Here’s a printed planetary gear I found on thingiverse.com. I’ve only made a few objects with the 3d printer, but every time its better that I could have expected.

The planetary gear is designed to be used on a nema 17 stepper motor. The gear requires 6 bearings for the planetary gears and one for the output shaft.

I’ve tested the gear several different ways and it seems to work great every time. I’ve run the planetary gear at high speeds by mounting it into a drill press. (3200 rpm). The gearbox is even more impressive when mounted to a stepper motor. The backlash appears to be about 1/4 of a step which is ends up being about 0.09 degrees. Hopefully the gearbox doesn’t wear in too much and it keeps the low backlash. Here’s a small video of my planetary gearbox in action.

The total cost of the planetary gear was about $13. The planetary bearings are 683ZZ and can be found cheaply at a local hobby store 4 for $6. The bearings are used in the Align Trex 600 helicopter. If you purchase the bearings from vxb they are 10 for $25. The other bearing (6x17x6) is fairly cheap, around $2. The stepper motor was purchased from sparkfun for about $15.

Here’s where to find everything you might need to make this planetary gear.

http://www.thingiverse.com/thing:8460

http://www.sparkfun.com/products/9238

http://www.vxb.com/page/bearings/PROD/6mm/606ZZ-1

http://www.amazon.com/Bearing-3x7x3mm-683ZZ-600-550E/dp/B000IVQ02S/ref=sr_1_3?ie=UTF8&qid=1320526125&sr=8-3