You asked for it so here it is. The highly scientific method for making rings out of stone.
First I drill a hole in a thick (1/4 to 3/8 inch) slab the size of the ring that I want to make. 11/16" for a size 7 and 13/16" for size 12. I will be making other sizes when I replace the hole saws that I destroyed drilling agate. In the past I drilled the entire slab, cut around the holes with my trim saw then ground the blanks to where they were close to round by hand. I am switching to drilling the ring size hole then taking a much larger hole saw and drilling the outside of the blank.
The slab clamped in the drill press clamp. My biggest worry here is that the slab will crumble when it gets full of holes.
I have switched to the slab clamped to a brick that is in the tub of water. The clamp will still work if it is easier for you.
I turned the column on the base and lag screwed the base to the table so I would have the room under the drill press table for the clamp
This is my super scientific ring dop stick. Until I came up with this little jewel my rings were pretty uneven. I used small drum sanders to make a holder for the rings so they could be worked on my grinder/polisher.
I spin the drum sander against a file to get it the right size. It is a lot of trial and error a little at a time until the ring slides on the rubber tight enough to hold it from spinning. The good thing is that if you go just a little to far you can tighten it up by turning the nut, It is important to brace the file in such a way that it does not bounce. Because if it bounces you will get a holder that is off center and the ring will be wobbling like crazy. This is the toughest part of the super duper ring dop. I just happened to think that it may be easier to chuck up the drum sander in the drill press and file it down there.
I use the same polishing pads that I use on my cab polishing machine but now the ring is spinning and the pad is in my hand. I place the ring right at the top of the water. The spinning ring sucks up the water for some reason so it is not necessary to place it under the water where you can not see it. Moving to the drill press from the polishing machine has freed up one hand and made it a lot easier to smoke my cigars without getting smoke in my eyes and has there for increased production by two.
Once the ring is polished I file the sharp inside edge of the ring with a fine diamond file.
These are jade from Mel and the photos do not do them justice. They turned out ten times better than I expected and I would put them up against just about any jade ring that I saw in China. Well, except for the dust. lol With and without flash. The color is somewhere in the middle of the two.
This is dendritic jade also from Mel. It has been a bugger to polish and it still needs some work. I may have to polish it by hand. He said that it is rare so I made one for me and a couple for my son and daughter. There was also enough left over from the slab to make two cabs and they will be kept in the family also.