AVG and F symbol - fig 8-14/2018

[greenimi]

Figure 8-14 Specifying Restraint for Nonrigid Parts

Is F modifier in the circularity needed in figure 8-14?
I am asking this because in fig 8-13/2018 F symbol has been removed (relative to the equivalent figure 5-13 from 2009)
Why F was kept in 8-14?

 

[Garland23]

I don't think the F is needed in Fig. 8-14, because the restraint note is clearly meant only for the circular runout check and nothing else.

 

[jassco]

Circle F is needed. Otherwise, the roundness will have a different meaning.

 

[greenimi]

Otherwise, the roundness will have a different meaning.

What do you mean by "different meaning" ?

 

[Garland23]

jassco, according to paragraph 8.4.3 of the 2018 standard, I think that the AVG notation already tosses R#1 out the window. So I'd still say that the F is not needed.

 

[ctopher]

I agree the F'n circle (lol) probably not needed.
I don't understand the AVG meaning with the dim.

 

[3DDave]

In Figure 8-13 there is a single compound tolerance callout.
In Figure 8-14 there are two separate callouts.

Any "why" questions should be addressed to ASME committee members directly at the ASME Y14 committee meetings. No one but those who attend can possibly have any idea why anything is done in that group. Frankly, I have my doubts that most of them do.