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jointer knife bevel angle

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  • jointer knife bevel angle

    Just purchased a used jp06101 jointer. The knives need some help, dull and chipped. I am used to sharpening my own chisels, so I will probably make a jig. I have a Veritas MkII for my chisels. Wish I could adapt it for the jointer knives. (I know Veritas makes a jig for the knives, but I am tired of spending money for a while.) The best I can tell, the primary bevel on the knives is around 37 degrees. Does this sound about right? I ask this, because I do not know what the previous owner did with the blades. It also looks like there is a slight secondary bevel. Just for what its worth, I am a firm believer in flattening the back before starting on the bevel. The first blade I started on is a long way from having a flat back. It will have when I am done.
    "non illegitimis carborundum"

  • #2
    Re: jointer knife bevel angle

    I have answered my own question. Downloaded the JP06101 manual from Ridgid. Figure 48 shows the bevel angle to be 38 degrees. This figure also shows what might be an error. It says you can put a slight secondary bevel at the cutting edge, but the drawing, which shows a secondary bevel, has an arrow, labeled as the secondary bevel, pointing to the primary bevel, farthest away from the cutting edge.
    "non illegitimis carborundum"

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    • #3
      Re: jointer knife bevel angle

      Originally posted by Laflaone View Post
      I have answered my own question. Downloaded the JP06101 manual from Ridgid. Figure 48 shows the bevel angle to be 38 degrees. This figure also shows what might be an error. It says you can put a slight secondary bevel at the cutting edge, but the drawing, which shows a secondary bevel, has an arrow, labeled as the secondary bevel, pointing to the primary bevel, farthest away from the cutting edge.
      Thanks for pointing that out, Laflaone. I was thinking there was something wrong with that illustration, but wasn't sure. Now it makes much more sense.
      I put it all back together better than before. There\'s lots of leftover parts.

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      • #4
        Re: jointer knife bevel angle

        You are correct the labels are wrong and the secondary bevel shown (labeled cutting edge) is at the point where you would regrind the primary.
        Flattening the entire back of a blade is really only useful with a chisel. The back of a chisel actually guides the cut so it is important for it to be flat. For blades used in hand planes or jointers etc. only the edge presented to the wood is important. You can flatten the back but it may take forever (tried it once) and there is really no gain. If the back edge does not flatten readily you can create a slight back bevel to get a sharp edge. You can shim the flat (non sharpened back side edge) with a strip of tape on your stone or sand paper to create a 0.5 to 1 degree back bevel, just enough to get a straight sharp edge. You only need to do this at the finest grit (5 micron or less). When creating the micro bevel you only need to raise the angle 1 to 2 degrees and only make a few passes on your finest grit, you will barely see the micro bevel which means that subsequent resharpening only happens on the micro bevel so the task now only takes seconds unless you chip a blade. I found that the Veritas Jointer Blade Sharpener was and excellent investment.

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        • #5
          Re: jointer knife bevel angle

          Thanks, you two for your responses.

          wbrooks: I am taking a long look at the Veritas. I have their MkII for my chisels, and I love it. It's a quality tool. I think I am first going to make a jig based on the Veritas, but made of wood, and the same type angle adjusting screw. There is a very interesting review of the Veritas jointer sharpening tool at www.onlinetoolreviews.com. There is a dropdown window at the top. Just scroll down to the Veritas items. In this article, there is advice to first flatten the back, and it gives their reasons. One I would not have thought of: In manufacturing the blade, there are swirl marks on the back, which would lead to very fine saw teeth on the cutting edge. Your idea of a very slight back bevel would probably take care of that.
          "non illegitimis carborundum"

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