Re: [CAD_CAM_EDM_DRO] looking for some gearheads

H & J Johnson wrote:

> David, after re-reading my previous reply I guess I did sound a bit brisk.. I
> appologise if toes were stepped on..
>
> That being said, when someone is looking for these reducers
> to fit a 34 or 42 NEMA, or a 90 or 115mm motor frame.. chances are
> that they are looking for something to use in the drive side of a project
>
> I'd sure like to find a worm drive w/ 10 arc seconds
> of backlash.. I have a use for one, granted they are cheaper than
> the planetary reducers and harmonic drives I was going to buy. :-)

Some worm drives have an eccentric adjustment to vary the gear
engagement. If the worm wheel is well-centered, you can bring
the worm in almost to zero clearance. I did this on a very old
dividing head, but that is probably built to tighter tolerance
than a small gear reducer. There are also some worm drives that
have a coaxially-split worm. The two sections of the worm meet
right over the center of the worm wheel, so it is essentially
equivalent to an anti-backlash gear set. These can have
extremely small backlash.

Jon