I have a problem. I am ripping a 10/4"x9" hard maple board and my
table saw blade keeps getting squeezed by the blade and stops the
motor. The board is straight and has been jointed, the problem is
that the board seems to want to warp toward the blade when cut. What
do I do about this?
I have a Delta 36-982 contractors saw running on 220V and a brand new
24tooth Freud thin kerf blade so power is definitely not the problem.
I have done this cut before on other boards with the same dimensions
with no problem.
You're most likely dealing with "reaction wood":
You've very lucky that it didn't get thrown back at you.
Throw that particular board in the direction of the scrap pile and be done
with it, as it will likely always be prone to warp and/or twist.
... and start using a "splitter" on your table saw, it will safer all
It's the wood. Look at the annual rings may tell the tale. If you've got a
lot of curve, you could be releasing tensions that cause the kerf to close.
Case-hardening, or as mentioned, reaction wood from a branch load or curved
growth can cause this as well.
One of the reasons why splitters are used, because the wood binds on them
versus the blade. If you have a bandsaw and just a bit of talent at
following a line, you might be able to get the pieces apart, but if both are
curved, they'll be pretty much useless anyway.
I would say power and the thin kerf blade are part of the problem. If you
had adequate power you would not be stalling the motor. The thin kerf blade
is probably causing the problem in addition to your wood probably not being
"IF" you have had no problems before, then your wood is probably the
problem. Not properly dried.
The use of a splitter will help however you can also use wedged shaped shim
stock to hammer in the kerf behind the blade to help keep the board from
wanting to close back up.
That said, the thin kerf blade is probably also working against you. If you
are cutting deep and the blade does not remain "flat" it will flex "as thin
kerf blades do" and rub against the blade as you are witnessing. Once a
thin kerf blade begins to flex it tracks in the wrong direction and the
situation becomes worse.
I would immediately try a regular kerf blade and go a little slower.
I have done this before and it works. Be sure you put the wedge far
enough behind the blade. If the blade hits the wedge, it will throw the
wedge at you faster than you can say 'what the f--- just kicked me in the
stomach?' . Also DO NOT put the wedge in while the blade is spinning.
Start the cut until it starts to bind, turn the saw off, then put in the
wedge and re-start the saw.
After reading all the posts it sounds to me like reaction wood is my
problem. I was using a splitter when this problem happened. I did
however get through this particular piece though (see below). I am
not crazy about the idea of throwing the wood out since it was over
$100 and I'm pretty cheap (that $ could be a new tool).
I'm pretty sure it was dried properly. I purchased it from Owl
Hardwoods which is a pretty good chain in June. I have left it to dry
on a drying rack with 1/2" spacers between each board for an
additional 4 months in my basement and the AC has been on all summer
to remove humidity (there is no exposed ground/gravel in the basement,
just concrete all around and 2 covered and sealed sump pumps)
The method I used to cut this wood was:
-Remove the splitter.
-Pull the board off of the blade
-Lower the blade and rip 2/3 the height of the board on the first pass
(this would not allow the reactive wood to twist)
-Flip it over and cut the remaining 1/2 o the height (it did twist/
warp, but there was far less exposed blade so it did not bind)
As was suggested that particular piece was smaller than intended due
to the multiple passes so I made it straight again on the jointer and
will save it for a later project.
I started over with some of the remaining wood from the original
9" (minus 2.5 from the messed up board). This time I ripped it using
the method above with an extra 1/4" so that I could fix any warping on
the jointer and end up with the correct dimensions.
Anyone see anything wrong with this?
CarlC suggested that it will always be prone to twisting... Do you
mean after it is finished? If it is now cut, square and straight will
it twist some time in the future (like after my project is completed
The wedge idea sounds like a good one too, I did think of that but
there was not enough room when using the splitter (the wood had not
made it past the splitter yet).
Thanks for all the advice,
Millions and millions of BF of hard maple leave the woods, mill and kiln
with nothing more than a species/grade spray paint slash across them around
here. End checks have nothing to do with twist.
If the new form is stable for a few days it should be stable for the future,
especially with some finish added to slow the uptake and loss of moisture to
a crawl. Some of the most dimensionally stable woods in my shop are the
curly stuff. Tighter the figure the more stable.
I assume (yeah,yeah) that a dealer means it's KD, so your operator could
certainly have made a mess of things for you by putting a 2" piece in with a
1" schedule. "Case-hardening." See Hoadley or
http://www.fpl.fs.fed.us/documnts/fplmisc/rpt1652.pdf for some information
on stress created by poor kiln practice. It would take a few years of
cycling or a rehydration to break it.
You just need to be aware of the pitfalls so you can make a relatively
informed decision on what to do with that particular piece.
What is fact, according to you, is that this particular piece exhibited
enough internal stresses when it was cut to bind your table saw blade with a
You may have already released all/most of the stress on the first cut, maybe
not. That's the question which only time will tell ... do you want to put
that piece in critical place in a project worth doing, NOT knowing what it
will do in the future?
That said, I don't think I've ever run across a piece of wood that couldn't
be used some place in a project ... even it was just cut up to make floating
It's a pretty good possibility that you've found out the answer to your
original question ... what you do with it is your call.
On Oct 21, 5:23 pm, firstname.lastname@example.org wrote:
If you use a hold down and featherboard to control the cut, you can
cut partially through the board until it is slightly past the blade,
then raise blade to cut thru with your free hand, leaving an uncut
spacer tab at the front of the board to keep the board from pinching
the blade. I saw this at the Grip-Tite feather board booth at the
woodworking shows. He was ripping a twisted junk board from the cull
bin that really wanted to pinch- used a splitter they make for 10
bucks. It is just a simple pin behind the blade that moves left and
right and was only a half inch high.
I bought their featherboards, and they tossed in the splitter for free.
It was already dried when I purchased it (although I do not know the
%). But just to make it a little dryer I stacked it so that air can
circulate. I did not seal the end grain. Should I have done this
when I purchased it? Or should I do it now? Or were you assuming I
purchased it green? I will be assembling this into furniture in the
next few weeks and do not want it to warp after I assemble it. If I
must discard the wood I suppose I will have to take the loss and try
to make sure I inspect the wood more carefully for this potential
I'd let it sit for a couple of weeks and see if it moves now that it was
cut. Once in place, it will probably hold OK as it will be attached to other
pieces. Sort of like framing lumber if you build the wall right away.
OTOH, I've heard a couple of stories where furniture would self destruct two
years later because wood moved or was not allowed to move properly with
Sealing it now won't do anything. I assume by dried it means kiln dried and
that can vary by operator to operator. It could have had as much moisture as
a 2x4 from the borg as far as anyone knows. I agree that at this point it
will be hard to tell what it will do.
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