True Position Control Frame

[[Ne...]]

Hello Group

I have a part with a true position control frame see. picture. I was wondering what the R means where the diametric symbol
should be. What I could find out was this is an old symbol. The original rev of drawing is from 1989. Was hoping someone else
had seen this. Datum G is a bolt hole circle on the top of the part and Datum E is the Plane on top of the part. These are 28 hole that go around the part. The part is about round about 16 inches in diameter.

Thanks for the help

Neil Van Swol

True Position.GIF

[[Er...]]

I have seen this once or twice on our very old legacy drawing. For us, the interpretation is a radial zone around the nominal axis. So R 0.02 is the same as ø0.04.

But that might not be your case. So proceed with causion.

[[Ne...]]

Thanks Eric, That is how we are interpreting as well. If someone else has a different view, please let me know

Thanks,

Neil

[[SH...]]

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I think it should be 0.04 millimetre diameter tolerance zone.