Originally Posted by
Burkhardt
If you have to make many of these donuts, I would not discount the vacuum fixture(s). A flat one to machine the first side and a female half-donut mold for the other side. For larger quantities (more than 5 or 10?) it might save you a lot of time and a little material. I use that method for bowls and dishes, below is a disposable fixture for a squarish bowl. The narrow donut would need a better gasket, though.
That said, I would probably turn the donuts on the lathe with a similar custom vacuum chuck. Even faster and you can sand and finish the surface on the lathe with minimal effort.