One of the difficult tasks of working alone is squaring large face frames and cases. It seems that I can never get my tape measure to behave when I need to measure from corner to corner to square things up. So I built this squaring jig to make this a simple task.
The jig is easy to build. I made the corner block with a 90° notch by first drilling a centered hole in a square piece of ¾" plywood. Then you can set up the miter gauge on your table saw and make two 45° cuts in the block. Finally, screw the corner block to a ½" plywood backing block, like you see in the illustration below. The arm is a piece of ½"-thick hardwood. A hole in one end of the arm allows you to secure the corner block to the arm with a ¼" hex bolt.
The jig makes it easy to work from the far end of a frame or case. You first slide the block over the corner and lock it into position. Then just extend the long measuring arm diagonally across to the opposite corner. With this jig, you don’t need to remember any measurements. Just place a piece of masking tape at the end of the arm and mark the the corner, like you see in the inset photo above. Then you can quickly move the jig to check the other diagonal and compare this distance to the mark you just made. Now, I no longer worry about the size of the case or face frame I’m working with. It’s easy to get them squared up. And I don’t need anyone around to give me a hand.
