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So what's the big deal about a riving knife?

by BlankMan
posted 07-26-2012 08:21 PM


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53 replies

53 replies so far

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NewEnglandsWoodWorks

117 posts in 2417 days


#1 posted 07-26-2012 08:31 PM

A riving knife can be used during non through cuts.

-- Brett

View jmos's profile

jmos

792 posts in 2185 days


#2 posted 07-26-2012 08:34 PM

I would love to have one instead of my splitter, but no one makes one for my saw. My big gripe is the guard and the splitter are one piece, so if your saw has a two piece design, maybe it’s not such a big deal.

The pain is using my crosscut sled, it requires removing my guard and splitter. Likewise non-through cuts, have to pull of the guard and splitter. Narrow cuts, have to pull it off. This usually means I have my splitter in place less than I should since I don’t always bother putting it back on.

I just bought a Shark Guard, which is a two piece design, that should eliminate the issue with my crosscut sled and narrow cuts (haven’t tried it yet, so I can’t say for sure). Still stuck with non-through cuts, but it should be an improvement.

As far as actual operation, I agree, I’m not aware of a design difference where a riving knife will help that a splitter will not. It will be interesting to see if someone else does.

-- John

View MedicKen's profile

MedicKen

1610 posts in 3277 days


#3 posted 07-26-2012 08:44 PM

The riving knife remains in the same place at all times regardless of blade height. The knife will be very close to the rear of blade which will not allow any of the work piece to come into contact with the blade after the cut. A riving knife is much safer than a tradional splitter and I wish manufacturers would have kept them instead of the cheap blade guard and splitter design which looks to me to be an after thought and not an actual safety device. Manufacturers had the riving knife concept figured out a hundred years ago, why fix what nots broken?

-- My job is to give my kids things to discuss with their therapist....medic20447@gmail.com

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knotscott

7754 posts in 3191 days


#4 posted 07-26-2012 08:53 PM

The biggest advantage of the riving knife is that it’s more likely to be in place when needed. It’s also in closer proximity to the bladem, which is plus. All in all, both devices accomplish the same task. There are some real good examples of splitters, but to me, it’s hard to argue that a RK isn’t a more elegant solution to the problem. I’m just not convinced it’s a huge improvement or a “must have”....it’s certainly not worth a large premium to me. I sure wouldn’t pass up a great deal on a nice saw over the RK…..especially when there’s an aftermarket riving knife called the Bolt On Ripping Knife (BORK) that’s retrofittable to several older style saws that originally came with splitters vs a RK….a pretty neat device IME.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View SnowyRiver's profile

SnowyRiver

51453 posts in 3296 days


#5 posted 07-26-2012 09:19 PM

I agree with what has been said. Its important to have the riving knife close to the blade so the wood cant get between the knife and blade on the back side of the blade. A lot of riving knives also are shaped like a reverse shark fin and come up over the back of the blade a bit to keep the wood from riding up on the blade. I have a 3 hp saw and never used a splitter or riving knife until one day I was just about killed with a kickback. I put the riving knife on and feel much safer now. The riving knife that I have, as some have said, doesnt go up and down with the blade, but it does tilt with the blade. I have several different height knives for different applications. I have a quick release lever on the mounting so it can easily be taken on and off.

-- Wayne - Plymouth MN

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crank49

4023 posts in 2786 days


#6 posted 07-26-2012 10:26 PM

Since the RK is attached to the saw’s arbor mounting, and rides up and down with the blade, it can be curved to match the shape of the blade. A splitter, even one that tilts with the blade can’t follow the contour the same way. If the splitter was shaped like a RK it would be destroyed by the blade when it is raised and lowered.
Either device is better than nothing and the real value of the RK is that it is almost never in the way, there is hardly ever a need to remove it.

View oldnovice's profile

oldnovice

6391 posts in 3183 days


#7 posted 07-26-2012 11:05 PM

On my Craftsman TS the splitter is part of is part of the blade guard. My TSis very old, can I get a driving knife from an after market source?

