The bearing will likely be a tight fit depending on your print quality. So you may need to experiment with different sizing for the bearing, in order to spin smoothly.
Newest version added on July 18th, 2025.

Design is based of what Gordon Tarpley designed for his costume. https://youtu.be/yBYv5iC9-XA?si=rIboaQ9m4h4Q7FVX

Jesse M incorporated Gordon's design into his c3po torso models, however he made the inner ring split into 2, my version is a complete ring, like Gordon intended, which allows it to spin easier without warping interference.

You can mod Jesse's torso to fit with my parts, you just have to remove his track system to attach my inner ring to take it's place.

Basically its an inner ring, and then a thin ring with tabs slides over it (theres a combined version too). And then a shoulder bearing has tabs that interlock over the thin ring.

This is roughly scaled 105% of Jesse M/Don Post size. So rescaling may be necessary for you.

I also have a shoulder bell model for this, which matches up with the hinge.