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/showthread.php?t=46114&highlight=sofa

[Al Navas]

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

Best ways to avoid kickback:

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.
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!!!
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.
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-woods/Articles/Tablesaw/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!!!

[Art Mulder]

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.
...

I also saw this demonstration ... a few years ago there was a video of Kelly Mehler doing this demo at a woodworking club. And like Sam said, the piece goes flying back and to the left.

I also agree with everyone who said to use a splitter. I've had that splitter save my bacon a few times. I've seen it happen where there are some internal stresses on the board that get released as the board is cut, and I see the cut close up on the splitter, and close up beyond the splitter. But thanks to the splitter, it CAN'T close up on the blade, so I can either finish the cut, or safely turn off the saw.

But I have also modified my technique, somewhat, after seeing that Kelly Mehler video. (I tried googling, but I can't find it anymore, too bad as it makes an impressive demonstration.) I either try to stand slightlly to the right, as I feed stock through the saw. Or, I try to stand farther to the left of the blade. It depends on the cut and the piece.

best,
...art

[Tom Andersen]

Art,

I believe that your comments on the splitter are right to the point. Anyway, they raise the question whether the splitter should have exacly the thickness of the saw kerf, or be a little thinner. For various reasons, my saw didn't have a satisfactory splitter so I made one myself of steel plate. I made it a little thinner than the kerf because it is impossible to align the splitter and the blade infinitely well, and a splitter that is tending to squeeze might be worse than a splitter that is a little thinner than the blade.

Right or wrong? Do people here change splitters when they change to a blade with another thickness?

Tom

[Nissim Avrahami]

Tom

I just checked my TS original blade and Riving knife (Elektra beckum – Metabo group).

The blade kerf is 2.8 millimeters (stamped on the blade) and the Riving knife is 2.3 millimeters.

0.5 mm = 5/256” or 0.019” (if my calculation is correct).

Anyway, if the Germans did it 0.5mm narrower, they know why...

Edit: Ooops, sorry Tom, I did not see that you are from Sweden and mm are normal for you.

niki

[Charlie Plesums]

Many people assume a splitter and a riving knife are the same...

The splitters that I have had have all been thin pieces of sheet metal, sometimes with wimpy pawls to try and hold the wood down and keep it from pushing back. They towered over the blade, so often had to be removed (for non-through cuts). I had almost no confidence in these.

My current saw has a riving knife that is almost as thick as the blade, and rises and falls with the blade. It can be adjusted to the height of the blade (I keep it just below the blade height so it stays in place with non-through cuts). Even lumber with stresses that clamp on the riving knife so hard that I cannot push them through the saw have not kicked back.

[Al Willits]

Probably opening up a can of worms here, but....

Just wondering, what does the average TS need to operate safely and correctly?

I'm looking at the Grip Tite system for one, and also the shark guard to make using the guard easier, wife has mentioned the rollers that D Marks uses and wondering if they are a good idea?

Also the anti kickback pawls on the Hybird saw are a bit weak, the hole in my wall shows that, so not only do I need to be more careful, but a set of after market anti kickback pawls and riving knife might be nice.
Any suggestions on aftermarket pieces?

Understood, proper cutting technique is most important, but anything that helps make it safer or easier is nice.

Al

[glenn bradley]

Tom,
My splitters match my blades more of less; thin kerf and regular, one for each but not blade-specific. MJ Splitter is only $15. That's less than my co-pay at the doctor's office for stitches. Buy two.

[Al Willits]

OK, let me try again...:)
I asked what basic things would people recommend for a safe and easier to use TS and got no response.
Was that an improper question, or ?

This is my first table saw and would like to make it as safe and functional as possible, there is a ton of after market items out there, and I was hoping to cut the learning curve down a bit.

For instance, there seems to be at least two different version of the Gripper system, the GRrrrr riper and the Grip tite system, any difference in them as far a function??

Just looking for some of the stuff you all have found benificial to install on your TS or any of the power tools out there.
tia

Al

[Charlie Plesums]

There are lots of accessories that some people love and others find just get in their way, perhaps causing a distraction (unsafe).

