Splitter vs Riving Knife

[mike wacker]

Hopefully it's too late for the answer to this question to make any difference (See my Gloat Thread), but what is the difference between a riving knife and a splitter? The two people I have asked in person (one at Rocklers and one at Woodcraft) both answered with the peverbial dumb look. Don't take that wrong I like these guys but niether could tell me the difference.

[Jason White]

A traditional splitter sits near the back of your table saw, usually several inches behind the blade. The idea of the splitter is to keep the saw kerf from closing up behind the blade, which can cause the wood to "pinch" the blade. The blade then takes your workpiece and throws or "kicks" it back toward you (hence the term "kickback"). Splitters are a good idea, but most sit several inches behind the blade, are hard to align properly, and are not always effective (I have one). Often my kerf will close up before it even reaches the splitter.

A "riving knife" sits directly behind the blade and will also go up and down when you raise or lower the blade, making it more effective in preventing kickback.

I'm sure others here with actual riving-knives can attest to the superiority of the riving knife versus the traditional splitter. I wish I could somehow retrofit my contractor saw with one, but alas, you can't do it.

I do wish that Biesemeyer made a "snap-in" splitter that would fit my RIDGID tablesaw. If they did, I would buy it.


JW

[Randal Stevenson]

While they are both designed to keep the kerf from closing behind the blade, the riving knife is closer to the blade (mounted as part of its mechanism), and will raise and lower WITH the blade. Most that I have seen, by default are taller then the blade, but it isn't uncommon to here of people getting another, and cutting one down, so you can use it in non through cuts.

[mike wacker]

Thanks, Got it.

[lou sansone]

a riving knife also tilts with the blade.

[Matt Lentzner]

IMO, the riving knife is a required piece of safety equipment. I personally, will not buy a saw without one. I'm waiting for them to become available on hybrids.

[Tim Marks]

a riving knife also tilts with the blade.
I always assumed that EVERY splitter tilted with the blade. What saw is this not true for? A splitter that didn't tilt with the blade would be a huge safety hazard, because if the blade was slightly tilted, it would block passage of the wood past the blade, possibly causing kickback.

The splitter on my Ridgid 3650 tilts with the blade. It is a pretty nice design... tool-less removal and installation.

This picture showing the attachment on the (similar) Ridgid 2424 stolen from Leeway Workshop's Shark Guard website (shows the shark splitter bolted to the ridgid support). You can see that it is attached to the blade support mechanism, so it tilts with the blade.

http://www.sawmillcreek.org/attachment.php?attachmentid=76610&stc=1&d=1197051417

My views on splitters vs. riving knives are probably tainted by the fact that my Rigid has one of the best, since it is very sturdy, and easy to remove and install. Other saws are not so well equipped, so users of those saws probably feel more of a need for a riving knife.

I think there are three important advantages of the riving knife over a splitter (the first is the most important):
1. Hugs the back end of the blade with minimum gap to prevent binding (typical splitter can be 1-2" behind the blade depending on the blade height)
2. Retracts with the blade so it doesn't have to be removed (and forgotten) during cuts that don't go all the way through. This is important from a safety standpoint: CONVENIENCE = SAFETY. If a safety mechanism is inconvenient it tends to be disgarded.
3. Mounting point is closer to the blade then some models, so it will deflect less under load. My spliiter is mounted a foot behind the blade, so it can be deflected easily, allowing wood to contact the side of the blade.

Will I sell my TS so I can get a riving knife? No. Will I refuse to buy any future tablesaw's unless they have a riving knife? No.

Well, maybe.... My concern is more for my son then for me; he is 5yo and likes tools (thank god), and likes to help me out (sometimes). One horrible moment envisioned in my brain is him walking behind me while I was cutting something, and then refusing to move when I saw him... and then the board kicked back and almost hit him. It is one thing to consider the price of my safety, but something altogether different to consider the price of his safety.

[Tom Veatch]

I always assumed that EVERY splitter tilted with the blade. ....

There are two types/implementations of splitters. One type is incorporated as a part of the blade guard along with anti-kickback pawls, will tilt with the blade and comes off if the blade guard is removed. Another is the type that is mounted on the throat plate/insert (http://www.woodworkingtips.com/etips/etip060900ws.html), is usually either aftermarket or shop built, is fixed with respect to height and angle, and is usuable with the blade guard removed.

