Evaluation of a sphere

[[Al...]]

Hi all,

I've a question regarding how to interpretate the evaluation of a sphere that is a datum.

Do you think use as datum 3D-line from A1 to A2 is correct?

How can i evaluate it to use as datum?

[[Ma...]]

Do you have curve?

I don't think that small part is spherical.

I would not recommend 3d line.

[[Al...]]

I don't have curve.

What about to use only the A2 point? The refence datums are A and B.

I try to use the 3D line as datum A and cylinder as datum B or A2 point as A and circle as B.

Do you have other suggestions?

 

 

[[Ma...]]

I am not sure how your callouts looks like, but i have an idea.

Before getting circle A2 you should establish main axis ( some cylinder to get close to axis A2-A1 )
Now you can get circle A2. Then you can make point A1 with calculation: simple trigonometry - R=36,06 / a=25,5 / b = √(R²-a²) = 25,4965 ( it's almost 45° )
So your A1 would be further from A2 by 25,4965.

It's not common to have datums like this, but here i think that datum A is indeed 3d line from A1 to A2.

Then your datum B should be circle to you be able to rotate alignment to 22,36°

[[Al...]]

Thanks Martin, this is an appreciated confirmation.

[[Cl...]]

The distance between A1 & A2 is too short for a stable datum. I would measure the sphere using lots of points. That gives you A1. Then create two more theoretical points. One at 51 +X from center and one 51 -X (A2) from center. Then construct a 3d line from those three points.

Edited February 24, 2025