Riving Knife

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Introduction: Riving Knife

The importance of a riving knife can not be underestimated! If you have ever worked with circular saws then you know what I am talking about. Without it one of the most terrifying thing called kickback can easily occur.

My Makita MLT 100 contractor table saw came with a riving knife but this one had had one big flaw that really annoyed me. To fix this issue I made a completely new one and I would like to share how I did it with you!

I also made a short video of the build. Check it out!

This project is nothing really special or complicated but I hope that someone will find it useful.

Let´s get started!

Step 1: Tools Ans Materials

You will need:

  • Sheet metal with thickness bit thinner than your saw blade.
  • Optional: spray paint
  • Old riving knife or a template
  • metal file
  • drill bit
  • calipers
  • oil for lubrication
  • steel punch and a hammer
  • jigsaw with metal cutting blade
  • marker
  • clamp for holding your workpiece

Step 2: But Why?

As I said my original riving knife had one big flaw. It was caused by it being too tall. It was designed so that it could hold blade guard/dust extractor, but I newer used it. Yeah, I know that you are supposed to use all the safety features that come with the table saw, but I personally find it much safer when I actually see the blade at all times.

The height of the riving knifed was a big pain in the buttocks. I could only make through cuts as the knife prohibit the workpiece from moving forward. It also blocked the movement of my table saw sled. Every time I wanted to use my slede or make a groove cut I had to remove the knife. It took quite a bit of time and I did not feel too comfortable sticking my hand inside the saw next to the blade to remove the thing.

At one point it was too much for me and I decided to spend a few hours to make a new riving knife. I did not really want to just cut the old one shorter as I might want to use it's features in the future (probably not, though).

Step 3: Mark and Drill

Use your already existing riving knife to trace out the shape of a
new knife. It is a good idea to clean the metal with acetone before you start marking as it will remove any oil and dust that is on the metal. There is also a good chance that you do not have an old knife to use as a template. In that case, I can think of two possibilities. Either you find the shape by trial and error with wooden/cardboard test pieces. Or you get the template from someone like a person from woodworking forum or maybe the manufacturer might even send you one. The height of the knife should be just a tiny bit shorter than the height of the saw blade.

Use a drill bit to make holes in the correct locations.


Step 4: Mark and Cut

Use metal cutting blade and oil for lubrication to cut out the shape.

After that, it is a good idea to also use metal files to smoothen the
rough edges. After all, the saw blade is already dangerous enough - you don´t want to cut your fingers with the riving knife.

I also like to paint everything that is even remotely dangerous red so I would stay more alert around it. So I did also with my new riving knife. Be sure to use acetone to clean the blade thurally before applying the paint.

Step 5: The End

Success!

Now I can make grooved cuts and the sled works also perfectly. And also it does not stick out from the table when the blade is fully retracted. I can now easily slide my fence over without bumping into it.

I hope you liked this simple project!

Cheers

Andu

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    8 Discussions

    1
    Tangent-Man
    Tangent-Man

    9 months ago

    This is wrong -and in my opinion possibly dangerous.


    The riving knife thickness should be thicker than the body of the
    blade you are using but thinner than the kerf (resultant cut in the
    wood).


    See HSE UK government safety information on Table saws for correct illustrated explanation of why this it the case.

    0
    BaznSuz
    BaznSuz

    1 year ago on Step 5

    Thanks for this. I have exactly the same problem with the riving knife on my table saw. Never occured to me to make a new one - dumb or what? Now I have a solution :-)

    0
    domino88
    domino88

    3 years ago

    Great Instructable! I can't stress enough the importance of the riving knife. I too have an MLT 100 Makita table saw and I had removed the original tall riving knife for exactly the same reason: it blocked my sled. I had been planning to modify it in a similar fashion for over two years! That is until I hurt my hand really bad due to a kick back that would have never happened had the riving knife been there. I did not touch that saw again until I modified that riving knife. I would never use a table saw again without a riving knife. If you are in a similar position, stop and take the 15 to 30 min to add a riving knife.

    If your saw has no riving knife, you can add a wooden splitter on your throat plate:

    http://www.woodsmithshop.com/media/pdf/107/107-zer...

    Safety first!

    0
    CraftAndu
    CraftAndu

    Reply 2 years ago

    Hi! My MLT100 just broke down again and I was wondering if you have ever had the same problem. The threads of the motor raising mechanism are worn out so I can not raise the blade anymore. It is not that big of a deal since the new part only costs 17€ but I still lose precious building time. And it is the second time this has happened to me! I suppose I should have oiled the threads once in a while. I have also attached a photo from the plans showing the exact part (321). It is the big aluminium part in front of the motor.

    Has this ever happened to you?

    Screenshot_2016-09-26-08-55-40.jpg
    0
    CraftAndu
    CraftAndu

    Reply 3 years ago

    I could not agree with you more! Circular saws are really dangerous and must be handled with great caution.

    0
    studleylee
    studleylee

    3 years ago

    I had never heard of this. Cool!!

    0
    elturro
    elturro

    3 years ago

    Nice work! I did the same thing recently, but just cut the riving knife that came with the saw shorter.

    0
    CraftAndu
    CraftAndu

    Reply 3 years ago

    Awesome! :)