Thanks for this pointer. I analyzed the example file you gave (which is a modified version of the example file I gave).
Hmmmmmm…
Rail-revolve didn’t do exactly what we wanted.
Looking at the documentation, we see that RailRevolve actually re-scales the profile shape in the radial direction.
“The profile curve, in addition to being revolved, stretches along the revolve axis using the revolve axis origin as the scale base point.”
As the threads taper closer and closer to the center axis, they also get squished shallower and shallower. What we want is for the thread profile to be moved rigidly, without changing shape.
So I don’t think RailRevolve will work for tapered threads. But it should be fine for straight threads.
Sincerely,
–Anthony Yan