ATM gear backlash in Alt. drive

[Adam Perkins <scopeguru@yahoo.com>]

Hi,

I'm approaching the point in my computerised Dob project where I ned to
commit to a gear reduction scheme.

I got to thinking about those gear boxes bolted to the front of
"gearhead" motors such as the surplus ones listed in the Herbach &
Rademan catalog.  

I accept the fact that a generic surplus gearbox may have lots of play
and periodic error.  Mel's software would hopefully handle any PEC
needed.  

The Altitude axis seems like a good candidate for one of these reducers
because I can over-balance the OTA slightly to avoid any backlash.

The Azimuth axis offers no such loading on the gear train.  Has anyone
had problems using different reduction methods on the two axes?

I like the single worm-gear and roller approach, but if I can avoid the
cost and alignment headaches of a worm drive, I'll be happy.  Are there
additional problems inherent in the design of those little gearboxes?


Adam Perkins
Covington, Louisiana
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