[Tim Marks]

either aftermarket or shop built
yep, forgot about those things. Sort of like the "MJ Splitter" from microjig:
http://www.microjig.com/AVI/MJSplitterAnimatedGIF.gif

Can anybody name a saw that either does not come with a splitter or comes with an OEM splitter that does not tilt?

[Matthew Voss]

Tim-

A riving knife travels up and down with the blade as well - a splitter does not. Also, Some riving knives can be lowered just below the blade for protection when making non-through cuts.

Tim - scratch that - sorry, didn't read the end of your post...

[scott spencer]

A riving knife is a more elegant design solution to keeping the workpiece from closing up and binding on the blade, but a splitter is also effective when properly aligned and in place. It's hard to gauge how much more effective the RK is than a splitter in it's most basic function in actual use. All the theoretical advantages favor the RK, but when properly installed, both systems are capable of preventing the kerf from closing. The RK tends to be in closer proximity to the blade, but most reactionary wood won't close the gap for several inches past the exit side of the blade, and any splitter I've seen is within close enough proximity to do the job. The ability to raise and lower with the blade is a function that the splitter can't do at all, and is a leading reason for leaving the splitter off for some tasks, which brings us to the primary benefit of the RK...you're more likely to have it place when needed. I've read a lot and thought about the differences between the two, but haven't yet experienced any revelations or insights that prompt me to view the RK as much more than an improvement to the splitter...it's not a technology breakthrough that significantly changes the safety of the process, but it does reduce our tendency to ignore prevention.

IMO, it's important to have one or the other in place and properly setup. I view a splitter or RK to be more important than the blade guard, but that's just my opinion. I think I'd enjoy having a riving knife on my saw, but I don't view as important enough to warrant paying a significant premium for it.

[scott spencer]

...Can anybody name a saw that either does not come with a splitter or comes with an OEM splitter that does not tilt?



...hole saw...:D



.

[Steven Wilson]

The riving knife mounting assembly is part of the trunion assembly of the saw. So, when you raise, lower, or tilt the saw blade the riving knife follows suite. Having the riving knife fixed with the saw blade allows the riving knife to be set right behind the blade (3mm) and follow the curve of the saw blade. So what? Having a curved riving knife right behind the blade makes it very hard for a piece of wood to be picked up and thrown - it prevents kickback. This is in addition to its role in keeping the kerf from closing up on the back of the blade. This is different from a splitter which is either mounted on a throat plate, part of the cabinet, or part of the top. A splitter can prevent the kerf from closing but it sits too far away from the blade to prevent kickback. Get a riving knife.

Riving knives are generally fairly large and substantial enough that they can be used for mounting an overblade guard and dust collection assembly.

[Dan Lautner]

Webster Dictionary 2007

Splitter : A useless attachment invented by Delta or some other American company. If properly used and not removed or lost may help prevent kickback if the gap between the blade and the splitter is not too great.

Riving Knife : A TS attachment that eliminates kickback. You would be a fool to buy or use a TS without a Riving Knife.


Dan

[Gary Keedwell]

Webster Dictionary 2007

Splitter : A useless attachment invented by Delta or some other American company. If properly used and not removed or lost may help prevent kickback if the gap between the blade and the splitter is not too great.

Riving Knife : A TS attachment that eliminates kickback. You would be a fool to buy or use a TS without a Riving Knife.


Dan
I don't really think it serves any purpose to refer to thousands of woodworkers as "fools". But on the other hand I was probably a "fool" not to marry a rich woman.;):)
Gary

[Joe Spear]

Up until recently most woodworkers in the United States didn't have much of a choice about getting a tablesaw with a riving knife. The options were very expensive European saw or a small Ryobi. Those of use who bought saws with splitters instead of riving knives were victims of our relative poverty, not fools. By using a splitter and a blade guard and by using safe techniques, a saw user can greatly reduce the hazards, even if a riving knife would be better. Now most companies are starting to produce tablesaws with riving knives in the price range that we can handle. A SawStop would be safer than Grizzly, Jet, Powermatic, or whatever with a riving knife. But somebody who opts for something besides a SawStop isn't a fool, just bowing to practical financial considerations--or even making a decision that he or she can handle the saw safely without a riving knife and/or instant blade braking system.

[mike wacker]

Webster Dictionary 2007

Splitter : A useless attachment invented by Delta or some other American company. If properly used and not removed or lost may help prevent kickback if the gap between the blade and the splitter is not too great.

