Sorry for the repost, but the original did not show up on my server.
Yes, I meant a flycutter. I'm sure I could make it somewhat safe with the rod and a brace to stop the drill from breaking my thumb. I almost broke my thumb once with a 3" hole saw on a metal cabinet. So I know what that's all about.
But the circle cutter seems like a saner idea, so I'll buy a new toy for the Rotozip.