your replies are Gold! Really thank yu!This lathe i am trying to convert doest have a lead screw...it has an anthreaded bar with a slot in it that moves the carriage ...so only a feed screw if you can call it like this...The idea to make a mechanism for holding ballscrew nut would be perfect...so you could move alla the time manually and alsobe able to makhold the screw when you need it...i have a pc with a parallel port in it with the paid version of mach3 and laso with windows xp...its only for this reason...