Brent Miller wrote:
>
> >BTW does anyone know what is the finest of incremental angle that a
> >stepper motor can produce?

> These were based on a reducing gear called a "harmonic drive", and
> had something like 1500 or 2000 steps per revolution.  They were
> made by United Shoe Machinery (USM).  I haven't heard much of
> either the motors or the company recently, and a quick web search
> didn't find anything.

Another proof there just isn't a free lunch. Good high ratio gearing
but a poor single tooth sure had to take a lot of torque. There were
a lot of variations on this system including some whose flexible case
deformed to add to the amount of gear surface area engaged.

Walter Banks