Ball Gear Bearing

This uses Barspin's Fully Assembled Ball Bearing from Thingiverse (https://www.thingiverse.com/thing:143467) and Emmett's Gear Bearing Customizer from Thingiverse (https://www.thingiverse.com/thing:53451).

It is a ball bearing with a planetary gear in the center. No supports required and it takes about 6 hours. It may take some force to free the gears in the center and to remove the integrated supports for the ball bearing. The center shaft fits in the center gear at the center and takes about 10-15 minutes to print. I slowed down the printer speed to about 70% on the LCD when I printed it to make sure that the filament has time to cool between layers.

Edit: I added a larger version on a separate post.
https://www.prusaprinters.org/prints/31818-gear-ball-ball-bearing

Print instructions

I used the 1.5mm detailed setting with 20% 3D honeycomb infill.