Cadillac Height Gage information?

Depends. If you want to use it in an ISO certified app, then it should be calibrated to 10 millionths. (10% of the gage calibrations.) IF not, then check it against gage blocks with a 50 millionths indicator. The gage is no better than the surface plate it will be used on, I have the same gage, but have the 6" riser for it, the errors in the riser are known and those have to be taken into account in use. (THe errors are in millionths, and in my use, not a factor.)

IF you want to do the calibration right, that is, checking the screw, we checked ours every .100" over an inch, making sure that we re did it with a .112" or .113" block to check for drunken threads in the screw. (Never found one, but it was required proceedure.) Slide the indicator along each of the surfaces, from outside to the inside, there should be NO movement of the indicator. There shouldn't be any rough spots for the full length of the travel, it has to move freely with no binding.

IF you do find any errors, it's not fatal, note them and take them into account while you're using it. Wonderful piece of equipment when you've "Gotta have it right the first time." Think of it as an infinite set of gage blocks.

Thanks for all the nice information. I have done lots of things in my life but height gages did not get their due.

Bob AZ