which screws for 4'x4' plasma table?

[dsmdude]

Looking for recomendations on which ball screws to buy for a 4'x4' plasma table I am starting to build. I'd like to order them from mcmaster if possible so if anyone could recomend some part numbers of the screws and nuts needed it would be greatly appreciated. The planed power for the screws will be www.lowcostcncretrofits.com plasma table package deal (2 / MAE 1080oz.in Stepper Motors for x-y drives) timing belt driven in a reduction. The lengths of the screws should be 60 inches for the design I am using. Any help is greatly appreciated!

[jcc3inc]

Sir,

I'd seriously consider rack and pinion for an environment as dirty as plasma cuting. With a spring loaded drive pinion against the rack, much more dirt is tolerated. And if you are using reduction anyway, rack and pinion is simpler.

I prefer 20 degree pressure angle rack and pinion. Also 24 dp gearing seems good as you need AT LEAST 18 teeth on the pinion to avoid undercutting. I'd use maybe 30 teeth on the pinion.

Regards,
Jack C.