Cross Tenon Coat Rack

This project explores the possibilities presented by 3d printing to advance traditional joinery techniques beyond what is possible to do in wood alone.

Like other 3d-printed/mixed media projects I've done before, the design builds all the complexity into the 3d-printed pieces and lets the wood be as simple as possible. The challenge for this project was to get a tight fit at the joint while using only wood and the 3d-printed connector - no glues or fasteners of any kind. Consequently, the system had to be able to accommodate variations in the wood while also maintaining the predetermined geometry of the 3d print. Ultimately, I landed on the cross tenon shape as an evolution of the traditional wedged tenon joint. The cross tenon joint allowed for a customizable fit for each joint that turned out to be very sturdy, as it can expand in four directions rather than just two.

I did a quick mock-up of the joint with a scrap of wood and 2 3d-printed pieces that fit perfectly inside each other.

To make the joints, I used two different colors of 3d-printed resin so that the geometry of the joint would stand out. My first attempt was a very minimal design, and turned out to be too wobbly when assembled with the wood. The second time around I doubled up on each joint and added cross members to stabilize the wood pieces.

I made the 3 wood pieces out of a single plan of white oak. The process was very straight forward as the final design for the wood was so simple. I planed and jointed the plank, ran it through the table saw to get the proper dimensions, and marked and drilled the holes for the 3d-printed joints. I set up a guide on the drill press to ensure that the holes were always centered on the wood.

My first assembly attempt was with the original, slim joints and the whole thing proved to be too wobbly for comfort. Once I re-printed the sturdier joints and drilled an additional set of holes in the wood, the whole thing came together like butter. Once the white joints were in the wood I hammered the clear crosses into the joints until they wouldn't go any further in and then sliced off whatever was remaining. I finished it all with a clear coat of poly.

The coat rack turned out to be steady and sturdy enough to hold all sorts of things, not just coats! Sunglasses, bags, hats, and yoga mats!