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Thread: riving knife??

  1. #1
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    riving knife??

    i have been hearing alot about riving knives in table saws lately. i am not sure i know what they do and why they makes the saw safer. can anyone explain that for me. if i remember correctly i think they help to fight against kickback??

    thanks
    chris

  2. #2
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    Chris, the riving knife or a splitter (they are two different tools that do a similar job) prevents wood that has stresses in it froom closing up behind the blade. Without a RK or splitter, the wood could close up, pinch the blade at the back, the blade picks up the wood and throws it back right at where you are standing, whacking you in the face (or other parts of your body).

    That about sums it up I think.
    Thanks, Mark.

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  3. #3
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    Let me add that the ones I have seen also come up over the top of the blades. The raise and lower with the blade. That keeps the wood from coming to rest on top of the blade that is spinning toward you. That where the kickback happens, the wood getting on top of the blade, teeth grab the wood and rocket it toward you.

    From what I understand it's a great thing. In theory anyway.

  4. #4
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    Quote Originally Posted by Jeff Horton View Post
    Let me add that the ones I have seen also come up over the top of the blades. The raise and lower with the blade. That keeps the wood from coming to rest on top of the blade that is spinning toward you. That where the kickback happens, the wood getting on top of the blade, teeth grab the wood and rocket it toward you.

    From what I understand it's a great thing. In theory anyway.
    That's exactly it, they rise and lower in tandem with the blade. So, they can be used with non through cuts and with angled cuts.

    They are a great thing in practice as well as in theory. I have one on my circular saw (Festool) and really wish that I had one on table saw.

    One other thing, I understand that they can not be retro-fitted to the traditional North American style table saw. If they could be, I would right at the top of the queue to purchase such a retro-fit. I have seen a couple of claims that they can be, but no proof.
    Last edited by Frank Pellow; 12-14-2006 at 10:44 PM.
    Cheers, Frank

  5. #5
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    Quote Originally Posted by Frank Pellow View Post
    They are a great thing in practice as well as in theory.
    I'll agree with that. I have one on my PM2000 & I'm sure I've seen it save me from kickback once or twice in the short time I've had the saw. Great safety feature. I think you'll be seeing it on more new saws.

  6. #6
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    thanks guys...that is basically what i thought. but i wasn't sure if there was more to it than that.

    frank...i'm a little confused...how can it be used on non-thru cuts??
    wouldn't the non cut section hit the RK and stop the board?

    chris

  7. #7
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    Quote Originally Posted by Chris Mire View Post
    thanks guys...that is basically what i thought. but i wasn't sure if there was more to it than that.

    frank...i'm a little confused...how can it be used on non-thru cuts??
    wouldn't the non cut section hit the RK and stop the board?

    chris
    Chris, the riving knife is set to be even with the top of the blade, and it travels up and down with the blade (and sideways for bevel cuts). Since it is no higher than the blade itself, a non-through cut can still clear the knife.

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  8. #8
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    Quote Originally Posted by Frank Pellow View Post
    One other thing, I understand that they can not be retro-fitted to the traditional North American style table saw.
    From what I have seen your right. I gave my Delta contractors saw I sold and my old Unisaw a good looking over and there is no easy way I can see to attach a riving knife to either of them. The problem is that there is no where ton the arbor bracket to attach one so it can raise and tilt with the blade.

  9. #9
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    chris, here`s a couple pics of a riving knife.....

    Attachment 2192

    Attachment 2193

    Attachment 2194
    [SIZE="1"] associated with several importers and manufacturers.[/SIZE]

  10. #10
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    And here is a few photos of a plain old splitter.

    First, this is the home-made splitter that I made for my General International 50-185 tablesaw. It is just a piece cut from an old shelf standard. Just a flat piece of metal with a notch out of it to fit around the bolt.
    Attachment 2201Attachment 2202

    I like a splitter like this a lot, as it lets me use a crosscut sled without removing it.

    Next, here is some pictures of the microjig splitter from the Lee Valley website. This is another aftermarket splitter kit that you can get, which will fit just about any tablesaw.
    Attachment 2203Attachment 2204

    Finally, if you visit www.leestyron.com you can see photos, videos, and other information about the shark guard. I don't have one, but it has been very well spoken of by people on various WW forums. (it incorporates both a splitter and guard, for many brands of saw.)

    ...art

    ps: and yes, if I was in the market, I'd want to look seriously at a saw with a true riving knife. The splitter is good, the riving knife is better, IMHO.

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