Summary

This is a fun quick print item to show off. I was really surprised how well it works. It uses Air soft bullets that measure 6mm in diameter.

Instructions

I used .27mm layer, 50% fill, 2 shells.

To get the balls in. Pause the print at 58%-60% and place 10 balls.
For the Replicator 2 this is done with a filament change.
I've printed quite a few of these and never had trouble with the head hitting the balls. They move around easily and don't cause a crash.

If you have a hot air soldering iron you can heat the whole thing and spin it a few quick times with a small load and the thing will be almost as smooth as a metal gear.

The files are:
.010" clearance between ball and race
.005" clearance between ball and race
The solidworks file.

Working Bearing 1.25 x .375 with Airsoft balls