Riving knife VS splitter

Jeff Horton

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Got a question. First off, I know what a Riving knife is and how it works. But what I don't understand is what makes them so much better than a splitter? I mean it's just an improved splitter.

The only advantages I see are, that is pretty much stays on the saw. It's closer to the blade for that rare time a board clamps down quickly. Not knocking them, but I don't see it as such a huge improvement.

On another forum there are people saying they won't buy a new saw unless it has one. OK, fine. But whats so improved? What am missing? Or is it they just have the Wants and a bad case of Stuffitus?
 
For me, the biggest difference is that a riving knife doesn't sit above the top of the blade. This means I won't have to remove it for non-through cuts such as cutting rabbets or kerfing or tenon shoulders or other kinds of joinery. If I don't have to take it off as often, I'm less likely to forget and leave it off for the next "splitter-friendly" cut.

That, to my eyes, is an enormous benefit to the safety of the saw. Most of the reason folks take their splitters off is because it gets in the way. A riving knife rarely gets in the way, thus increases the likelihood that it'll be in place when it needs to be.
 
The ONE thing I understand that is better about a properly designed riving knife is that it can be used on a non through cut, where a splitter can't. But I have also heard some talk about the riving knives on their saws being taller than the blade, which won't work with a non through cut. Don't remember the brands that were being talked about.
I personally think that I would like a riving knife on my next saw, but only if it is what I would term a true riving knife. If it is just a built in splitter that goes up and down with the blade, then I'll pass. Jim.
 
For me, the biggest difference is that a riving knife doesn't sit above the top of the blade. This means I won't have to remove it for non-through cuts such as cutting rabbets...

But since most dado sets are 8", you'd have to remove the riving knife anyway, wouldn't you?
 
But since most dado sets are 8", you'd have to remove the riving knife anyway, wouldn't you?

Sure. A dado's about the only kind of cut I can think of that would commonly be used. I wouldn't be cutting rabbets with a dado head, myself. I forgot that many folks do use dados for their rabbeting. I was thinking more of the two-cut rabbeting methods.
 
For me, the biggest difference is that a riving knife doesn't sit above the top of the blade. This means I won't have to remove it for non-through cuts such as cutting rabbets or kerfing or tenon shoulders or other kinds of joinery.

Lets try this again.

This is the pretty typical of the Riving knives I have seen.

RivingKnife.gif


SawSplitter.jpg


How do you do a dado without removing it?
 
I never said you could use a dado without removing the knife. Maybe I wasn't clear, though. I would want no saw that had what you've pictured and claimed they were true riving knives. My opinion is that a riving knife MUST sit below the top of a normal sized blade and never be more than 1/4" away from the teeth at any given hight or tilt. I believe I formed this opinion after reading anecdotal definitions of the standards applied to European saws. I don't know if the numbers are exact, it's just what I've got stuck in my head as my opinion of a true riving knife.

I don't know of any riving knife that would stay on with a dado head that was smaller than the designed blade size. Say, a 10" dado blade on a 10" saw - that'd be a nifty dado but would take quite a few horsies to push.

My response was to explain why a riving knife was much better than just a regular splitter. If it's a true riving knife (one that is defined as above), a user wouldn't have to take it off for most non-through cuts made with a standard blade. Maybe that's where I created confusion? I didn't specify standard blade size. I made no reference to a dado in my original response, but I guess that mentioning a rabbet implied it to some folks. That was not my intention. I apologize for any confusion. I'd meant cutting rabbets with the two-cut method using a standard sized blade.
 
I'd agree with Jason. The two pics Jeff posted look like splitters to me, since they are taller than the blade. To my understanding a riving knife is no higher than the blade.
 
I also agree, Jeff, those are splitters:D

I have a riving knife on my Festool TS55 circular saw, that thing works all the time every time, perfectly!

festool-plunge-cut-561188.jpg


If you had something similar on a table saw, yeah, I can see that being an asset. :wave:
 
I agree with Jason. To me, a riving knife doesn't have to be removed for any cut except when you change to a dado head. Even when using a sled, the riving knife can be left on the saw.

A riving knife should not stick above the blade and it should rise and tilt with the blade.

The advantage I see with a riving knife is that you'll leave it installed. With a splitter, you have to remove it for many different cuts. Some splitters don't tilt so when you want to do an angle cut, you have to remove it. Most of the time, when you want to use a crosscut sled you have to remove the splitter. When you want to make a thin cut, one where you'll use a push block and push it completely through the cut (and the saw will cut the push block), you have to remove the splitter or you couldn't push all the way through. When cutting tenons, you have to remove the splitter.

