×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • 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!
  • Students Click Here

*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.

Students Click Here

Jobs

Is the CSYS always the origin

Is the CSYS always the origin

Is the CSYS always the origin

(OP)
All,

When designing 3-d tubing, we start with a coordinate system at one end and develop the geometry to the opposite end. We place a table on the drawing with the xyz coordinates and bend radius to each point. The drawing didn't state the tolerances are non-accumulative.

The problem: The gage maker started in the center of the part and worked to each end of the tube. He believes has the accumulative tolerance from point to point.

Question: Under what circumstances would the coordinate system (from which all dimensions originate) not be the origin of reference?

Adrian  

RE: Is the CSYS always the origin

What dimensioning standard is being applied to the definition?

RE: Is the CSYS always the origin

I rarely seen a tube dimensioned from the center. But, it also depends on the design. I have seen a tube on an airplane engine dim from the center because it was the mounting point with fittings on each end. Most of the time it is dim from one end, point to point. The tolerances are whatever works as long as the end point is where it needs to be. For aircraft engines, the mfr usually gives us start/end & mounting points.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Apr 30, 2008)

RE: Is the CSYS always the origin

(OP)
ringman:
Ansi Y14.5M-1994 drafting standard applied to this drawing

ctopher:
The tube is detailed/dimensioned from the csys end but the gage maker started his design from the center of the part.

RE: Is the CSYS always the origin

I don't understand the gage maker's actions, unless he has some further customer information that you don't.  He could be  working from an "as used" state rather than an "as manufactured" state.

I used to work with automotive exhaust and rigid AC lines, we always started from one end and worked towards the other.  Our tubes were made on a manual tube bender, though I'm not sure why a CNC tube bender would be any different.  Tolerances were per the title block, usually +/-.19 for exhaust and +/-.010 for AC lines.

"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?

RE: Is the CSYS always the origin

(OP)
MadMango:
I agree with you. Engineerings position is the gage maker made the gage improperly or he didn't know how to read the print. My goal in posting this delima was to make sure I am not missing something.

Thanks for the feedback!  

RE: Is the CSYS always the origin

I have had my share of dealing with tool designers not knowing how to design tools or read drawings.
I once had a tube with several bends that had to fit at the end +/-.05 mm. The tool designer didn't know how to convert and made it +/-.5 in. Very expensive to remake the tool.
I suggest your gage maker fix the tool to match the drawing or you will have problems later.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Apr 30, 2008)

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

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!


Resources