This is probably something really simple!
I bought a used 2000 VMC 3016, just getting it running.

If I put a mag base indicator on the mill table with the indicator against a tool holder in the spindle.
Then jog the X axis until the indicator shows 0.100" movement,
the DRO on the machine says X has only moved 0.084"

This was really driving me nutty until I figured out what was happening!

Is there a scaling factor somewhere in the machine setup that I have to set?

Thanks,
Robert Paisley

My machine has metric ballscrews and the inch ballscrew parameter was set.

Easy problems are better than the alternative!
Robert

I've never seen as much as .016 difference between DRO and TIR due to backlash but it's easy enough to check and fix if thats your problem. I can't imagine that being your problem however on a machine as new as that unless it's been run REAL hard. I ran a 1996 model that had to have the thrust bearings replaced cuz the backlash couldn't be adjusted out of it. Just a thought.