If not, can I attach one to the table insert behind the blade? Obviously it won’t be quite the same as a real RK!
Should it be the same thickness as the blade?

I am asking these questions because there are a number of cuts that require removing the guard and splittter that always make me uncomfortable.

-- "I never met a board I didn't like!"

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patcollins

1605 posts in 2680 days


#8 posted 07-26-2012 11:12 PM

old, i have a old craftsman saw where the splitter and blade guard are one piece. Its sort of a pain so I got the microjig splitter, however I am very disappointed with it. I got it installed good enough now that it keeps me safe and i can use my Gripper push block also from microjig.

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jmos

792 posts in 2185 days


#9 posted 07-26-2012 11:18 PM

oldnovice, the BORK is the only aftermarket riving knife I’m aware of http://www.theborkstore.com/

I tried the microjig splitter and found it worked OK, but was rather finicky to setup.

I just bought a Shark Guard. I received it but have not had any time in the shop to try it out. It’s two pieces, you can take off the guard and leave just a flat splitter, so you can use it with crosscut sleds or for cuts where the fence is so close the guard would interfere. It seems well made, I can’t wait to try it out.

The splitter/RK is usually a bit thinner than the blade.

-- John

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MrUnix

5913 posts in 2014 days


#10 posted 07-26-2012 11:20 PM

My old Craftsman TS is the same.. splitter attached to the guard. First thing I did when I bought the thing some 20+ years ago was to ditch the splitter and guard. Haven’t had an incident yet, not even a close call in all that time. Of course, back in the 70’s while working as a carpenter, it wasn’t at all uncommon to hold a piece of wood in one hand and cut it with a circular saw in the other :)

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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dnick

985 posts in 2197 days


#11 posted 07-27-2012 03:53 AM

I am confused. I have a new Craftsman hybrid for 9 months now, & it has a splitter & a riving knife, & I’ve used the riving knlfe, let’s see…... about zero times. Both raise & lower with the blade, splitter same height as blade, riving knife is higher than blade. I read the first comment, how could I make a non thru cut with the riving knife higher than the blade? The blade guard & pawls attach to the riving knife & it’s so difficult, I don’t bother. I use a hold down ” stick” with the push block, & the splitter. Also have a lot of zero clearance inserts with their own splitters. I was really surprised to learn the riving knife was really useless to me. The splitter & riving knife fit over the blade the same way, the difference is the splitter is the same height as the blade, what’s the advantage of a riving knife higher than the blade ? Really don’t get it.

-- dnick, North Hollywood, Ca.

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TopamaxSurvivor

18067 posts in 3491 days


#12 posted 07-27-2012 04:05 AM

How could you use a dado if the riving knife it higher than the blade?

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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BlankMan

1490 posts in 3168 days


#13 posted 07-27-2012 04:42 AM

Bob, I don’t think you can.

Scott we’re thinking along the same lines it appears.

Hey Wayne is that a BORK?

As was stated early on , a riving knife can be used on non through cuts, which I knew. So? A non through cut is not going to pinch so the need for a riving knife or a splitter (if one could be used) is a moot point.

And having the riving knife closer to the blade I can see but with the splitter I have and the blade set to cut 3/4” stock the splitter is only 2-1/2” from blade exit which is pretty close to have the wood start to deform and close the gap. Never had that happen ever. With the blade at full height the distance decreases to 3/4”. And following the contour of the blade which of course then makes it closer to the blade I don’t see as any great advantage because again, I don’t believe the wood is going to pinch that quickly. Well at least from my experience.

The splitter I have on my Unisaw is a Delta part. Not widely known and not widely publicized. Knew about it when I got my Unisaw so tracked it down an bought one. Not only is it a sturdy splitter it’s a kickback preventer and it lowers when doing non through cuts. That is a big plus and was one of the reasons I wanted one. Having to unbolt and then bolt it back on can lead to, “oh, one quick cut I don’t need it…” thus not taking the time to bolt it back on.

