Designing a Gage to check GD&T

[brunsqm]

I am trying to design a functional gage or gages that will check the position tolerance and the profile tolerance relative to A,B,C on this drawing.

Couple questions: Can I have one gage to cover both requirements?
Are my datum simulators for X,Y,Z located based on the nominal profile of the part or do I incorporate the surface profile tolerance in locating the datum simulators?

I wish they would have used MMB for B & C on the profile tolerance as I believe that would have made my gage simpler.

Any help is much appreciated.

Jodi

 

[pmarc]

No, you can't use one gage to cover both requirements, because both callouts use different datum references (A|Y|Z in position FCF, A|B|C in profile FCF).

 

[brunsqm]

I thought that would be the case.

What about locating the Y,Z datum simulators? Are they located nominally or do they take into account that the outer profile of the part has a profile tolerance?

What is they best way to check the profile tolerance? A Go gage using expanding mandrels for datums B & C with a no-go pin?

 

[pmarc]

Simulators Y and Z are located nominally relative to each other (that is, as defined by basic dimensions on the drawing). The thing is that due to part-to-part differences in actual geometry of the outer contour, different parts will be touching simulators Y and Z slightly different.

As for profile check, yes, expanding pins (mandrels) should be used for simulating datum features B and C. The outer boundary of profile tolerance zone could be verified by a go gage (a pocket of similar shape build to the size of profile outer tolerance zone). As for verification of inner boundary of profile tolerance zone, some will say that you could use a pin of dia. 1 and try to stick it between the part and the gage pocket all around. If this pin does not go, it means the inner boundary of profile tolerance zone is not violated. (I would personally prefer CMM or optical comparator for this check).