Well Internet, you win... I'm making a fidget spinner since people won't stop asking. I've been thinking about building my own wooden ball bearing for a couple years now and decided this was a good project to try that on. The balls are the only thing I didn't make since they're cheap to buy and painful to make. These are 1.5" diameter hard maple balls and I bought them for $.50 a piece. The bearing races were made from 3 pieces of 3/4" baltic birch plywood and so was the body of the spinner. The body was cut out on the X-Carve by Inventables to make sure the pieces lined up perfectly. Once glued together I used a round-over bit in the router table to remove the sharp edges.
For the bearing race, I needed the parts to be firmly attached for turning, but not so firmly that I couldn't break it apart to put the balls inside. I lined the pieces that would make up the bearing races with painters tape and then glued them together with CA glue. You won't believe me how strong that hold is until you try it yourself. It is also nice since no residue is left on the surface of the wood.
I attached the race blank to a faceplate on the lathe with hot glue. This allows me to turn the pieces side by side to their rough shape, and split them apart easily and cleanly with a heat gun. Once apart I coved out the inside of the outer race and the outside of the inner race. Constantly stoping to check my work and make sure the cove was dead centered.
I glued 2/3 of the race together, installed the balls, and glued up the other 1/3. I was careful not to use too much glue since I didn't want to glue the balls together. Assembly of the races was made easy by using some 3/32" brass rod as alignment pins. This ensured I could take the race apart without introducing any misalignments when reassembling. They weren't needed after the pieces were glued together, but I just left them to save the hassle of filling the holes with wood.
I thought I would like the look of the entire thing being stained but hated it immediately after doing it. I sanded off the flat surfaces to give it some contrast and was much happier with the look. I gave the spinner 3 coats of spray lacquer and painted a simplified version of my logo onto the fingers of the spinner. I gave the balls a light waxing and found that the more I spin this thing, the better it works. I think the balls are slowly polishing themselves.