"Barry N. Turner" wrote in message
...
I put my roughed-out box elder bowl back on the lathe yesterday. Its about
10" in diameter by about 6" tall. It had dried some, so I had decided to
thin down the walls to hasten drying by taking a few hollowing cuts off the
inside of the bowl. Although the bowl walls are well over an inch thick (1
1/8"), I get a low frequency vibration when I start the cut near the rim of
the bowl. As I near the bottom, the vibration diminishes and goes away.

The bowl is mounted in my Super Nova chuck with a 2" stub tenon. The
chuck is tightly seated against the spindle....no plastic washer or
anything. The 2" standard jaws are tight on the tenon. The tenon is
intact....not cracked or anything I am no longer using tailstock support
as the bowl is now hollowed. The Crown PM 5/8" Ellsworth grind gouge is
freshly sharpened. Still I get the vibration. Any ideas would be
appreciated. Thanks.

Barry

PS Is it time for me to replace my Super Nova with a new Stronghold
chuck? Do I just need to put this blank on the rack, wait a few weeks and
let it finish drying before I come back to it?

=========================
Barry,
I'd say it's not too unusual. you probably have some distortion from the
drying it has already done. That, combined with the normal tendency for a
bowl wall to vibrate when cutting near the rim, is not abnormal, and may be
more or less pronounced depending on wood species, size and shape of the
turning. If you can put your left hand against the back side of the bowl
opposite the cut, (Or have someone else do it for you, the vibration should
either go away or be greatly damped. If not, I'd start looking for a crack.
FWIW

Ken Moon
Webberville, TX.