Re: [ATM] Focuser speed reducer

["Don Clement" <don_clement@charter.net>]

Gary,



There are many ways  to eliminate backlash in leadscrews. A common way is to
use a tapered split nut such as are found in almost every micrometer head.
Here is a link to that might help:
http://www.liutaiomottola.com/Tools/Backlash.htm



Don





> Don,
>
> Could you explain more about the "zero backlash nuts". I'm working on a
focuser that would benefit from them - it's strictly for personal use!
>
> Thank you,
>
> Gary Fuchs
>
>
>
>
> >
> >I don't use or need speed reducers. Just use a single fine pitch
leadscrew
> >with zero backlash nuts.  The advantage is no backlash or play from an
added
> >gear (or similar type) reduction mechanism. There is also excellent
> >repeatability and ultra-smooth movement because the leadscrew nuts
average
> >over many threads and have a very large contact area. Of course fine
focus
> >is inherent with leadscrew focusing whereas the Crayford design has  the
> >inherent coarse focusing limitation in which a focus reduction mechanism
> >must be added for any type of fine focus. Also the contact area of the
> >Crayford is very small, a point or line contact at best so there is also
a
> >limitation on maximum load before slipping occurs.
> >
> >
> >
> >Don Clement
> >
> >Running Springs, California
> >
> >
> >
> >
> >
> >> I've seen lots of great focuser plans out there, but I've never seen
> >> plans or even a commercial source for a speed reducer like the ones
used
> >> on feathertouch and moonlite focusers to get dual speed focusing.
> >> Anybody have plans or a source for such a beast?
> >>
>

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