Thought there were plenty of OA based rings. Time for Olde school golden age GL ring. Support is needed I used 0% infill with 5 shells(perimeters) (which is almost solid) and 100 micron slice. low temp in ABS is best. scale as needed (default is a bit small for me) The clean-up of the support is a chore. And yes i am still on my purple Plastic ABS (been a while since i fired up the printer) The photo was before I did any finishing on the ring. It definitely needs a little filing before i try casting. But it is a close approximation of what I can later refine with little effort.