Realizing that it’s essentially a cycloidal drive meshed with a planetary gear set, he got to work in CAD and, in seemingly no time, had a design to test. You can see the full results of his ...

The videos below show you the theory: the stepper drives a sun gear with two planet gears orbiting, each of which engages a fixed ring of 56 teeth, and an output ring of 58 teeth. Each revolution ...