Dave, I put the tape measure in the pictures so you could judge the size. The large ring fits the crucible I’ve been pouring. I thought it was a 10. However looking on line at crucibles and comparing dimensions I may have A16 size with a bottom diameter of 5 “. Don’t know about the small ring, no crucibles that size came with the furnace.
I was dropping hints to my son who lives in Ellenville, NY. He's going to see the Bills hand the Jets a beating next week and he'll be "just up the road". He isn't biting. Pete