One problem in your definition comes from the way you create the elliptical cutters. You cannot use the entire elliptical curve for the surface revolution. Instead, you need to provide just half of it. One way to do this is by splitting the ellipse at t = 0.25 and 0.75.
Once your cutters are clean revolutions, the rest is simple:
Lin_424266_final.gh (79.7 KB)