Irregular Feature of Size

[greenimi]

If datum feature A is to be defined which option would be the best:
- plus-minus size and relationship to the primary / secondary --such as pos| Ø.xxx|B|C|
or
- basic size diameter Øxxx and profile|xxx|B|C|

(B and C being primary and secondary datum features, not shown on this drawing from 2018 version of ASME Y14.5)

and the second major question: could be legally use basic size diameter Øxxx with position (instead of profile)?
(I am trying to use position maybe because I would like to modify it at MMC which I cannot do it with profile)

Just an academic purpose exercise.

 

[3DDave]

So surprised the creators of this particular monster failed to describe exactly that.

I'll toss in positional tolerance on each of the three pins.

The fun part is that the acceptable variation isn't a diameter, and depends on the number of pins involved.

 

[greenimi]

I would like to see some good examples where those concepts are used and how they are used (with direct toleranced dimensions or with basic dimensions).