I
sometimes borrow use of a floor model planer. I have cherry planks
that are warped and recycled wood. I learned the hard way that the
feed rollers push down hard enough to flatten a bow. I shimmed the
bow on a sled to plane the hump off, but that doesn't work well
enough. And there's no wide jointer here, so my question: I'm
shopping for a used portable planer for myself. I've read advice to
use a planer as a substitute for a jointer. Are there models that
won't put so much pressure on the wood? Or is there a technique I
haven't discovered? - J.
Brooke Althouse
Tim
Inman:
Technically, one should use a jointer to flatten one side, then a
planer to "thickness" and surface both sides. As a practical
matter, this is seldom done in a working shop. If you're going to
surface down to something like a standard 3/4 inch, then I think you
should be able to get along just fine by being careful and smart when
you use your planer. If you're going for 1/8-inch stock, then we
might need to talk about making a router sled, for example. Some
planers have segmented infeed rollers that could be helpful to you
for taking out cupping, but these are usually found on higher-end
floor models.
Here's
what I'd do: First, be sure the blades in your planer are sharp and
set correctly! Dull knives in a cutterhead are never helpful. If
you're trying to take the bow out of a board, you need to be able
to take light cuts, and turn the wood several times. Begin by running
the board through the planer with the cup or "hump" down. Make a
light cut. This first step may seem counterintuitive, but it will
yield two nice flat little edges on the board for the next cuts.
Now flip the board, and take another light cut. This will start
truing up the top of the "hump." Once you've made these two
passes, just continue making light cuts, flipping the wood as your
judgment tells you. You'll need to flip the board several times to
get the best surfaces on your wood.
Be
gentle and take light cuts! The heavier your cut, the harder the
pressure rollers will push down on the wood, flattening the cup but
not removing it. The duller the knives, the more they, too, will have
to press down on that board to make their cuts. Lighter cuts mean
more planer time, but light cuts will almost always give you a nice
flat board for your efforts. Once the cup is cut out and the board is
flat on both sides, you can take a heavier cut if you want.
Rob
Johnstone:
While most of us have gotten away with simply running some rough
stock through the planer, the proper technique requires flattening
one face of the lumber before we do that. A jointer is a common way
to do it, but it can be done with a hand plane as well. You mention
that you don't have a wide jointer at hand, and I know how
frustrating that can be. One alternative is to rip your rough stock
into narrower pieces that will fit on your jointer. Number and mark
the end grain so that you can the glue the pieces back together after
you have surfaced them. If you are careful, the glue lines can be
nearly invisible. Not an ideal solution perhaps, but workable.
Chris
Marshall:
Along with Rob's reasoning, this might be a good opportunity to
pick up a long jack and jointer plane and learn how to use
them—especially if you don't want to rip, joint and re-glue your
wide stock back together again.