I was wondering this because I read things like buy a new saw not an old one because you don’t get a riving knife and this and that and I just can’t see basing that on, to me, small items like this. Table saws have survived a long time without the latest whiz bang new gadgets.

Been aware of the BORK for a while now, (thanks Scott) but am having a hard time deciding whether a riving knife is so much better then the splitter pictured below which does tilt with the blade. Right now I’m leaning not. Well I guess a better way to put that would be not to use the word “better” but leaning towards not buying which is a 180 from a few months ago.

-- -Curt, Milwaukee, WI

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MonteCristo

2099 posts in 2004 days


#14 posted 07-27-2012 04:56 AM

I agree with Knotscott. The advantages aren’t earth shattering but there are advantages pure and simple. I think North American saws were slow to include riving knives because they were invented elsewhere. Luckily, in the end the best design is finally going to dominate.

-- Dwight - "Free legal advice available - contact Dewey, Cheetam & Howe""

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TopamaxSurvivor

18067 posts in 3491 days


#15 posted 07-27-2012 05:43 AM

Guess that will increase router and bit sales, eh? ;-))

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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knotscott

7754 posts in 3191 days


#16 posted 07-27-2012 09:13 AM

I think it’s more important that one or the other is in place on a saw, than which one. IMHO a splitter or riving knife is one of the most important safety devices available, if not THE most important. Too bad all the TV shows remove them for demonstration purposes…

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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SnowyRiver

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#17 posted 07-27-2012 01:06 PM

Curt…my riving knife is a SharkGuard. He offered a package with several different heights. There are older saws out there that have fittings for a riving knife. My PM66 is a 1988 model and the knife fits on it. On some saws the splitter is part of the blade guard as some have said, but in other cases it mounts on the back of the saw cabinet so you can see the splitter would be quite a ways back from the blade. That was the way my PM splitter was mounted when I bought the saw. The riving knife not only keeps the board from pinching the blade, but it prevents the wood from drifting away from the fence and crossing into the back of the blade as you are pushing it through.

-- Wayne - Plymouth MN

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George_SA

314 posts in 2029 days


#18 posted 07-27-2012 01:31 PM

Main advantage for me is that once it is installed, you forget about it. No removing and putting back for non through cuts. In terms of functionality in preventing kickbacks, I think it is the same as a splitter, except that it is always there, where one might forget or be in a hurry and not put the splitter back after making a non through cut. I wouldn’t buy a new saw just for the riving knife though.

-- There are some things that money can't buy - Manners, morals and integrity

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BlankMan

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#19 posted 07-27-2012 02:18 PM

Thanks everyone. I’m thinking I’m going to stick with the splitter. What I’m getting is that both a splitter and a riving knife will prevent a kickback by preventing the wood from pinching the blade thus causing a kickback but the splitter I have will also stop a kickback if say one occurs because the wood cocks or pinches between the blade and the fence.

Keywords, prevent and stop. A riving knife may prevent but it won’t stop. That to me says the splitter has the advantage.

-- -Curt, Milwaukee, WI

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George_SA

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#20 posted 07-27-2012 02:24 PM

True, I think “prevent” gives one more peace of mind, but on the other hand I have never had a kickback with my riving knife and hoping I never will have one.

-- There are some things that money can't buy - Manners, morals and integrity

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BlankMan

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#21 posted 07-27-2012 02:46 PM

Yeah well I’m ashamed to admit this but I got nailed twice a month apart a year or two ago, had a black a blue mark both times the size of a cantaloupe and they hurt like h. Made two mistakes, stood it it’s path which I still don’t know why because I know better and make it a point not to do, except those times, and didn’t have the splitter up.

I was trimming the boards only take a kerfs width off so they didn’t pinch the blade they pinched the fence. But having a riving knife even though it would have been there would not have helped but the splitter more then likely would have stopped it.

