True Position

[[Me...]]

Does anyone know where the section is in the ASME standard that explains True Position for ALL features above the callout?

Example: In line features like Chamfer, Counterbore, & Bore all in line with a TP callout.

[[Br...]]

Counterbores yes, Countersinks No. There's really no support for a position tolerance being applied to a conical feature. In my opinion, it is NOT a feature of size. A circular cross section of a cone could be considered a feature of size, but not the entirety of surfaces of the cone. Profile is what would need to be used to control the surfaces of a cone. When you think about it, it makes sense. How do you derive an actual mating envelope from a cone? Because the surfaces aren't directly opposed, some expanding conical envelope would sort of just slip out as it expanded. The most you could say is if you had basic dimensions, you could have a basicaly defined "True Profile" of the cone shape that contacts all the high points of the cone surfaces. This is effectively how a datum simulator for a cone would work. Then you have to ask--What would the tolerance zone even look like? There are 5 degrees of freedom to control on a cone. A typical cylindrical tolerance zone just wont do. It would have to be argued that it is an irregular feature of size with a boundary condition at best. None of this is discussed in Y14.5. Cone features are completely left out of the "Location" section of Y14.5. You will find the explicit examples for locating a conical feature in the Profile and Runout sections.

Anyway, sorry for being long-winded. This is what you really asked for:

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[[Me...]]

I'm more concerned with the in-line counterbore than the chamfer in regard to our company. We made a $25,000 titanium part that had a very tight true position callout for a dowel bore that had an in-line clearance bore below it. The features were all in line and had a TP callout below it and no one at my company understood that it applied to everything above it...But it is definitely good to know about the chamfer, I absolutely agree with your opinion on profile.

No one at my company agreed with me about the bore at the bottom also having the TP applied to it so I wanted to find it in the standard. I do agree with my company that it might be irrelevant to place a TP callout on a clearance bore below a pressed pin but that's what was on the print.