Just tried the idea that was in my head

[Alan Morrison]

A couple of changes if I make another one. I would like a circle right in the middle.

 

[Mortalis]

Very interesting!

 

[jttheclockman]

I like it. Very interesting. I wonder what a mortiser tool can do using the same methods. They drill square holes.

 

[mark james]

Well done. The symmetry is superb.

 

[SteveJ]

Nicely done. I've never mastered the art of cutting those circles.