It is a legal callout but.....probably not functionally applicable.

Ask your engineering people what is the true function of the datums. Without knowing the function of the part, how it is assembled it is hard to come up with an answer to this. They need to look at the function of the plane/diameter relationship and other features on the part. If the length of the diameter is not sufficient for controlling axial "wobble" then it would be more appropriate to use the face (where the perp callout is) as the primary datum and not the axis of the diameter.

I stress to our design people that GD&T was based on fit and function of the components and/or finished product. All datums should be functional (mating features when possible) features and not something that looks good on paper. Enough preaching....

Duane Wade
CMM/Gage Technician
TeleFlex Automotive - Pedals Division
301 W Ohio St.
Kendallville, In 46755
219-349-1985
dwade@tfxauto.com