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"S" in a circle. It's no longer needed?

"S" in a circle. It's no longer needed?

"S" in a circle. It's no longer needed?

(OP)
I know the answer already i believe but i have some people here that doubt me, even knowing i have the ASME standard. According to ASME Y14.5M-1994 the "S" in a circle is no longer need, correct??. "S" use to mean "regardless of feature size"

I'm assuming the ASME didn't add this back in, correct???

Solid Edge V20

RE: "S" in a circle. It's no longer needed?

"S" was obsoleted in the 1994 standard and I did not find anything in the 2009 standard restoring it. "S" is gone!!!!

Dave D.
www.qmsi.ca

RE: "S" in a circle. It's no longer needed?

(OP)
TY

Could anyone scan a copy of just the new MODIFYING SYMBOLS and post it? if it legal and all..:)

Solid Edge V20

RE: "S" in a circle. It's no longer needed?

Please ref to standard Y14.5 1994 Appendix D paragraph D3 page 215 and Fig.D-1 on page 216. RFS symbol is no longer required.

SeasonLee

RE: "S" in a circle. It's no longer needed?

(OP)
LOL LOL, that's the deal. I did reference the page cause we have the whole standard. But still have some people who think they know the ASME standard back-wards and for-wards. One person had the gull to say "Maybe they forgot to put it in" Then i bring it to my boss's attention, he ones that thinks he knows it all, and he just gave me a bunch of crap and said he's not going to worry about it threw the drawing in the trash. O also he said "Well the customer (DELPHI) had it that way so it must be current"

Solid Edge V20

RE: "S" in a circle. It's no longer needed?

I wouldn't worry too much about it, given the grief you're seeing over it.  The use of the symbol isn't going to result in an incorrect part.

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

RE: "S" in a circle. It's no longer needed?

(OP)
I'm not going to worrie about any more after what just happen. I thought on the way back from lunch i'd stop by the new girl office who's doing all of our documentation and see if she understood my email. To say the least, i don't have a very good opion about her anymore. See also part of it is that they were drawing the "S" with a circle in our doc's and i was trying to convey to her that it's not needed. WHAT A JOKE around here at times

GO RED WINGS!!!!!!!!!!

Solid Edge V20

RE: "S" in a circle. It's no longer needed?

I feel your pain, and have learned to better pick my battles than I used to.

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

RE: "S" in a circle. It's no longer needed?

To use the symbol, you have to reference the 1982 standard on the drawing.  In the 1994, it is only mentioned as something that is being killed off.

The reason that it is no longer necessary is that the 1994 standard makes RFS the assumed value, instadd of MMC.  So, it is actually a good idea to NOT use it, as it would create confusion as to which standard you are using and whether no symbols means MMC or RFS.  If MMC is even suggested as default and your drawing is done to 1994, then you can be really screwed.

I would suggest that it is not correct to use circle S, especially if you are now invoking 2009 on that print.

And, the S was not "forgotten" in 2009.  That comment suggesting this is extremely off-the-cuff.  Every statement change in the standard is debated endlessly before its inclusion or exclusion.

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

RE: "S" in a circle. It's no longer needed?

Is there a note specifying which standard to interpret the drawing to?  That will probably cover your butt if the situation arises regarding MMC that fcsuper mentions.  It is no excuse to assume MMC if the drawing is to be interpreted to the '94 standard (for example) just because RFS is erroneously used.

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

RE: "S" in a circle. It's no longer needed?

(OP)
TY ewh, i looked up one of the original drawings that has the customer Title box on it, it says ASME y14.5-1994

Solid Edge V20

RE: "S" in a circle. It's no longer needed?

I have to agree with fcsuper that misuse of the symbol can cause problems down the line, but you have to choose which battles to fight.  It sounds like your work environment is similar to mine in that some things have to be put aside in order to tackle the bigger problems.

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

RE: "S" in a circle. It's no longer needed?

Oops, I meant to post "...in order to tackle the bigger opportunities."

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

RE: "S" in a circle. It's no longer needed?

The '94 standard had RFS as the implied condition if no modifier was present.  Rule #2(b) allowed the use of the (S) modifier.

The '09 standard eliminated Rule #2(b), making it illegal to use the (S) modifier.  I don't agree with this decision myself, but that's what the committee voted for.

Evan Janeshewski

Axymetrix Quality Engineering Inc.
www.axymetrix.ca

RE: "S" in a circle. It's no longer needed?

There you go!  It is legal to use it under the '94 standard.  Thanks, Evan!

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

RE: "S" in a circle. It's no longer needed?

Evan

Rule #2a is an alternative practice of Rule #2. Rule #2a states that, for a tolerance of position, RFS may be specified in feature control frames if desired and applicable. In this case, the RFS symbol would be the symbol from the 1982 version of Y14.5, please ref to the attached examples of Rule #2 and Rule #2a ( from Alex Krulikowski GD&T Workbook ).

Would you please advise where I can find out Rule #2b.

SeasonLee
 

RE: "S" in a circle. It's no longer needed?

SeasonLee,

I'll leave out the obvious Shakespeare joke here.

You're right, it's Rule #2a in the '94 standard.  The section that it's in is 2.8(b) on page 28.

