Students exercise: stool

A classic stool might seem a simple thing to build, but it actually has 16 joints, so it lends itself to a good exercise on mortise and tenon joinery. I designed this one to show students a number of variations on the same joint: through, blind, haunched, wedged and pinned. As you can see in the picture, it is made from oak and the pins and wedges are made of African Blackwood (Dalbergia Melanoxylon), which is a very dark, hard and dense timber (one of those that don't float in water). It is a nice simple object, but if we come closer we see in the details how it was made. I love it when the engineering of the piece is the decoration itself. And then this curved chamfers at the underside of the top discretely add a sense of lightness.

A close-up of the African Blackwood accents and the lighter colored medullary rays running across the leg. This is not random, but a choice.

The mortises are made at a perfect 16º angle, to house two wedges of 8º.

Two identical 8º wedges.

Once driven in the joint, he wedges will expand the tenon, forcing it to conform the 16º mortise.

After glue-up, the last thing to do is trim the joint flush with the leg. Best done with a block plane.

The pins are perfect 8mm cylinders just made with hand tools.

Right after glue-up. The pin locks the leg and the rail together as it pierces through the hidden joint.

I enjoy very much using my tools on this dark mysterious wood. A pleasure to work with.

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