How to Assemble the Tamiya Twin-motor Gearbox - Cheap Small Robot Propulsion!

The Tamiya twin-motor gearbox is terrific for small robots - it's cheap (8.95 at Pololu.com) and the motors are plenty strong enough to power a small robot.  You can also choose from two different gear ratios, 58:1 and 204:1. In this video, I am assembling the gearbox with a 58:1 gear ratio.

Here's the finished robot on one of the first test runs: