This is something I've wanted to try, seems like it'd be a real
challenge, just wondering if I could do it small enough for a bottle
stopper top. I've seen ornaments that are really cool done this way,
just nothing as small as a stopper.

Ruth,

I don't see any reason why this shouldn't work. The stopper might be
somewhat fragile. I'd suggest that you make a couple I/O turnings to get
a feel for the mechanics of what is happening. Last Christmas I made I/O
tree ornaments similar to Bob Rosand's except that I used an I/O ball
instead of a hollow ball. There is a picture on Saw Mill Creek.

Hope this helps,

Harry