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.



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, 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:


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...



.

[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