Sphere features to planes 2?

[fsincox]

This is the spherical part I have discussed here before in past posts. I was unsure of the concept of a spherical zone to a plane, The inspection people were dead set against it. So I asked here.
I finally have a picture I can post.
I am interested in opinions on the approach to this part and discussing these options again now with a real picture to go with it. The part is called a “butterfly’. Basically, an air flow/passage regulator that goes inside a bore and it carries a piston ring for sealing. A shaft goes through the main body and closes down the air passage when instructed by an actuator system connected to the other end of the shaft. The part has a spherical OD with a groove for a sealing ring. The shaft will contains a spline on its OD that is press fit into the bore to serve as a driver
The basic part starts as a casting (datums X & Z).

 

[pmarc]

Frank,
Your spherical feature and associated .008 (S) positional tolerance relative to B(S) look fine to me from technical point of view. The only relationship that can be controlled - horizontal location of sphere's center point to datum plane B - is grasped. The center of the sphere has to be somewhere in between two parallel planes .008 apart, parallel to datum plane B, with the middle of the tolerance zone being located at basic 0 from the datum plane B.

One question however - not implying it makes no sense, but what is the functional reason behind having 3 different positional callouts applied to .1248-.1261 round hole? Especially that those callouts use almost the same datum references.

 

[fsincox]

pmarc,
Thank you for taking your time and looking.
The boreline has .030 rough location basically to the cast bosses it must be roughly oriented to. The .005 was the symmetry requirement of the boreline to the sphere in one direction, the .008 is really to keep the boreline and the groove from intersecting in the other direction and still allow more tolerance in that direction than would a cylindrical zone of .005. The use of a common framework is to imply this all must happen in a single installation/simultaneously.
This is an old drawing I am updating. If I had my way, I might have used a general profile all over to the groove and the boreline and remove all of the cast datums completely. Theoretically speaking, this is a little more process oriented than I personally prefer.
Frank