GD&T for a hollow sphere...

[pvhtran]

Hi,
I'm new to GD&T and currently have an assignment to work on. Basically, I have a hollow spherical shape but the sphere itself is elongate at both ends (distal and proximal), each end has a different dimension. The overall diamter is important. What I did was give a radius of R.945 (D = pi * R^2) which gives a diameter of 1.79". My question is, can I have this radius as a REF (R.945 REF) and then have the sphere as basic dimension, that is a total length in diameter and total length in height. What symbol of GD&T I need to add in the radius to ensure the parts come out as a sphere? Please help and let me know.
Regards,
Paul

 

[CoryPad]

SR (meaning spherical radius) is the GD&T symbol you need.

 

[ewh]

What you are describing is not a "sphere" (think marble or ball bearing).

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

 

[CheckerHater]

Sphere usually doesn't have an end, not to mention "both ends"

How about some sketch?

 

[MintJulep]

You have a think that is not a sphere, but you are asking how to dimension it so that it is a sphere.

Please explain what you need to accomplish. Not how you think it should be done.

 

[pvhtran]

Hi all,

Thanks for the quick response. Here is the pdf file for the drawing. I want to have the ball shape but how would I add GD&T to ensure that I have the ball shape. Please help. I really appreciate your advice.

Thanks,

Paul

 

[UncleCrazyHorse]

The center axis of the part could be referenced as Datum A.

Seems like you could apply a Profile to datum A to the outside of each wire in your basket (note, I don't see thickness controlled on your print either) and change the "8X R.945 REF" to a basic dimension. The end result is a sphere, but it seems that controlling them as individual radii would provide the same level of control.

Be careful not to over-tolerance. Wire baskets rarely follow a completely spherical pattern.

 

[MechNorth]

Please add a cross-section of the members to your drawing, then re-post.

Jim Sykes, P.Eng, GDTP-S
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