I had looked it up in the Former Practices appendix in the '09 standard, which says that Rule #2(b) has been eliminated.  Looks like there's another typo in '09 to report.

Evan Janeshewski

Axymetrix Quality Engineering Inc.
www.axymetrix.ca

RE: "S" in a circle. It's no longer needed?

(OP)
ctopher, not at work but, is that from the 2009 standard??

Once back to work tomorrow i'll have to get the ASME standard out and look up #2a

If true, thinking of not saying anything....ponder

Solid Edge V20

RE: "S" in a circle. It's no longer needed?

Well, at the rocket shop I work at, we sre stuck with using the circle S on all our new program drawings (to 1994 standard)  because we have both new programs and old sustaining programs to the 1982 standard, and engineering management does not want to confuse manufacturing with two systems---Rule 2A being the obvious justification.

When new programs come on board with 2009 as the contractural GD&T std, it will be interesting to see if they can deal with it.
  
 

RE: "S" in a circle. It's no longer needed?

(OP)
Here's something that made me shack my head. remember a few threads back i told how my boss threw away that drawing i markup to remove the "S". Well i open the drawing today cause i had to reference something and notice he had our detailer remove the "S"'s...... Funny...A

I guess he does listen to me once i awhile.....

Solid Edge V20

RE: "S" in a circle. It's no longer needed?

Perhaps fcsuper hit on it. Someone else also told him to take out the circle S's, or he knew you were right, but didn't want to admit it to you.
  Just recently I told a designer to remove something from a drawing that was bad practice and he refused. Another good designer who was doing some part time checking saw the same drawing, made the same comment to him, and he changed it for that person.
So a full time checker's word is not valid, but a designer/part time checkers' word is? Makes me feel a little like Rodney Dangerfield.

RE: "S" in a circle. It's no longer needed?

(OP)
Or maybe cause i ended up telling him that it's a alternative method allowed in the 1994 standard but removed in 2009. Any ways, least it removed and let's see if they follow this standard now....

Solid Edge V20

RE: "S" in a circle. It's no longer needed?

As long as the "S" was applied to a TOP it is allowed as alternative practice. You can't use it on perpedicularity at all.  

Powerhound, GDTP T-0419
Production Manager
Inventor 2009
Mastercam X3
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

RE: "S" in a circle. It's no longer needed?

Amen, powerhound. This is about Position only. It is the only place we still use the circle S.

RE: "S" in a circle. It's no longer needed?

The 'S' is no longer required - however it is implied. If there is no other symbol there to over-rule it the 'S' is really there anyway.

RE: "S" in a circle. It's no longer needed?

inspector:
That was our original arguement. That is why it was dropped in the first place, but our engineering management isn't buying it.  

RE: "S" in a circle. It's no longer needed?

If your drawings are per the 1994 standard then there's nothing for engineering to buy into...they have to abide by the standard. If they want to change it then have them attend the next Y14.5 meeting.

Powerhound, GDTP T-0419
Production Manager
Inventor 2009
Mastercam X3
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

RE: "S" in a circle. It's no longer needed?

What do you guys think of the decision in '09 to disallow use of the explicit (S) symbol?  I don't see the logic.

When training on the '94 version, I always recommend to students to put the (S) in the feature control frame even though it's an alternative practice.  To me, the presence of the explicit symbol clearly shows that the designer really intended RFS as the condition.  The "no modifier" implied condition leaves open the possibility that an (M) or (L) modifier was intended but accidentally omitted.

But now when I start training on the '09 version, I won't be able to recommend use of the explicit (S) because the practice has been outlawed.

Personally, I don't see the harm in giving the designer the option of using the explicit modifier instead of the implied condition.  But there must be other reasons why the committee voted to remove that option.  What do you guys think?

Evan Janeshewski

Axymetrix Quality Engineering Inc.
www.axymetrix.ca

RE: "S" in a circle. It's no longer needed?

(OP)
Me personally don't know the logic behind removing the "S". But, when i was trained i was told to leave it off. So now i just know if no "S" means RFS. Plus here, we are always pushing our customers to use "M" when ever possible. Easier for hard gaging on the floor

Solid Edge V20

RE: "S" in a circle. It's no longer needed?

In 1973, MMC was the default modifier if no modifier was specified, and RFS had to be specified to apply (Rule 2A).
  In 1982 this was modified to manadate the applicable modifier (MMC,RFS,LMC) for position and make RFS the default for other tolerances, dropping rule 2A to be more in-line with international practices.
 Then in 1994, RFS became the default over MMC in a new rule (para. 2.8(a) to further be in-line with ISO and this is when circle S was removed. They kept the option, however, with 2.8(b)to satisfy those who would be confused and those that liked it (such as our friend Evan, and the management at my place).
 
  So I see the total dropping of the circle S in the new 2009 standard as a further capitulation to ISO practices, which is OK, since it is an extension of rather than reversal of the current practice.
 
I don't agree with "belt + suspenders (braces)" approach that putting in the circle S tells everyone "Look, I really meant to do this.  I didn't forget my circle M!

Follow the standard, agree nor not, for pity sake.
    

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