Gage Pin Verify..Off Topic

[[Mi...]]

Little off topic but a question just the same...

So when the labs verify a pin gage, is it recorded as Maximum Inscribed / Minimum Circumscribed Circle taking the 3 largest or smallest points???

Or do they use a least squared approach?

[[De...]]

Labs would not be using a CMM to check gage pins.

There are more accurate and more efficient methods for checking them.

[[Mi...]]

If you measure the diameter of the pin with lets say 2500 points. What points do you use to output the diameter?

If a pin lets say 1.0000mm and its measured at .99998. How does it arrive at the .99998? Is it an average of all the measured points? Is it the 3 largest?

Just trying to figure out when a lab checks my pins, how they get the results they report. I guess I am use to a CMM and its GX GN GG etc...



Also know that most labs do not verify with a CMM I just used that as an example.

[[De...]]

The thing is they do not do that type of a check on gage pins. The standard doesn't require it. They are essentially just doing a series of two point diameter checks, so its hard to state what the 'equivalent' CMM check would be. I would expect in most cases on a quality gage there should be so little deviation in the form that the difference should be very minimal between different evaluations.

Either way the relevent standard for checking pulg gages is ASME B89.1.5-1998.

Per section 4.5.1 the following is stated.

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So essentially they are taking a two point diameter measurement 90 degrees from each other. This is done in the middle and then at either end of the gage pin. These measurements are generally done with a laser mic or super mic depending on the accuracy required.

I am no expert on gage pin calibration, but I am pretty sure an additional separate check to verify form and taper of a pin would be performed based on the requirements of the standard and the gage class of the pin.

[[Mi...]]

I see what your sayin. Makes sense to me!

Thanks

[[Ro...]]

at my previous job we did pin gage calibration in-house, we used a laser mic.
i have no idea what they used as far as evaluation (Max inscribed or Tangential), and for the little bit that i was in charge of that crap (I always found a way to get out of gage cal duties) i dont remember having the option to select an eval method.
But we had several thousand pins, most were carbide and or Class X so it only made sense to pay the money for a laser mic so we didn't have to send out a couple hundred pins a month for cal.

[[Mi...]]

Im with you Roberto I am sooo trying to get out of this but I cant see how. I have pins that are ZZ here so not really a tight tolerance..

Thanks