Well, the way I figure it, the more metal from the chuck jaws
contacting the wood the better. If your chuck jaws are straight, then
you want a straight tenon or mortice. If your jaws are dovetailed, then
you want to match that angle EXACTLY. If the angle isn't very close,
then you are putting a lot more pressure on one part of the side than
on the other, and this will cause breakouts, and I speak from
experience. You also want the mortice or tenon to be the same diameter
or as close as possible to it. I bought the idea that angleing the
sides will draw in the jaws to any significant degree. The single
biggest factor in getting the bowl to remount on center, with little or
no wobble, is to leave the scraper or whatever you use to cut the
tenon/dovetail with at the bottom/end of the cut where the jaws will
contact, so that it just barely rubs, removing almost nothing. This
will even it up a lot, because, 1/64 of an inch here can be 1/8 by the
time it gets to the top outside edge of a big bowl.
robo hippy
mac davis wrote:
On Wed, 28 Jun 2006 13:26:28 -0400, Gerald Ross wrote:


I assume these are for grasping a spigot, or tenon. What I am talking
about is jaws that go into a recess with dovetail sides so that it pulls
the piece into the jaws as you tighten them.

When I was using spigot (straight) jaws I rounded oval tenons with a
hole saw. I left the guide drill bit in until the saw got started then
dropped out the drill bit and cut down the length of the spigot. The
original live center hole guided the drill bit for the start. This was
done on a drill press so there was no need to set up a jam chuck or cole
jaws.

No, they're for both... The jaws in the picture have a more pronounced "lip"
than on my Oneway jaws, but same theory.... cut the recess at 90 degrees and
expand into it flush..
From what I've seen in the pictures of the Nova line, they have a pretty
definite angle and require a dovetail..

I actually used to cut a dovetail recess for a while because George and others
recommended it.. only to find out that you don't do that with the Oneway jaws...
lol

I think it was Bill Grumbine's DVD where he mentioned using right angle tenons
and recesses for the oneway that made me realize my mistake...
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm