Bob La Londe wrote:

I was actually thinking of stone. Specifically granite, for a non
traditional idea, but it looks impractical to DIY and its way to
expensive to have done. Granite is cheap. Cut granite is very
expensive. I was hoping to be able to make cuts up to 3-4 feet thick.
Looks like I either need a $50K machine or to spend the rest of my life
on one project. Neither is palatable so this idea will have to pass for
now.

You can drill a starter hole with a diamond core drill, although 3-4
FEET is going to be slow going. Once through, you can use aircraft
cable (braid) with oil or water and diamond grit to saw it. I think
that's what the pros use.

Jon