# Kickback!!



## DonkeyHody (Jan 22, 2015)

WARNING! Unflattering photo of an old man’s bruised and flabby belly follows. If you are offended by such, DON’T SCROLL DOWN!


OK, I’ve been doing this for a while. I’ve read a lot about tablesaw kickback and how to avoid it. I’m an engineer, and I’ve given a lot of thought to the physics behind the subject. I’ve watched videos and drilled into my brain the several causes of kickback and developed rules to keep it from happening to me. My tablesaw fence is set to within a gnat’s hair of parallel to the blade about 0.001 inch (measured with a dial indicator) wider at the rear. I’m generally quite careful, as evidenced by the fact that I’ve never had an injury requiring more than a band-aid in 30 years of increasingly serious woodworking. It isn’t that I thought it COULDN’T happen to me, but I thought I was smart enough and careful enough to prevent it. Well . . . I was wrong.

I was ripping a piece of ¼” Plywood about 20” X 27”. As the cut was nearing completion, a slight bow in the plywood combined with the very low blade height allowed the ply to ride up on top of the blade. Nothing happened until I moved my left hand nearer to the blade to push down on the trailing edge. Suddenly, all hell broke loose! The plywood pivoted in place almost 180 degrees about the right trailing corner until the (formerly) left leading corner slammed into my gut. If I didn’t have my tablesaw sitting on a 3 ½ inch riser, it would have hit me 3 ½ inches South! And it happened FAST! 

I know from my training at work that accidents are rarely the result of just one mistake. They are usually the result of a “perfect storm” of circumstances, any one of which could have prevented the accident. So, I know I did several things wrong. 
1. I didn’t use my splitter even though I usually do. I had just removed my crosscut sled, and my next cut after this one would be with the crosscut sled too. I thought about using the splitter, but made a conscious decision not to bother. After all, it was just a piece of ¼ “ plywood.
2.	The plywood was slightly bowed from being stored on edge for several years, but I used it anyway. After all, it was only ¼”, and the bow would be easy to pull out.
3.	To avoid splintering, I lowered the blade until only the carbide showed above the plywood. This is the one mistake that I didn’t already know to be a contributor to kickback.

A couple of circumstances prevented the accident from being worse:
1. My leather shop apron distributed the load across more soft tissue and prevented a puncture wound. 
2.	The plywood slid under my hands instead of carrying my hands into the blade.

So, I’m counting my blessings and promising myself not to get complacent again.


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## Stick486 (Jan 4, 2013)

ouch!!!
watch that bruise very carefully....
you may have internal damage you don't know about....
and that's not such a good plan....

so you now grasp that a low set blade is a lot more dangerous than set where the bottom of the gullets are set to the top of the material being cut...


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## RainMan 2.0 (May 6, 2014)

Ouch is right . Sorry to hear about your inccident Andy . Guess I better brush the dust off my riving knife and install it .
As I mentioned I never stand in the path of pieces that size , only full sheets when there's no choice

Andy I set the runout on my fence more than .001 , more like .006 to .01


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## Stick486 (Jan 4, 2013)

Andy...

where is your riving knife???


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## Stick486 (Jan 4, 2013)

RainMan1 said:


> I set the runout on my fence more than .001 , more like .006 to .01


Rick...


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## RainMan 2.0 (May 6, 2014)

Stick486 said:


> Rick...


Stick I find it easy to stand to the side and I've got short arms . My cat like reflexes help to


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## greenacres2 (Dec 23, 2011)

Andy--i'm glad it wasn't worse. I tend to run my blade too low, thanks for the painful reminder.

Rick--I think what you meant to say was "As I mentioned I never stand in the PLANNED, PREDICTED AND EXPECTED path of pieces that size" Trouble is, every now and then the path changes without our choosing, at speeds too fast to duck from. And defiitely get your riving knife dusted off--and i'll remember to put mine back on as well!!

earl


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## DaninVan (Jan 1, 2012)

Andy; we're _all_ glad_ it wasn't worse!!!
Not to be a nagging nanny in your hour(s) of pain...but where's your blade guard/anti-kickback pawls?
Leeway Workshop, LLC
_(If you order _now_ you should have it, uhh, sometime... they're not very speedy over there; each one's custom made.)


