Re: ATM Journal Bearing Materials

["J. Christopher Westland" <westland@ust.hk>]

Dear All:

I am considering construction of a fork mount which should be able to hold
up to about 50 lb (About 20 Kg) and wanted some advice on bearing material.

I was planning on using a tapered stainless steel shaft -- about .75 inch
diameter at the bottom, 3 inches at the top -- to mount the fork, and
setting this in a teflon rod about 5 inches diameter, and about 15 inches
long lathed out to the same contour as the tapered shaft, which would be
force fit inside a 5 inch ID aluminium tube.  The whole affair would be
mounted on top of a tripod.

This, I felt, would be the best journal bearing alternative to a comparable
tapered ball bearing mount with similar dimensions.

My Question: Will the azimuth motion friction on my mount be low enough to
easily drive with a buyers type worm gear drive?

Are there particular advantages to ball bearings versus journal bearings on
such a mount?  What kind of bearings do the commercial drive systems
(Mountain, Losmandy, Meade, etc.) use on their shafts.  Would anyone
recommend a good source for designs for mount construction?

Thanks in advance

Chris Westland