The little drawing in the last pic is all I used to make it. Someone wanted to make a cannon ball mold and I made the drawing and was told it would not work. So I went out to the shop and made it. Just used stuff from my junk supply. It is a block to lift a rectangle bar with a alum disk on top of it. Then I drilled and reamed a 1/4 hole on centerline in the machine that turned on another drilled and reamed hole drilled from the top that is the center of the radius . The hole drilled on centerline is where I put the cutting tool. The cutting tool should be a 1/4 round piece of hss or carbide held in alum disk with set screw. The round tool bit I ground down from the top too .125 thick that makes the tool dead on center. I also made the end a full radius. And because the tool location was drilled and reamed right from the spindle
Makes it true to centerline . After drilling you don’t move cross slide. It was easy to cut the part and took only about 5 or 10 min to do. To set radius I checked dia of alum disk an extended the cutter out to what I needed. Hope this makes sense.
I forgot to say that I set the radius by checking across the dia of disk and extending
The cutting tool out of disk then locking it in place. If disk was 1 inch and tool extended out 1/4 inch I would know radius was .75 and I would get 1 1/2 dia ball
Size. By the way I didn’t have a 1/4 round cutter at the time so I used a dowel pin as cutter and it cut the alum with no problem.