We have a number of turned parts which have an eliptical fillet for stress flow. the problem is, our lathe wont do elipse's so we have to add arcs to approximate the elipse. Ideally we do not want to add more than 2 arcs because of programming time.
I have looked at a number of formulas such as French's Construction for approximating these elepse but they all seem to be well off and it seems the best way to do it is by eye.
Has anyone else tried to do this sort of thing and how did you go about it?