# How effective are riving knives at preventing kickback?



## REH (Sep 19, 2012)

Safety is important to me. Yet, unfortuantly, there is usually a dollar price tag associated with safety.

I have not found many (none actually as yet) used table saws with riving knives (that ride up and down in a fixed relationship with the saw blade). I wanted to buy a used TS to get more bang for my buck and save some money. But I am having second thoughts given that I will give up this safety feature.

How effective are riving knives? Are there any studies that attempt to quanitifty how much kickback is reduced by thier use?

How do you justify giving up added safety compared to the potential of your injury. Losing a finger(s) would hurt or eliminate my playing of guitar. A high price for saving some money by giving up safety features.


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## Tennessee (Jul 8, 2011)

I ran two different table saws for years without riving knives. Maybe one or two kickbacks in over 20 years. One put a hole in the wall. I learned to stand off to the side when cutting.
That being said, now that I have a decent riving knife on my Rigid 4512, I cannot imagine running wood through a table saw without one again save for blind cuts. I probably am very lucky.


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## teejk (Jan 19, 2011)

Tennessee…you aren't lucky, just typical. I think I've had one kickback on a TS in 20 years (on a board where I ignored the signs that "it wasn't happy"). But if the riving knife works then by all means use it. 10,000 boards without incident get erased by the exception.


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## Loren (May 30, 2008)

Generally it is tension in the board that causes problems
when ripping. If you rip your solid woods on the band saw
the problem goes away. A decent and properly set up 
band saw can rip very straight and wood loss is minimized. 
After that you can joint the edge or skim it straight on the
table saw safely.

In terms of crosscutting and breaking up sheet goods the
riving knife is not needed, imo.

Do I rip solid woods on the table saw? yes… and I do it
with a retracted (short) fence like they do in Europe. The
short fence gives the wood somewhere to go if it wants
to distort away from the blade coming out of the cut. With
a long fence then the wood is forced sideways into the
blade in such circumstances. The riving knife is useful
but not a panacea for safe ripping.


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## Tennessee (Jul 8, 2011)

Loren: I'd agree with that, no guard is 100% safe. I also have a rather rugged set of kickback teeth on the back end of my guard which mount to the riving knife, something I actually consider more worthy.


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## crank49 (Apr 7, 2010)

I like my riving knife and it would sway my decision in buying a table saw of comparable values otherwise. 
But, a choice between a 10 year old big iron cabinet saw, without a riving knife and a modern cheap hybrid like what I have now, if they were the same price, I be all over the big iron.
I would come up with a way to at least add a splitter to the big saw.


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## OggieOglethorpe (Aug 15, 2012)

In my experience, they're very effective.

Along with eliminating the obvious danger of released stress in solid wood allowing the kerf to close on rising teeth, I find it helpful on sheet goods. The knife helps keep the cut stock against the fence, which I find useful with larger sheets, especially when bevel ripping.

I have never liked anti-kickback pawls. They totally interfere with sleds, jigs, and zero clearance backup fences. I've also had them scratch the work. This can be repairable with solid wood, but can be a real issue with plywoods.

The beauty of a properly set up riving knife, which ends a hair below the blade, is that you can leave it in place all the time, regardless of through, non-though, sleds, jigs, whatever… To protect you, a safety device needs to be installed, not on the shelf or floor.


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## Swyftfeet (Jun 15, 2012)

I picked up an old Griz 0690 off Craigslist, right tilt, no riving knife. I do use a feather board, a push stick, and a Micro-Jig to keep my self as safe as possible given the circumstances. One thing I noticed when working on my current project is that when ripping 4/4 black walnut the boards seem to be rubbing the blade (Brand new Freud Fusion ATB) and I am getting a little burn randomly through the rip, mostly the first third of the cut. I have jointed the one edge that rides along the fence, and I have checked(several times) the parallelism of the blade and the fence and it seems to be within about .002" But still seems to be pinching in some cases. This does not occur when ripping stable stock, like plywood or mdf. Is this normal? Would a riving knife fix this?


