The rod collars are already pre-drilled with a set screw. Just had to drill and thread into the brass tube and make sure it’s lined up.
You guys inspired me.
I stopped by my local counter-top / monument shop and asked about a few broken scraps of slab marble they had laying around. They said, “take em”, so I did.
Back home in my shop I made the arbor/collet out of some aluminum bar stock on my mini-lathe which fits into a recessed hole I drilled in the stone. Then the two were epoxied together. Some stick on felt pads on the underside to guard against scratches along with a few super strong hook grabbing neodymium magnets super-glued to the top and it’s all good.
Wow, so many talented people making submissions to this site! Thank you all. Adios Philip:D