In article ,
"James \"Cubby\" Culbertson" writes:
Thanks folks for the insight. As for jointer/planar width, I'm using
handplanes to join the edges and smooth so there is really no
limitation to the size. I'll take the consensus that somewhere
between 3-5" is appropriate. I've had marked changes in boards given
my extremes in humidity levels (New Mexico).

cc,

I think the important thing to understand is, when you edge joint
them and glue them together they effectively become one big board for
lateral movement purposes. One 20" board is going to expand and
contract across the grain just as much (or as little) as 5 4" boards
glued to make one 20" panel. The trick is that you're a lot more
likely to get warping and cupping out of a 20" board than from a glued
up panel. Similarly, a 20" panel made from two 10" boards is more
likely to end up not flat in some way than a 20" panel made from 20 1"
boards.

In some designs, this doesn't matter, if there's something holding
both ends so it can't twist. For example, a headboard is usually
stuck in a very long mortise. Similarly, breadboard edges on a table
prevent warping. So can floating panel construction.

When you consider how wide to make the boards, you also need to
consider exactly how the boards will be restrained from warping. If
there's no constraint - a non-breadboard-edge table, for example,
you'll want narrower boards. If the wood is constrained from moving
out of flat, you may be able to go with wider boards, which will look
better.

Regardless of whether you go with narrow stock or wide to source your
panel, you still need to remember to account for seasonal expansion
and contraction across the whole panel width, however.

-BAT