A proper jig serves two basic woodworking functions: securing a workpiece and guiding a cutter. It should add control (and thus precision) and speed to the joinery process. The jigs in this article meet all of these demands, allowing you to cut a mortise-and-tenon joint in the time it takes to hone a chisel. I tested them by cutting roughly two dozen mortises and two dozen tenons on each. Most of the test samples measured within 0.002 in. of their intended dimensions, which is well within the recommended tolerances.

The FMT in the Leigh FMT jig stands for frame mortise and tenon, and this machine was specifically designed for making these joints. Leigh’s pin-and-template guide system is as close to foolproof as it could be. The auxiliary baseplate has two tapered pilot pins that engage slots in a template for mortising, and they ride the perimeter of the same template to mill matching tenons. Raising or lowering the pins alters the fit of the joint in repeatable 0.001-in. increments. The Leigh jig is compact to the point of being portable, and its looks, with its exceptional level of finish and engineering, are not deceiving. In operation, this jig was exceptionally smooth and precise. Also, the owner’s manual was refreshingly comprehensive, clear, and concise.