Riving Knife : A TS attachment that eliminates kickback. You would be a fool to buy or use a TS without a Riving Knife.


Dan

Thanks all for your responses, but Dan, please don't sugar coat your opinion in the future. ;o)

[Pat Germain]

The splitter that came with my Craftsman saw was such a worthless piece of tin I think it actually made cutting more difficult and perhaps less safe. I just bought one of those MJ splitters and hope to install it soon.

My next TS will definately be equipped with a riving knife. In the meantime, I'll keep cutting with the rest of the festival of fools.

[Steve Schoene]

I suspect that 98% if the benefits of riving knives stem from them not having to be removed for non-through cuts or cross cuts. Splitters have to be removable to accomplish many cuts and therefore are liable to be forgotten for the next ripping operation. But if you religiously use a splitter you will have added substantially to safety while ripping. By the way, I have had zero problem keeping my Biesemeyer splitter aligned.

But very soon, all tablesaws in the US will have riving knives since UL listing will require them. New models first, but eventually even older models will have to be redesigned to encorporate the riving knives. (But don't count on retrofit versions.)

[Tim Marks]

Riving knives... can be used for mounting an overblade guard and dust collection assembly.
So can my splitter... :D


Splitter : A useless attachment ... You would be a fool to buy or use a TS without a Riving Knife.

Have you owned a TS with a splitter or are you just basing this on what you read here? Yes, a riving knife is nice, and maybe some day I will own a saw with one (but not a cheap almost useless portable benchtop saw). But the splitter on my saw is far from useless, and does a pretty good job. The only time that I have ever got kickback was when cutting very narrow pieces off of a board that the anti-kickback pawls couldn't engage because of it's width.

Incidently, you can always buy the SHARKGUARD splitter modification that makes your splitter more effective by putting it closer to the blade and making it a bit wider.

[Cliff Rohrabacher]

I use the terms interchangeably to refer to any item that is fixed to the saw and serves to prevent the stock from closing on the blade.

I think one of the expressions (riving) is an old world term and the other is a new world term and both mean the same thing.

Some have articulated a distinction on where they mount and how they operate however I am pretty sure that those distinctions are simply the result of where and how people placed them over the years.

In this application it is gerund noun. That is to say it is a noun that also describes and serves as it's own verb form. Cleaver is another gerund noun, so too "bowling ball," "boning knife," "paring knife," and (ta da) "riving knife."

The word Rive means: to cleave, split, separate.
The word Split does too. I rather suspect the Victorian expression "riving knife" hearkens back to a time when people were more "wordy" in their speech patterns.

ERGO: "Splitter" the un-lettered man's word for riving knife.

In any event I only use mine rarely. I'll mount it only if I have a lot of work to do that is highly likely to close on the blade. Otherwise I'll grab a few little wood wedges and shove 'em in the kerf on the far side of the blade. Works great.

[Art Mann]

I have noticed that there is usually an inverse relationship between the degree of experience of the tablesaw operator and the degree to which he insists that a riving knife is essential for a tablesaw. Most cabinet shops I have been in never use a riving knife or a spliiter. The 30 year veteran professionals generally just laugh at such statements.

I would agree that the consistent use of either device will lessen the chances of a kickback.

Interesting . . .

[Chuck Burns]

I have noticed that there is usually an inverse relationship between the degree of experience of the tablesaw operator and the degree to which he insists that a riving knife is essential for a tablesaw. Most cabinet shops I have been in never use a riving knife or a spliiter. The 30 year veteran professionals generally just laugh at such statements.

I would agree that the consistent use of either device will lessen the chances of a kickback.

Interesting . . .

And lots of those thirty year veterans are minus a digit, or two or three. My grandfather was one of them. I've been using table saws for nigh onto 47 years, since I was 10 and I recently purchased a saw with a real Riving Knife (which saw shall remain nameless since the mere mention of it drives some people stark raving nuts <G>). It is must first experience with one and, after using it for a while, I'm here to tell you I would not willingly own a saw without one. In discussing this with people I find that most people who have actually used a saw with a RK really want one.

I'm not a big fan of government mandates; but I suppose it's a good thing that all car are equipped with seatbelts, and I didn't like it when rotary mowers were required to have blade stop mechanisms but I'd imagine there are a lot less injured feet now. So I support the requirement of a true RK. And recomend them highly.