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## lenh (Feb 27, 2009)

Brings back memories. Exact same scenario happened to me a few years ago. The kickback got me on the inner right thigh. 

A couple of inches to the left and my username would be "squeaky."


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## DaninVan (Jan 1, 2012)

I've mentioned _my_ moment of pain and infamy in the past, here.
RAS +wobble dado blade = almost lost my thumb. Many stitches and a _lot_ of pain!
Exactly the same blade track across the wood as yours and I _was_ using the anti-kickback thingy on the radial arm saw.
You can't have too many safety devices.


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## Stick486 (Jan 4, 2013)

RainMan1 said:


> Stick I find it easy to stand to the side and I've got short arms . My cat like reflexes help to


good luck w/ that....


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## BrianS (Nov 7, 2004)

Well, I'm sure we've all been close to an "Oh SH!T" moment like this once or twice. Glad it wasn't any worse for you. 

I'm with Stick tho, get that bruise checked out. With the speed that wood was moving, could easily be something more than just surface damage.


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## DaninVan (Jan 1, 2012)

"...and I've got short arms "
Exactly Rick; it's the 'short arm' you need to worry about!


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## Stick486 (Jan 4, 2013)

DaninVan said:


> "...and I've got short arms "
> Exactly Rick; it's the 'short arm' you need to worry about!


lighten up0...
he didn't say stub....


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## DaninVan (Jan 1, 2012)

"Stub"?
Here all his time I thought the reason those characters in Westerns were called 'Stubby' had something to do with saddle pommels...and sudden stops.


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## Stick486 (Jan 4, 2013)

DaninVan said:


> "Stub"?
> Here all his time I thought the reason those characters in Westerns were called 'Stubby' had something to do with saddle pommels...and sudden stops.


close enough...


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## DonkeyHody (Jan 22, 2015)

Stick486 said:


> Andy...
> 
> where is your riving knife???



I have a snap in splitter, (photo below) that I often use, but I decided against it this time because I was only making one cut before returning to the crosscut sled. It's quick and easy to add or remove, but it doesn't go up and down with the blade. OK, I was lazy and stupid. 

No, I don't use the splitter with a dado blade, I just stuck it in to take the photo. 

I don't think anyone's reflexes are quick enough to get out of the way of a kickback. If you're in the way, you get hit, period. I calculate that the rim of a 10-inch blade is moving over 100 miles per hour. The fact that some of the tooth marks are mostly sideways, running parallel, and they don't connect tells me piece was moving near blade speed. I don't think the blade slowed down very much. This is a 5 HP Unisaw. I ordered a 3 HP, they shipped the 5 by mistake and let me keep it instead of paying return shipping.


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## Jerry Bowen (Jun 25, 2011)

Andy, like the others, I sure am sorry about your accident, and yes, it could have been worse. We all need to learn from this or at least be reminded about our tools can be. 

I think that from what you described, it is fare to say that you got careless and did not do what you knew to do. How often we get in a hurry and don't do what we know we should do to be as guarded from potential accidents. 

in my case, I hope anyway, that due to a similar incident I have learned to be more and more careful, but of course that is no assuance that it won't happen again anyway, but I do suspect that if and when it happens again, it will be due to my carelessness

I still have a bump in my stomach that is about half the slze of a marble that will probably never go away. At the time of the accident, the bump was larger than the one on Andy's stomach. It was not as red as Andy's looks however.

Jerry


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## Phil P (Jul 25, 2010)

Hi Andy

Sorry to hear about your kickback. Hope that you'e on the mend. They happen to everyone, but some more than others

I have a couple of points which maybe you as an engineer might appreciate. Yes, you were running minus a riving knife, which greatly increased your chances of a kickback, but you were also running the saw _without_ a crown guard over the blade. In the UK it is drilled into all us joiners and wood machinists that the riving knife is only part of the solution - the guard must also be in place whenever possible. This is because in the event of approaching the point of kickback the crown guard above the blade (it's only 2 to 3mm above the material, and the edge of the crown guard should be below the top of the blade) will help restrain the materials so that they cannot climb on top of the blade and be launched so easily. I realise that there are major problems with the design of guards on American saws but it is possible to make a safer guard which will work with even a dado head and offer better dust extraction to boot. There's an article over at Badger Pond which shows one man's solution

