I'm a casual basement turner - been doin' it for lots of years. Still
consider myself a novice, though. Just got into bowl turning in the past
year, and enjoy it tremendously. I use local woods, because that is what I
can get economically. I will polish my technique with these and ... I
digress.

I recently got a PSI bowl rim chuck. One of the dedicated ones with big jaws
and an assortment of pegs to screw into the jaws according to how big your
bowl is, up to about 8" in diameter. I am mostly happy with it, but had a
chance to learn something this evening that I could not learn any other way.
Had a catch, while cutting a foot on a birch salad bowl. Not particularly
startled, as I have had a catch before. More than once before. Well, this
time, I was using the long pegs with the triangular-shaped rubber cushions on
them. Supposed to be pretty good for getting a good grip on the outer
circumference of a bowl. Well, yeah, but if you get a catch, toss those
screws away. Two of them snapped, and a third one bent.

These are not robust screws! The manufacturer starts out with robust screws,
but then turns them down to a much smaller diameter, to match the screw
diameter of the shorter pegs that come with this chuck. The screws are hard,
and the effect of turning them down to re-thread the new small end produces a
notch effect - making a weak spot in the screw. The rubber sleeves on these
screws is much thicker than the plastic composition sleeves on the smaller,
shorter screws that come with this chuck, and provide for enough "give" or
flex in the bowl mounting that a small catch becomes a big one - with the
attendant possibility of bent or snapped screws.

I will yet prevail. Just gotta learn from this, and change my ways, a bit.

tom koehler




--
I will find a way or make one.

if you get a catch, toss those screws away.
Two of them snapped, and a third one bent.

I'm guessing, but it sounds like maybe you didn't have the tailstock up to
hold the bowl in place. It's always safer to use the tailstock except
when you get down to cutting off that last tiny bit in the center. It's
even a good idea to do the sanding with the tailstock up and cut off that
last little bit afterwards.

On Wed, 14 Oct 2009 23:01:01 -0500, Mike Paulson wrote
(in message ):

if you get a catch, toss those screws away.
Two of them snapped, and a third one bent.

I'm guessing, but it sounds like maybe you didn't have the tailstock up to
hold the bowl in place. It's always safer to use the tailstock except
when you get down to cutting off that last tiny bit in the center. It's
even a good idea to do the sanding with the tailstock up and cut off that
last little bit afterwards.


you're right as rain. As I said, this was something I could not learn any
other way. Am using the tailstock now.
tom


--
I will find a way or make one.