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 that 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. 

Saw version →[https://www.printables.com/model/1325900-fingersaw](https://www.printables.com/model/1325900-fingersaw)

Post-Printing

This can take a bit of work to get spinning. 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. It may also work better on printers better than mine.

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