Need Help!- POS-OPER Display mystery VF2 SSYT

[Mic6]

So, hopefully someone can point out what I'm over looking here. I have a part mounted in a fixture. I wanted to check the height so I loaded my indicator in a drill chuck, zero'd the indicator on the mounting surface, zero'd my POS-OPER Z to 0.0. Jogged up to the top of my part and zero'd the indicator to get my height. I jogged up to remove my tool, did something else and forgot what the value was, so I reloaded the chuck/indicator, zero'd the indicator on the mounting surface just to make sure nothing moved, and my POS-OPER was Z.03. I thought I had bumped my indicator, so I tightened everything up, re-zero'd the indicator to the work mounting surface and re-zero'd the POS-OPER z0.0. Part height was correct. So after all this I jogged up, removed/re-inserted the chuck/indicator, jogge dback down, checked my zero surface and it was Z.03 again. I did this a few more times and the Z value kept increasing .03 or so. Even the machine zero pos was changing. I even put the indicator in an ER collet, same problem.
Now if I zero the indicator and display, check my part, jog up to home and come back down to measure, nothing moves. Theres no way my hand was bumping it. I made WAY sure of that. How can it not be repeating when i take it out and put it back in. The actual cutting tools repeat no problem. Very Strange

[Donkey Hotey]

0.030"? Thirty-thousandths? Have you watched the display for changes when you remove the tool, then put it back in? What kind of indicator? Is this a test indicator with a reverse switch on the back (maybe it's backlash of some kind).

So if you don't remove the tool, but you jog home and come back it's OK?

I'd have to guess something is up with your indicator. If tools are OK and repeating, it's got to be something else.

Just curious: what's in the Z offset register for that tool? Wear offset? I'm wondering if the action of releasing the tool, somehow pings the tool offset table each time its reloaded.

[ckirchen]

If your indicator has an adjustable tip that uses friction to hold it in place or your indicator holder is jointed, the impulse from the unclamp/reclamp cycle is probably causing parts of the indicator/holder/chuck assembly to move relative to the others. Given that the impluse is the same each time (because the air pressure and bellville washers in the drawbar don't change), the change in measurement is going to be roughly the same.

Just so that you know everything is all right, mount the indicator to the machine and zero it on a given point on the toolholder. Jog the Z up and unclamp/reclamp the tool. Jog back to the indicator; the DRO should read zero.

When I use an indicator, I will not touch it until all measurements are completed. If I touch it, I consider the measurements compromised and I start over.