Because of all the "put it on, take it off" of a splitter, most people take it off and leave it off. At school, they're anal about the splitter so people (including me) use them. But at my home shop, I don't use one.

I'd love to have a TS with a true riving knife. When I buy a new saw, it'll have one or I won't buy.

Mike

[The best safety equipment is that which never has to be removed.]
 
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Question about a riving knife, how thick should it be?

I think, if memory serves, that the splitter on my DeWalt BT-744 is attached to the carraige that moves up and down and tilts with the arbor as well :huh:

If so, I'm thinking I could modify my splitter more to make is closer to a true riving knife :dunno:

I found the pics of my prior modification to the stock (useless) guard.........

ts_spliter_1.jpg
I cut the large bit off, and left a much smaller part with the ant-kickback pawls in place.

ts_spliter_2.jpg
here you can see it mounted, I'm fairly certain that the part it mounts to moves up and down and tilts with the arbor. :huh:

ts_spliter_3.jpg
Here it is with the stock insert.

ts_spliter_4.jpg
it works OK as is, but honestly, I really do not like the anti-kickback pawls, they more than often get in the way and are just a pain.

I'm wondering if I were to cut this down further, to make it more like a true riving knife, one that does not go above the top of the blade, and travels up and down, as well as tilts with the blade, if it would work?

Thus, I ask, should the riving knife be a certain thickness? It has to be thinner than the blade I guess, but by how much :dunno:

Cheers!
 
...I'm wondering if I were to cut this down further, to make it more like a true riving knife, one that does not go above the top of the blade, and travels up and down, as well as tilts with the blade, if it would work?

Thus, I ask, should the riving knife be a certain thickness? It has to be thinner than the blade I guess, but by how much :dunno:

Cheers!
I think you're on the right track. (I've always hated the anti-kickback pawls. In the way for nearly every cut.) You have the technology to trim up the splitter, and if it does indeed travel with the blade, it should work great as a riving knife. As far as thickness, I don't have any experience that would help, but I'd think just slightly thinner than the blade would be workable.
 
The photos I posted were the the only ones I could find quickly. They probably incorporate those plastic guards that we all hate so. I know exactly what your talking about when you say "Real Riving Knife".

Because of all the "put it on, take it off" of a splitter, most people take it off and leave it off. At school, they're anal about the splitter so people (including me) use them. But at my home shop, I don't use one.

Got to say I am surprised to hear that Mike. I just won't hardly use mine without a splitter in place. I use to, but once I understood why a what a splitter did I changed my mind. Now using the original guard, no way. Hate those things.

I have made a couple of splitters for my saw and still refining mine. This is my latest version and my favorite so far. I took an old plastic guard off an old Craftsman saw and cut it up. Got rid of pawls and plastic guard.

I need to make one more change and I think it's a keeper. I need to trim trim the length so I can tilt the blade all the way with it in place. Otherwise I am very happy with this.

101_2339.JPG 101_2340.JPG

I have to take it out to use the dado's. But it's one bolt and only takes a few seconds, so I use this one. It rarely ever comes off the saw. Making it was simple. Just took the angle grinder and a cheap cutting wheel and went to town. A little grinding and it's done.
 
The photos I posted were the the only ones I could find quickly. They probably incorporate those plastic guards that we all hate so. I know exactly what your talking about when you say "Real Riving Knife".

:huh:

This is the third image returned from a google image search for "riving knife"
riving_knife.jpg

This is the fourth.
3-riving-knife.jpg

Both of these are proper (IMHO) riving knifes. Now, I will grant that the first image returned is zoomed in too close to be understandable, and the second result is just wrong:
RivingKnife.gif

Glad you got it straightened out now. I too hope that my next saw, if I ever get one, comes with a proper riving knife.
 
Question about a riving knife, how thick should it be?
... I really do not like the anti-kickback pawls, they more than often get in the way and are just a pain.

Stu,

I don't know what to think about the pawls. Mine are on, yes they're a pain, but I've never had a kickback with that setup, and as you know, I do any number of foolish things... ;)

There's a discussion of thickness on this page:

http://www.leestyron.com/sharkridgid.php

As far as that goes, you have all the tools and skills necessary to make one of those. I picked that page because it's got a blow up of the parts. From what I can tell, he's using pawls... ;)

Thanks,

Bill
 
Granted, the riving knife design does have some important advantages, such as mounting close the blade and raising and lowering with the blade. All good to have.