I’ve been doing this woodworking thing for a while and it kind of flabbergasted me that I let that happen, and twice. That’s one thing that always bothers me, complacency, or let the mind wander for a split second. That’s why I sometimes wonder if all these new safety features might lend themselves to that, complacency, and one really won’t be any safer because you’re relying too much on them. You just really have to pay attention ALL the time which in my case includes “where am I standing” and remember and not be lazy and pull the splitter up. “One quick cut” and you just don’t think it’s going to happen you did it thousands of times before…

-- -Curt, Milwaukee, WI

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George_SA

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#22 posted 07-27-2012 02:58 PM

After about 30 years of woodworking, inattention and being in a hurry caused me to put my thump on the blade. One of the basic safety rules: NEVER reach over the blade. Fortunately I followed another safety rule of keeping the blade height just above the wood. No bone was cut in my thumb, but I had a 3mm wide kerf which has affected the feeling in my thumb. I was lucky that time.

I agree with you that if you (edit) only (edit end) start relying on the features for safety, then you are actually operating your saw in an unsafe manner which might bite you when you least expect it.

-- There are some things that money can't buy - Manners, morals and integrity

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Craftsman on the lake

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#23 posted 07-27-2012 04:07 PM

splitter/riving knife explanation:

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

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oldnovice

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#24 posted 07-27-2012 04:36 PM

My splitter has two anti kickback pawls and they work very well when the cut is normal to the saw top but when I want to cut off off vertical I need to remove the splitter and the pawls with it.

That’s is why I am considering a RK! And the BORK looks like the best choice for my saw.

-- "I never met a board I didn't like!"

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crank49

4023 posts in 2786 days


#25 posted 07-27-2012 05:42 PM

Dnick, I have a Craftsman 21833, same saw as the popolar Ridgid 4512.
Its riving knife mounts below the table insert and rides up the same slot as the blade.
It is only about 1/4” from the back of the blade, is curved to follow the contour of the blade.
This design has three positions relative to the blade height.
In the highest position it is above the blade and the top blade guard and anti-kickback pawls can be hooked onto the top of the riving knife. There are slots there for this purpose.
There is a release below the insert plate which will let the riving knife rotate back and down till it is just slightly below the top of the blade. It is still only about 1/4” behind the blade in this position and still works as it should, but does not get in the way of “non-through cuts” or interfere with sled use. In the lowest position the top blade guard can not be attached to the RK.
To me, this is what a riving knife is supposed to be.

As far as wood closing up and pinching the blade in less than 2” from the back of the blade, yes it can. I have had this happen with some black gum befor I had the riving knife. I don’t think that could happen now with my riving knife in place..

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Loren

9560 posts in 3463 days


#26 posted 07-27-2012 07:05 PM

Mounting the guard on the riving knife is a better way to do it.

Manufacturing the mechanism for a riving knife is more complex
than a splitter mounted off the back of the saw. If you’ve
ever had the splitter go out of alignment and removed the
splitter and guard from a saw because the splitter was
annoying, you’ve discovered one of the reasons why
Europe adopted riving knives.

Riving knives probably result in less guard removal.

I always use my saw guard when I am able. I’ve added dust
collection to it and the work area stays substantially cleaner
as a result.

So why a riving knife?

A: because it’s a better, safer and more reliable guard mount
which facilitates better dust collection also prevents
kickback in ripping solid woods.

I wouldn’t get hung up on retrofitting a knife to old saws, personally.
A vertical splitter stuck in an insert does fine for safety and
most table saw cuts do not involve tilting the blade. An overarm
guard is even more flexible than a riving-knife mounted guard
and makes it even less tempting to not use it… especially
with dust collection on top.

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Cato

698 posts in 3128 days


#27 posted 07-28-2012 12:16 PM

I have never felt comfortable running my TS without either a splitter or riving knife on it. Something about looking at that naked blade spinning is intimidating.

I have only had kickback a couple of times and been lucky, but luck is not something I want to count on. I could at least stall out my 1.5hp saws if they bound in a heavcut, but I don’t think that would happen on my 3hp TS so I try to put whatever safety measures I can in place when using it.