I suggest that you start with the basic saw, use the equipment that came with it, until you are comfortable, rather than trying gimmicks. Then, if you then find you are having a problem (for example, keeping the work against the rip fence), buy a toy to help keep the work against the rip fence. If you can't get sufficiently accurate miter angles, buy an enhanced miter gauge or build a sled. Etc.

The only tool I consider basic and necessary on a table saw (besides a lot of careful common sense) is a push block that holds the work down on the table as it moves it through the blade. If I had to limit myself to one push stick, I would keep the one I made from 1/4 inch plywood, about 4 by 12 inches, with a notch near the trailing end of the long sides.

Although I now have some super equipment, over half of the furniture shown on my web site was made with a Home Depot contractor saw and a home made cross-cut sled - no other accessories.

[Cliff Rohrabacher]

I have had one kickback (one). It was about 30 some odd years ago. I was ripping down an 8" square by 4' long of Mahog' for guitar necks. I had no riving knife no blade guards (Yah that's me all right We don't need no stinking safety gadgets).

Anyway, it clamped itself to the blade as the cut relieved stresses in the lumber. WHAMMO !!! quicker than thought it was in the wall behind me.

And yah I was - as I aways am - standing off to the side. So I didn't die that day. However, a cement block in the wall behind me did die. A Cement block!! Woo hoo.

[Cliff Rohrabacher]

OK, let me try again...:)
I asked what basic things would people recommend for a safe and easier to use TS and got no response.
Was that an improper question, or ?


Get a good riving knife mount it and use it. That is what they are for.

Stand to the side of the blade in case the riving knofe doesn't catch the kick. They usually do but - - - - -

Do not use your belly to shove the wood.

[Sam Chambers]

OK, let me try again...:)
I asked what basic things would people recommend for a safe and easier to use TS and got no response...

For instance, there seems to be at least two different version of the Gripper system, the GRrrrr riper and the Grip tite system, any difference in them as far a function??

Al, I'm no expert, but here are my thoughts...


A splitter or riving knife is an absolute necessity. This will minimize the chance of kickback.
You also need some way to keep your hands out of the blade. Either use a blade guard, or some kind of push stick/block. Personally, I use a pair of Grr-ippers.
Never work when you're tired or distracted. Table saws cut through flesh and bone as easily as they do through hardwood.
Never reach over a spinning blade to do anything. If the piece is falling off the back of the saw, let it fall. And duck!
Practice your technique. If classes are available in your area, take one.
Have some way to turn off the saw without taking your eyes or hands off the workpiece. The OFF button on my switch is big enough that I can turn it off with my leg.


Hope this helps!

[Tom Andersen]

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

I could use some more info on this. I often have construction wood, say 2 x 6 inches, lying and rip it into the pieces that I need. Would that be considered unsafe by you folks? The main problem that I see is that construction wood sometimes can be a little warped or deformed in different ways but normally I don't systematically plane wood before ripping. What is your opinion on that issue?

Thanks
Tom

[Al Willits]

Thanks guys, I have push sticks all over the garage so I use them no matter what I'm running, and I stand off to the side and the saw's off switch is where if need be I can shut the saw off with my leg, so I got a good start on it.
Did pick up a magnetic feather board, figuring to use that instead of my fingers when possible.

Did look at the Gripper at woodcraft and wondering if it works or if using it is more trouble than its worth?

Decided against the rollers as the feater board should do pretty much the same, and like mentioned, don't want a saw that has more doodads than required.

Riving knife sounds like a great idea, any suggestions on where or who's to get?

tia
Al

[Charlie Plesums]

Riving knife sounds like a great idea, any suggestions on where or who's to get?
The "real" riving knives are heavy steel plates that stay even with the blade, whether it is high or low, and follow it's tilts. I haven't seen an after-market riving knife, since it requires heavy steel/cast iron mounts on the same mechanism that holds the blade - the saw has to be designed to hold the riving knife.