The other point is thin materials in general. Thin ply can be full of stresses, especially the Chinese stuff we see more and more these days. In order to control the cut it's sometimes worth addiing a guide onto the rip fence to hold the work down. This can be as simple as a piece of 3 x 2 planed softwood held on temporarily with a couple of G-clamps (or feather boards for that matter) or more complex such as using a pair of Board Buddies mounted on the rip fence. This helps stop the material from being lifted off the table to the point at which the rising teeth can catch it and launch it in your direction.



DonkeyHody said:


> It isn’t that I thought it COULDN’T happen to me, but I thought I was smart enough and careful enough to prevent it. Well . . . I was wrong.


I've heard that a few times in my life. Even said it myself. I'd say that many woodworkers aren't aware that a 10in sawblade spinning at 4300 rpm (Unisaw speed) has a peripheral speed of about 11,260 fpm (or approx. 3430 m/min). In car terms that's a tad over 120 mph (or around 200 kmph). When a kickback occurs a good amount of that velocity is imparted to the object which is coming your way, so no way you are going to step neatly to one side and miss that in time. Which is a good reason to stand out of the firing line if at all possible when ripping timbers on the table saw

You might be interested in what we teach apprentices - it's pretty much encapsulated in this document on our HSE web site and is good advice to any saw user looking to reduce accident risk. Realise that I may be preaching to the converted, but maybe somebody else reading this will benefit

To end this there has to be a gory story. Back in the 1980s I did some weekend work for a joiners shop in return for the use of their kit. One Saturday morning there was a young lad (boss's son), maybe 18 years old, who was ripping down some American black walnut which was absolutely full of stress. He'd already had several loud jams when there was a massive bang! The saw was a 10HP 16in machine, hand fed, and it had launched a 2in thick by 20in wide walnut board backwards across the shop. In the process it broke three of the lad's fingers and left him with a massive gash in the left arm. He'd become so frustrated with this timber that he'd removed the crown guard to see what was going wrong with the cut. I think he was lucky no to have had much worse injuries

Regards

Phil






.


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## Stick486 (Jan 4, 2013)

DonkeyHody said:


> , but I decided against it this time* because I was only *making one cut before returning to the crosscut sled. OK, I was lazy and stupid.


You hit the nail on the proverbial head...


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## DonkeyHody (Jan 22, 2015)

Thanks to all for your concern and advice. I'm convinced that the bruise is only skin deep because it's not nearly as tender today as yesterday, and it doesn't hurt unless I push it firmly. 

Phil, I followed your links and I like the design of the overarm guard. However, I don't see myself building one. I'll do two things different that should help prevent a recurrence. 
1. I'll use my splitter except when the operation won't allow it. 

2. I'll raise the blade high enough for the gullets to clear the workpiece and then some. 

Thanks again for all the replies. I'm back in the shop today, wiser and more careful.


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## RainMan 2.0 (May 6, 2014)

Phil that was a scary story and I could hardly imagine how painful that would have been breaking three fingers! :fie:

My biggest concern is a router bit breaking at 23,000 rpm , as I've read here that there are documented cases of people dying from that .
I would feel better if I had a bullet proof vest while routering . Could use it when I cross the border into the States too, so it could serve two functions


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## Phil P (Jul 25, 2010)

RainMan1 said:


> Phil that was a scary story and I could hardly imagine how painful that would have been breaking three fingers! :fie:


The thing is, Rick, that everyone I know in the trade has a few stories like that, not to mention a few scars. But major injuries really aren't that common - in fact it's well documented that the two most dangerous pieces in any tool kit are the Stanley knife and the step ladder....... Who'd have thought that?



