Pin Gage Use vs. Calibration Frequency

You have valid points. However unless you have absolute strict controls on the use of the pins and gauges you do not know when or how often they are used. If you do not set a reasonable interval for evaluating the pins and gauges then you run the risk of approving something or setting something up wrong but not knowing it. Which risk is worse? Calibration too often or making a bad part?

On and ring or thread gage when you get it calibrated dip it in wax. If it wasn't used during the cal period let it go another year.

Not necessarily. The good folks at Meyers Gage put out a paper on the fact that, yes, some gages grow on their own.
This is why pins and rings can get bigger with time, and use has nothing to do with it.

WHY GAGES CAN GROW IN DIMENSION
Hardened steel does have the propensity to grow in dimension.
The growth is usually noticed in larger sizes because it is an inch per inch type growth. What happens is when the steel is hardened the molecules are trapped in stasis. Slowly the molecules relax and retained austenite is changed to martensite, as they relax they cause an expansion of the material. The gradual relaxation process takes about a year. The larger the size the more the change is noticed. The tighter the tolerance the more the movement is noticed.
To combat this phenomenon gage makers require that their hardened steel be triple cold stabilized. The process requires the gage to be cycled three times through a freeze/thaw process. This procedure will reduce the probability of gage growth. Note the use of the word ‘reduce’ instead of ‘eliminate’. This a major reason to have gages calibrated on an annual basis even if they have been subjected to little or no use.

Michael_M said:

We use a 'calibrate prior to use' system for our gauge pins. Can you forgo the calibration and use a calibrated Micrometer to 'verify' the pin diameter before each use?

If the pin is worn, remove and replace.

I don't know if this will work for the standard you are following.

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We are ISO registered and have been doing the same thing for over 15 years. If a pin leaves the area we have a sign out sheet and when it returns the pin is verified again before putting it back in the case. If pins are damaged or lost we just replace them and "verify" them. Keep it simple. Our process states:

1) BEFORE: Calibrate before use with the 0- 1" Micrometer (xxx or zzz) to verify the pin size before using the pin.
2) AFTER: Use the 0- 1" Micrometer (xxx or zzz) to verify the pin size before putting back in the case.
Notify the Quality Manager if there are any problems. Do not use pin if it is damaged or not correct.

Like QChas, we sign pins out and 'verify' them before they are returned. I created a VBA excel sheet that tracks how long the pins have been out on the floor and how long the pins have been sitting in the quality room. I was looking to see what others do in regard to this. If the pins only need to be 'calibrated' every year perhaps I'll change my code to how many times they are checked out and time exceeding one year.