Dimensioning of an elliptical plate...

[kingsboy55]

Hi, I have a 'simple' plate, elliptical in form internally and externally. Around the perimeter is a group of 16 holes and a group of 4 smaller holes.
Does anyone have any suggestions or thoughts about how to dimension it?
Attached are a couple of thoughts, I think I prefer making the 16 holes a datum and controlling the ellipses to them but I'm open to suggestions.
See attachment for the two options I produced.

Thanks.

Attached is an amended sketch of using the ellipse as the datum.

 

[kingsboy55]

Attached is a corrected sketch, I failed to identify the internal ellipse as a datum originally

 

[notats]

Hello Kingsboy-
Well, to be kind, the 1st drawing doesnt show -C-, the 2nd drawing shows -B- as 2 different features.
So, as interesting as this drawing is, I need some help connecting the dots on this one?

Look forward to the next drawing but it is a challenging part I think.


notats

 

[3DDave]

Just use datum A for all DRFs. They will qualify for simultaneous requirements. What you are looking at otherwise is making the part more complicated to inspect and allowing more variation in a difficult to determine way.

 

[TheTick]

The curve resulting from constant-distance offset of an ellipse is NOT another ellipse.