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## HorizontalMike (Jun 3, 2010)

All I can say is that the riving knife drove my purchase of the G0690 TS. I hate splitters and kickback pawls, so the way Grizzly integrated the Riving knife sold me. Unlike Crank, I sold out for the riving knife , and I do have to say my newer G0690 can probably be classified as "big iron" since it tops out over 600lb. with the router extension table.

FWIW, I also use the Yellow Board Buddies rollers on the fence as an added measure of safety. They work well and are easy to adjust to the current need/cut.


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## Sgaffin (Mar 22, 2012)

In a shop with about 270 college students. The only kickbacks where wen the riving knives were not attached. It does take time to take them off when they are in the way but I don't think it affected production time as much as some people make it out to be.


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## MR_Cole (Jun 1, 2012)

I have pushed a board through the table saw that was pinching on the riving knife so hard that i couldn't get it through the table saw. Without the riving knife i would be picking bits of wood out of my skin. That being said, It feels alot safer to use a table saw with a riving knife. You can get a used ridgid table saw for $200 with a riving knife.


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## klassenl (Feb 13, 2011)

Another vote for buying a saw with a riving knife. Mine is a General 50-200. Good saw.


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## teejk (Jan 19, 2011)

cole…to push that hard tells me the board "wasn't happy". I watch those and generally toss them in the scrap pile. I figure if they can't handle a cut, they won't like being put in any finished piece either.

and horiz…do those rollers eliminate the need for my home-made feather boards (say e.g. running a board on edge of 3/4" stock for panel dados)?


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## HorizontalMike (Jun 3, 2010)

*teejk: "...and horiz…do those rollers eliminate the need for my home-made feather boards (say e.g. running a board on edge of 3/4" stock for panel dados)?..."*

YES. The "Yellow" Board Buddies only roll ONE way and lock if you try to roll them backwards toward the operator. You want the "YELLOW".

http://www.grizzly.com/search/search.aspx?q=board%20buddies&cachebuster=1134331692494796.5 
Yellow = Table Saws (roll clockwise)
Green = Shapers (roll both directions)
Orange = Radial Arm saws (roll counterclockwise)

The Board Buddy Track allows you to adjust positions of the board buddies. This mounts on your fence.


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## Milo (Apr 24, 2009)

Ed,

I am kind of surprised no one said anything about a simple splitter behind the saw blade. For the most of us, 99% of our cuts are vertical cuts against the fence. With this cut, a splitter is no different than a riving knife. A riving knife just moves with the blade when you make an angled cut. And the pressure on the board is different in an angled cut.

Just get a good splitter, adjust your fence, and you'll see a huge difference in kickback.

And this is from the guy who once sported a perfect diamond shaped bruise for a week from a piece that shot off the table, bounced off my stomach so fast I didn't feel it (at first!), went through a window in the door, and landed 20 feet from the shop!


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## REH (Sep 19, 2012)

"Losing a finger(s) would hurt or eliminate my playing of guitar. A high price for saving some money by giving up safety features."

*If this is important to you, then I would save my money and get a SawStop. 
A riving knife may help kickback, but it's not going to help if you accidentally hit your hand on the blade.*

Good point, Jonathan. As I think about it, I'd rather pay $50,000 than lose a finger. So a Sawstop is really not much cost as insurance to avoiding that experience. And a riving knife is not much cost to help avoid kickbacks.

I see clearly, that for me, I should take advantage of the safety features that are currently available.

Thanks for all the input.


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## EEngineer (Jul 4, 2008)

You can get a used ridgid table saw for $200 with a riving knife.

No! You cannot! I spent some time looking a few years ago. They ain't there. Oh, everybody runs into that special deal once in a while, but, in general, they ain't there.

Kickback problems are easy to solve. Don't cut dangerous wood (you'll know real early when the internal stress is going to cause problems) and it is never a good idea to stand right behind the blade whether there is a chance of kickback or not! Don't crosscut with the fence (Norm covered this 20 years ago) and make yourself a crosscut sled.


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## Grandpa (Jan 28, 2011)

Mike, Jonathan and I have never used the board buddies and they just look like they would be in the way of a push stick or push block? How wide can the board be and the buddies still work?

