Why so much kick-back?

[Mike Vermeil]

After reading all the talk about kick-back in the earlier thread about TS power, and considering how much time is devoted to kick-back in all forms of woodworking publications & websites, I've got to ask, where does all the kick-back come from?

I've been working wood for about ten years now. I started with a little Craftsman direct drive saw, and moved up to a Unisaw a few years ago, and can honestly say that I have never, ever experienced kick-back when I didn't know that it was coming. I've only had it happen twice that I can remember, and both times I knew kick-back was a good possibility based on the stupid way I was using the saw, and was ready for it.

Believe me, I'm not bragging. I've had my share of work/hobby related injuries, including the time I ground my left index finger to the bone in a bench grinder fitted with a wire buffing wheel - not to mention the time a 390 Ford cylinder head fell over on my tennis shoe-covered toes.

I've always just been curious, is it really that common of a problem?

[Eric Apple - Central IN]

"When expected" is key to me in your statement. Either by experience or education, you learn the "when expected" part. If you know to expect kickback cutting a certain way, you usually would avoid cutting that way and avoid the kickback. Other times you might use a featherboard or some sort of jig because you can recognize the situation might lead to a kickback. Kickback is common, it's happened twice to you in 10 years. Had you not been ready with your fingers and body out of the way, twice in 10 years may not seem insignificant.

I also ground off my fingernail to bone in a grinder. Ouch!! I guess thats more like a "grab and pull in" rather then kick. I now use nicked up pliers to hold small parts. Just a few days ago I saw someone else mention they did the same thing. A couple of threads on grinders might help someone.

[Lee Schierer]

I don't get many either, but they can do damage when they occur, particularly with the higher HP saws. Knowing what causes them and watching your set ups to avoid them does work to prevent kick backs.

Just about the time you get complacent is when you do something wrong and the wood jumps at you.

[Kevin Gerstenecker]

In my experience, the most common cause of Kickback is the saw kerf closing as the wood is past the blade, causing a pinching of the blade, the material is then in a "bind" and it is thrown back at you. I have only experienced kickback when I was doing something I knew darn well I shouldn't be doing, but thought I could pull it off. You really have to watch when cutting warped, twisted and crooked boards, those are the rascals that will bite you. If you have your saw tuned properly, and are using it for it's intended purpose, the chance of Kickback will ge greatly reduced. Hard Knots, and hidden fasteners will also cause it, so inspect what you intend to cut, and always be diligent when using used lumber................make sure there are NO nails. I know a guy who was smacked HARD in the chest when he was trying to make a plunge cut for a stopped Dado in some very seasoned Oak. It knocked him out COLD! The best thing is to think all processes thru before diving in, and if there is the least bit of doubt about a procedure, just DON'T do it.

[Bill Esposito]

I found that the mill where I buy my rough cut wood must dry the lumber too fast because it almost always warps when I rip it. I've learned to give myself extra width so I caj joint it straight again but without a good splitter, warping while riping is a recipe for a kickback.

[Jim Stastny]

Kickback is "primarily" caused when the rear teeth of the saw blade, those coming up out of the table, catch a bit of material, lift it, and shoot it back it the direction of the front of the table. The reasons for kickback are manifold. However, warped wood and an impoperly aligned blade/fence are two major ones. Because a splitter keeps the wood away from the back teeth of the blade is why. IMHO, it is the number one safetly feature to have on a saw.

[Sam Chambers]

IMHO, you can't be ready for kickback. OK, let me rephrase that - you can be "ready", but you really can't do anything about it if it happens.

For those of you who think you can react fast enough, think again. I did the math one night, and here's what I wrote in another post:


Assume the blade is moving at about 120 mph. Let's be conservative and say that a hunk of wood hurled back at you by the blade would be half that speed, or 60 mph. Anyone want to calculate the time it would take an object to travel less than 3 feet at 60 mph? It's moving at 88 feet per second, so it travels the 3 feet (or less) to your body in about 0.034 seconds. Can you move that fast?

That's what has me concerned about kickback. It happens so fast that you really don't have time to react. Plus, based on a demonstration by Kelly Mehler (author of "The Table Saw Book") at the Atlanta WW show, the wood does not come back at you in a parallel line with the saw blade, but to the left of the blade, because the work is trapped between the blade and the fence and wants to rotate. I've always heard that the safest place to stand is to the left of the blade, but I can't say that anymore.

So, even when using effective safety equipment (the stock splitter and blade guard don't qualify), we all must accept that woodworking is a potentially dangerous hobby and we might get hurt.

