Jim's truly simple ball turning tool

[Jimsehr]

I see you have one puck per radius size. I’m planning on two per puck at some point. Any issues with that?

If it was me, (and it will be in the future) I'd go with Rex's approach, or add another clamp or two. That looks like there could be a bit of chatter or vibration due to the end not being clamped near the puck. Clamp seems small and far away, but that's only my opinion. One could make a big plate that covered the lip of the compound over the piece and have a stud coming up, and clamping it with a nut, similar to a QCTP compound nut, but using a couple of flat ended screws is probably a lot easier.

There is no reason you could not put ten different size radius on one puck.
My first one I made was for 4 common sizes.