Turning Archive 2005

Subject:
New Chuck (longish)

Bud Gabaree
>Help!!! After using my new Supernova 2 for a week and 1/2, I'm becoming disillusioned.
Let me start by saying that for a year I've been using a modified Buck metal lathe chuck. This is a 6 jawed chuck that I had modified to be able to grip a wood tenon. It has worked fabulously, but I recently lost my grip while transferring it to the lathe and busted a jaw.
I bit the bullet and shelled out for a SN2. First, I was disappointed that the range of the supplied #2 jaws is limited. To get the best grip, the tenon can only be something like 2 inches across. I have convinced myself that a tenon is the best method, being easier to deal with the bowl bottom when finish turning.
Well, after 2 bowls, one each of cherry and hickory, with diameters of only 10" and a depth of 5" became detached from their tenons, I reasoned that I need a bigger tenon.
I ordered and just received the 75mm jaws and was disappointed to see that the inside limit of the jaws is the same as the original jaws. Only in expansion mode can you enjoy a larger grip.
What am I doing wrong? I have been careful to mate the shape of the tenon to the inside profile of the jaws, and inded, the grip remains strong. But each turned bowl so far has broken from its (too small?) tenon (green wood).
Is there a jaw set for the SN2 that will grip a larger tenon at the jaw set's optimal diameter? Can I rely on the #2 jaws to adequately grip a larger tenon?
Thanks in advance for all the worthy advice I know this post will generate.
Bud

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