The plate joiner in my shop gets a lot of use for joining cabinet parts. But it’s always tough to support and hold the large workpieces (like cabinet sides) in place while trying to make an accurate cut. To make this job easier, I built this jig. An adjustable cleat on the jig is positioned so the top of the workpiece is flush with the top of the jig. All you need to do is just clamp the workpiece in place (photo at right). This way, you can rest the fence of the plate joiner on the top of the jig (and workpiece) while making the cut.
The jig is simply a box with a large face piece. The face is attached to a support assembly that clamps to your workbench. An adjustable cleat on the front supports the workpiece.
The cleat can be moved up or down and then secured by tightening a plastic knob in the centered slot. To keep it aligned horizontally, the cleat has hardboard splines at the ends that run in shallow grooves in the face.
