Simiultaneous requirements
Simiultaneous requirements
(OP)
For some reason my brain isn't firing on all cylinders this morning, so here's a quick Q ...
See the attached picture. Regarding the two profile tolerances: At first glance it might seem like the part is allowed to tilt into a parallelogram shape. But since the two profile tolerances have common datum references, they are understood to be gaged simultaneously.
The other side of my brain says that they should just use one profile tolerance that uses the all-around symbol.
Any comments? I only ask because it's a pain to get these folks to make any drawing change.
See the attached picture. Regarding the two profile tolerances: At first glance it might seem like the part is allowed to tilt into a parallelogram shape. But since the two profile tolerances have common datum references, they are understood to be gaged simultaneously.
The other side of my brain says that they should just use one profile tolerance that uses the all-around symbol.
Any comments? I only ask because it's a pain to get these folks to make any drawing change.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com





RE: Simiultaneous requirements
What is datum C? I will assume this is the bottom mount face, not visible on the view.
An all round profile WRT datums A, B and C is completely meaningful to me. Even with just datum C, you are defining a tolerance zone. Your maximum angle would be atan(.05/2.5).
What do they want it to look like?
--
JHG
RE: Simiultaneous requirements
Good thing: the lower-left corner is dimensioned by basic dimensions and controlled by FCFs. It also appears to be straight. This implies basic 90 DEG angle applied to this corner.
The mathematician in me says “good enough”. But not everyone will be convinced.
RE: Simiultaneous requirements
I agree that all-around profile would be better, but the current callouts seem to be the same thing.
CH, if these profiles are gaged simultaneously, they override the title block tolerance (which is ±1º).
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: Simiultaneous requirements
RE: Simiultaneous requirements
RE: Simiultaneous requirements
Pmarc, that's what I was thinking, but it sure would be more straightforward if they just used one feature control frame and did the all-around symbol!
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: Simiultaneous requirements
RE: Simiultaneous requirements
Are datum feature A and B center planes or side faces?
If center planes, are the width and height FOS? Do they have LMC and MMC?
RE: Simiultaneous requirements
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com