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?

 

[axym]

CheckerRon,

I'm not sure I understand what you mean by "radii extending around non circular features". Do you mean applying the all around symbol to something like a fillet radius, in the same way that "TYP" is used?



Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[PeterStock]

I would agree with the use on dimensional features such as fillets or chamfers as long as it is clear what is meant by all around. I.E. ALL AROUND what?

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

 

[CheckerRon]

axym and PeterStock: Yes, I am talking about putting the all around symbol on the bend of a leader which is calling out a radius or a chamfer in lieu of using a word description such as "ALL AROUND", or "CONTINUOUS" under the dimension.
We do not use "TYP"---too vague.

 

[cadman1964]

We don't even have that option to put that symbol on our dimensions. It's only available for GD&T stuff.

We apply the word "ALL AROUND" to any fillet or cham where needed. We eliminated the word "TYP" here cause of the same reason you mentioned, to vague.

I don't agree at all with your GD&T guys. How i understand it, this symbol only meant for GD&T. Plus i could see it being missed very easily on dimensions.


Solid Edge V20

 

[ewh]

What is the definition of the symbol? My understanding is that it represents "ALL AROUND". Therefore, I would not have a problem using it in place of the terminology.

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

 

[PeterStock]

The CAD systems I work with do not have it implemented either. For this to be properly useful, the option to use the all around or all over symbols would need to be added to the software. As an alternative a symbol with modifyable text could be used. I tend to interpret a radius or chamfer dimension that looks like it is all around as all around in any case.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

 

[CheckerRon]

That's separate point,cadman, but we have a CAD problem with it too. The all around symbol is only in our GDT symbol pallette (Pro/E Wildfire 3.4), so we have to create a circle that we can hang on the elbow of the leader and associate it. Design seems to be willing to do this, however. Don't ask me why.

 

[cadman1964]

Ok if you put it like that..

Sounds like to me there wasting time by doing it this way when its faster to just throw a note under it saying ALL AROUND.

So to answer your OP

"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?"

NO!!!!


Solid Edge V20

 

[EdMcCabe]

Solidworks includes the all around symbol on thier available leader styles, so it's easy to apply to any field note. Not sure if it's correct or not, however. I also kind of don't like it because the 1st time I went to apply the all around symbol to a profile tolerance, it took me forever to find out how to do it. I kept expecting it to be somewhere in the GD&T menu, but it's an option on the leader.

 

[axym]

CheckerRon,

After reading your clarification, I say no. I don't see it as a valid extension of principle. Here are the reasons why:

First, the definition of the all around symbol specifically mentions the leader from the feature control frame. A radius or chamfer does not have a FCF.

Second, the definitions of "all around what" mention surfaces all around the part. A radius or chamfer would only apply to a subset of the surfaces all around the part (the fillet or chamfer surfaces, and not the flats and/or other surfaces in between).

Third, Profile is the only class of tolerance that can apply to a group of different feature types and hence can really be applied "all around".

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[ewh]

I agree that it is a waste of time to manually create a circle to hang onto a leader rather than simply adding the note, but other than that I see nothing wrong with it. If it could be mis-interpreted it should not be used, but if the interpretation of the symbol is universal, I think that "extension of principals" could easily be invoked.

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

 

[fcsuper]

As long as the use of it is clear and unamibigous, it should be fine. All around a block might not be unambiguous though, as the question would be "all around what" or "all around in which direction?"

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group

 

[cadman1964]

As a draftsman, if your drawing is properly laid out there should be no "all around what" or "all around in which direction"

Solid Edge V20

 

[ewh]

"what" and "which direction" weren't in the original issue as I read it. These types of additions do add more complexity and possible mis-interpretation. However, if you are refering to an odd shape where there would be only one interpretation, it does not make you a poor draftsman to utilyze the symbol. It's use does not create an improperly laid out drawing, but a more concise one, which should be the goal of a good drafter.

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

 

[vc66]

I say no good.

Easier just to write "ALL AROUND". Also less ambiguous. Also, less of a problem with pretty much all CAD systems.

I see no upside to using the symbol.

V

 

[cadman1964]

OK, if your a company that abides by the ANSI standard, again I'd say no. On page 46 section 3.3.18 it states -

"3.3.18 All Around Symbol. The symbolic means
of indicating that a tolerance applies to surfaces all
around the part is a circle located at the junction of
the leader from the feature control frame."

So from that you're only suppose to use that for feature control frame

Now, if you a company like the one i work for and don't abide by the letter of the ASME law. Than i would probably prove to them there wasting valuable, if they really are, doing it the way they are.

Solid Edge V20

 

[PeterStock]

The all around symbol originated from weld symbols, as such the used in GD&T is an extension from that practice. It is not that much of a stretch to extend that to dimensions.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

 

[aardvarkdw]

Peter,

You beat me too it! I was going to bring up that same point.

And the fuel piles higher...

David

 

[ModulusCT]

I believe using the wording 'ALL AROUND' for a dimensional situation like this is appropriate. ASME Y14.5M does not use the hanged circle in the way you guys are talking about... I would not assume that's it is acceptable to use in any other manner.

There are references in the spec that state that adding local notes to clarify situations like this are OK.