I may have done something stupid tonight. Well, maybe not stupid...
ignorant
at least. First time I tried running a 12 inch wide rough-sawn (red
oak)
board through my Delta planer. I started, like I always do, feeding
it

OK, I see one possible problem here already. If you don't have a 12"
jointer
(and most of us don't), you shouldn't be trying to plane 12"-wide
boards. You
simply *cannot* remove warp, twist, bow, or cup from a board with a
planer,
and I haven't seen a rough-sawn board yet that didn't suffer from at
least one
of these maladies to some small degree.



Nope.

The standard practice to plane out cup is to take VERY light passes on
the high part of the board until it is planed flat.(light passes
prevent the rollers from just pushing the board flat). Then flip the
board over and plane that side parallel. I've done this any number of
times with no problems. Just be aware that you may end up with a fairly
thin board depending upon the amount of cup.

Warp and twist can be removed by hitting the high spots with a hand
plane or shimming the board so it rides "flat" and can't be pushed down
by the rollers. It is likewise sent through in light passes until the
top is flat and then flipped over and the other side made parallel

Bow is taken out with a jointer or a tablesaw as it relates to the wood
being bent in a different "dimension" than what would be addressed by a
planer.