Re,
I apply the quote from "Boileau".

By observing very closely the curve of my spring, I noticed that it had misalignments of control points (it is perhaps a lack of control of "ReconstructCurve").
So I went back to my job, it's a little better.
I know that the curve of the small angle is still not compliant for a fabrication (machining). But hey, I trust the technician who will be able to remedy this detail!

I would appreciate that an expert (there are some who come to the forum) explain to us the right method to achieve this kind of spring.

And Booleano inspired me, I made a better quality Blender rendering (again I should work a little more on the subject ...)

- Zooen