Are you after a Surface body (as indicated in your thread title)
or are you after a Solid body?
Your Sketch7 is not fully defined and is not on a plane perpendicular to the start of the helical curve.
Do you really want to go to the center?
How will this be manufactured?
HELICAL SURFACE.SLDPRT.zip 82.6 KB
As I said in my email:
A solid, I guess, it could be a surface if that is easier. I need to machine the top surface in MasterCam using a ball mill to create a helical lens. We need it to have the smallest possible discontinuity at the center.
I see what you mean about the sketch not perpendicular to the start of the helix but am not sure what makes it not fully defined. Can you elaborate?