Originally Posted by
cncserveng
when threading you are machining mm/rev or inch/rev, so the spindle encoder, belt and pulleys need to be good.
backlash comp is for the ballscrew nut, if the support bearings at each end are good and the belts/ pulleys are correctly adjusted then the backlash can be adjusted up to 0.004", if more the ballscrew is defective.
pitch error comp is quite different, it is a laser measured pitch check and data is entered into a comp table to optimise the axis positioning, it is of no use in your case.