[Dan Lautner]

"Have you owned a TS with a splitter or are you just basing this on what you read here?"

I'm bashing the stupid american companies that only add riving knives after the government forces them. Countless fingers and injuries would have been prevented had these idiots added riving knives years ago. About 10 years ago I bought a Delta Contractor saw. I always felt that thing was an accident waiting to happen and rarely used it. I bought a festool saw about 5 years ago and realized how a riving knife eliminates kickback. I bought the new Bosch TS when it came out and the thing is a joy to use. The riving knife works great and is adjustable for non through cuts without the use of tools. Now I'm in the market for a cabinet saw and a Riving knife is a 100% must have. I'm looking at the New Jet, the PM 2000 or the new General if it comes out soon. If I was going to spend saw stop type money I would buy a compact slider instead.

Dan

[Tim Marks]

I'm bashing the stupid american companies that only add riving knives after the government forces them.

Didn't the Consumer Product Safety Commision implement this ruling at the request of the Power Tool Institute, which is made up of a group of AMERICAN saw manufacturers? Maybe they saw the handwriting on the wall, but they were involved:

http://www.cpsc.gov/library/foia/foia06/brief/tablesaw.pdf


If I was going to spend saw stop type money I would buy a compact slider instead.
hear, hear! I am still drooling over the grizz 10" slider even though I have absolutely no room to use such a beast.

I wonder when the $13.5k SS slider is coming out:D.

[Steven Wilson]

Have you owned a TS with a splitter or are you just basing this on what you read here? Yes, a riving knife is nice, and maybe some day I will own a saw with one (but not a cheap almost useless portable benchtop saw). But the splitter on my saw is far from useless, and does a pretty good job. The only time that I have ever got kickback was when cutting very narrow pieces off of a board that the anti-kickback pawls couldn't engage because of it's width.

I owned a Jet Contractor saw, a Powermatic 66 (w/ Beis splitter), and now own a euro slider. Only fools or those who have never seen a saw equiped with one would equate a splitter to a riving knife. Kerf closing is but one function that needs to be performed. The more important function, from a kickback point of view, is keeping the back of the blade from grabing and launching wood. A properly set up riving knife (curved knife set about 3mm from the blade) will prevent the back of the blade from grabing wood, a splitter won't. Handling non-through cuts with the riving knife attached is something you can do if you want but I don't as I set my riving knife higher so it can support dust collection.

If you want to improve your splitter get rid of the anti-kickback pawls. They cause more problems with kickback than they solve (i.e. they can angle thin pieces into the back of a blade).

[Gary Keedwell]

Bought my Uni 12 years ago. For 11 years all I had was featherboards. Last year I installed Board Buddies and recently installed my own splitter. With my BB and splitter, I can stop in the middle of a ripping operation and then safely resume without any problems. That seems pretty safe to me, especially when I had nothing for 11 years.:rolleyes::)
Gary

[Larry Conely]

This is the riving knife on my INCA 2200. I've had this saw for 15 years. The riving knife was just one of the many features that lead me to purchase it. Not only does it permit non-through cuts but the whole arbor assembly rises and falls in a straight line rather an arc. I cannot factor the safety increase, but I've never had a kickback in the time I've owned the saw.

Larry

[Tim Marks]

Only fools or those who have never seen a saw equiped with one would equate a splitter to a riving knife.
With phrases like that bandied around, I feel like I am on that OTHER board...

[Joe Dusel (Vista, CA)]

What is really being discussed here is a cheesy cheap splitter such as found on the Delta Unisaw and clones versus the good old fashioned type splitters which track the blade and are located where they are effective. The Europeans mandate the good type splitters for safety reasons. Here is the U.S. we have a choice of buying a safer machine - or not.

As I was taught and have read the older American machines used to have the good kind of splitter, but that went away to make cheaper machines. I did a search on old Oliver table saws and did see a picture of one from 1921 with a substantial guard and a good splitter.

Joe

[Jim Kountz]

I don't really think it serves any purpose to refer to thousands of woodworkers as "fools". But on the other hand I was probably a "fool" not to marry a rich woman.;):)
Gary

Thank you Gary, I was hoping I wasnt the only one who thought that was less than a thoughtful comment. What the hell did people do for years before anyone even spoke the words "riving knife"?:confused: I guess ALL those folks were fools too!! :D:D
Sheesh!:rolleyes: