Y14.5 1994 5.11.1.6 Holes of Different Sizes. Deprecated in 2018?

[Lee Saxon]

Y14.5 1994 5.11.1.6 Holes of Different Sizes states that you can create a FRTZF / Composite Tolerance for features of different sizes (ie ones where you can't simply use one callout with a '2x') by drawing the FCF (plus a notation such as "TWO FEATURES") separately from any size dimensions, and giving it its own leaderlines to the features in question.

Now, the example they give is a callout "such as 'TWO COAXIAL HOLES'," and the related Figure 5-53 also uses a coaxiality example, but based on the text (and the title of the section being "Holes of Different Sizes" rather than something about "Coaxiality"), I believe it is valid to use this for separate holes that are not coaxial. Tec Ease agrees:

https://www.tec-ease.com/gdt-tips-view.php?q=121

(a) Do you think they/I are wrong?
(b) Is this no longer valid? I can't find an equivalent in the 2018 Standard? Should I not do this? This seems SUPER useful to me: I often want to use a bolt flanked by holes for locating pins and it feels obnoxious to use a bunch of tertiary datums to do that.

 

[greenimi]

See this discussion.

https://www.eng-tips.com/viewthread.cfm?qid=469869

 

[chez311]

I see no reason why you can't attach "nX" to non-coaxial holes as long as the intent is made clear through the use of multiple leader lines or otherwise (note - the additional "nX" notation is necessary as multiple leader lines do not by themselves create a pattern).

Another option would be the use of "INDICATED" as in "INDICATED X" with accompanying X marking each feature of the pattern.

These are both mentioned in Y14.5-2009 para 1.3.42 and Y14.5-2018 para 3.44

 

[chez311]

Just to add a figure from 2018 whose 2009 equivalent (fig 7-52 which uses "TWO COAXIAL HOLES" notation) was mentioned in the thread posted by greenimi to support the use of "nX" with features of different sizes. For non-coaxial holes some other additional clarification would typically be required to show which features are included in the pattern, for example multiple leader lines.

 

[Lee Saxon]

Thanks y'all! 10.5.3.4 & Fig 10-52 were exactly what I was looking for!