On 28 Aug 2004 05:32:30 GMT, firstname.lastname@example.org (RWatson767) wrote:
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.
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