Repeating Datum Feature Identifiers 1

[ringman]

Does anyone see a problem with repeating datum feature identifiers when used on a second or third sheet, or for that matter, in a separate detail or section on the same sheet? And, if so is it necessary to label as ref in some manner?

I did a search on the Y14.5 Std and found no results.

TIA

 

[ewh]

No, there is nothing wrong with repeating datum identifiers (and often needed), unless it would add nothing to the understanding of the view in which they are placed. Like highway designators on a map, they add needed clarity of "where you are going" and "where you have been". Repeating the controls applied to those datums, however, should be considered "double dimensioning".

When the people fear their government, there is tyranny; when the government fears the people, there is liberty. - [small]Thomas Jefferson [/small]

 

[ringman]

No intent to repeat the FCF. Question has arisen whether ref or not.

 

[ewh]

I don't think ref would be appropriate in this situation. I have nothing to back this up except that, while I often see datums repeated, I have never seen it done as ref, ref seems to be overkill, and not using ref will not cause any ambiguity or confusion in understanding the intent.
I would stick to my guns and have the dissenter provide the documentation as to why they should be ref.

When the people fear their government, there is tyranny; when the government fears the people, there is liberty. - [small]Thomas Jefferson [/small]

 

[KENAT]

ASME Y14.5M-1994 Section 3.3.2 toward the bottom of page 41.

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.

Took me approximately 30 seconds to find, longer to type out. You're not even trying now are you ringman;-).


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

 

[ringman]

I was. I did the search on the computer. Apparently did not plug in the proper description.

Thanks Kenat

 

[KENAT]

I just looked in the symbology section under Datum Feature Symbol of my hard copy and there it was.

That's the trouble with any kind of help or search, you really have to ask the right question.

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

 

[ewh]

Caught me being lazy again...

When the people fear their government, there is tyranny; when the government fears the people, there is liberty. - [small]Thomas Jefferson [/small]