wrote in message
oups.com...
I have a Delta 16" lathe that I thought had bad bearings or a spindle
that was bent because I get a lot of vibration especially on larger
bowls. Hats off to Delta, they sent me new bearings and a spindle for
free and a new belt (it was out of warrarty), but I'm still getting way
too much bounce when the bowl is turning. On a 12" bowl it's hard to
keep the tool edge on the wood! I have the supernova chuck and it
seems to hold the piece very well, but if something in the worm gear
was off would it cause the vibration? And if so how would I be able to
check it. I'm at the end of my rope in trying to figure this out. Oh,
and I have around 450lbs of sand on or in my lathe also. Any insight
from anyone would be a great help.

If you are turning a dried softwood bowl blank, there are at least two
conditions that will give "out of round" vibrations even if the lathe
and the chuck are in perfect contition:
- The fibre directions will make your iron flutter and then jump
if you don't have perfectly sharp tools, and sometimes even then
if the wood is hard enogh, like some exotic woods, oak or elm.
- The blank may consist of dark corewood and light sapwood
in unequal distribution, and the difference in specific weight
makes the bowl behave like "out of round", even if it is perfectly
round.

The only solution I know is to take your time; sharpen those irons
and turn at slower speeds.

Bjarte