The evolution from my first, second, and now third table saw has been better for me each time. My R4511 had a decent riving knife splitter and I got an aftermarket riving knife for non thru cuts as the OEM riving knife had an attached blade guard.

My Jet has been the best for me with its modular system where you can take off each component without tools and it literally takes only a couple of seconds to do. I still had to buy a low profile riving knife for some non thru cuts, but I always run one or the other.

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knotscott

7754 posts in 3191 days


#28 posted 07-28-2012 01:37 PM

”...Keywords, prevent and stop. A riving knife may prevent but it won’t stop. That to me says the splitter has the advantage…..”

Guess I’m missing it….what advantage does a splitter have over a RK?

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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BlankMan

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#29 posted 07-28-2012 02:18 PM

Physically stop a board when kickback occurs i.e. after it has started. That statement is based on the splitter I have and pictured.

-- -Curt, Milwaukee, WI

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knotscott

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#30 posted 07-28-2012 02:32 PM

There are versions of riving knives that have anti-kickback pawls also, that I’d think would maintain there inherent design advantage over the splitter.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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BlankMan

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#31 posted 07-28-2012 02:35 PM

Loren, ”you’ve discovered one of the reasons why Europe adopted riving knives” as I stated a riving knife would not have stopped the kickback I had occur, the splitter I have would have physically stopped it. Read my experience again and tell me how a riving knife would have stopped those incidents from occurring.

Also ”A: because it’s a better, safer and more reliable guard mount which facilitates better dust collection also prevents kickback in ripping solid woods” that’s what people say, I’m not seeing that. It will not physically stop a board the splitter I have which is pictured will stop a board., it may prevent a board from pinching the blade and kicking back and so will a splitter, but it will not stop a board.

I’m looking for facts not opinions.

-- -Curt, Milwaukee, WI

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BlankMan

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#32 posted 07-28-2012 02:36 PM

Thanks Scott, I was not aware of that, never seen one, I would have to agree. I’d like to see some, got any references? Wondering how they incorporate the pawls so that it still is not higher then the blade and still move up and down with the blade

-- -Curt, Milwaukee, WI

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BlankMan

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#33 posted 07-28-2012 02:42 PM

A riving knife with pawls to stop a board might get me thinking about getting a riving knife again…

-- -Curt, Milwaukee, WI

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Loren

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#34 posted 07-28-2012 03:15 PM

Sorry I even bothered to advise you. I won’t do so again.

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knotscott

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#35 posted 07-28-2012 03:41 PM

Curt – They exist on several saws that offer a stock riving knife, but am not sure of any offered as an aftermarket item to fit your saw. Maybe Sharkguard?



-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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BlankMan

1490 posts in 3168 days


#36 posted 07-28-2012 04:46 PM

Thanks for the pics Scott. Well then it looks like with the pawls the riving knife loses its “staying in place for non through cuts” advantage. So again it’s just like a splitter but does still have the advantage of being closer to the blade. And again it looks like removal for non through cuts and we just came 360.

Loren, first you said,

FACTS, huh?

yeah. I see.

then to changed it to

Sorry I even bothered to advise you. I won’t do so again.

Yes the facts. You said it’s better, safer, and more reliable. How is it better? How is it safer? How is it more reliable? Maybe more reliable because there’s no need to remove it, that I can see.

And you stated I discovered why it was adopted, tell me how a riving knife would have prevented the kickback I had? I contend it would not have stopped the kickback I had occur because it was a blade/fence pinch and a riving knife without pawls is not going to stop a board.

Others are offering up information as to why. About the only advantage I’m seeing at this time is that it’s closer to the blade. The examples with the pawls that actually stop a board then make it higher then the blade so it then doesn’t have the non through cut advantage anymore.

So, I’m really starting to think that a riving knife is a bit better then a splitter due to proximity to the blade but not the greatest thing since sliced bread like all the hype it gets. Somewhat of another bandwagon I guess.