Jonathan….. I have never used a riving knife but I thought they came in different thicknesses to match your blade. Am I wrong here? If they are then they wouldn't be the same as a splitter…..right??

Well, Mike educate us a bit.


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## Loren (May 30, 2008)

Board Buddies will work with the fence as little as 1/2" 
from the blade as I recall. I haven't used them in
quite awhile but they do work as claimed. You can
sort of feed on board after another to push the
work. I think I used a 30" or so long offcut as a 
push stick when needed.


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## WoodWorkWarrior (Sep 21, 2012)

+1 for the riving knife. I bought a Grizzly G0715P and a riving knife was a must. The Grizzly saws have a quick release riving knife for blade changes and other options. Very handy and super fast. Ultimately safety is your responsibility and proper technique and use of a saw will mitigate the vast majority of potential injuries…although it sure helps to have more safety features (and gives a bit more peace of mind).


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## Tootles (Jul 21, 2011)

Grandpa, you are correct that riving knives come in different thicknesses to suit the kerf cut by your balde. I know this because I sometimes work with a saw (not my own) that has a thinner riving knife than the blade. It is dangerous - I regularly face the risk of a kickback. I am, of course, working on getting a new riving knife.

It is my understanding that splitters are always thinner than the kerf of the saw blade - certainly that is the case on my personal saw. It does help, but it is not as good as the riving knife that I have fitted to the same saw.

The other issue with a splitter is that unless the blade is raised to its maximum height, the gap between the blade and the splitter is often too big to be really effective.

One thing that I have found is that using an effective push stick can help to reduce the risk od a kickback - depending on the task of course. Today I was ripping a short (500 mm / 20") piece of thin (12 mm / 1/2") timber and was stuggling to keep it down on the table because the blade was catching it and lifting it. I stopped half way through the cut and quickly made myself a "push shoe" instead of my usual push stick. That allowed me to apply pressure along the length to keep the timber down on the table while at the same time pushing it through the blade.


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## Grandpa (Jan 28, 2011)

Thank you Tootles for your response. I thought that was the way they were made but like I said above I have never used a saw with a riving knive. I have been in the woodworking field for 50 years and I try to practice safe work habits. Sometimes that isn't enough though. I have only had a handful of kickbacks in those 50 years. I think about 4 or 5 so I think I have been very fortunate. The nearest I have come (I think) was when I was teaching adult evening classes in a local school and was walking 20 feet behind the saw. The person that was running the saw did something that probably wasn't the right thing to do. The little piece of wood flew off the saw and did hit me. Nothing serious but it got my attention and also their attention. 
If riving knives came in one thickness and you used a thin kerf blade the kerf wouldn't go over the knive or if it were thinner and the blade was a thicker blade, it wouldn't do the job or keep the board opened like it should. This is like you are describing above. The riving knive could be slightly thinner than the saw blade and still work but that is *SLIGHTLY*. I under stand the splitter. It is in a fixed position and the blade moves independently from the splitter. 
We all want larger saws and more power. That means they have the potential to throw those pieces of wood faster and farther. Not that the smaller saws are not dangerous too. 
Thanks again for the input. You and I are seeing this the same way. I suppose that either makes both of us right or both of us wrong….LOL


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## ssnvet (Jan 10, 2012)

My first TS was a 1950 vintage 8" Craftsman I got at a garage sale for $20. The saw had a broken fence and I was clueless about tuning a TS then, so I wound up having sevral kick backs. I was fortunate, and the worste injury I had was brused knuckles. The saw scared me so I gave it away.

Since I got a "decent" saw (Emerson built Craftsman TS with the AL rail fence) I haven't had any kick back incidents. I attribute most of this to education…. with this saw, I took the time to actually learn something about TS alignment and use…. and a lot of that knowledge came straight from the well written and illustrated owners manual.

I've used the saw more than ever since setting up a new basement shop last winter, and I use the splitter with pawls whenever ripping.

