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True Position Gage - For Alex D.

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Posted ByKelly Bramble on January 28, 2002 at 07:26:40:

Alex:

If the True Position is given at MMC for the holes(Maximum Material Condition) then you do as follows:

.472(MMC of Holes) - .008(Total Tolerance) = .464 (This is the "Virtual Size" of the hole and the size of the gauge pins. In practice, one may reduce the pins a little to compensate for inaccuracies of the check tool. Additionally, the pins are not typically "fixed". Depending on the Datums (DRF) one often designs the check tools with retractable pins. Contact with the DRF (typically planar surfaces) is in order of DRF presidence, then the features in question are verified.

Check out /calculators.htm for GD&T type calculators.

Hope this helps!

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Subject: Re: True Position Gage - For Alex D.

Comments:: Alex: : If the True Position is given at MMC for the holes(Maximum Material Condition) then you do as follows: : .472(MMC of Holes) - .008(Total Tolerance) = .464 (This is the "Virtual Size" of the hole and the size of the gauge pins. In practice, one may reduce the pins a little to compensate for inaccuracies of the check tool. Additionally, the pins are not typically "fixed". Depending on the Datums (DRF) one often designs the check tools with retractable pins. Contact with the DRF (typically planar surfaces) is in order of DRF presidence, then the features in question are verified. : Check out /calculators.htm for GD&T type calculators. : Hope this helps!

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