RainMan1 said:


> My biggest concern is a router bit breaking at 23,000 rpm , as I've read here that there are documented cases of people dying from that


We used to have a shop with a CNC router, so I've seen quite a few breakages. Most of the time (at least with straight bits) the cutter just drops vertically and that's all. The biggest issue is if you hit metal when routing, such as a screw embedded within a piece of chipboard. Then the carbide or even the end of the bit can break away. I've had a few scratches on the hands off that, but nothing to worry about, because the pieces weigh very little (so relatively low kinetic energy). I'd say main thing is to keep your face out of the way or wear safety spectacles (I wear specs all the time, and they are safety rated)

Regards

Phil


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## Stick486 (Jan 4, 2013)

Phil P said:


> The thing is, Rick, that everyone I know in the trade has a few stories like that, not to mention a few scars. But major injuries really aren't that common - in fact it's well documented that the two most dangerous pieces in any tool kit are the Stanley knife and the step ladder....... Who'd have thought that?
> 
> Regards
> 
> Phil


I'd thought it was the straight bladed screw driver...
and who ever invented that drive ought to dug up and really punished...


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## Gaffboat (Mar 11, 2012)

It's the "I'm only making one cut" thought that gets us. Every time I catch myself thinking that, I immediately chastise myself and take whatever steps and however long is needed to do it right. I know from experience that taking the quick shortcut is a tough habit to break. I guess it's a matter of mindset. I always unplug my tools before making an adjustment and rather than get annoyed when I fail to plug it back in before trying to use the it again, I pat myself on the back for doing it safely. Positive reinforcement is good even when it's self administered. :yes4:


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## Stick486 (Jan 4, 2013)

DonkeyHody said:


> Thanks to all for your concern and advice. I'm convinced that the bruise is only skin deep because it's not nearly as tender today as yesterday, and it doesn't hurt unless I push it firmly.
> 
> Phil, I followed your links and I like the design of the overarm guard. However, I don't see myself building one. I'll do two things different that should help prevent a recurrence.
> 1. I'll use my splitter except when the operation won't allow it.
> ...


go to a riving knife that raises and lowers w/ the blade instead...
raising the blade too high is not such a good plan either.... stay w/ the gullets nearly clearing the material...


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## russmatt (Aug 27, 2014)

Wow! A great lesson to all of us to always be alert and careful (apologies, but my "cat-like reflexes" no longer exist). I have removed all that supposed "safety stuff" from my table saw and have substituted three things, which are (1) an expectation that working with power tools with sharp edges is always hazardous, (2) full and absolute concentration on what I am doing right now, including using push sticks, hold-downs, feather boards, and anything EXCEPT my body to hold things in position, and (3) never having more than one tool operating at a time. I can always buy more lumber if I mis-cut it, getting new kidneys or a new spleen is considerably more difficult. Hope you are healing well, and that, as the say, "whatever doesn't kill you, makes you smarter."
russmatt, Pa, USA


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## RainMan 2.0 (May 6, 2014)

Phil speaking of specs , I have watched numerous YouTube videos with guys standing what looked to me like they were directly behind the table saws blade with no safety glasses or eye protection ? 
Scares the hell out of me as I've had a few carbide teeth come off my blade and heaven forbid there directed at you when they come ff . I wear a full sheild plus reading glasses if I have to be close to see what's going on .

Stick , I find having the blade up high is better for dust as it's not pushing the cut material towards you but down instead . With the blade high it is also pushing the material down more in theory .
I don't raise it up as much recently as I find it looks to intimidating


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## RainMan 2.0 (May 6, 2014)

Gaffboat said:


> It's the "I'm only making one cut" thought that gets us.


Oliver you called it right there


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## jw2170 (Jan 24, 2008)

Thanks for posting, Andy.

...We can all learn from incidents like this..We do not want members to have to change their name to 'Lefty'....


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## DonkeyHody (Jan 22, 2015)

jw2170 said:


> Thanks for posting, Andy.
> 
> ...We can all learn from incidents like this..
> 
> I hope someone (besides me) can learn something from this. I certainly didn't post it to make myself look smart (or sexy).


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## Stick486 (Jan 4, 2013)

DonkeyHody said:


> jw2170 said:
> 
> 
> > Thanks for posting, Andy.
> ...


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## DaninVan (Jan 1, 2012)

Or 'The Late'...


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## Phil P (Jul 25, 2010)

RainMan1 said:


> Phil speaking of specs , I have watched numerous YouTube videos with guys standing what looked to me like they were directly behind the table saws blade with no safety glasses or eye protection ?


