I was cutting 1/4 flooring on my RAS, the finish was too slick for the anti kick back pawls. it threw the piece at me and hit me 2 inches right of the family jewels, tearing my leather apron and blue jeans on its way. Didn't break the skin but I had trouble sitting on my orange size balls for a long while.
Think semi-elastic collision and, if the door was leaning against the wall, angle of incidence vs. angle of reflection.
er
Snip
IMHO standing to the side and letting the wood fly by is part of the problem. I have on several occasions had the wood fly by while I was not in the line of path of the blade and have been hit. Again, IMHO it is when you do not have a FIRM hold and let go of the stock that the kick back has the opportunity to develope. The push sticks that simply allow you to push the stock through from the back edge of the stock scare the hell out of me. You have to keep the stock down on the table surface to prevent it from flying back. With out downward pressure there is nothing to keep the board from lifting and possibly kicking back. I have often had the stock start to lift up and I simply push back down. Often the piece is damaged but the wood stays on top of the saw. I find that with a firm hand or with the use of a push stick that allows you to apply downward pressure along several inches of the wood so that the blade simply cuts a gouge rather than kicking the wood from the blade keeps the situation from developing.
And to go a bit farther,;~) Many believe that a more powerful saw is likely to do more harm. Again IMHO and with my experience a saw with a dull blade and or less power is more likely to kick back than one with more hp and a sharp blade. I had many more close calls with my old Craftsman with the 1 hp motor than my Jet with the 3 hp motor. I believe that when cutting stock that was a challenge for the saw that I would handle the stock with a lighter grip/touch to prevent stalling the motor. The light hold on the wood would often present a problem. With 3 hp I always have a firm grip and easily push the wood back down to the table surface should it begin to raise up. With more power the blade simply cuts a new path rather than grab and throw the wood back with that light grip.
IMHO being in position to firmly hold down the wood and learning to deal with and not panic during a developing situation that would lead to a kick back is better than trying to keep out of the way.
Do not procede with any procedure that you would feel unsafe in doing.
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In roughly 30 yrs I've never experienced any instance of severe kickback.
I do not use the TS splitter.
My only real conscious practice is to routinely push _everything_ completely through and take offcuts away immediately and to ensure blade is at proper depth to clear surface.
I've had two, both my fault, not the equipment
Late at night wanted to make just one more cut. full bevel cut on a right tilt and I was just a little too lazy to change the fence over to get the tilt going away from the fence. Trapped piece kicked back, caught me in the side then traveled another ten feet and put a deep ding in a solid ply shop door. Bruise on my side lasted for weeks.
second was on a planer. Put a piece in that was too short for the machine. Kicked out and turned the feed hand black and blue and unusable for a week or so.
As mentioned, I knew better in both cases. Wasn't the fault of the machines, simply operator error.
Frank
I find that with more HP the saw and the sharp blade are more likely to cut the wood thather than catch it and throw it back. Its the under powered saws that require you ro finess the wood through with a light hand that tends to catch and throw the wood.
My experience with the more powerful saw is that it indeed does not jam or stall nor with a firm grip does it rip it outta there and send it flying. My experience with more power and a firm grip the blade simply cuts in another direction. Similar to a hot knife cutting into room temperature butter I find less resistance with a change of cutting direction which normally leads to a kick back.
Do not fear the sharp blade. It will more easily cut your wood rather than catch the wood and throw it back than a less sharp blade. Additionally, fingers will cut off just as easily with a blade that has had all of its carbide teeth broken off . I have been there and done that. Fingers are MUCH softer than wood. ;~)
Well, the very best way to avoid danger is - to avoid it. I'll say that with out qualification. If you're not there, you can't get hit. If you haven't seen the classic body positions from the basic woodworking literature on how to rip on a tablesaw, look at them. Good information.
And letting go is a great option in my opinion, it's one that I developed by reading accident reports in my former job, where most fatalities were from delaying ejection (trying to salvage something) until out of the envelope. When it doubt - punch out.