However, I think the claim that a splitter will be used less because it is difficult to remove and replace is not necessarily true. Some improved splitters are very quick and easy to remove and replace. I use the Biesemeyer Snap-In splitter on my saw and it probably takes 5 seconds at the most to remove it, and less time to replace. It stays on my saw most of the time. If your saw does not have a riving knife, you are not stuck with the original equipment splitter. :)
 

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My old Ryobi BT3000 had one of the things that passes for a riving knife on the other saws that are now produced with them. In a clash of regulations, the guard and pawls were "permanently" attached to the riving knife meaning you had to remove the entire assembly for non-through cuts. I fixed that by breaking the guard and pawls off, then cutting the riving knife so that it was the proper height, slightly below the level of the top of the blade when installed properly. Since I find dado stacks to be a PITA, I never had to remove the riving knife after that.

EU regulations do not allow for arbors on table saws to be long enough to install a dado stack which eliminates the need for the riving knife to ever be removed from the saw.
 
How did I missed this post....

Ok, Riving Knife...some history....At the 60th the traditional Splitter (or "Spreader" according to OSHA) was dropped in UK (and later all Europe) and the "Riving Knife" took it place...of course, the makers were given the time to adjust themselves to the new regulation (usually, around 5 years) but at the end of the period, "no entry to EU without riving knife" (and all the old TS's had to be modified)...

First for Stu, the Riving Knife (RK) thickness
RivingKnifeD.jpg


European RK and US RK are a little bit different because of the OSHA safety regulations that demands the Anti-Kickback pawl (or fingers) to be attached to the RK and that means that the RK, must be higher than the blade....I think that there are more problems with the US RK but let's leave them aside.

The Euro RK is installed some 1/8" below the blade(but can be adjusted up/down) and 1/8"~5/16" (max) behind the blade...it goes up, down and tilts with the blade but remains all the time at the same reference position to the blade till (like welded together) and it will disappear under the table together with the blade...
Dsc00008.jpg


The Blade guard is "clicked" into a groove on the RK and tight with wing nut....and must include dust removal port (according to the "dust control" regulation) so, it takes 1 second on...1 second off....it was done that way to encourage the usage of blade guard...
Rivingknife.jpg


You may ask why the EU regulations do not require the "Anti-kickback pawls"...from what I read around, I understood that, they claim that they are not exactly effective and are more bothering that helping and many tend to remove them...so the EU "invented" new regulation..."The rip fence must be adjustable in length and have two positions; High for thick wood and Low for shallow wood cuts
Ripfencehigh.jpg



Ripfencelowbevel.jpg



It's called also "Short Fence" and it comes to prevent any kickback due to "Reaction wood"...
01-2.jpg



02-2.jpg



03.jpg



04-1.jpg


There is another EU safety regulation that is in force since 2005..."The blade must stop rotation within 10 seconds"....and from the end of this year, all the woodworking and metalworking rotating machines without permanent guard...

As I understood from reading around, there are some problems with inertial forces that can damage the motor or lead to arbor nut getting loose (my blade stops within 6 seconds) due to the high deceleration and that's the reason that a dado blade that is very "Massy" cannot be installed on the new designs and if the blade diameter is more than 10", a stop pin should be installed on the arbor and the blade must have mating hole...

That's all what I know...

Regards
niki
 
....I think the claim that a splitter will be used less because it is difficult to remove and replace is not necessarily true. Some improved splitters are very quick and easy to remove and replace. I use the Biesemeyer Snap-In splitter on my saw and it probably takes 5 seconds at the most to remove it, and less time to replace. It stays on my saw most of the time. If your saw does not have a riving knife, you are not stuck with the original equipment splitter. :)

I agree! I have the Biesemeier splitter and the Delta Uniguard mounted on my Shop Fox cabinet saw, and they both stay on the saw for all cuts, except non-thru cuts like dados, or kerfing for bending.

I also still have the pawls on the splitter. I did drill a small hole thru the splitter body so that if I need to raise the pawls - like for a really narrow cut up against the fence - I can pull the pawls up and put a short piece of 1/8" dowel thru the hole to hold them up and out of the way. The still spend about 99% of the time down and operable, though.
 
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