeze to get clean cuts with a router or circular saw. I was hooked.
Using a straightedge guide seems pretty straightforward, right? But there are a few tips and tricks I use to get the best results.
The main difficulty in using a straightedge is positioning it for accurate cuts. That’s because the edge of the guide isn’t set on the cut line. To locate the guide correctly, you need to know the offset from the edge of the tool base to the blade or bit. But measuring for each cut can be a time-consuming process. A set-up block makes positioning the guide a snap. You can see how this works with a router. Align the dado in the block with the layout line, then slide the guide in place and lock it down. (Be sure to make a set-up block for each bit.)
The same principle works for your circular saw, too. It’s easy to assume that the guide automatically sqaures itself when you lock it in place. But that’s not always true. When you need to make a precision cut, use a framing square to guarantee your accuracy.
Sometimes the end of a plywood panel can look a little ragged after making a cut with a circular saw. To clean up the edge, I clamp the straightedge to the bottom side of the panel about 1/8" away from the edge. This guides a flush trim bit to create a perfect edge.
The final use for your straightedge I’d like to share is as a clamp for thin stock. Ordinary pipe and bar clamps can cause thin panels to bow. The low-profile heads on the guides make it easy to center the clamping force on the panel.
