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


datum call out on section view

datum call out on section view

datum call out on section view

  • round part with multiple diameters
  • one of the diameters is a datum
  • this diameter dimension has the datum flag attached to the extension line, directly in line with the dimension line

What is the proper way to identify this datum on other views?
do we:
A) just attached it to one side of the diameter
B) create a reference version of the diameter dimension and attach it to this one just like the original/official one
C) I'm pretty sure it should not be attached to the centerline
D) none of the above
E) ???

RE: datum call out on section view

Please have a mockup drawing attached.
3.3.2 /ASME Y14.5-2009
Where the same datum feature symbol is repeated to identify the same feature in other locations of a drawing, it need not be identified as reference.

RE: datum call out on section view

It is legal to repeat your datum feature flag on the other views, there is no need to call it reference.
If your CAD system allows it, create "empty" dimension without numerical value.
If in the other view cylinder appears circular, you may create leader and attach flag to it.
No, centerline is no use.

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

RE: datum call out on section view

Maybe I need to clarify. I am not thinking the "datum" may need to be identified as reference. But I was not sure how to attach it to the other view(s) and the reference concern was about creating a reference dimension in each view that I want to identify the datum in.

So it sounds like I need to create a reference dimension in each view (or as CH suggested a blank dimension)to attach the datum flag to. And yes I am aware of the leader on views that the datum shows as round. But if I have a side view, a projected side view (because of some features that are not round), and a section along the axis side view; that I will need to create two reference/blank versions of the dimension for these other tow views

RE: datum call out on section view


Your datum must be attached to a feature. Attaching it to a diameter specification accomplishes this. In a view without the diameter, attaching it to the feature means the same thing.


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!


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