What’s this kind of joint called?
I have built a couple of laser-cut and CNC-routed kits, recently, that use this clever arrangement of tabs, slots, and a couple bits of cheap hardware to securely butt one panel against another at a right angle. One panel has a pair of rectangular ports with a round hole in between, and the other has a matching pair of tabs with a smaller T-shaped slot between. In use, the ports receive the tabs and a screw passes through the round hole and along the upright of the T to mate with a square nut captured in the arms of the T. There are many possible variations and the technique has lots to recommend it from a manufacturer’s standpoint.
