"mac davis" wrote in message
...
THere are several "how to" web pages, but basically, you either leave a
short
stub on the end of your work, called a "tenon", which is gripped in the
jaws
like a big drill bit,

It's not the grip on the tenon but the registry of the nose of the jaws to
the piece which counts. As with a mortise and tenon joint, the shoulders,
where the load is spread over a wider area, is where the real resistance to
racking lies. Keeps the piece from flopping itself loose. If you have a
dovetail tenon, you can have the jaws of the chuck draw up for you rather
than having to press and tighten.

or you turn a "recess" into the end of the work, which the closed chuck
jaws
open out into to grip it... sort of like expanding a sanding drum to hold
the
paper on..


Actually, you make an undercut mortise to accept a wedged tenon. The
interior doesn't "grip," it draws the piece tight up against the nose of the
jaws by wedging action. In this case the shoulders are inside the recess,
not outside, but they still work the same way.

There are also chuck screws or pin chucks, (which I use a lot), which are
held
in the chuck jaws and screw or wedge into a small hole drilled into the
wood,
usually used on the part of the wood that will be hollowed or cut off...