Hi Rick

My two main concerns are my fingers/hands and my eyes. I regard sawing in the same way I regard grinding - worthwhile putting on glasses for (but as a full-time wearer probably less of a chore for me). I think the worst tool for throwing stuff back at you, though, has to be the lathe. We have a guy who comes in from time to time who has three or four big "dents" in his forehead - he's a trade wood turner and has had various pieces "explode" on him over the years. Nowadays he works in a face shield.......



Stick486 said:


> I'd thought it was the straight bladed screw driver...
> and who ever invented that drive ought to dug up and really punished...


The comment was based on hospital statistics , Stick, which they always give you when you are training as a First Aider. Presumably people don't need hospitalisaton for most of those injuries. In any case who uses slotted screws these days? We went onto Pozidriv/Supadrive something like 30 years ago. I've stabbed my fingers a few times over the years - normally with a Phillips bit in a cordless whilst installing plasterboard (sheetrock). Hurts at the time, and can bleed a bit, but normally doesn't require a trip to A&E (ER). I've lost fingernails that way once or twice. Just a hazard of the job, really

Regards

Phil


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## Stick486 (Jan 4, 2013)

Phil P said:


> In any case who uses slotted screws these days?
> 
> Regards
> 
> Phil


they just don't seem to go away....


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## neville9999 (Jul 22, 2010)

Work safe Andy. N


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## Cherryville Chuck (Sep 28, 2010)

Stick486 said:


> they just don't seem to go away....


The only ones you see here come with hardware made in the US. Anything made here comes with square drive. Robertson invented them because he stuck himself in the hand with a slotted driver. If you wanted to buy slotted here you would have a hard time.


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## Shop guy (Nov 22, 2012)

I had a similar experience about a year ago. I bet you don't forget the riving knife next time. Sorry for your pain but you just became a safer operator.


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## rrrun (Jun 17, 2014)

Thank you for the cautionary tale. Very well presented ... and I learned a lesson right along with you.

Though I'm not bruised, thankfully.


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## DesertRatTom (Jul 3, 2012)

Had that happen on my old Delta contractor saw, which had no riving knife. I didn't have a leather apron, so it scraped my belly up pretty thoroughly. Shortly after that I got a Gripper and stopped using warped ply. I generally let the sawblade tips clear the piece by a little extra. I break down ply with my DeWalt 18v saw, then cut to exact sizes on the table saw. Also have a new saw, a Laguna fusion, which has a very cool riving knife setup.
Learned my lesson!


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## firstmuller (Aug 28, 2014)

RainMan1 said:


> Stick I find it easy to stand to the side and I've got short arms . My cat like reflexes help to


If your not careful, those arms could get shorter yet!:no:
Allen


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## RainMan 2.0 (May 6, 2014)

firstmuller said:


> If your not careful, those arms could get shorter yet!:no:
> Allen


You guys crack me up . For the first time ever I am going to install that riving knife thing . Well as soon as I find it lol


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## Phil P (Jul 25, 2010)

If you don't mind this being in German there's an explanation of kickback here which shows how I was taught to deal with it and puts into pictures my comments above. Note riving kinfe but no guard - it explains that by reducing the height of the teeth above the material you obtain a _better quality cut_, but the danger of a kickback is *increased*. Even more so if the riving knife is poorly aligned. From SUVA in Switzerland

Regards

Phil


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## Bryan Rocker (Jul 10, 2014)

I can totally relate to this thread. A few years ago I had just cut a chunk of 3/4" plywood at a 45 degree angle to make some french cleats. In my haste to get it done quickly I straightened up the blade pulled it down to about 2" gap and was going to cut it up into a few pieces. First one cut, second one cut, both setting next to the running blade. Third one started pushing the first one into the teeth, in the time for me to think about it the blade grabbed hold of that cleat and flung in the back of my right hand into my chest on the way back to the garage door some 10' back or so. I hurt for months, nothing broken except my pride.......

Its always those quick this won't take a second cuts that cause us the most problems......we men are knuckle heads some times........


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## AzOwl (Jan 25, 2015)

Not to brag or anything but to underscore the importance of wearing safety glasses too..

