Re: Shopbot, Rack and Pinion, Ball Screw, Acme precision screw?

I have owned a "ShopBot" since they were pulled about by cables and
had bead-chain driven encoders. The present set-up is using micro-
stepping drivers and a geared stepper with a proprietary gear-train,
I was told, eliminating or greatly reducing back-lash.

The rack and pinion are indeed 20 pitch 14.5 pressure angle gears.
Bishop-Wisecarver "Dual-Vee" wheels run on CNC bent rails.

If one is planning on routing wood, the accuracy of a ShopBot is
acceptable. I can think of many cases where 'hand' work has been
double checked and each part or section goes under inspection while a
CNC machine's work with "Out of specification" work goes out with
inspection of only the first few parts when the machine was new and
the tooling fresh.

While there is seldom "too much gun" when trying to kill something,
there can be a waste of powder and lead.

Ron Brown

Diplomacy is the art of saying 'Nice doggie' until you can find a
rock. - Will Rogers