On Tue, 28 Sep 2004 10:48:37 -0700, "Bob Darrah"
wrote:

I turn like to turn boxes. To turn the chuck marks off I use a jam chuck. I
was having a problem with the boxes cracking when I would jam the piece onto
a piece of hard wood.

depending on the shape of the box, you might try jamming it INTO a
recess, rather than over a tenon...I used to do this a lot before I
switched to chucks. Also, in either case, try making a less than tight
fit, and using a soft paper towel to pad it to just the right
snugness. (I also use a very small rubber tip, like a crutch tip, over
an insert in my live center in the tailstock to put some pressure on
the box when I don't feel totally safe.....the small area under it is
easily sanded away....