Ya know, if I could keep my splitter with its pawls and have a riving knife, that might be the cats pajamas…

-- -Curt, Milwaukee, WI

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BlankMan

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#37 posted 07-28-2012 06:16 PM

Looking at the BORK some more I saw a video of it and it looked like it didn’t stay level with the top of the blade throughout the blades height adjustment. At full height the BORK was notably higher then the blade. Then it dawned on me that that was because the arbor swings in an arc. That was then confirmed in a post by Bob Ross who stated that was why the BORK also has a height adjustment.

The Shark Guard which looks like a really nice system and has pawls does not appear to move up and down with the blade. Drat. So still unbolt, bolt…

-- -Curt, Milwaukee, WI

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knotscott

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#38 posted 07-28-2012 06:42 PM

I love my BORK, but there are no pawls on it. You’re correct that the swing arm causes variation relative to the blade height….simply put, the knife travels farther than the blade, whether up or down. My solution is to set the knife height where I want it for the most common blade height, then it’s almost always really close to where I want it. The height relative to the blade is easily adjustable….a few seconds and it’s done. Bob Ross is great to deal with.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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CyberDyneSystems

251 posts in 2004 days


#39 posted 07-28-2012 11:59 PM

I was dubious re riving knives for some time, mistakenly associating them with splitters.
If you don’t yet realize how much splitters suck, it’s hard to sell you on the advantages of a riving knife.

Again, I was just like you until I got to be around a saw equipped with one for a while and truly see the difference in how they function first hand.

Let me put it this way.

I’ve been using good cabinet saws for decades, Powermatics and Unisaws..

In all of them the splitters have been dutifully removed, placed into a box on a shelf and never used again.
This is there fate, due to the splitters cumbersome nature, it’s insistence eon being in your way and interfering with even some of the most basic cuts.

the SawStop we now have came with a riving knife.
It is still in the saw, being used daily.

That’s the big deal.

The splitter you are constantly aware of, it is usually in your way, and they all tend to be pretty hack.
The riving knife, you don;’t even need to know it’s there. It is rarely in the way.. ( and good ones pop out in seconds if needed )

Lastly, you don;t want with pawls!
The SawStop comes with both the riving knife, and a full on guard with pawls.
Again, they are totally different animals.
One is on the saw at all times, the other hangs from the side on it’s dedicated peg, largely unused.

-- Without the wood, it's just working

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jmos

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#40 posted 07-30-2012 01:31 PM

The plus I see with the Shark Guard is that the guard and the pawls are easily removable, without tools, so you can leave the splitter in place for all but non-through cuts. Since I don’t do that terribly often, I should be able to leave the Shark Guard in place most of the time.

For me, having to take off the OEM splitter, which requires removing the insert and getting a wrench, to use my cross cut sled, and for narrow rips, is a pain and results in the guard and splitter being on the saw less often. I don’t think anyone will argue that either a splitter or riving knife is better than nothing.

I think part of the conflict here is the assumption that splitters are almost always removed. If that is true then a riving knife is clearly better. However, if the splitter is in place, the benefit of the riving knife over the splitter (especially one with pawls) is less clear.

-- John

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MedicKen

1610 posts in 3277 days


#41 posted 07-30-2012 02:25 PM

All of the discussion/debate on whether a splitter is better than a riving knife or visa versa is a mute point unless one uses common sense. If the saw is set up correctly, fence parallel to the blade and miter slots parallel to the blade, the chances of kick back are almost slim to none. Also, operator positioning will go a long way into avoiding injuries if a kick back does occur. That being said, I think there is a place for both a riving knife and a splitter/guard assembly. Hell, they have been available on table saws since the 40’s. They were big and cumbersome and yes, removed even then. I personally prefer the riving knife because I like knowing that nothing will get caught on the back of the spinning blade. As for the new splitter/guard assemblies they look like crap and an after thought to me. Oh, and try using a splitter with a dado head.

-- My job is to give my kids things to discuss with their therapist....medic20447@gmail.com

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blackcherry

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#42 posted 07-30-2012 02:49 PM

...

