Regarding Common Zone in GD&T

[GeraldANDREWS]

Hello Friends,

Is it Possible to give Datum Common Zone for Different height surface?
Is it Possible to give Datum Common Zone for Different height surface with Flatness?

For me, the plane or surface which have same level or height ,we can give Common Zone with Datum with flatness.
Kindly see the attached image for your reference.

Kindly give your suggestion regarding the same.

Thanks

 

[GeraldANDREWS]

Kindly see the attached image for your reference.

 

[Belanger]

Attachment doesn't work -- maybe check for a file extension ( .jpg, etc.)
Also let us know if you are working to ASME or ISO tolerancing standards.

But in general the answer seems to be no to both of your questions. A single datum can be created from two surface that are offset from each other, but that is usually done with two letters combined with a dash, such as A-B. The flatness of these two coulddf be controlled with profile of a surface, designating the distance between them as a basic dimension (in ISO, called a theoretically exact dimension).

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[GeraldANDREWS]

Hello Belanger,

Thanks for your answer.

Kindly see the attached image for your reference.

 

[GeraldANDREWS]

Image

 

[CheckerHater]

Gerryrose,

From the appearance of your CZ symbol you work to ISO.
Yes, you can apply CZ to features set apart from each other. See picture.
Like Belanger said, you have to use basic (theoretically exact) dimensions to show exactly how much the surfaces are apart.

 

[GeraldANDREWS]

Thanks Guys.

I am sorry for the files couldn't open.

This is the format we work for ISO.

Hope at least the pdf will open this time!!!!!

 

[fsincox]

Gerry,
I love the position of the surface and all, too. "CZ" has been part of your standard longer than most of us have been doing this.
Frank

 

[Belanger]

Now I see what you were originally asking -- a picture indeed helps! (From your first question I thought you were trying to create a datum from surfaces at different heights.)

Yes, your latest picture will be fine; flatness with CZ keeps them coplanar and creates the datum, then position with the given distance locates the top side from datum A.



John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[GeraldANDREWS]

Thank you all for your explanations.