Composite Profile on Revolved Surface

[weavedreamer]

I've pondered two approaches to what is being attempted to be described. The intent is to keep the orientation of the profile to the centerline, much like keeping a nameplate horizontal on the door while not being as concerned with it's location.

 

[Belanger]

It comes down to what number you want to have control the orientation vs. the location. (In both proposals the size is controlled by the tighter .028.)
Thinking about location -- Proposal 1 locates the part around datum B within 0.1, while Proposal 2 also locates it within 0.1 (although only at point B).
Thinking about orientation -- Proposal 1 controls it within .028, while Proposal 2 does not; in fact the orientation is somewhat up for grabs in Proposal 2 because the position tolerance doesn't carry down onto the curve.

So my initial thinking is to go with Proposal 1. (An aside: to designate a tolerance between points A and B, you don't need the "PT" but just the letter. Also, in Proposal 2 you don't need the word "boundary" under the profile callout because profile is always a boundary idea.)

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[weavedreamer]

Thanks. Unless I hear (or see) otherwise, Proposal 1 is on the print.

I was familiar with the point about "PT". Is "boundary" being dropped for 2009?

 

[Belanger]

No -- boundary was only a word to be used with the position symbol. Profile tolerances by definition are always a boundary thing, not an axial thing.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems