[J P Stein]

If you're not using gauge blocks you have no one but yourself to blame.
Any make of tool can get knocked out of whack. Thirty years of QC (the last 20 or so inspecting machined parts) experience will teach you some stuff. I did learn to trust our cal cert lab. My 1 inch Mitutoyu mic measures down to half a tenth.....till the battery goes dead. How often do you need to measure a half tenth? .000005

BTW, it's 25 deg outside, the East wind is blowing down the gorge and it's snowing....I'm staying inside .