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

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Forum topic by BlankMan posted 726 days ago 3101 views 0 times favorited 53 replies Add to Favorites Watch
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BlankMan

1487 posts in 1948 days


726 days ago

Topic tags/keywords: tablesaw riving knife question resource

Really. I don’t see any real advantage over a good splitter. Except maybe when ripping angles.

Yes it goes up and down with the blade. So?

At times I considered getting and installing one on my Unisaw but now I don’t know…

There’s been talk about buying a new saw verses old/used to get new safety features like a riving knife. What in a riving knife makes anything safer then a good, in my case, anti-kickback splitter?

-- -Curt, Milwaukee, WI


53 replies so far

View NewEnglandsWoodWorks's profile

NewEnglandsWoodWorks

117 posts in 1197 days


#1 posted 726 days ago

A riving knife can be used during non through cuts.

-- Brett

View jmos's profile

jmos

681 posts in 965 days


#2 posted 726 days ago

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

1599 posts in 2057 days


#3 posted 726 days ago

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

5364 posts in 1971 days


#4 posted 726 days ago

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....

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SnowyRiver

51451 posts in 2076 days


#5 posted 726 days ago

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

View crank49's profile

crank49

3333 posts in 1566 days


#6 posted 725 days ago

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.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View oldnovice's profile

oldnovice

3578 posts in 1963 days


#7 posted 725 days ago

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!"

View patcollins's profile

patcollins

944 posts in 1460 days


#8 posted 725 days ago

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.

View jmos's profile

jmos

681 posts in 965 days


#9 posted 725 days ago

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

View MrUnix's profile

MrUnix

452 posts in 794 days


#10 posted 725 days ago

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 - To be old and wise, you must first be young and stupid

View dnick's profile

dnick

892 posts in 978 days


#11 posted 725 days ago

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.

View TopamaxSurvivor's profile

TopamaxSurvivor

14578 posts in 2271 days


#12 posted 725 days ago

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

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

View BlankMan's profile

BlankMan

1487 posts in 1948 days


#13 posted 725 days ago

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

View MonteCristo's profile

MonteCristo

2094 posts in 784 days


#14 posted 725 days ago

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""

View TopamaxSurvivor's profile

TopamaxSurvivor

14578 posts in 2271 days


#15 posted 725 days ago

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

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

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