Expanded use of ALL AROUND Symbol 1

[CheckerRon]

This topic was addressed in thread 1103-200357 some time ago, without a definite resolution. I am bringing it up again for the members to comment on.
The ALL AROUND symbol was introduced in ASME Y14.5 in 1982 to apply to Profile of a Surface tolerance. It is also in paragraph 3.3.18 of the 1994 spec with the word "profile" missing, but in reference to a tolerance, verses a dimension.
The new 2009 spec also applies it in paragragh 3.3.19 relatuve to profile tolerance of all surfaces.
The new spec even introduces an ALL OVER "2 concentric circle" expansion of the principle for 3 dimensional application of profile of a surface.

So here is my question for debate: Is it proper or correct, using an "extension of principles" justification to expand the all around synbol to dimensional features such as radii extending around non circular features?

This is being used on radii drawings of parts at my place and is a topic of controversy among design and drawing check.

We have two ASME GDT certified people who think it is OK, and are using the "extension of principles" arguement as their justification.

As I read the standard, I believe it cannot be justifably expanded from tolerances to dimensional features, and should only be applied as the standard dictates.

What say you?

 

[JLang17]

If you have a profile with radii at corners and straight sections between them, I don't think the all-around symbol can be used on the radii dimension leader. The reason being that the dimension is only applicable on the radii - but the all-around symbol is telling you to apply it everywhere on the profile outline.

 

[ewh]

???
I'm not sure I understand that, JLang17.
If you are refering to a situation such as this example, how would you dimension it? "4X R.XX" or "8X R.XX", or "R.XX ALL AROUND"? If you use ALL AROUND, how is that different than using the circle? Intent is clear, isn't it? While it is not directly proscribed, this use is neither directly prohibited by the standard.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[cadman1964]

ewh
I would use ALL AROUND to dim this feature due to the rad including the corners of the part.

Now if the corners were not rad, it would be R X.X 4X

Solid Edge V20

 

[KENAT]

Like Cadman, I'd probably base whether I allowed it on the situation.

Ron, I believe you are working Government contracts, so I'd lean on the side of caution and not use it in the application you describe.

At my place, where most people dont' even know what ASME Y14.5 is, I'd probably allow it if the intent was clear. However, like cadmanI don't think our CAD does it automatically/intelligently so would discourage it for that reason.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[energised]

I have drawn a simple die with a square clearance cut of .06" all around the female feature, a square with radiussed corners, on the bottom side. I had the circle on the leader to imply the .06" was all around the feature. After reading this post, my interpretation is that the circle is used for tolerancing purposes, and that I should dimension this feature .06 ALL AROUND and remove the circle.

 

[CheckerRon]

Yes, Supercub, you should change it to "ALL AROUND".

I am not so concerned that readers will misinterpret this callout applied to dimensions.
Any reader familiar with weld symbols or all around profile-of-a-surface tolerance will get the intent, but it was a real stretch for me when colleagues tried to use Y14.5 to justify. Besides, it's just easier to all the words.

Some of the posters above have given me more good reasons not to permit or perpetuate this practice.

 

[nrostrander]

CheckerRon,

I Would like to comment simply to state that I, for one, have seen and used the "all-around" symbol on dimensions before, as there is no notation in the standards saying otherwise. The only time I woul use it, is perchance the definision of the symbol is absolte. Needless to say, there is an obvious meaning and no other posibility as to its use. Now if per say there was any, key word (any), chance of misinterpritaiton of the afromentioned symbol and it's meaning, then it's use in that situation shall be simply, no-go. I for one would rather use the symbol when possible, but I ensure that the situation would allow for it in my interpritation. I would also like to note that as some people may use it, and some people may not within any givin organization, I strongly recomend having an internal specification detailing the use of the symbol prior to implmentation.

V/R
Nathan
CAD Technician/ISO Director
Compass Systems, Inc. (

http://www.compass-sys-inc.com/

)

 

[CheckerRon]

I concur, nrostrander, that such use should be documented in a company standard, or DRM before using it. Today's drawing creators tend to assume that anything a CAD system can do is acceptable. I have seen some really horrid examples of this. Therefore I am big on sticking to accepted, documented stndards and not venturing off on your own.
There are notations stating otherwise, however. Check out the paragrahs I note in my OP.