Re: ATM Design advice for tracking Dobs

[andydtg@phoenix.net]

Mel Bartels wrote:

>I looked around a long time and never
>found anything suitable that was in our price range.  The harmonic
>drives are beautiful units, ingeniously designed with minimal error, but
>at $1000-$2000 per unit, a little steep.  Other traditionally designed
>units were barely acceptable and they cost $500 - $700.  So, your best
>bet is going to be to scrounge for used precision gearing like the Byers
>stuff that was meant to be put right on the polar axis of an equatorial
>scope and machined to have as little error as possible.  I hope this is
>ok with Dave, but I might go ahead and mention that Dave Radosevich has
>a collection of Byers surplus stuff - you will just have to ask him and
>see what he has and what he wants - 

Some of you may know that I mfg hobbed HDPE worm gears, the smallest
currently is 240t 7.775 dia. Periodic error is in the 20 arc sec
range. I'm going to experiment with making smaller gears, 120 & 180
tooth might be possible. Check with me privately about prices, they're
*much* cheaper than even surplus Byers gears.

Hope no one is offended by this quasi-spam.

Andy Saulietis / DTG Alt-Az-Fp Drive Systems
12617 Harriet Ln
Santa Fe, TX 77510 USA
409-925-8854 Voice/Fax