Ok, Mesh Enabler does it's job with this rather simple case.
But the general problem is: Even if a mesh can be converted to a solid, it's outer surfaces still consist of thousands of tiny planar faces. Large file size and bad response times come along.
In this case I created a substitute revolved part, after some trials. There's been an intersection in the profile; I only found it after some partly revolutions. In the end I deleted intermediate bodies, but the file size still was big, because of hidden geometry in the file.
A STEPOut-STEPIn brought back acceptable file size.
2019 files attached. Additional clean-up is possible, resulting in less overall faces.
Walter Holzwarth
![EESignature EESignature](http://autodesk.i.lithium.com/t5/image/serverpage/image-id/1272565i464DC3DC646B4F11/image-size/original)