This is a fun print-in-place fidget that I came up with a while ago, after the saw version was too painful for some and the name of this one invented itself. Version 1 was the original, and in retrospect looks more like an off-road tire. Version 2 fixes it to look more like an actual gear so it can mesh with others.

I printed this on a VERY out of tune printer so it might be loose on more dialed-in ones, that said, I have had success with vice clamping between two quarters, or putting one side of a pair of pliers on the inside of the ring and squeezing the two pieces together from multiple angles. After spinning it for a bit, you can add some lubricant to make it work better.

It may not overhang correctly and need some filament cut out with a knife in order to work.

I tried experimenting with a looser tolerance version but it was less satisfying to spin.