On 27 Nov 2004 02:18:57 -0500, Allan Adler
wrote:


Clean the rack and pinion, making sure that there's nothing stuck in
the root, the very bottom of the teeth. Uneven wear, or uneven
spacing when the rack was made? Either are possible, Rack and
pinions are available from Boston Gear, Browning and others. If it's
older US made scope, no problem. If it's a newer import, Rotsa Ruck.

Accepted lube is RT-44, using way oil or any other substitute is going
to guarantee problems with lube migration, or shiny stains where you
don't want them.

IF you replace the rack, you might be tempted to use the nylon rack,
bad idea, I've done it and it didn't take long to switch back to the
brass. Rivetted sounds like an import, 0-80 screws are what I use.
It ain't rocket science, pretty straight forward job.

Helical focuser is also an option, and I've made a couple of those
too, each has it's benefits and drawbacks. Personal preference there,
neither has a clear advantage over the other unless you're putting a
camera on the focuser, in which case the helical is out.