Re: Re: What do we want?

----- Original Message -----
From: Jon Elson <jmelson@...>
> This is actually quite small, on typical sprockets with even 10 teeth or
so.
> The big problem is power-grade roller chain starts out with mediocre
> range of pitch error, and it gets a LOT worse as the chain ages. One of
the
> components is eccentricity in the rollers. There is a precision grade of
roller
> chain, which would help. But, I won't use a toothed belt, gears or
anything
> between the encoder and the leadscrew - only a helical coupling.