ATM bearings

["Kreig McBride" <astroguy@nas.com>]

Looking for advice and thoughts about bearings.

Wanting to design and build a german equatorial mounting and thinking of
what to use for bearings.    I plan to use stainless shafts.  Wanting to
reduce the amount of machining to a minimum and also consider ease of
assembly.  The bearings would be seated into aluminum plate.

The options include:
    traditional sealed ball bearings    (APEC-1 or better, what would be
required?)
    bronze bearings  (sintered pre lubricated)
    teflon
    composite bearing materials (with some kind of acetal resin overlays as
a porous membrane to hold lubricants)

How do I deal with thrust?
    Use a seperate trust bearing?
    Use a teflon plate for thrust?
    Must I use locking collers to keep the shaft in the housing, or depend
on press fits to keep everything together?

Obviously  this is not a complicated issue yet when designing I realize the
simple things can bring interesting questions.

I would appreciate facts more than opinion, looking for information on stuff
that really works.

Thanks,  Kreig