Hi Rich

The bottom of your recess or the back edge around your tenon is where
your chuck's JAWS should sit AGAINST, that is what keeps the blank from
wobbling, DO NOT make the recess or tenon to deep/long.
The other problem with the tenon jaws is that you have to have a very
close fit size wise as well as the dovetail's angle has to be close.

You can try this for your self: draw an accurate circle, let's say 3"D
now draw an other accurate circle 1/8" larger or smaller that has one
side against the larger/smaller circle and see how much in contact you
still have ??.

You'll see that you lost at least 50% of the contact surface area, if
you would take 1/4 of that circle as a dovetail jaw, so it is very
important to have a very close fit size wise and also dovetail angle wise.

Now if you keep your tailstock up against your turning at all times
there will be not much of a chance that your piece of wood will come out
of your chuck and it will stay wherever you first centered it, it does
however restrict your access to and manner in which you are able to turn
your project.
Taking this in consideration is why I chose a Oneway chuck with their
standard jaws they do have a superior design IMO.

Have fun and take care
Leo Van Der Loo

res055a5 wrote:
So I've been playing with my new chuck...don't happen to own a dovetail
scraper, so I
used a skew chisel to cut the dovetail. Cut it at an angle all the way to
the bottom of the
hole I turned, which was the same distance as from the face of the chuck to
the end of the chuck.
I noticed that the chuck dovetails for only about half that distance, but
didn't think that would matter.
It apparently did matter because my piece flew off the chuck a couple of
times. So I tried mounting it
where the dovetail ended and the straight part started and so far that seems
to have worked. I have
reservations about whether I should make the hole bigger and turn it
dovetail for half the distance and
straight for the other half. that way the face of the chuck would make sure
that my wood was straight.
directions for the chuck seem a little vague (I'm dumb??).
rich