On Nov 29, 6:01*am, dustyone wrote:
Hello,

I have been working with the Springett tools, in conjunction with his
WoodTurning Wizardry book. *I've been able to make several reasonably
good captive cubes, but I've only been able to do so by undercutting
the sphere freehand, (without the use of the undercutting tool
(Crown)). *This leaves a rather imperfect surface on the inside of the
sphere. *Has anyone used the undercutting tool? *Is there a trick to
its use? *When I use it, I usually shatter the sphere. *Will the
Springett video help?

Best regards,

CB

I'm not really sure what the Crown Undercutting Tool is, but I'm
always used the highest level of the Crown Chinese Ball Tools to
undercut the rim when putting a cube inside a sphere or another sphere
inside a sphere, as in the Chinese Ball. With the Crown Chinese Ball
tools, you are limited to a 2-1/2 inch diameter ball. The advantage of
the Chinese Ball Tools is that the handle presses against the outside
of the ball and as you move it across the surface of the ball a very
clean cut is made on the underside of the outside.

I've been making Chinese Balls since 1998 and have made well over 200
of them. I've also made cubes in a sphere using the one cutter to
undercut the outside of the ball.

I hope this helps you a bit.

Fred Holder
http://www.morewoodturning.net