I think one of the biggest 'safety aides' to preventing kickback on a TS is having a jointer, as I never put a wobbly board on the TS or rip a board with a warped edge against the fence. Joining one face flat and one edge straight makes ripping very safe.

I'm refurbishing a mid '80s vintage Jet cabinet saw, and will be definatley looking into a shark gaurd.

If I had the doe, I'd definatley go for a new TS with a riving knife…. but I've proven to myself that I can be safe without one, so I don't consider it a necessity.


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## JohnEinNJ (Dec 22, 2011)

Here's another brand of "board buddy"-like rollers that's on sale right now. I bought a set, but haven't tried it out yet…

http://woodworker.com/anti-kickback-hold-down-mssu-96974.asp

Incidentally, the first set they sent had a stripped screw-hole. Woodworker.com sent a new one out before I sent the old one back. 5 stars for customer service.


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## HorizontalMike (Jun 3, 2010)

You can use Board Buddies down to less than an inch. The roller actual is extendable and can be lengthened and/or shortened as needed. You can also change the height of them for use with 1/4"(0") and roughcut over ~9/4 (my experience). They can get in the way on occasion, though I would say in a minor way with thin and narrow cuts. It is possible that a less than 3/4" featherboard might be better on these very small/thin cuts. Other than that, I would NOT sell these things short. They work well and are easy to set up.


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## AJswoodshop (Mar 2, 2012)

Always use a riving knife with a table saw! Without it, the board slightly goes of the fence and into the blade, it's going to fly back at your face. It happens so quickly, that you don't have time to dodge the flying board from the kickback. HorizontalMike said that you can use the board buddies, those are good too. Again, never use a table saw without the riving knife. Because if you don't use it, you'll have a really nasty looking face.


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## Grandpa (Jan 28, 2011)

Am I correct when I say you can't use a traditional push stick or push block with the board buddies? You can't push past the axles for the yellow wheels. Do you use a push stick under those axles and push horizontally under them? That is what I see.


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## HorizontalMike (Jun 3, 2010)

Grandpa: "...Am I correct when I say you can't use a traditional push stick or push block with the board buddies? You can't push past the axles for the yellow wheels. Do you use a push stick under those axles and push horizontally under them? ..."

I use push stick with Board Buddies all of the time. On occasion I will use the push stick UNDER (right hand) and with my left hand I have a push stick that I assist with pushing but mostly for holding the cut piece DOWN as it passes the blade. Most of the time my piece against the fence is 2-4" wide and thus I do not have to "duck" under a Board Buddy. I would imagine that it is no different than a featherboard in that it ALSO would require one to use a push stick "under" the featherboard on occasion.

Bottom line is that IMO, BBs are more versatile than standard featherboards. They can more easily be adjusted for a longer/custom reach than a featherboard. Both can equally be adjusted in height with ease. I also feel that the BBs are stronger at holding the piece down without an increase in friction.


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## dnick (Nov 17, 2011)

I use splitters with zero clearence inserts most of the time. I use micro jig splitters for thin kerf, shop made for full kerf. I have a Craftsman 22116 that has a splitter & a riving knife. They both perform the same function. The riving knife is higher than the blade, the splitter is the same height as the blade. I haven't used the riving knife yet.


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## Grandpa (Jan 28, 2011)

Sorry to hi-jack the post but this was a good time to ask some questions about the Board Buddy. I have never used one of those either and I do appreciate the testimony. Thanks for allow me to do this. I don't own a saw with a riving knive and have never used another saw with a riving knife. I am not opposed to them, I just don't have access to one. 
When I have trouble with a board rising at the blade, the blade is getting dull. When I experience this I change to a sharp blade. They seem to cut before the board can pick up off the table. just my feelings. I have splitters but they get in the way. Like I said I have been doing this for 50 years and have probably done some dangerous things but I have never had an accident. I do worry about my grandchildren. I DON'T want them hurt nor does any one else. I might look into a Board Buddy though. Thanks Mike, for the answers.


