CNC acetylene torch table drive

Hello,

I am looking at Xylotex.com 425 in oz motors to drive the long axis of
a 4'x8' torch table. I'd like to use a 3/8" pitch by 1/2" wide belt
that functions as a rack. The pinion is a pulley of 2" diameter. I'd
like to have one drive motor on each side of the long axis.

Would I be able to drive the pulley directly with the motor, or do I
need some gearing on the motors? The carriage will be the is the
lightest possible tube, just to carry an acetylene torch head.

My concern is having adequate traction between the belt rack and the
pulley. Is gravity sufficient to hold onto an upward-facing belt rack?

I've considered ball screw assemblies, but it appears that I don't
need such high accuracy, and simple belt drive will get me at least
1/30 inch accuracy on the torch table, and better if I use
microstepping. Are the 3/8" pitch pulleys sufficiently accurate as I
indicate with the calculated 1/30 inch? I am trying to do the
rack-and-pinion belt instead of ball screws for lower cost. The
original design was screws- but I'm moving onto rack and pinion, with
2 motors on the main axis to get the drive mechanism away from the
working area.

http://openfarmtech.org/index.php?title=Torch_Table

Sincerely,

Marcin
http://openfarmtech.org/weblog/
http://openfarmtech.org/index.php?title=Overview