GD&T - Profile

[HJackson]

I have a Surface Profile callout on an mechanical drawing from the 70's. The callout is for the outer form of a rectangular shaped part. The callout, Surface Profile to datum A .030 TOTAL, with the words ALL AROUND under the callout. The callout is dimensioned to the indicated outer surface with a chain line on the inside of the outer surface and a dimension line from there. Does this callout imply the part can be undersized 0.030 on each of the surfaces? The basic 5.000 dimension can technically be 0.060 (0.030 for each surface) under 5.000 and 0.000 over 5.000.

 

[3DDave]

Unless this is part of an ISO requirement "TOTAL" and "ALL AROUND" are not usually used; "TOTAL" in particular should not be in the Feature Control Frame. However, I don't have the 1973 version of the ANSI Y14.5 or earlier that might have been used.

That math seems correct as far as it goes; however, the entire perimeter surface must meet that requirement all at the same time, so making just those measurements, while sufficient to reject the part if they are out, are not enough to show the part is acceptable.

 

[ewh]

Short answer - yes

"Know the rules well, so you can break them effectively."
-Dalai Lama XIV