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## lj61673 (Oct 31, 2011)

Kickback has nothing to do with blade sharpness. It occurs when the wood makes contact with the back teeth of the blade as it passes through the cutting area. This can happen with stress wood or if the fence is not adjusted properly pinching the wood between the fence and the back of the blade. No amount of push sticks or "board buddies" can prevent that. 
Prevention starts with the rip fence properly adjusted at .002"- .003" away from the blade at the back end. Using a dial indicator mounted in the right hand miter slot makes this task simple.
That together with a properly adjusted riving knife (not splitter) is the BEST way to avoid the chance of kickback.


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## Ironrooster (Sep 5, 2012)

HorizontalMike
Thanks for the board buddies info and link. I had not realized they had a set for RAS - ordered one today.


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## REH (Sep 19, 2012)

In a shop with about 270 college students. The only kickbacks where wen the riving knives were not attached. It does take time to take them off when they are in the way but I don't think it affected production time as much as some people make it out to be.

Thanks, Sgaffin. At least you (above) and a very few others directly addressed my question about the effectiveness of riving knives.

*My question was "how effective are riving knives in preventing kickback?" * It was NOT "how do you avoid kickback on a table saw?". It seems that many posters had trouble focusing to address my question.


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## BillWhite (Jul 23, 2007)

OK! I'm a wuss.
I use the Board Buddies (remnants from my RAS), a splitter, pawls, Grip Tites, a guard, and anything elase I can find to prevent gettin' beat senseless.
So far, I've prevented any explosive results. I said, "so far".
Bill


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## HorizontalMike (Jun 3, 2010)

Bill,
As long as you can still count to 10 on your fingers you are doing good. That is unless you are special and count to 12:


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## lj61673 (Oct 31, 2011)

*My question was "how effective are riving knives in preventing kickback?" It was NOT "how do you avoid kickback on a table saw?". It seems that many posters had trouble focusing to address my question.*

Knowing how kickback occurs is a prerequisite to knowing how and why a riving knife prevents it. Riving knives are the MOST EFFECTIVE tool in preventing kickbacks. 
Focused enough for you?


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## REH (Sep 19, 2012)

Riving knives are the MOST EFFECTIVE tool in preventing kickbacks. 
Focused enough for you?

Yes. Thanks for being able to focus and anwer. I appreciate it.


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## HorizontalMike (Jun 3, 2010)

lj61673,
Kickback prevention IS reduced when using Board Buddies, except maybe in the isolated example you sited of "stressed" wood.

Kickback prevention is not always an either or proposition. IMO, there is an undeniable synergy between using a riving knife *with* either featherboards or Board Buddies. That resulting layer of protection is greater than the sum of the two protective/preventive systems added individually. That being said, it is relevant to bring into the conversation the riving knife's synergistic partner in kickback prevention effectiveness.


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## lj61673 (Oct 31, 2011)

Mike, (cover your ears Ed to avoid learning something you didn't ask) a properly installed and adjusted riving knife prevents, re: does not allow, wood to come in contact with the back teeth of the saw blade as it passes. No other *single* safety device can do this. Board buddies "help" to keep the wood against the fence but do not provide the barrier that a riving knife does.


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## HorizontalMike (Jun 3, 2010)

So you agree. You just state it differently.


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## Tootles (Jul 21, 2011)

Riving knives are the MOST EFFECTIVE tool in preventing kickbacks.

But the riving knife must be the right thickness for the kerf cut by your blade, otherwise it loses some of its effectiveness.

It seems that many posters had trouble focusing to address my question.

Ed, I see that you have only been on LJ's a few days. Once you have been here a while you will see that this is just how it goes. Topics ramble around and get sidetracked in many directions. Along the way, a lot of people who may not be actively taking part in the conversation learn a lot more about the specific topic and a whole lot more. It's that breadth and depth of information, and the willingness to share it, that makes LJ's a great place to learn.


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## HorizontalMike (Jun 3, 2010)

*Riving knives are the MOST EFFECTIVE tool in preventing kickbacks.*

But the riving knife must be the right thickness for the kerf cut by your blade, otherwise it loses some of its effectiveness.

And let us NOT forget about technique, or lack there of. Having had a kickback WITH my riving knife in place, I have been made aware of this also. *;-)*


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