ChamferEdge on circular hole sees variable diameter result

I make a ChamferEdge 0.025 and the result when I dupEdge sees a variable diameter result from 0.051 to 0.053 and various centre marks just analysing one portion.
Chamfer causes variable diameter.3dm (80.8 KB)
Why ?

if I hide all layer except construction lines, I see 3 different radial dimension points. Maybe there’s a cause?
sorry for my bad english, it’s not my native

Yes you will, this is what I refer to, I can pick and get different diameters around the DupEdge result of the Chamfered Edge.

So what is going on . ChamferedEdge was a constant value of 0.025 around a circular edge yet result is gar from circular.


The variation is ±0.001", your tolerance setting (more obvious if you display your dimensions to four decimal places instead of three).

Can’t complain at that!

EDIT: Rhino 7 is more accurate - something for you to look forward to!