"Andy McArdle" wrote in message
u...
I made myself a drum-chuck and a 2"dia bumper curved to match the bottom
of
the bowl. Well... as closely as I could.

Long story short, the bowl trimmed nicely although I did have a hairy
moment
when first introducing the tool a bit too quickly and it caught in the
chip.
The bowl shifted slightly off-centre but no damage was done and everything
turned out for the best. No pun intended. So, I've added yet another
useful method to my repertoire and all is well in my little world.

Thus the advantage to centering a bit higher on the bowl with that tapered
circle. Gives you a bit better control over shifting.

Of course, If I had vacuum need and capability, I'd keep a spare roll of
duck tape somewhere handy instead of stored with all those pencils I have
down in the shop....