GD&T profile tolerance help

[bigchainey]

I am new to the forum and also to profile tolerances and for the most part I understand the concept of a profile tolerance. the attached picture shows my question the holes have 2 profile tolerances attached to them and I am not sure how this works. could someone please explain this to me?

 

[bigchainey]

Any guidance would be really appreciated!

 

[powerhound]

The upper segment is controlling the form of the feature, unrelated to any datums. The lower segment says that your profile tolerance zone is .0035 wide but is unequally disposed about the true profile. Only .001 of the zone is outside the true profile while the other .0025 exists inside the true profile. So the 2 dimensional, .0015 zone basically lives inside the .0035 zone and can shift within it in order to fit each linear slice of the feature contour into it.

John Acosta, GDTP Senior Level
Manufacturing Engineering Tech
SSG, U.S. Army
Taji, Iraq OIF II

 

[bigchainey]

okay just to make sure I understand. The .0015 would be like an edge finish requirement and this tolerance would reject for things like chatter or poor edge quality. while the .0035 unilateral by .0010 is checking for position and fitment to datum A.

 

[powerhound]

Instead of position let's say location. Other than that, I think your understanding of what I've said is correct.

John Acosta, GDTP Senior Level
Manufacturing Engineering Tech
SSG, U.S. Army
Taji, Iraq OIF II

 

[bigchainey]

Awsome! This clears up all of my confusions!