Right-angle brace gives you a corner on clamping tasks
Anytime you need to hold two large workpieces at a right angle, say while you're screwing or gluing them together, you need one or more of these plywood triangles. As shown in the photo above, these right-angle braces have two notches for accepting clamp jaws. The circular cutout comes in handy for temporarily holding the brace in place with a spring clamp while you position bar clamps on the notches. It also gives you a way to hang the jig on a peg when you're through.
The more you use this shop helper the more jobs you'll find for it. Although we designed the brace for carcase assembly, we also found it handy for holding an on-edge picture frame rigidly to a bench as we sanded the frame's edges.