Tolerance for Digital Indicator Calibration - Machinists Indicators

B

bradhaz

#1
I'm drafting a work instruction for in-house calibration of machinist indicators used for setup and ran into a tolerance snag for digital AGD gages. I pulled T.O. 33K6-4-889-1 and NAVAIR 17-20MD-11 from Gidep and am using both as a baseline (thanks for the pointer Hershal). Each make reference to increased tolerances allowed for greater spindle displacement based on dial revolutions.

Is there an accepted technique I can use to transfer dial tolerances to a digital device?

Or is it a non-issue based on inherent design?

We just had our first third party assessment for AS9100. Personal gages are not used for product acceptance or calibrated. It became an observation due to 'process monitoring'. At first I took issue (hate having my knuckles rapped). But I do agree with the intent and feel that any employee who brings their own gaging should be provided with the assurance that it is accurate enough to do the job at hand. I'm not looking for a loophole to assign unwarranted tolerance - only whats due. Can anyone shed some light?

Thanks, Brad
 
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BradM

Staff member
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#2
Brad, I am sorry that I missed your post earlier.

I am not sure what you mean about "transferring" tolerances. Can you explain that one to me?

As far as calibrating employee-owned equipment, we have had several really good discussions on that here.


http://elsmar.com/Forums/showthread.php?t=21242

http://elsmar.com/Forums/showthread.php?t=20820

This one seemed to elicit the most responses:

http://elsmar.com/Forums/showthread.php?t=19110

It might be informative for you to look through that one.

I agree with your logic for the most part. While there are good arguments on both sides, I have fairly well reserved to the notion that non-calibrated instruments become a pretty decent risk. But as you see in the above threads, there are good points on both sides.

Main thing: develop a good identification system and stick by it.
 
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