During my remodel project a few years ago, I was using my skill saw to cut out an existing window opening into a doorway. The house is stucco and there is metal mesh around the window frames. I had about 4" to go when i remembered my safety glasses were over on the workbench - It was one of those 'I'm almost done... next time" when the blade hit the metal lath and 2 pieces went into my eye.

I was very lucky that I didn't loose my sight but I had to sit there awake and sit very still as the doctor used a long needle to fish the metal out of my eye. Now I get the glasses on before picking up the tool.

Good luck on healing quickly.


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## RainMan 2.0 (May 6, 2014)

AzOwl said:


> Not to brag or anything but to underscore the importance of wearing safety glasses too..
> 
> During my remodel project a few years ago, I was using my skill saw to cut out an existing window opening into a doorway. The house is stucco and there is metal mesh around the window frames. I had about 4" to go when i remembered my safety glasses were over on the workbench - It was one of those 'I'm almost done... next time" when the blade hit the metal lath and 2 pieces went into my eye.
> 
> ...


Al I wear a full sheild as that scenario does concern me . Watched numerous YouTube videos with guys cutting wood on a table saw with no eye protection and there eyes were in the path of the blade .
Boggles my mind watching them as I didn't know anyone was that careless . I have had carbide teeth missing on my blade and could hardly imagine if one came off and got you in the eye .



I started thinking about kickback again and I have never had a piece of wood touch the top of the blade and kick back , it's always been kicked out between the blade and the fence , so I'm not seeing where a riving knife is going to help ?


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## DaninVan (Jan 1, 2012)

Rick; there was a thread here in the last couple of weeks re having the blade set barely above the top surface of the wood causing the piece to lift and 'slingshot' back.
It's certainly happened to me..._but I use a blade guard with anti-kickback pawls!_
No harm no foul?


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## Phil P (Jul 25, 2010)

RainMan1 said:


> I started thinking about kickback again and I have never had a piece of wood touch the top of the blade and kick back , it's always been kicked out between the blade and the fence , so I'm not seeing where a riving knife is going to help ?


I think you've missed more than one point there, Rick. A long fence (especially if incorrectly aligned) can force material onto the rising teeth at the back of the blade, so can reaction timber where the kerf closes up and attempts to pinch the back of the blade, so can reaction timber which spreads outwards and causes a trap between blade and long fence, so can operator error (especially with shorter pieces). so can lack of outfeed support on longer pieces where the timber can start to "bow-up" during the cut (and narrower pieces can be worse because they have a greater tendency to twist - and go into the blade), etc, etc. Don't think that "reaction timbr" means just hardwood - I've had softwood and even badly stored chipboard behave this way. In addition the European approach of fitting a crown guard above the blade whenever possible limits the direction in which the timber can launch, should it happen.

I've been doing this job long enough to have seen some bad accidents, and as I'm not a lizard and can't regrow them, I tend to treat my fingers with respect

Regards

Phil

_Just because it hasn't happened doesn't mean to say it can't......._


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## DonkeyHody (Jan 22, 2015)

I started thinking about kickback again and I have never had a piece of wood touch the top of the blade and kick back , it's always been kicked out between the blade and the fence , so I'm not seeing where a riving knife is going to help ?[/QUOTE]

You can get a "skitterback" by letting any piece of wood loose on the top side of the blade. However, unless the wood is dropped from a distance, the teeth don't get enough bite on the wood to impart any serious velocity. It'll skitter back and maybe scare you into hurting yourself, but it's unlikely to cause much damage of its own. I've seen video of a kid deliberately dropping blocks of wood from height onto a spinning blade, and that's a different story. 

But real kickback depends on the fence to anchor the piece so that it is pinched sideways against the rising teeth on the rear of the blade. Then, the blade gets a firm bite on the wood and the wood is soon travelling at near blade speed, which is in the neighborhood of 100 mph. You will often find the classic arc from the blade teeth on the bottom side of the wood, just as mine did. 

This pinching action becomes more pronounced the farther the fence is from the blade. A riving knife or splitter helps prevent kickback, not by keeping the wood off the top of the blade, but by preventing it from being pinched sideways into the rising teeth on the rear.


