CNC drilling question

Which would be more accurate for a servo based setup using a step compatible drive;

1. Use screw TPI, gear ratio data, encoder CPR etc. to arrive at step resolution for X, Y and Z axes

or

1. Use 1 above then fine tune using el cheapo HF dial indicator on each axis under software control

Using dial indicator seems standard for backlash measurement.

You have to use #1 to determine your steps per unit setting.

The dial indicator can give you the backlash amount if your controller software supports backlash compensation. Backlash compensation doesn't work particularly well, so it's best to adjust things mechanically to get the least possible backlash.

If your controller software supports a pitch error mapping table, you can tediously use the dial indicator to map the pitch errors of the screw along the entire axis travel.

Pete C.