true position callout

[Hiltonmj]

Hi, I have seen an unusual callout in a standard stating "spherical radius to be located at true position within 0.01 total indicator runout".
Aside from the lack of datums the wording to me is not something I have came across in GD&T (though I am fairly new to this). Has anyone came across this kind of wording before and could explain what it means?
If it was my option I would have used a profile tolerance to control the spherical radius. I have doubts as well on whether this is actually a feature of size that a true position could be used.

 

[greenimi]

I have seen an unusual callout in a standard....

Would be very helpful to let us know which standard....

 

[Hiltonmj]

Sorry, this is actually another problem I have with the standard. It doesn't stipulate what GD&T standard they refer too. I can only assume that it coming from an American standard that it is using ASME Y14.5.

 

[greenimi]

...Sorry, this is actually another problem I have with the standard. It doesn't stipulate what GD&T standard they refer too. I can only assume that it coming from an American standard that it is using ASME Y14.5....

Well, you embedded a picture in your initial post.
Where that picture it's originated from?

Based on the picture's structure (with key / legend identificators) looks like it is from an ISO standard (not ASME), but I might be very well wrong.

 

[Hiltonmj]

This is from API 7HU2 for hammer unions.

 

[Burunduk]

Looks like a way to say "total runout".
They probably didn't mean "true position" as the Y14.5 term that describes the basically defined tolerance zone center for the tolerance of position. A position tolerance for a spherical feature would control a theoretical center point (if the feature had any opposed points - which it doesn't), and the mention of "total indicator...." would be out of place.