Kickbacks

[Andrew Melamed]

How can you prevent a kickback and why does it happen? Should you stand derectly behind the piece your ripping or to the side so a kickback doesnt hit you?

[Dave Falkenstein]

Kickback occurs when a piece of material is trapped between the fence and the spinning blade, or when a loose piece on the scrap side of the blade (usually left side) accidentally comes in contact with the spinning blade.

One of the ways to reduce the chance of kickback is to use a splitter, which tends to hold the pieces of material in place until the saw blade comes to a complete stop. I like the Biesemeyer removeable splitter - pricey but worth every penny, IMHO. To further reduce kickbacks, make sure your cut material is well past the blade, and never try to remove material before the blade has stopped spinning.

Stand to the side of the material being cut to avoid injury if a kickback does occur.

[Charlie Plesums]

A kickback occurs when the back of the blade lifts and throws the wood. This is often caused by poor alignment, so the rip fence is pushing the wood into the back of the blade. A riving knife, the thickness and height of the blade, is designed to hold the wood away from the blade, but is not easily added. A splitter helps, but isn't as thick or solid as a riving knife.

If you are cross cutting, be sure the off-cut cannot be caught between the fence and the blade - a recipe for a projectile.

European saws are designed to be used from the side, not in line with the blade. American saws leave the operator position behind the blade...one of many reasons I have a European saw. Stretching to use an American saw from the side introduces new risks...not usually recommended.

[Bob Dodge]

How can you prevent a kickback and why does it happen? Should you stand derectly behind the piece your ripping or to the side so a kickback doesnt hit you?

Andrew, I've seen some incredible pics and heard some tragic stories involving kick-back. Those guys that end up with only serious bruising can count themselves lucky.

One pic I saw, involved a 2 x 4 thrown partway through a garage door. Another involved a 42 year-old father of five, who ripped a piece of framing lumber. Apparently, stresses on the binding 2 x 4 caused it to split, and the kick-back piece punctured his abdomen. I presume his work-mates tried to extract the wood, and he died a short while later. Absolutely horrifying story.

Ripping construction-grade lumber without one flat face on the surface of the saw-table, can be really dangerous.

[Eddie Darby]

How can you prevent a kickback and why does it happen?

I rip on the bandsaw whenever I can.

[Al Willits]

Stand behind the saw and kickback?
Only so far had it happen once, the piece grazed off my thigh and put a hole in the wall behind me....I consider myself lucky, I also then remembered the words of my wood shop teacher...stay out of behind the saw blade....

I now stand with my left foot slightly under the table, right foot back in almost a fighters stance and run the saw from the side, I find leaning up against the saw gives me a bit more stability and in this posistion I can shut the saw off with my leg...like when I cut a 6' board and only had 5'10" of space behind the saw....

Different strokes for different folks... but this works for me.

Al

[Ben Rafael]

Ripping construction lumber on a TS is insane, too many powerful stresses and it is irregularly dried. Use a BS or a circular saw.

[Sam Chambers]

Like many of you, I was taught to stand to the left side of the blade when using a table saw. But then I saw Kelly Mahler do a demonstration at a woodworking show a few years ago. He used a piece of rigid styrofoam insulation to demonstrate a violent kickback. He stood behind the benchtop saw - on the outfeed side, that is - and slowly fed the insulation through the saw. The blade guard/splitter was removed. Then he let go, and ducked. A few seconds later, the insulation came into contact with the rear of the blade, and BAM! - The piece of foam went flying...flying right where we have all been taught to stand, on the left side of the blade. Mehler then retrieved the foam board, which had flown an impressive distance. He showed the marks the saw blade teeth had made, and how the kickback occurred. Basically, as the rear teeth of the blade caught the board, it picked the board up, and created a pivot point where the board met the fence. It was a very enlightening demo.

Now I always use a splitter, which is the best way to minimize the chance of kickback.

[Nissim Avrahami]

Here you can see the correct usage of the TS and how the kickback happens.
Roll down to the title “Preventing table saw kickback”.
http://www.powertoolinstitute.com/safety/tablesaw.html

niki

[Henry Kinney]

I just read an article, I think it was on the Newwoodworker site, that recommended raising the sawblade a little higher than I have been taught. What are everyones thoughts on how high to raise the blade.

