On 4 Apr 2007 14:49:11 -0700, "
wrote:

Hi Prometheus

I use my mega jumbo cole jaws very often, they are very flexible to
use and have a much better holding power than the longworth style
jaws, they also have the ability to hold wood pieces that you can turn/
shape to hold more involved shapes, like rolled over rims etc.
However you do need a good woodchuck for those to bold on to, and they
are not cheap. :-)))

Nope, not cheap at all- and while I do turn a few bowls a month, I
have so many other irons in the fire that the money can go to better
use elsewhere!

If you decide to make the longworth chuck, you could make the arc cuts
in those disks less steep, so you would get more gripping power as the
rubber buttons would move less in and out for the same amount of disk
rotation, drawback would be of course be that you would need a couple
of chucks to cover the sizes you would be able to hold.

I also ran across a site that was selling a commerical version, and
they were using a spanner wrench to tighten them using a series of
holes around the rim. That's likely to be the route I'll go.

The rubber buttons that are used, are readily available in the beer
and wine making places/stores, they are used to hold the airlocks in
the carboys when making wine, they do come with or without holes, the
ones I use in my carboys do have 8mm/5/16" D holes.

Perfect! I had a nagging feeling that I knew where to find them, and
couldn't quite drag it out of the back of my mind. Now that you
mention it, I did buy one of those the one and only time I attempted
to make wine (when I was a teenager, and trying to circumvent the
law... )