True position of sphere
True position of sphere
(OP)
Is there a difference between the following feature control frames (FCF) to control the position of a sphere using the attached intentionally incomplete drawing to put it into context?
FCF A
|TP|SØ.1|A|B|
|TP|.05|B|
FCF B
|TP|Ø.1|A|B|
|TP|.05|B|
My instinct is that they are equivalent - the lower frame truncates the poles of the spherical tolerance zone in both.
FCF A
|TP|SØ.1|A|B|
|TP|.05|B|
FCF B
|TP|Ø.1|A|B|
|TP|.05|B|
My instinct is that they are equivalent - the lower frame truncates the poles of the spherical tolerance zone in both.





RE: True position of sphere
Is there a difference between the following feature control frames (FCF) to control the position of a sphere using the attached intentionally incomplete drawing to put it into context?
FCF A
|TP|SØ.1|A|B|
|TP|.05|B|
FCF B
|TP|Ø.1|A|
|TP|.05|B|
My instinct is that they are equivalent - the lower frame truncates the poles of the spherical tolerance zone in both.
RE: True position of sphere
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: True position of sphere
I'm not sure I see your point. Re FCF B, doesn't the actual center of the sphere have to meet both conditions, i.e., lie within the a .1 diameter cylinder and within the planes separated by .05? In my head, I'm imagining a cylindrical tolerance zone that is .1 in diameter and .05 tall. Since the cylinder's axis is coaxial with datum axis A, doesn't that include in/out of page?
In FCF A, the resulting tolerance zone would be a sphere with its poles chopped off.
I drew the tolerance zones in the attachment. Let me know what I'm missing.
RE: True position of sphere
RE: True position of sphere
I'm not totally comfortable with either option. I'm just saying that they don't seem to be the same, and B is probably ambiguous.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: True position of sphere
Basically, In the second statement you expect A alone to esablish a zone it alone can not support as it is a circular zone in a veiw diretionally oriented in the plane of the paper since it is shown in that view. I suspect you think it is a zone controlling into the depth of the paper, like a spherical zone would automatically do.
I am not a fan of seperate incomplete frameworks unless now other way will gey the job done.
RE: True position of sphere
I have a lot of interest in this subject myself.
thread1103-314840: What Is The Correct Position Tolerance Zone Of A Sphere To A Plane
thread1103-322523: Sphere features to planes 2?