I agree with Robert that a picture of the problem would help.
How large (diameter) and thick (deep) are you trying to turn? Are your recesses 2-3 inches in diameter?
I cut mine where the closed jaws just fit in the opening as show in the picture. When expanded they will be at optimum holding area.
Other problems may be that the item it too thick, like 6 or more. The standard 2 jaws are not made for that much leverage.
Are your recesses too deep? The top of jaws should fit tight against the wood and the wood should not contact the base.
Did you make (or have) a tool to cut the dovetail to the correct angle? I use a old bench chisel but a large flat screwdriver will work also.
I assume the bowl came off, and not that the recess broke. You should have at least ½ of sound wood surrounding the recess and 1 is much better.
How deep sorta depends on the wood, for green wood I go about 3/8 deep.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety. Benjamin Franklin
Last edited by NCPaladin; 12-06-2011 at 09:55 PM.