I have two identical holes on center line drilled on opposite ends of a part. One hole is datum A Ø.189/.195 and the other is the feature under consideration, also Ø.189/.195 with a position requirement of φ|Ø.002(M)|A(M)|. We are trying to verify conformance by using the tightest fitting gage pins in each hole, placing the pin in Datum A in the rollers of a concentricity gage with the indicator tip on the pin placed inserted into the feature under consideration. Using this method, I know we can add the bonus tolerance from the feature calculated by (Øgagepin-.189) to the positional tolerance of .002 and get up to .008. Can we also add the datum shift as well calculated by (Øgagepin[A]-.189) for a potential total positional tolerance of .014? My instinct says NO! But this has sparked a healthy debate and I wanted to get some feedback. We would prefer to check this with a functional gage or CMM, but that is just not in the cards right now.
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