Calibration Procedure for ID Micrometer Calibration & Extension Rods

In our shop we have Mitutoyo 4-5" ID mics with Extension rods out to a maximum 80". We currently calibrate the ID mic head with a calibrated OD mic by transferring the feel from a known reference rod standard.

Does anyone have an example calibration procedure for ID mics?

How should we proceed in calibrating the extension rods?

A Quick Bump!

Can someone help?

Thank you very much!

Stijloor.

Another quick "Bump". My Thanks in advance to anyone who can help with this one.

I would get ahold of Mitutoyo and ask them. http://www.mitutoyo.com. On the right hand side there is a spot Small Tools Knowledge Base. From here you can ask a question and they normally respond within a day.

I'll try Mitutoyo and see if they have advice. Thanks

Procedure for Inside Micrometers: 17-20MD-09
Tolerances in the procedure range from 0.0002" to 0.003" depending on the range.
Procedure for End Standards: 33K6-4-369-1
Tolerances in this procedure range from 0.00005" to 0.0004" depending on the range.

Measurement equipment:
http://www.prattandwhitney.com/Content/Laser_and_Digital_Long_Length_Measuring_Machines.asp

In my experience inside mics and end standards have always been calibrated with a super micrometer + gage blocks. Your usual super mic doesn't go out 80 inches, but they do make them, as shown by the URL I provided above. The cal procedures are pretty straight forward. You test the inside mic at several evenly spaced test points throughout the range of the micrometer for each attachment/extension. End standards are even easier; only one measurement can be made. Making measurements on a sensitive super micrometer can be tricky and will require training/experience.


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