ATM bearings, part II

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

Thanks to everyone for your thoughts and comments about bearings and related
topics.

For my particular project, I am looking to mount an 8" refractor f/13.3 and
wanting the mount to be ridged, accurate, smooth, easy to assemble for some
portability and esthetics.

Car axles are a good idea for smaller mounts, already mounted to bearings
and with slight modification, a good choice for small scopes.

The use of an automive rearend and axle does not fit into  my idea of
esthetics, however such an assembly can work.  Pillow block mounted bearings
should work will but agian, not fall into the esthetic category.

Bob Walkers suggestion of 3" tubing instead of smaller solid shafting is
right on and correct.  Some weight loss and great stability.

Stability in a mount is paramount for good performance and the suggestion of
the use of sleeved or "plastic" bearings could indeed result in some
sloppiness.  Obeserving at 400+ magnifications, very slight arc second
wobbles do become a concern.

So for now, I am looking at sintered bronze bearings and/or tapered rolller
bearings and 2"+ shafts for this project.

One more comment on esthetics,   A good looking instrument, ergonomically
and esthetically designed is more likely to be used than something that
might work well but still be an ugly clash of mixed aluminum, plywood, and
mixed harware.  Now before I get flamed on this comment, first, beauty is in
the eye of the beholder, and second there are many nicely designed scopes
with these material combinations.

Thanks,  Kreig