[bloke]

The original post was from 2007. I don't think he can hear you from that far away...

[Rich Carlstedt]

Thanks Bloke !
I missed that..

We had a 5 inch 5 axis CNC Boring Mill (85,000 # worth)
at work in a non temperature regulated work envirionment and
yet worked to very close tolerences.(.001)
There is so much to thermal expansion as you know so I
thought I would join....looks like I missed the boat...by a long shot !
Years ago there was a fellow who kept loosing Y location and it turned out
to be loose Ram Clamps, and not a servo drive problem
Back to basics..

[pgf545]

I know this is a 07 post but I just had the same issue with one of our VM2's last week. I have been running a VMX42 for several years but I need to do another job so the boss said to run it on one of the VM2's. I started running it at 8000 and noticed the tool depth changing. I rechecked tool and noticed it was about .001 to .0015 deeper. My thinking was that there was a little expansion in the spindle itself and maybe some of the heat transfered to the tool holder and that was my total expansion??? I set the tool a little higher and reran the program again.