Is this GDT&T Correct?

[grunt58]

We received a fabrication drawing from a customer which states a machined V ring is to be flat and parallel to a datum A. I'm not sure that it can be flat and parallel since it is a ring. Is the callout correct? If not what is the correct GDT&T callout?

Drawing attached.

Thanks

 

[J Macias]

The parallelism tolerance is correct - it controls the orientation of the top (sharp edge) of V-shaped feature with respect to datum A.
That edge must be between two planes which are .005 apart - say, if you place this part face -A- down on a surface plate and indicate the top edge around, the total indicator reading shouldn't exceed .005.
The flatness tolerance is redundant as parallelism controls form deviation implicitly.

 

[Sem_D220]

I would add to the said above that there might be a tangent plane modifier needed for the parallelism control.

 

[AndrewTT]

This is the first time I have seen "REF" next to a FCF. I'm not sure what to make of that.

Also, the Flatness refinement of the parallel requirement near the 1.56 dimension is a redundancy. If that surface has to be parallel to {A} within .005 then it will have to be flat within .005 also. This error is what gives me pause for the rest of the drawing, including the OP's area of interest.

 

[grunt58]

I assume the ref is in regards to calling out twice. Its already called out at the bottom. I'm sure the ref and double call is a no no. I would just call it out in the detail view but that is just me; I didn't create the drawing. I need to figure out how to fabricate and machine the weldment.

I didn't think the flatness made sense based on the parallel but I'm no expert in GD&T.

Thanks for the replies.