I'm not going to risk my fingers for _any_ piece of wood, I don't care if it's ebony. Nor would I recommend it to anyone else.
the physics involved look something like this: your compound bow is human powered. you can never put into it more than about 1/3HP. it stores a bit and releases it progressively, but I doubt that it's applying more than that 1/3HP. this is why your arrows are so light- otherwise they wouldn't be able to go so fast.
a longbow shoots a heavier arrow, but it takes one very strong guy to draw it. a longbow was supposed to be able to penetrate chain mail- it'd probbly penetrate 3/4" plywood.
crossbows usually are too high a draw to be pulled by human arms. they are mechanically cranked, and shoot an even heavier bolt. they would penetrate plate armor. prolly not even slow down much through plywood.
my tablesaw is 3HP. it can launch a chunk of wood approximately 9 times as heavy as your bow can shoot an arrow, as fast. that is a lot more energy being delivered to that piece of plywood.
I don't know if it would penetrate 3/4" plywood in a kickback. I hope I never find out.
On Fri, 04 Nov 2005 03:25:37 GMT, "Mike W." scribbled:
About 15 years ago, I was doing a test cut on my table saw. I stupidly used a short piece of 2X4 (about 4 inches long). I was holding it gingerly instead of using a push stick and didn't have a firm grip on it. Needless to say, it kicked back right on my left tit. I yelled out and cursed in at least three languages. The LOML thought I had chopped off a hand or something. No blood on the outside, but my tit turned all kinds of neat colours, purple, blue, green, red, yellow, etc. No permanent damage. Luigi Replace "nonet" with "yukonomics" for real email address
I had 3 cases worth mentioning. One was a 45 degree cut with the main panel on top of the blade and the off cut under and away from the fence. The off cut kicked back and hit me in the abdomen. I have done the same cut a number of times since, and the off cut piece hasn't ever kicked back since. Another time, I was crosscutting some short pieces. I put a block on the fence to measure with and to provide room so that the pieces wouldn't bind and kick back. Well, the pieces were wider than long, and one turned sideways and kicked back. The other time was on a construction site. A guy provided a Ryobi bench top table saw for ripping some siding into corner blocks. This is a saw that has trouble cutting dry 2 x 4 material. A buddy ripped off a 4 inch wide piece and left it. It slowly kicked back and barely cleared the table saw. I imagine the weak saw, and with no outfeed table so the piece arched and barely contacted the blade, and a low fence combined for a wimpy kickback. I told him that if he had been using my shop saw (Unisaw) that the off cut would have gone across the pool, across the driveway and into his truck, and he didn't seem to understand. robo hippy
Power does not come into this calculation, but force. (Power as in energy per time, energy as in force times path length) Also momentum (mass times speed) is an issue.
I will give you three. Two that have happened to me during 35 years or so of table saw use. One very serious one that happended to a friend of my son:
1) Many years ago I got a piece of 1/2" plywood (about 2' square) crossed up in the table saw that WAS fitted with a splitter. I think the mass of the plywood just overpowered the splitter and pawls because it lifted off of the table and a corner of the piece hit me in the chest. Hurt-no band aids.2) About four years ago I was cutting ripping the edge off of a piece of 2x about 1-/2' long and got a kickback (no splitter - shame!). I saw it coming and stepped aside. The piece of wood flew about 10' across the garage and ended up hanging from a hole in the sheetrock. Could have hurt real bad.
3) I have posted about my son's buddy a couple of times since it happend last spring. He was planing some thin stock in a surface planer. They don't know exactly what happened but a piece of stock, apparently about 1" square and several feet long, got past the rollers and impaled him in the abdomen. He ended up with much of the stock protruding from his back. Luckily it missed most organs but did nick an intestine. He spent quite a bit of time in the hospital and as of a month or so ago he was 'almost' back up to speed. Unusual but rest assured this could happen with a table saw too.RonB
Loads of them, never stood where they were going to get me.
