You did a fantastic job. Very clean cut.Thanks for the idea.
I'm using a drill press with a forstner bit, a fresh piece of wood underneath, and clamp on the button. It cuts through smoothly if I go slow...but the breakthrough on the back side always makes a cracking sound, even when it's just fine. I think it's the last scrap of the hole finishing off.
Scares me each time it does it, but the button has been just fine so far!
Ceramic is the perfect description of this stuff. Hard and brittle.