I have seen after market items that sometimes are called riving knives, such as small removable splitters that stick into the zero clearance insert plate, but now that I have a real riving knive, I have very little faith in those add-ons. Maybe they are better than nothing, but I didn't bother with my old saw.

[Ben Rafael]

I could use some more info on this. I often have construction wood, say 2 x 6 inches, lying and rip it into the pieces that I need. Would that be considered unsafe by you folks? The main problem that I see is that construction wood sometimes can be a little warped or deformed in different ways but normally I don't systematically plane wood before ripping. What is your opinion on that issue?

Thanks
Tom

Tom,
Warped wood should generally be flattened before being placed on a TS, especially if it is twisted. WIth crosscutting it is not as big a safety issue as with ripping. Ripping twisted construction grade lumber on a TS will eventually give you a kickback. Construction grade lumber is not dried correctly(or at all really), so it is usually wetter in the center than on the ends.
I use a circular saw or my band saw for ripping it.

[Jerry Jaksha]

Warped wood is a relative term. Every #2 pine board you buy at home depot is cupped or warped. They can be cut on a tablesaw without kickback, if you hold it down with constant pressure just before the blade. Just don't try to do this with your fingers!

You may have seen me demonstrating at the woodworking shows. I buy a dozen pieces of 50 cent cull 1x8x6' at home depot and rip them narrower and narrower until they are 1/4"x 1/8" x 6' . They might have a 1" cup or be warped up to 3" in 6'

You need a spring loaded pressure roller just in front of the blade and a anti- kickback hold down on the trapped piece between blade and fence.
A zero clearance throatplate is essential for narrow strips.

Check out the video at
http://www.grip-tite.com/
to see how it is done.

You can do the same thing with home made jigs. It is just faster with the Grip-Tite.

[John Appleseed]

I am left handed so I naturally do things with my left hand, when ripping on the TS I use the push stick with my left hand, thus my body is to the right of the saw blade........is that a disaster waiting to happen???

[Jim Becker]

John, best to choose safety over "handed-ness"...IMHO. Hand closest to the fence is best for moving material through the cut.

[Art Davis]

I've had a few kickbacks, usually due to operator dumbness, and am very concerned about table saw safety. Have seen Kelly Mehler quite a few times at shows and am always impressed by his presentations. Even if I don't remember a lot of the specifics, it keeps me aware each time I turn on the TS.

On accessories----I have the Gripper (or however many r's and/or p's are in the stupid thing's name!). It seems to work okay, but I am always concerned about moving my hand over the spinning blade. Even though it is under the Gripper, that thing is only plastic!

I also have two Grip-Tites. They seem to really take the worry out of ripping narrow pieces for me. As I have a Biesemeyer fence, I had to purchase a metal facing for it that they sell. I had a real problem getting it mounted just right. You have to drill the face of your fence in four places (not a think to undertake lightly!) and either use screws or inserts. I did the latter, but in the process I got the bottom edge of the facing plate a millimeter or so too low and the darned thing dragged on my table top. After talking to Jerry Jaksha of Grip-Tite, I finally solved the problem. He was very accomodating, but I'm not sure that drilling your fence is a good way to go---and the instruction manual isn't easy to read. Now that I'm up and running, though, I think this is a very fine product and worth you considering. (Usual disclaimer: no connection with the company!)

Art

P.S. There's a pretty good discussion of the Grip-Tite system on www.woodshopdemos.com

[Al Willits]

Just wanted to say thanks for this post, life on the TS has gotten much more enjoyable.
Since my last post I launched piece number two, into the garage door and all projects stopped, Beasty will have to wait for her cabinets.

I now have made one sled, and another is almost finished, added a extension to the TS and installed the Buddies on the saw, just this has helped in my quest to keep the garage and myself undented.
Only thing I can think of I still is the Shark blade guard and that will come soon.

I also found with a bit better blade, my miter saw makes some really nice cuts, waaay safer than laying them long boards on the TS and trying to keep them from wandering as I cut.

Once again, thanks all.

