Clamping flanges make all the difference
Routing dadoes across panels requires some kind of straightedge guide for the router. A T-square guide is a great tool for the job because registering the crossbar against the edge of the workpiece automatically positions the fence at 90° to the edge. But a typical T-square guide can be difficult to clamp in place. When faced with routing shelf dadoes in some relatively small, curved shelf sides (see page 52), I decided to design a guide that would be quicker and easier to use. The secret? Clamping flanges. Glued to the top surface of the crossbar, these cantilevered strips enable me to clamp the jig to the work, and the work to the bench at the same time. I can eliminate the hassle of clamping the workpiece to the bench and then clamping the jig to the workpiece. The flanges are such an improvement that I seldom use my standard T-square guides anymore.
Size your jig to fit the job
The dimensions shown here will create a jig sized for general purpose work, but feel free to alter the size. Note that dedicating a T-square to a particular router-and-bit combination allows quick jig positioning by simply aligning the router bit notch in the crossbar with your cutline.
• Use straight-grained, stable hardwood for the fence and crossbar, milling the parts perfectly straight and square. Use plywood or hardboard for the clamping flanges.
• Attach the fence to the crossbar with screws and glue after drilling clearance and pilot holes to prevent splitting the wood. Square the two parts perfectly.
• After attaching the clamping flanges, make sure to clean up any glue squeeze-out on the bearing edge of the crossbar. Make sure to position the small clamping flange to allow unimpeded travel for whatever router you plan to use with the jig.