The 12" distance is quite long but should be
o.k. You don`t indicate the size telescope this
will support. A 1" shaft diameter may be o.k. for
a 6" to 8" telescope. In any case ball bearings
would be ideal for the polar axis, and needle
bearings would suffice for the dec. axis. If possible use a thrust bearing where the dec. axis meets the polar axis. As most of the load bearing
weight is at this point, it will make for a much
smoother movement. However, balance is of the
most importance. If properly balanced, the
effects of weight become less important.
Don Kocsis, 1920 Merl Ave. Cleve. OH., 44109