"Kip055" wrote in message
...
When I rough turn I make a tenon at the base of the green wood blanks
The problem is once the blanks is dry the tenon becomes oval. I have not
yet found an ideal way to true the tenon before placing it in the chuck
for
finishing.

I normally do rough outs and leave a tenon as opposed to a dovetail
recess. If
you leave the tenon larger than that which gives you "full coverage" with
the
chuck jaws, you can jam chuck the dried piece with the oval temon, true up
the
tenon and outside and chuk to reverse the inside. A dovetail recess would
also, I expect, be out of round after drying. My guess is that this would
be
harder to re-true than a tenon as you don't have the nice convenient
depression
from the tailstock left from the roughing operation.

That's why you plan ahead, all right. The wood's going to distort the same
regardless of your holding method, so you want to know where both centers
were to reference for re-turning.

My pin jaws/chuck method is quick, easy, and reliable, though you could as
easily leave a modest 1/2" rise in the inside bottom of the bowl, bore a
"shoulder" with that 35mm Forstner you use for cabinetry, then a concentric
smaller bore to use as your centering reference. This works for folks who
core their wood, either by gripping inside, or jamming a mandrel centered in
the small hole, shouldered on the larger.

I suppose if you're one who follows the new belief that bottoms need to be
roughed thinner than the sides, you'd have to use the sides themselves
against the chuck. Just tougher to maintain a good aspect until you're
ready to reverse.