Woodworkers have always been very clever about making strong and attractive joints — think of the strength of a mortise and tenon, or the artistry of a well-made dovetail. These joints have been around for ages and can be executed with nothing more than chisels and a hand saw, plus a lot of practice, of course. But new tools bring new challenges and new opportunities in joinery, like this interesting “hammer joint” that can be made with a laser cutter.

This interesting joint comes to us from [Jiskar Schmitz], who designed it for quick, solid, joints without the need for glue or fasteners. It’s a variation on a wedged mortise and tenon joint, which strengthens the standard version of the joint by using a wedge to expand the tenon outward to make firm contact with the walls of the tenon.

The hammer joint takes advantage of the thin kerf of a laser cutter and its ability to make blind cuts to produce a tenon with a built-in wedge. The wedge is attached to a slot in the tenon by a couple of thin connectors and stands proud of the top of the tenon. The tenon is inserted into a through-hole mortise, and a firm hammer blow on the wedge breaks it free and drives it into the slot. This expands the tenon and locks it tightly into the mortise, creating a fairly bulletproof joint. The video below tells the tale.

While the hammer joint seems mainly aimed at birch plywood, [Jiskar] mentions testing it in other materials, such as bamboo, MDF, and even acrylic, although wood seems to be the best application. [Jiskar] also mentions a potential improvement: the addition of a ratchet and pawl shape between the wedge and the slot in the tenon, which might serve to lock the wedge down and prevent it from backing out.

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