Smart questions
Smart answers
Smart people
Join Eng-Tips Forums
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

Join Eng-Tips
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

MadMango (Mechanical) (OP)
11 Apr 08 14:00
We are having some drawings kicked-back by QA due to not having the CL symbol to define a centerline in a cylindrical part drawing.

I looked in Y14.5M-1994, thinking that one of the Fundamental Rules stated you didn't need it, but couldn't find it.  Can anyone help?

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of Eng-Tips Forums?

powerhound (Mechanical)
11 Apr 08 14:05
ASME Y14.2M-1992 specifies the rules for a centerline and the "CL" marker is not included in this. See para. 2.6 on page 2. Where is your QC getting the idea that the drawing is wrong if the "CL" isn't there?  

Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

MadMango (Mechanical) (OP)
11 Apr 08 14:11
QA/QC has constant battles with all other departments.  They glaze over some things and focus in on others when it serves their purposes.

Any references for the -1994 edition?

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of Eng-Tips Forums?

powerhound (Mechanical)
11 Apr 08 14:17
The most recent version of 14.2M was reaffirmed in 2003. Is there any real basis for this rejection of your drawing such as reference to a standard?

Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

Helpful Member!  TheTick (Mechanical)
11 Apr 08 14:21
Start dogging them for chapter and verse for why it's "required".  They won't have anything.
MadMango (Mechanical) (OP)
11 Apr 08 14:21
I was looking to point the standard out to them, so they will release some parts.  There is no "real basis" for most of what they reject.  Thanks, I will look in 14.2M.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of Eng-Tips Forums?

fcsuper (Mechanical)
11 Apr 08 14:30
ASME Y14.5M wouldn't likely have reference to how to identify a callout of a centerline.  This is not a dimensional element.

The place for it would be ASME Y14.2M, as powerhouse just checked.  There was a chance ASME Y14.100 might say something, but it doesn't say anything about this there either.

No examples in any of the standards I have access to show a CL. This makes sense since a centerline is self-explanatory.  If it is drawn as a centerline, that's what it is.  It doesn't need any further identifiers.

If one doest want to use it to signify the center of the part, I guess one CAN use it, but as far as I can find, there are no standards that even define what it means, so there's really not point anyway; unless you put a note on the drawing stating its definition.

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

Xplicator (Mechanical)
11 Apr 08 14:41
In all of Chapter 3 of ASME Y14.5M-1994 does it mention a centerline symbol or CL.  In all the standards ANSI/ASME and ISO the CL is not supported.  What I have found has already been cited by Powerhound.  I have even looked back at some drafting  instruction books.  CL is mentioned but only as being = to an actual centerline.  I believe this is old school thought and symbology that I have witnessed in use.  It does make it clearer, but it's use is overkill since the centerline already indicates such.   
ctopher (Mechanical)
11 Apr 08 14:51
I don't use it. But, I have used it a few years ago where the CL of the part was useful to the customer. It was not CL symmetrically center of the part, just CL of the part in relation to the customer's interface.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated 10-07-07)

fcsuper (Mechanical)
11 Apr 08 20:31
Xplicator, you had me confused for a second.  You mean that Chapter 3 does NOT mention the CL symbol, right?  :)

The closest that Y14.5M comes to mentioning use of center of an object is symmetrical outline.  But it shows methods from Y14.2M, and not CL for this sort of detailing.

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

Xplicator (Mechanical)
11 Apr 08 22:55
Slip of the digits and submitting without proof reading.  But, yes I meant that in Chapter 3 which is titled Symbology there is NO mention of CL or it's use.
KENAT (Mechanical)
14 Apr 08 10:39
Back in the UK I had a senior guy tell me it had been dropped from the standards and was no longer correct.  This would have been BS 308 or 8888.  However, as you're in the US probably not much help.  I don't recall seeing it in any of the Y14.100 series standards.

KENAT, probably the least qualified checker you'll ever meet...

ewh (Aerospace)
14 Apr 08 11:11
Sounds like another "belt and suspenders" situation.  I have to agree with the others to have QA produce a valid reason for having the symbol, as the line font does indicate whether it is a centerline or not.
I have seen it used to specify a particular centerline with a note indicating of what it is the centerline.  For a general cylinder, I see no reason for it.

Believe it if you need it or leave it if you dare. - Robert Hunter
 

fcsuper (Mechanical)
14 Apr 08 11:12
Another term I've seen on molded components is PL for parting line.  Since there is no other way to denote it, this would make sense as a mandatory item (as long as it is defined).

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

TomFin (Mechanical)
14 Apr 08 11:29
Like TheTick states, you should ask QA to quote this privy "CL" business. Show them how all the cylindrical drafting examples pulled from Y14.5-1994 provide dashed center lines without employing the letters "CL"
 

Failure is a prerequisite of successful design

MadMango (Mechanical) (OP)
14 Apr 08 11:36
Thanks all.  Another battle won, but the war is far from over.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of Eng-Tips Forums?

Brandy7 (Automotive)
15 Apr 08 9:44
              CL Was Replaced by:
The SYMMETRICAL OUTLINE SYMBOL is used when limited drawing space and only one-half of the symmetrical shape can be shown (Previous symbol was CL prior to 1986) See 5.6.6 DOD-STD-100 / DOD-D-1000 Drawing Requirements Manual.  
fcsuper (Mechanical)
15 Apr 08 10:06
Yeah, I noticed that.  The problem I have with sym outlining is that it assumes symmmetry and doesn't make clear how tolerances apply.  In many cases (and even in the example in the standard), the sym centerline on the part isn't itself based on a feature, so all dimensions from that CL are actual double when both directions of sym are taken into account.  I cannot imagine myself using this method.

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

CheckerRon (Mechanical)
15 Apr 08 11:27
Your right fcsuper, the symmetry dark double lines (Fig 1-33 of Y14.5M-1994)define a symmetrical centerline, but a poor way to dimension. It is OK for pictorials however,as in ASME Y14.2M-1992 Fig 3, and that's the only time I would use it. The "CL" abbreviation is still in the latest ASME Y14.38a-2002, but is not used in dimensioning.
  I might rarely use CL in a removed view on another sheet, when showing dimensions off a centerline of a datum feature by attaching a leader and note to the centerline that states "CL OF DATUM B". Even then, only is it is not obvious.
fcsuper (Mechanical)
15 Apr 08 13:59
That's about the only use i have for CL too, Checkerron.

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

TheTick (Mechanical)
16 Apr 08 9:45
Some time ago I questioned whether the "CL" symbol actually existed in any written standard.  I thought it was just "engineering folklore".  I think it was Heckler that set me straight.

Even so, I can't imagine it is mandatory in any case.  I would worry about an organization where it would be that necessary.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close