Cptenaud, this was started between centers. Very out of balance because I didn't want the bottom of the curve at the center point. The center of rotation is about 1/3 from the bottom. Turned just like a bowl. Outside first, make a tenon, reverse into a chuck and turn the inside. reverse between center in tail stock and padded chuck jaws and turned away the tenon. Lots of air turning in between wood. Lots of fun