×
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

Surface Profile with NO datum reference frame

Surface Profile with NO datum reference frame

Surface Profile with NO datum reference frame

(OP)
Typically, when we DO see datums specified on a surface profile callout, that tells us to set the part up to datums and measure the surface relative to those datums.  No best-fitting allowed.

Also typically, if we DO NOT see a datum reference frame on the tolerance, that tells us we are allowed to best fit that surface onto its nominal shape, using all 6 DOF.

I have a situation where a surface profile tolerance is on a print with NO DRF.  The customer is telling me that it is IMPLIED that this is wrt datums, even though none are specified.  

Further, he claims this is part of his company's specs. I looked at the spec, this situation isn't covered.  But the spec does reference ASME 14.5M-1994.  So I looked at the ASME spec.  I couldn't find it in there either.

So my question is this --- what does ASME say about surface profile  tolerances that do not reference datums?  Is it IMPLIED that datums are specified, or does no DRF mean best-fitting is allowed?

RE: Surface Profile with NO datum reference frame

recommend you RF this post/thread, and repost in forum:

Engineering Methods/>Drafting Standards, GD&T & Tolerance Analysis

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