Overiding Rule #1
Overiding Rule #1
(OP)
Why was the ability to override Rule #1, with straighness on a FOS dimension, created in the first place?
I'm curious to hear other people's opinions.
I'm curious to hear other people's opinions.
Thanks,
Sean





RE: Overiding Rule #1
Frank
RE: Overiding Rule #1
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: Overiding Rule #1
http://www.mechsigma.com/newsletters/2003_02_Newsl...
Straightness is number 3. I wouldn’t even try to explain it better
RE: Overiding Rule #1
1) Special note stating such override
2) Stock material is not applicable
3) Straightness control on a FOS dimension
So in terms of geometric characters, there is only the one way. That's why it's curious to me. But after thinking more on it, I tend agree with fsincox and his comment about an unrealistic envelope. In a lot, if not most cases, straightness control of a FOS (axis or median plane) would be for long parts. By virtue of the indirect form control of Rule #1, the envelope for a part that is long can be unrealistic if the size tolerance is relatively small.
I think this logic makes sense.
Thanks,
Sean
RE: Overiding Rule #1
RE: Overiding Rule #1
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: Overiding Rule #1
I was really focusing on geometric characters, more than anything, and the fact that there is only one that applies and even that has to be specifically relative to a FOS dimension. Just a nice mental note, that no other geometric characters override Rule #1.
Thanks,
Sean
RE: Overiding Rule #1
True as long as you are working to '94 version of Y14.5. In Y14.5-2009 there are two additional ways to override rule #1:
1) Independency modifier (I in a circle) - which is nice and short substitute of text note.
2) Flatness control on a FOS dimension - controlling derived median plane of a non-cylindrical FOS.
RE: Overiding Rule #1
Season
RE: Overiding Rule #1
I will review the 2009 standard on this topic!
Thanks,
Sean