When a tree grows on a hillside, stresses can build up in the
lumber derived from the tree. Reaction wood is caused by
these stresses, which when relieved during milling, will seriously
compromise the dimensionally stability of the timber. In other
words, it will warp or bow when you rip or resaw it.
Reactionary tends to warp or bow "immediately" after it is cut. The
wood will often widen while being cut or the kerf will begin to close up
as the cut is being made.
Swingman and I worked on a kitchen/bathroom remodel 5 years ago and I
built a boat load of drawers for the bathrooms. We used hard maple and
while ripping a piece to width it closed back up on the blade near the
end of the cut and threw the keeper side back at me like a missile. Hit
me just above the belt and thank goodness I was also wearing an apron.
That was not pleasant. Fortunately only a large bruise.
A great reason to have a splitter on oru TS.
I love this newsgroup. Very little noise and a whole lotta info.
R U kidding me!? I saw that shop safety film in the 9th grade. The
film stated the reason the piece of wood got shot back was cuz; no
guard thingie; the blade was set too low, hitting the work at an angle
guaranteed to turn it into a projectile; not using "push stick". The
film showed the actor's intestines wrapped around the lance-sized piece that
impaled him. A total hoot fer a nineth grader, but deadly serious,
I see a lotta youtube vids showing a guy pushing work into the
tablesaw blade with no push stick and the blade seemingly set quite
low. What should I know that was not shown on that safety film from
I'm going over, today, to look at a tablesaw I might use to make
Thank you for the info on "reactionary" wood.
It's ok to set the blade lowish, I believe the current thinking is that
having the gullet just clear the wood is the best compromise between not
exposing too much blade and trying to get the blade moving down through
most of the cut.
Your fence needs to be parallel to the blade. This will reduce the
likelihood of a piece applying pressure against the blade, which is one
of the first ingredients in a kickback recipe.
Do not trap the workpiece between the blade and fence. If you're taking
only a 1/8" off, set the fence so the wide side of the board is against
the fence and the small side is cut off.
Realize that there are pieces that are just too small to be cut with a
power saw of any kind safely. You may have to plan ahead on a project
that uses them to make sure the final cut leaves you with an exact
I don't think lack of a "guard thingie" would be a factor in
that particular problem, but lack of a splitter or riving knife
As Puckdropper said, setting the blade low has advantages and
is considered an OK practice today. Avoiding kickback means
having a splitter/riving knife so that the kerf can't close on
the blade. Also, as Puckdropper said, don't do thin cuts on
the fence side (as you push the wood into the cut you'll tend
to rotate it towards the blade if you're pushing on away side).
Push sticks, feather boards, and outfeed tables or rollers to
keep the board from lifting off the table are also good ideas.
And, from personal experience, avoid cutting thru knots. Even
what looks like a tight knot can come loose when the teeth hit
it, and having half a knot whistle past your ear like a bullet
really gets your attention.
Thank you fer setting me straight.
I realize this is not half a century ago, but I still wondered. Thnx
fer educating this geezer neophyte. I know what a feather board is
and jes looked up "riving knife".
Kickback pawls are probably what I thought to be the "guard thingies"
I saw on that ancient woodshop safety film.
I discovered our HOA has a rusty Craftman tablesaw and equally ancient
Craftsman radial saw. Neither has a dado set, so I'll prolly wait fer
my buddy, who has all three.
Rarely have used a TS guard since I got rid of my old overhead system,
but never fail to use BOTH a push block, and a splitter.
The splitter/riving knife is the single most important device for
preventing kickback on a through cut there is.
In the thousands of shop photos, it would be rare to see a glimpse of my
table saw without some type of splitter ... this is one I made out of
the old Delta guard that came with the saw ... not quite as effective as
a riving knife, but a whole lot better than no splitter:
The splitter is attached to the blade guard mount common on a Unisaw:
Made from an old Delta blade guard part, so, unlike a riving knife, it
does not move up and down with the blade (but it does tilt).
It has proven very difficult to adapt older table saws with a riving
knife. There have been many attempts, most IME are not worth the money,
and are kludgy and fussy.
Plus, the one's I've seen in action fail the most important attribute
with regard to any "add on" to a table saw:
~ It must be so convenient, intuitive and easy to use that you never
fail to use it. ~
I'm contemplating the purchase of a SawStop, and the number one feature
that attracts me, besides the safety factor, is the built-in riving
knife. Basically, I will never buy another table saw for shop use that
does not incorporate a riving knife.
SCROLL RIGHT for three photos.
My own design and build. Attaches to the back of the table saw table
(with a wide French cleat), and has two folding legs, with adjustable
feet (not shown).
You can throw one together in a morning in the shop.
Correct but most guards have a splitter of some sort. And unfortunately
most guards are probably more likely to cause injury than not, given
enough time and the right circumstances.
I will never forget the dufuss on one of the DIY channels, IIRC Brad
Stagg on the Ultimate Workshop showing how to cut a dado, WITH THE GUARD
IN PLACE. The look on his face when the wood hit the splitter was
priceless as was watching him get out of that situation with out mishap.
Maybe not so much, now that riving knives are becoming popular.
I have to admit having done almost the same thing, wanting to
quickly put a 1/8 groove in a piece and hitting the splitter.
I'd like to think that if I had changed the blade (which of
course I didn't for the 1/8 groove) I would have remembered not
to put the splitter back on.
Speaking of push sticks, avoid making the Birdsmouth style. That's a notch
cut out of the end of a piece of wood. Sometimes plastic molded ones are
sold as "push sticks" or "getting started" tools, but those should be
avoided. They're dangerous. They put pressure on the very end of the
board, which encourages it to lift.
A "shoe" style or other form will be much better. They keep pressure along
the entire board so it's not likely to lift.
The utility of the birds mouth style is the last few inches of cut,
where they keep your hand well separated from the blade. At that point
if the board lifts it's not because you put a little pressure on the
At least if you subscribe to the "never put your hand above the blade"
philosophy, which I do and some don't.
Today.... ;~) Wait till school lets out, the squirrels will be plenty.
Well I'm not perfect and capable of making mistakes, unlike many that
don't have much to show except their vast knowledge of how it will never
happen to them. And eventually they make mistakes....
I do a lot of woodworking, compared to most. I know the risks and do
what I can to guard against problems but do this long enough and you
either accomplish little or one day you get hurt. Some never get hurt,
some never have been in a car wreck.
A splitter is not always particle, like when cutting dado's or groves.
I was using a push stick but again, something happened and you don't
have time to think about that after something goes wrong.
You are going to have to be the judge as to what saw is best for you.
My advise is to buy a good as you can afford. And past that get a
SawStop. IMHO underpowered saws are more dangerous than those with
plenty of hp. I would never consider less than 3hp but those are pricey.
Whoa BABY! I'll make sure mine is on when I cut. You may have just
saved a life, thank you.
I've been thinking about making a splitter to mount on the insert
itself. Guess I'll be looking hard for one know.
I have seen, altho not made one myself, splitters that are
just a thin piece of wood sticking out of a zero-clearance
insert. The key points are the splitter should be just a
tad thinner than the blade, and aligned perfectly behind
Of course, you also want it strong enough that, if the kerf
closes on it, it doesn't just snap off.
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