[Mark Singer]

If the saw is properly set up there is far less chance of kick back. The fence should be slightly "open" at the rear of the blade...about 1/64 th inch. Board Buddies really help since once under cannot come back... If you use the fence to measure crosscuts ...set a block next to the fence to start and the fence should be free at the point where the blade contacys the wood.

http://www.sawmillcreek.org/showthre...highlight=sofa

[Al Navas]

Several comments address excellent points, but I want to add a few things.

Best ways to avoid kickback:

1. Whenever possible, use a splitter with suitable pawls. Many stock splitters have sloppy pawls that fail to catch narrow cutoffs. Some operations do not allow use of the splitter.
2. When ripping, make sure you have jointed the edge that rides on the fence, and the surface that is on the table. If these are not perfectly flat, the work piece can deflect to the point that it pushes the cutoff into the blade - BAM!!!
3. When cross cutting: I believe the safest way is to use a cross-cut sled. Using this sled does not allow use of the splitter, but is does provide support to the workpiece and the cutoff. It also does not allow the work piece to get trapped anywhere.
4. ALWAYS listen to that little voice that says "this is not safe", or "this does not APPEAR to be safe". That little voice is usually right! Any trepidation at any time may contribute to making a mistake that results in a kickback.

Although hard to predict, built-in stress in the lumber can cause problems, such as closing of the gap behind the blade. This results in (both work piece and cutoff) pinching the rear of the blade, which results in one or the other being launched toward the operator. This is one of the main reasons that using a suitable splitter with properly-working pawls is highly desirable.

On a few occasions I wanted to cross cut some 2 X 4s that were so warped that I hesitated to do it on the table saw. I ended up doing it on the chop saw, to avoid the possibility of a kickback.

Enjoy safe woodworking!


...

[Nissim Avrahami]

Hi Henry

You can see the effect of “low blade” and “high blade” here (roll down to see the illustration)
http://home.att.net/~waterfront-wood...w/tablesaw.htm

It looks to me that “low blade” will through the work toward you horizontally but “high blade” will through the work up and toward you.

I think that the best is (except the blade alignment of course), to have a Riving knife or large splitter (at the thickness of the kerf), to use feather board (I’m using shop made feather rollers), and as Mark said, Board Buddies (I’m using shop made hold down roller).

There is another point that was mentioned by Al, the internal stresses that are released; that’s the reason that all the EU saws are provided with short rip fence that extends just beyond the riving knife, so the wood has were to go.

niki

[Jules Dominguez]

I just read an article, I think it was on the Newwoodworker site, that recommended raising the sawblade a little higher than I have been taught. What are everyones thoughts on how high to raise the blade.

I've seen a recommendation from one of the blade manufacturers to set the sawblade very low, but I don't know why that's recommended. I assume the feeling is that the less blade exposed, the better for general safety.
Tage Frid recommended setting the blade at full height. His rationale was that the blade is coming almost straight down down on the board at the point where cutting occurs and where the maximum force is exerted on the wood. Thus, the blade is forcing the wood down onto the tabletop. With a low-set blade the force on the wood is much more horizontal and trying to force the wood straight back to the infeed side. Tage Frid had a lot of experience and I think his advice is good. I follow it most of the time, but I lower the blade when the cut I'm making puts my hand uncomfortably close to it. I imagine that's what Tage did, too.
I also use a splitter all of the time for through cuts, make sure I have a straight edge against the fence, adjust the fence slightly open on the outfeed side, stand to the left of the blade, don't rip twisted boards, don't rip boards with major bows, put the concave side of a slightly bowed board downward when ripping, and use the Grip-Tite magnetic featherboards when both edges of the board I'm ripping are straight and parallel. All of the advice in this thread is good advice. I follow most of it and feel comfortable with what I do, but always try to stay wary and concentrated when ripping on the tablesaw. Which is primarily what I use it for.

[Eddie Darby]

Ripping construction lumber on a TS is insane, too many powerful stresses and it is irregularly dried. Use a BS or a circular saw.

Totally!!!