Datum Feature Symbol
Datum Feature Symbol
(OP)
Hello I have searched the wide-wide web along with some books and have fallen short to an answer.
My questions is as followed:
What standard does the [-A-] datum feature follow? Meaning the dashes specifically, and if the dashes have any meaning?
http://www.engineersedge.com/gdt.htm gives the following explaination:
"Datum Identification frame (Symbol) - The datum identification frame (symbol) contains the datum reference letter in a rectangular box, usually preceded and followed by a dash (any letter except I, O, or Q)."
To my knowledge, ASME Y14.5M-1994 says that a datum feature symbol is [A] with a 60deg triangle for a "arrowhead".
I am unsure of the ISO equivalent for GD&T.
So to sum it up, is it best practice to include dashes before and after datum letter, or not to?
My questions is as followed:
What standard does the [-A-] datum feature follow? Meaning the dashes specifically, and if the dashes have any meaning?
http://www.engineersedge.com/gdt.htm gives the following explaination:
"Datum Identification frame (Symbol) - The datum identification frame (symbol) contains the datum reference letter in a rectangular box, usually preceded and followed by a dash (any letter except I, O, or Q)."
To my knowledge, ASME Y14.5M-1994 says that a datum feature symbol is [A] with a 60deg triangle for a "arrowhead".
I am unsure of the ISO equivalent for GD&T.
So to sum it up, is it best practice to include dashes before and after datum letter, or not to?





RE: Datum Feature Symbol
RE: Datum Feature Symbol
WWW (World-Wide-Web)
Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 04-21-07)
RE: Datum Feature Symbol
If you have a copy of ASME Y14.5M-1994, you will find an explanation of the change in Appendix A, "Principle Changes and Imprrovements"; specifically under paragraph A5.
GDT_GUY
RE: Datum Feature Symbol
RE: Datum Feature Symbol
The datum you state is per ANSI Y14.5M-1982.
Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 04-21-07)
RE: Datum Feature Symbol
RE: Datum Feature Symbol
The standards are inexpensive to purchase. There's been a lot of improvements in ASME Y14.5M, so I'd recommend purchasing the new standard and to start using it. Just an idea. :)
Matt
CAD Engineer/ECN Analyst
Silicon Valley, CA
sw.fcsuper.com
Co-moderator of Solidworks Yahoo! Group
RE: Datum Feature Symbol
List Price: $145.00
Inexpensive, maybe from a company point of view if you have a reasonable budget for that type of thing.
From a personal point of view, that's quite a bit. I still haven't recovered from paying 70+ for Rourke!
KENAT, probably the least qualified checker you'll ever meet...
RE: Datum Feature Symbol
What do you think of Rourke when compared to other similar books out there. I'm am looking to making a purchase and been looking around, but been seeing mixed comments about whats available.
Matt
CAD Engineer/ECN Analyst
Silicon Valley, CA
sw.fcsuper.com
Co-moderator of Solidworks Yahoo! Group
RE: Datum Feature Symbol
Honestly I'm not much of a stressman, Rourke was what the chief stressman and a couple others used at my last place and that was a good enough recomendation for me.
It's probably off topic for this thread but I have seen a thread(s) asking about this type of thing. Can't remember which forum it was; Mechanical engineering other topics or somewhere in Structural Engineers I think. Sorry I can't be more help.
KENAT, probably the least qualified checker you'll ever meet...