Calibration of Micrometers - Can we put 2 gage blocks together?




Our Quality Manager if on indefinite leave and a calibration issue has just surfaced.

We are at the 60 day interval and the micrometers need to be calibrated before our audit next week. Our set of gage blocks includes .0625, .1250, .2500, .5000 and 1.0000 (certified to the NIST standards).

My question is: Can we put 2 gage blocks together (1.0000 + .0625), etc. in order to measure a 1-2" micrometer?

Any help would be greatly appreciated.


Douglas E. Purdy

Quite Involved in Discussions
Wetting Process


The person performing should be qualified and should know how to 'Wet' multiple blocks for the applicable check points!

Mike S.

Happy to be Alive
Trusted Information Resource

I don't wanna sound like I'm piling-on, but it does sound like a procedure (or better procedure) needs to be written for cal of mic's. But to answer you, yes you can stack standards and they are designed for this -- if the surface finish is correct and the standards clean you should be able to "rub/slide" them together so that they sort-of stick together to each other, then measure them.

Ken K

The term you guys are looking for is wringing qualities of the gage blocks. Check your calibration certificate for wringability. It should be included in a statement. Worn gage blocks would affect this.

What it is is the capability of the blocks to be stacked.

Yes, it is acceptable if your blocks are capable. The better solution would be gage blocks to measure the 1 - 2" range.

Ryan Wilde

Okay, so now we have established that wringing the blocks is okay (it will add about 20 µin/wrung surface uncertainty to your measurement over using a single block). That takes care of spindle linearity.

Sue, if these are standard outside caliper-style flat-anvil micrometers, how are you going to test the micrometer anvils for parallelism and flatness? Gage blocks won't do for these tests, and you will need a monochromatic light and optical parallels. Do you have these?


Geoff Cotton

Quite Involved in Discussions

Before we all start theorising and going into the bowels of how to measure atomic particles, can I ask a simple question……

what are you measuring with your micrometers?
:bonk: :ko:
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