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.

 

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.

 

"...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?

 

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

 

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.

 

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.

 

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

 

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

 

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

 

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?

 

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…

 

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…

 

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.

 

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.

 

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.

 

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.

 

...

 

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.

 

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

 

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.

 

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

 

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….

 

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.

 

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.

 

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.