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datum call out on section view

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djhurayt

Mechanical
Jan 18, 2001
220
Scenario
[ul]
[li]round part with multiple diameters[/li]
[li]one of the diameters is a datum[/li]
[li]this diameter dimension has the datum flag attached to the extension line, directly in line with the dimension line[/li]
[li][/li]
[/ul]


Question:
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) ???
 
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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.

 
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

 
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
 
djhurayt,

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.

--
JHG
 
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