Monthly Archives: September 2016

Stool with 3D Printed Joints

One of the things that interests me about 3D Printing is using it to augment existing fabrication techniques. I’ve already done some experiments with 3D printed joints for wood structures, but I’ve wanted to try building something with structural integrity. Printed PLA isn’t the strongest material, but the idea was to utilize its compressive strength, and minimize bending forces. I also wanted to restrict myself to only making 90 degree cuts in the wood, and minimizing the number of cuts I made.

I started with the joint for where the seat would join the legs. The goal was to make the joint easy to attach to both the legs and the seat, with holes to allow for easy sinking of screws.

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The star shape creates a straight edge on a side for any 45 degree rotation. There are 3 holes in the bottom which allow for screws to be placed that go directly from seat to leg (for strength).

After printing, everything went together very quickly.

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The problem now was that the legs bowed out too much when weight was placed on the stool. To solve this I decided to attach more supports to each leg, to prevent them from bending outwards (which was threatening to break the joints).

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At this point, the only thing left to do was to add some feet and do some light finishing.

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I think I could have made the¬†stool a bit more¬†aesthetically pleasing, but for a first attempt I’m pretty happy. It feels solid and sturdy when you sit on it. I also managed to only make seven 90 degree cuts in the wood (4 for the dowels, 3 for the legs, 1 for the seat).