[Jennifer@Indy.USA]

The only time I ever experienced a severe kickback that happened faster than I could blink.....was when I was cutting some smallish pieces for boxes. I was cutting all the pieces to size and had about 6 cutoffs (mistake #1) sitting on the table saw just to the left of the blade. I usually always shut the saw off after every cut, clear the table and then make the next cut. This time, I was in a hurry(mistake #2) and left them sitting there while I made the rest of the cuts. As I was making one of the last cuts on a piece about 4"x7", I was more concerned with the pieces of cutoffs that were getting ever closer to the outside of the blade.....I lost concentration and the board I was pushing through the blade crept up the backside of the blade and came back at me so fast I never saw it. It hit me right on the hipbone and ricocheted off me across the shop, hit the cabinets hanging on the wall, and then came back and ended up behind me hitting the back wall and dropping behind a pile of lumber. It was one of those accidents where you don't want to look to see the damage. I was extremely lucky and only had a very deep bruise that then turned into something like a hematoma. Very ugly and almost neon colored. It was gross! This happened about 4 years ago......and I just two days ago bought a splitter for my saw. I am the queen of procrastination! I never make a cut on my saw now that I don't think of that kickback. I just always think of what I would look like if that piece had flow up and hit me in the face. I now always wear safety glasses (which I had on that day) and a full face shield when I use the saw.

I just bought a new splitter last weekend and I'm hoping that it helps to make my saw a bit safer but I will still always play safe with my TS. I know first hand that it can be a wicked machine if you loose sight of what you're doing.

Jennifer

[Ian Barley]

I have to say that I have only once experienced a full blown, high speed kickback event. Thankfully my habitual stance kept me out of its way. That time was quite often enough to convince me of the desirability of keeping the various "minimisation" provisions in place at all times.

It may or may not be frequent based on all kinds of factors. Like most risks, what has to be assessed is its likelihood and its severity. Even if it only happens very occasionally it has a pretty high severity rating.

I did suffer an interesting variation on the theme the other day.

I was using a jig on my SCMS to cut a specific angle which I cut often. In an effort to speed things up I put a stop on the jig to hold the workpiece at the desired position. Without thinking about it I had produced a "trapped" cut. It was only a few cuts after I installed this stop that an offcut caught the spinning blade and was thrown - very fast - at the wall behind the SCMS from whence it bounced a struck me hard on the forehead. Sorry - that should read HARD!!! on the forehead.

Now this was no more than 2 ounces of timber which hit me after it had rebounded off a timber wall. It had also lost some of its energy as it ripped the depth stop off the jig. It caused me to fall down on my behind - somewhat dazed. I also had an egg sized bump on the point of impact and a large dent in my ego.

Suffice to say - the depth stop did not get replaced and I now treat the SCMS with the same respect I do the table saw.

Once again proof that the energy in our tools is more risky than their edges. The sharpness waits for you to come to it - the energy will chase you round the room.

[Cam.Hedrick]

Two were stupid mistakes....in a hurry to get something done....now I don't let time bother me so much. The other two were while using the power feeder to rip red oak on the Unisaw. One piece penetrated a 2x4 sideways and broke an 8 x 16 block, and the other one took out the guys shop cat that had decided to lounge behind the saw. Didn't kill the cat, but we thought it was dead! I guess it had seven lives left after that.:)
I believe in splitters and over head guards...Excaliber.
Stay safe all, and Happy Easter as Christ has risen!;)

[Jerry P. Doan]

Cam, I thought that a power feeder was also supposed to act as an anti-kickback device, and I have been considering getting one for my Unisaw. Could you provide some more detail about how the kickback you had while using a power feeder occurred? Thanks.

[Steve Clardy]

all the replys, has anyone considered that the blade height has a lot to do with kickback? I think it does. Think about it a moment. I was taught to run the blade height about 1/8" above the material. Always had some kickbacks or possible kickbacks.
I gave it some thought, and when the blade is low, if it wasn't cutting, it would ride up over the top of a round surface, which would be the blade.
I now usually run my blade height 1/2 to 3/4 above the material thickness. This actually helps keep the front of the board pushed down.
I went to a woodshow in KC 1 year and watched a booth operator cutting a board on a table saw. He was cutting 1/2" material, with the blade up around two inches. I asked him why, and he said he did not like kickbacks and this helped prevent a lot of it. My thoughts also.
And yes, I also know that the higher the blade out of the material makes more danger exposed to your hands and fingers.
Give it some thought. My 2 cents.
Steve

[jack duren]

jerry power feeds help out alot but arent 100%safe. i remember a guy cutting some stock for mantles one time. cant remember if it were 2", 3" or 4" rips. anyway when he made his last rip with the power feed, the left over bark edge got caught in one of the rollers and forced it into the blade. needless to say the sharp barked edge rocketed and stabbed him about a 1" from a very sacred place. needless to say he would not allow anyone to pull the piece back out. at the moment he wasnt sure what he had hit.....jack

[Jerry P. Doan]

Thanks, Jack. I guess I won't be buying one of these after all.