Finally got around to turning some Christmas tree ornaments and that
required hollowing through a half inch hole. Drilled the 1/2" hole
almost
through the shape I'd turned then used a dental tool as a scraper
to get back up under the top. Had a round bone bur and a Foredom.
So with the piece turning and the Foredom spinning the bur in the
opposite direction the hollowing was easy - great for stuff to about
2 1/2" reach. That's perfect for ornaments. There are other ball
type burs available if you don't have access to a bone bur.

So if you've got some sort of flex shaft and have avoided doing
small hollowing - try this route.

charile b