Relationship of Rule 1 with perpendicularity tolerance

[AM Engineer]

Hello all.

Please find the hand drawn drawing of a rectangular plate.

The bottom surface is datum feature A. The perpendicularity call out for secondary datum feature is given. Value is not specified intentionaly.

The question is

" As per Rule 1, the length dimension of 9.8-10.2 can be banana like. Having a form error of 0.4 simultaneously on both surfaces. Does this error has anything to do with perpendicularity with respect to datum feature simulator A".

Thank you in advance.

 

[AM Engineer]

Greenimi

Read what GDT Guru said.

"If there is a perpendicularity tolerance specified and its value is greater than the size tolerance, for example 2.0, the angle between the left wall and the datum plane A is controlled within 2.0. In that case, flatness error of the left wall of the 9.8-10.2 width is indirectly controlled by the size tolerance, that is within 0.4. In other words, that wall can have measured flatness error of 0.4 because this doesn't conflict with the specified perpendicularity requirement of 2.0"

Im sorry pmarc if i interpret you wrong. What im understanding is that flatness will be controlled within 0.4 if perpendicularity is 2.0 or any value greater than size tolerance.

If this is true, then flatness is not controlled to the extent of orientation, orientation is 2 while flatness has been limited to 0.4. So this is SOME EXTENT, not absolute EXTENT.

Please correct and advise.

 

[greenimi]

AM Engineer,

So, just to make it clear, are you disputing/ questioning the GD&T concept or the wording in your cited statement?

 

[AM Engineer]

Confused. Pmarc is maestro always. Cant dispute his wording.

Just trying to find out lapses in my understanding of statements.

 

[greenimi]

Looks like you are disputing the wording from the standard. And it is nothing wrong with that.

Here is your quote

extent of orientation, orientation is 2 while flatness has been limited to 0.4. So this is SOME EXTENT, not absolute EXTENT.

Here is the text from the standard
" Note that an orientation tolerance, when applied to a plane surface, controls flatness to the extent of the orientation tolerance."

I am not questioning the statements made by pmarc either and the concept(s) presented looks correct in my opinion.

Does this means that the statement in the standard " Orientation control applied to surfaces also control flatness upto the extent of orientation tolerance " is not absolutely true??