About this 3D model

This thing was made with Tinkercad. 8-ball bearings. Noodling around. A well-tuned and precise printer might just make this work. Can't test until I get my Printrbot, but might benefit from more bearings, larger diameter, scaling up. The individual balls just kiss the races inside and out. This design might also benefit from some kind of bearing holder. You can order one here: http://www.shapeways.com/shops/bitforge Check out the "Improved Ball Bearings" for greater precision and maybe even functionality.