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PurpLev

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#43 posted 07-30-2012 05:48 PM

I’ll add another vote for the fact that since I’ve had my saw, the riving knife has not been removed and is always on for through and non-through cuts (it’s positioned a sinch lower than the blade). something that a splitter simply cannot provide and would have to be removed at times. add to that that because of these same mechanics the riving knife is also much closer to the blade at all elevation settings and it should be evident why it does provide with a higher rate of safety.

a kickback cannot occur from pinching between blade (side) and fence. this would simply result in a lot of burning, the kickback is a tooth on the blade that catches the board from behind and throws it to the front (not side to side) – a riving knife being closer to the blade can prevent this where a splitter (depending on how much the blade is elevated) still leaves a large gap between blade and splitter where a board can still get caught and thrown at you.

nothing is ever 100% foolproof, but I’ll take 95% over 60% anyday when it comes to safety.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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Mainiac Matt

7397 posts in 2144 days


#44 posted 07-30-2012 06:35 PM

did you watch the video Dan linked?

removeable pawls (without tools) and two positions on a riving knife contoured to the blade…

that’s the cat’s meow in my book

-- Pine is fine, but Oak's no joke!

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exelectrician

2327 posts in 2243 days


#45 posted 07-31-2012 05:05 AM

I learned this trick from a world renowned cabinetmaker,

Take the blade out of your table saw and install a seven and a quater inch diameter ultra thin kerf blade, this blade does all the ripping and crosscutting you need on average, and the waste is reduced to almost nothing.

Kickback is greatly reduced because the exposed diameter is so small, likewise the riving knife is not needed because the kerf is is around 1/16th”.

But the thing that made me a believer was the fact that blade burn was totally eliminated.

I tried it, now all my super expensive 10” blades sit on the shelf.

-- Love thy neighbour as thyself

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TopamaxSurvivor

18067 posts in 3491 days


#46 posted 07-31-2012 05:11 AM

exelectrician, I knew I was watching this thread for a reason. Best idea I have heard yet ;-)

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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knotscott

7754 posts in 3191 days


#47 posted 07-31-2012 08:39 AM

I don’t understand why a narrower kerf would eliminate the need for a riving knife or splitter. It seems to me that reactionary wood would be more likely to close up on a 1/16” gap than a 1/8” gap….

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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Finisher

31 posts in 1954 days


#48 posted 07-31-2012 08:32 PM

haven’t read all of the comments concerning this matter but didn’t think a riving knife made that much difference. Two years ago I bought a Grizzly 0691 which came with a riving knife. It moves up and down with the blade which means you don’t have to remove it when you do partial through cuts. I must say it helps keep your work against the fence and keeps the material from binding in on itself as it some times does. I didn’t think it really mattered much when I first got my saw but now that I have used it for awhile I really appreciate having it.

-- James, Michigan http://www.northcapecabinetsandmillwork.com

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crank49

4023 posts in 2786 days


#49 posted 07-31-2012 08:46 PM

Electrician and Topomax, I never heard of these argumants for using a 7 1/4” blade, but it makes sense.

I have swithced on occasion, and recommended others do the same to make an under powered 1 1/2 hp saw act like a 3 hp. I know this works because the circumference of a 7 1/4” blade is almost exactly 1/2 of a 10” blade. By the same logic, the tip speed would be 1/2 as well.

But I would still want my riving knife, or at least a splitter. Getting hit by a chunk of wood traveling at 50 MPH isn’t going to feel much better than one traveling at 100 MPH. I’d also bet that a 1/16” kerf sliced through your hand would not feel any better than one of 1/8” either.

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ChuckV

3050 posts in 3342 days


#50 posted 07-31-2012 10:06 PM

Michael,

Wouldn’t the tip speed of the smaller blade be 72.5 % that of the larger one?

Maybe you’re thinking (7.25)^2 vs (10)^2 as in area instead of circumference.

-- “Big man, pig man, ha ha, charade you are.” ― R. Waters

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