We make centering vises where I work, and we used to have to manually adjust their center relative to a pin hole on the bottom before shipping them to the customer. One time I centered one and the report showed all zeroes, so I turned up the DISPLAYPRECISION all the way and it was still zero. I changed the dimension to mm and it showed 6nm from zero. Obviously this number would not repeat, so I refused to measure it again, but I printed that out and hung it on the wall as the "Centering Record"
I was at a measurement seminar years ago and the head guy from NIST at the time was the key speaker. He discussed how the standard for measuring GAGE BLOCKS was done. The gage blocks need to be placed on the long surface as the compression of gravity will alter their measuements..... yeah....
