Re: Geared Dobsonian question

Mel Bartels (mbartels@efn.org)
Mon, 6 Mar 95 14:16:57 PST

I have used roller bearings to reduce friction on my dobs for years. For manual dobs, I let 2/3 of the contact pts be roller bearings and the other contact pts the standard formica/teflon. This cuts the friction down on very large dobs to a more managable level.

For my computerized dobs, the 3rd point is a machined conical shaft attached to a precision gear reducer. With the roller reduction of ~40:1 and the gear reducer of ~60:1 giving a total reduction of 2400:1, one can attach motors directly to the gear reducer input shaft without need for further gearing.