Al

[Cliff Rohrabacher]

How can you prevent a kickback

lots of ways. Riving knives help a lot.
I rarely put my knife in. I just use due caution and stay aside the path of the blade. If the material looks like it's closing in on the blade I lift it off or push faster. I have used little wood weges more often than I have used my riving knife. It's an old trick and probably isn't practiced much, but it works.



and why does it happen?
Lots of reasons usually a bind betwen the blade and a fixed object like the fense ot the wood closed up on the blade from tension and POW. It can happen fast.


Should you stand derectly behind the piece your ripping or to the side so a kickback doesnt hit you?

I wouldn't, I don't.
In more than thirty some odd years I have had only one kick back. It was a doozie, knocking a hole in a concrete block in a wall behind me.

[Aaron Beaver]

Question, which piece kicks back most often, the piece between the fence and blade or the one on the other side? Or can only one piece kickback?

Just wondering so I can re-check myself to see if I am standing where I should.

[Mike Seals]

I had one kick back many many years ago, the one thing I noticed is that you can hear it coming. Listen to the sound your blades make and you'll know when something is out of whack. I never use the TS for cross cutting with a fence, just asking for trouble. I tend to use the table saw only with large pieces of wood, nothing small enough for the blade to lift easily. Always to the left of the blade, not 100% safe but better than directly behind.
Just remember, if the piece is small enough to launch, it probably will.

[Henry Cavanaugh]

Its my understanding that there are too types of kickback 1) letting go of the piece being pushed between the blade and fence will send piece straight back so standing to the left is safer. 2)the kickback that I am more worried about is the pieces coming together on the outboard side and coming back towards me standing to the left of blade. can someone clarify this. I have just purchase the MJ splitter to add to throat plate. Is that suffient on a delta contractor saw or is a metal splitter a better option. and who sells them? MJ just came out with a metal inside version of there plastic splitter that I didnt buy because of not knowing about it. is this one better? I was also going to have one splitter,throat plate for ripping when blade is up 1.25" which is 75% of the time and a second one when blade is up 3.5 inches. This way the splitter will be closer to the blade.

[glenn bradley]

Hi Al, late response to:
"OK, let me try again...:)
I asked what basic things would people recommend for a safe and easier to use TS and got no response..."

Depending on what I'm doing I use:
- Feather boards (side and/or top)
- Splitter
- Blade guard
- Grr-Ripper(s)
- Push stick
- Outfeed and/or side supports (table, rollers, etc.)
- Eye and ear protection
- Proper clothes (rolled up sleeves, no loose shirttails, etc.)
- Wax saw top and fence for smooth running
- Oh yeah, regardless of how defective it may be; my brain

Hope this helps ;-)

P.s. I never put "stuff" anywhere along the front of the saw where I stand, even for 'just a moment'. I don't trust myself not to leave it there and create a safty hazard.

[Aaron Beaver]

IMJ just came out with a metal inside version of there plastic splitter that I didnt buy because of not knowing about it. is this one better?

From what I heard the one with the metal inside is supposed to be better and more sturdy. Some people (not me) have had the splitter break on them. I own both the thin kerf and regular kerf splitter and two Grr-rippers. I plan on getting the blue one with metal in it soon even though I haven't had any problems.

[Ken Milhinch]

Do yourself a favour and buy a GRRIPPER, or better yet buy a couple of them. They don't replace the need for caution, but they sure make cuts on the tablesaw much safer.

[Jim Becker]

Its my understanding that there are too types of kickback 1) letting go of the piece being pushed between the blade and fence will send piece straight back so standing to the left is safer.
While this is certainly possible, it's not likely if the saw and fence are in proper alignment and a splitter is in use. It's a good practice to avoid disengaging from the workpiece if you can, but there are times when it cannot be avoided, especially in very narrow and long rips. Same applies for the off-cut material. The splitter will make it much less likely that the material can climb the back of the blade and be thrown. Obviously a taller splitter is most desirable for this protection (the MJ you ask about isn't the best in this respect), but any splitter is going to help. IMHO, a splitter (or riving knife) is the most important safety accommodation on the table saw because it guards the back of the blade that is coming up out of the table.