I decided to attempt a 10" platter yesterday, starting with 3/4" kiln
dryed hard maple. Straight grained. Flatsawn. Been lying around my shop
for about 6 months aclimating. Turned the bottom about 1/4" thick and
the rim about 1/8" thick, with a curved transition between them. Used
an expansion chuck for holding both sides (drilled a 2-1/2" groove for
the first chucking on the drill press). By the time I had the inside
turned, the thing had begun to warp. By the time I sanded it, put a
sealer coat (wipe on Poly) on it and took it off the lathe, it had
warped over 1/16" "out of flat"! What happened? I have had the
experience of releasing tension in wood while ripping, but there is
usually some kind of wild grain involved. I've read here about what to
expect with wet wood, but I would have thought very dry wood wouldn't
do this. Any tips on how to avoid this in the future, or should I
expect a few disasters, chalk this up to experience and move on?