it does seem odd to have vibration with walls over an inch thick - in
my humble experience, that ususally indicates that there is a hairline
crack and it's time to stop and find it - or if you know there are
flaws, then it's your sign to use the sequential approach.




On Sat, 28 Jan 2006 22:57:20 -0600, "Barry N. Turner"
wrote:

Another friend of mine suggested that I take the bowl walls to final
thickness incrementally, say an inch at a time, rather than making one
sweeping cut from rim to bottom. I think that may work. I just didn't
expect to have vibration when the walls were well over an inch thick.

It's not the lathe. All four (4) feet are solidly on the floor. I don't
think it was the speed either, but it could have been. I tend to turn
slower than most people I know. The blank appears sound. I have some
doubts about the 1/4" bowl gouge too. I have one, but have never used it.
Thanks for the advice.

Barry


"Bill Rubenstein" wrote in message
. com...
Barry:

I'd start by changing the speed a little bit and see if that helps. You
can run into speeds at which the blank resonates.

I think that a 1/4" bowl gouge is an almost useless tool. There just
isn't enough metal there to resist flexing even with a minimum overhang.
On the other hand, you might have tried a 1/2" gouge -- it may or may not
help.

I'd also look for defects in the blank. If there is a problem with ring
shake it often will show up as vibration and you would like to get it to
the firewood pile before it comes apart at 500 rpm.

Also, since I happen to know what lathe you are turning on -- make sure
that all 4 legs are sitting on the floor.

Bill

Barry N. Turner wrote:
I was hollowing a Sassafras bowl about 11" in diameter this afternoon.
The walls were about 1 1/4" thick and I was using my Crown PM 5/8" bowl
gouge with Ellsworth grind. Near the rim of the bowl, at the beginning
of the cut, I began to experience some vibration.

I put a fresh edge on the gouge and finished with little problem, but
still with some vibration. Then a thought entered my mind........had I
switched to a smaller gouge, say a 1/4" bowl gouge, which would remove
less wood per cut, would it lessen the amount of vibration? Thanks.

Bill

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