Steve:

You are correct to be concerned about accumulated error. I do a fair
bit of segmented work, and find that my optimum glue up is 4 rings (then
turn the inside shape and rough outside, true up the top face, then add
4 more, and so on. My largest pieces to date were a pair of urns that
stand 49 inches tall and about 24 inches in diameter. Needless to say,
it would be very difficult to hollow, sand and finish the interior if I
didn't do it a section at a time. With large vessels like this, I tend
to shape and sand the interior about 8 rings deep, staying about 4 rings
from the current "top". Once one gets more than 24" deep, I'll
typically add a finish (again, keeping the finished section reasonably
below the current top) so I only have to worry about final topcoats when
the whole thing is done. Outside can wait until the whole thing is done
before final sanding and finishing...

Thanks
--Rick

StephenM wrote:
I am going to take a stab at a segmented bowl. When gluing together the
"rings" of segments, how does one ensure that the rings remain centered
around the axis rotation for the glue block? It would seem to be that if
done by eye it would be OK for a layer or three but any error could
accumulate. If there a trick or technique for keeping the stacked rings
concentric?

Thanks,

Steve