Cylinder or Line as a Datum

[[FL...]]

Datum B is hole on our part, I was wondering if it best to measure it as a cylinder, then construct a 3d line and use that as the Datum instead of the cylinder. We have a perpendicularity callout of that hole to A (plane) I found repeatability is better using the line than a cylinder. Could I use that Datum B line for all other callouts, mainly profiles

[[Cl...]]

If the measurable depth of the cylinder is at least 3x > than its diameter it will work well as a Datum.

[[FL...]]

It is not

[[Cl...]]

Then the line option should work. I just used a very short 3d line from a very shallow

cylinder in a recent program I wrote, and it passed a type-1 Gage R&R <20%

[[FL...]]

The hole dia is 7.94mm with a depth of 9mm

Edited October 6

[[Cl...]]

I'd measure a circle at the very top and one at the very bottom. Then construct a 3d line.

Are you using this for spatial? What space axis is the cylinder in?

Edited October 6