ISO GPS: Does parallelism to a common datum also control coaxiality?

[Eurotex]

CAUTION: This post uses the ISO GPS system of geometric dimensioning and tolerancing

Can the parallelism tolerance shown in the below image (with respect to common datum A-B) be considered to control coaxiality of the A and B diameters? If so, would you assume the equivalent coaxiality/position tolerance to be 0.005?

 

[Eurotex]

Is there one continuous bearing bore in the housing?

Nope

 

[Eurotex]

If there are no other comments about how to perform the tolerance stack, I could ask something else about the drawing provided above.

Since this drawing uses ISO GPS, rule one does not apply (independent size and form is default). In the image provided "LP" stands for 2-point linear measurement and "SA" stands for average of measured values.

If "SA" was not present, I think I'd just add the largest size and cylindricity tolerance to obtain a value equivalent to an MMC envelope. Do you agree?

However, in this case we do have "SA". I guess I can still approximate an MMC envelope by doing the same thing as I mention above, but it would be an approximation neglecting any banana shape (and maybe other situations that I haven't thought of). Since this part is turned or ground (between centers), I wonder if a banana effect would be highly unlikely. Do you think this is true?

The below image illustrates a few variations that I could imagine. The far left is the banana case, while the two options on the right show cases where the "SA" modifier seems to be quite reasonable when generating an MMC envelope by just adding the largest size and cylindricity tolerance to obtain a MMC envelope (e.g. 7.025 for the datum feature A diameter).

 

[cr7]

Does parallelism to a common datum also control coaxiality?
Short answer: NO.

Would answer be "yes", if there was diameter symbol in second compartment?

 

[CheckerHater]

NO

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[Tarator]

cr7,

Coaxiality is a location control. Orientation (parallelism, etc.) does not control location. In order to control the coaxiality between these two cylindrical features, you will need a POS, or a PROFILE of a SURFACE, or a RUNOUT (circular or total), or a CONCENTRICITY (note: concentricity has been removed in 2018 version of ASME Y14.5, it was never recommended for use anyway) callout. There is no other control.

 

[cr7]

Tarator, thank you, nicely said.