Last one was in taking angled filler strips off the edge of a softwood board. These were maybe 1/2" x 1/4" at most, so pretty lightweight. The saw fired one off (between the blade and the fence) which flew a couple of feet then hit a light plastic toolbox on the shelf behind. It punched a neat hole in one side, then out the other.
So even if it's only a lightweight offcut, don't underestimate the energy in those trimmings!.
If I follow the description correctly, it went in a triangular path.
12" directly away from the saw, then 25" to opposite wall, then however far back to the saw. The total distance computation would require some angles, but has to be more than 37'. If it turned 180 degrees as you assume then the total distance would have been 50' (12 to one wall then 25 going past the saw, then back 13 feet to the saw). Whew...didn't add one little bit to the actual conversation there, did I?Dave Hall
Not sure these qualify as kickback, but they seem to line up with what others are posting.
First was a brief moment of misjudgment (read: stupidity). I was moving a piece of ~ 1' x 2' ply I had recently rabetted from the right extension wing of my TS to my workbench, and I swung it into the blade. Board caught me in the gut and knocked the wind out of me. No bruising or cuts, but enough of a scare to call it quits for the day. At the time my saw was a tiny little 50 year old Craftsman (crapsmen for the more clever in the group) with an 8" blade. I think my DW746 would've caused a bit more damage.
The other time was when I was planing a board that I now realize was way too thin... I was approaching 1/8". The board broke at a knot, and the planer sent half of it sailing out so fast that I never even saw it. My only clue that something happened was that only half the board came out the other end. (I had ear plugs AND over-the-ear muffs on at the time). I eventually found the missing half lying on my garage^H^H^H^H^H^Hworkshop floor by the door, with a fresh 1/2" deep impression in the door a couple above it. I'm not entirely sure how it got past the infeed rollers. Perhaps that half of the board was thinner than the half that had already gone through.
Work safe.
-John in NH
I think what Leon is saying George - and I agree with it, is that better control and observation will result in fewer kickbacks. Kickback is not something that is "going to happen". It does not have to be a part of your woodworking endeavor. Standing off to the side positions the operator to be in less control over the workpiece and increases the likelihood of kickback. Kickback is not magic - it is very predictable and very observable. Good practice makes a better preventative measure than adopting postions that lessen your control and observation of what's taking place.
I'm not in favor of letting go. That guarantees the outcome. Why let go when controlling the piece will result in an incident free cut? There's quite a bit of difference between controlling a cut to prevent a kickback and punching out of an airplane. Though at some point one could certainly draw an anology between a jet and an errant piece of wood...
Yeah - but that's not at all a part of what's being discussed. I'll take it one point further and say that I'm not about to willingly let a piece of wood go ballistic when I possess the ability to control it through the cut and to a restful place on the other side of the saw blade.
Duane, I'm with you, in 35 years I've never had anything like severe and I don't use the splitter. But I can still remember the first day of instruction on the TS in woodshop. Took 4 years in it with the same instructor, Mr Norman. A skilled woodworker with all digits he did not tolerate safety infractions at any level, from cluttered work areas to improperly maintained equipment. You didn't follow safety procedures you would never finish the class. Before turning on any equipment you had to pass a written exam on safely using it. Turning off equipment when a power outage happens is ingrained in me. Its like my military serial number.
Like you I try and make safety a conscious procedure. Because there is always a first time. My good shop buddy lost a thumb with his TS and he is just as safety conscious as anyone. Just needed to make one crosscut on a small piece of pine, he didn't take the 2min. to walk over and grab his sled and put it on. Why, he was going to rip a bunch of oak and thought he could handle the crosscut and save a few minutes. Just one time and one thumb. Ed
It fired past me at waist level (Skil bench saw), hit the door standing against the wall, came back past me, hit the opposite wall (in the air) and slid on the floor back towards me.
37 feet isn't as far as you think...
Possible, I suppose. It's more likely I'm cautious and don't like to attempt dangerous cuts.
The kickback incident I described earlier is the only significant kickback I've ever experienced, and it was a dangerous cut, and I was well aware of the danger.
It was also not a cut I would try again.
My only kickback was a badly executed crosscut.
Barry
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