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## DaninVan (Jan 1, 2012)

Andy; Phil covered a number of binding issues that aren't fence related.
As he's pointed out on many occasions, riving knives seem to be mandatory over there.
Maybe mandating them is over the top, when you can't even get guys to use their blade guards. Baby steps...


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## Phil P (Jul 25, 2010)

DonkeyHody said:


> However, unless the wood is dropped from a distance, the teeth don't get enough bite on the wood to impart any serious velocity. It'll skitter back and maybe scare you into hurting yourself, but it's unlikely to cause much damage of its own.


As you agree, even a 10in blade is running at more than 100mph at it's periphery, so in terms of serious velocity, how much speed do _you_ need? If you are sawing 6mm (1/4in) plywood running with the teeth coming just above the surface of the material and you lift that material just 6 or 7mm (1/4in) at the blade there is always a possibility that it can catch and come back in your direction fairly rapidly - and not just "skitter back" as you imply. The reason I tend to run with the crown guard set just above the work piece surface, but below the very top of the blade is to ensure that this cannot happen on 95% of cuts



DonkeyHody said:


> A riving knife or splitter helps prevent kickback, not by keeping the wood off the top of the blade, but by preventing it from being pinched sideways into the rising teeth on the rear.


I work in an environment where a crown guard is _almost always_ used in conjunction with a riving knife. The vast majority of cuts that you do when sizing timber or sheet material are of this type. The riving knife alone isn't a complete solution.

The fact that US forums regularly seem to refer to kick backs on saws, whereas on European forms it's much less of a topic maybe indicates something about the relative merits of "traditional" American saw set-ups (i.e. no riving knife, no crown guard, long rip fence and push blocks which allow the hands to run across/along the side of blades) vs. European practice (riving knife, crown guard, shorter rip fence and long push sticks). After decades of intransigence American saws are finally on the market with riving knives which is a start, but still isn't a anywhere near the complete solution

Regards

Phil


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## DonkeyHody (Jan 22, 2015)

DaninVan said:


> Andy; Phil covered a number of binding issues that aren't fence related.
> As he's pointed out on many occasions, riving knives seem to be mandatory over there.
> Maybe mandating them is over the top, when you can't even get guys to use their blade guards. Baby steps...


Uh . . . no argument here. I was quoting Rainman in the first sentence, but somehow it didn't show up as a quote. I wasn't trying to argue with Phil. My discussion was an attempt to explain why you need a splitter, even though it won't keep the wood off the top of the blade. Looks like I muffed it.


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## DonkeyHody (Jan 22, 2015)

Phil P said:


> As you agree, even a 10in blade is running at more than 100mph at it's periphery, so in terms of serious velocity, how much speed do _you_ need? If you are sawing 6mm (1/4in) plywood running with the teeth coming just above the surface of the material and you lift that material just 6 or 7mm (1/4in) at the blade there is always a possibility that it can catch and come back in your direction fairly rapidly - and not just "skitter back" as you imply. The reason I tend to run with the crown guard set just above the work piece surface, but below the very top of the blade is to ensure that this cannot happen on 95% of cuts
> 
> 
> I work in an environment where a crown guard is _almost always_ used in conjunction with a riving knife. The vast majority of cuts that you do when sizing timber or sheet material are of this type. The riving knife alone isn't a complete solution.
> ...


Phil,
I was attempting to make a distinction between the vicious kickback that a splitter will prevent and other, less energy-intensive forms of having the wood come back at you. The point I was trying to make was that while a splitter won't solve all your problems, it will save you from the worst. Now, can you send me a crown guard for my Unisaw?


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## Phil P (Jul 25, 2010)

DonkeyHody said:


> Now, can you send me a crown guard for my Unisaw?


No, but you could always build your own

Regards

Phil


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## DaninVan (Jan 1, 2012)

Something like this?
https://www.kmstools.com/general-international-excalibur-overarm-blade-cover-dust-c-2200


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## DonkeyHody (Jan 22, 2015)

Phil P said:


> No, but you could always build your own
> 
> Regards
> 
> Phil


I guess I didn't know what a crown guard was. I envisioned a crown guard as basically "wings" that are part of a riving knife and extend forward to cover the top of the blade. Thanks, but I'm just not ready to go that far. I am using my splitter faithfully now though.


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