I did sort of the same thing by mounting my drill in my vise and setting the trigger lock so the drill spins on its own. Then I rested the pipe against a 2x4 wrapped in a soft cloth and held it up against the spinning holesaw. It bounced a bit until I finally got it stable and the holesaw began to run in its own tracks.
Cut through in about five minutes. The whole time I was thinking I'd really like to use my cutting torch, but I didn't want to ruin the chrome, so I kept going.
