The qdd100 servo uses a planetary geartrain as the transmission reducer. This consists of an outer ring gear, an inner sun gear connected to the rotor as the input, and 3 planets connected to the output. The tolerances of these gears directly impacts the performance of the servo, namely the backlash and noise.

To date, I’ve been hand-binning these and testing each servo for noise at the end of production. To make that process a bit more deterministic, and with less fallout, I’ve built up a series of manual and semi-automated gear metrology fixtures to measure various properties of the gears.

I’ve got the 6x reduction planetary gearsets back in stock at mjbots.com, now combined into a single product listing for only a little more than the old ring gear – $25 for the whole set! Compare that to the $41 you needed for an entire gearset before!

In my quest to create a more dynamic quadruped, I’ve started accumulating a lot of parts from bulk buys that could be reasonably useful to other hobbyists and experimenters.  To maybe make life easier for everyone, I’ve started up what may be the worlds ugliest online shop where you can buy some of these components.  For now, I have some bearings and custom gears that are useful when building servos for dynamic robots.