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Please explain advanced deburring - detection of subtle burrs and how to get rid of them
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Thread: Please explain advanced deburring - detection of subtle burrs and how to get rid of them

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    Please explain advanced deburring - detection of subtle burrs and how to get rid of them

    I have a sense that I may not be properly deburring. To explain:

    I am a relative newbie but have read a lot over the past months and sharpened a number of knives (mine, family, friends) on 500 Beston, 1200 bester, 5000 Rika, 10K naniwa superstone, followed stropping on polycrystalline diamond-impregnated leather.

    I do standard deburring by ending on each stone with a edge-trailing swipe of each side, following by cutting 2 or 3 times into a felt pad, before proceeding onto the next stone. On the final stone, my 10K, I go strop and then come back to the 10K to touch up. All this is based on stuff I read online.

    I can definitely detect the burr on the more coarse stones, but it gets harder and harder for me to detect as I go up in grit. After finishing on the 5K or 10K where I'm using very light pressure as I go back and forth, detecting the burr is difficult for me. I know I'm sharpening the edge and not the shoulder mostly by the way it sounds on the stone.

    So deburring seems simple to me. Yet I've been told by veterans on knifeforums.com that deburring on certain knives, including my Global G-2, can be very difficult and even annoying. I never thought I had trouble deburring, so it raises the suspicion in my mind that maybe there is still a burr on the knives I sharpen, i.e. I just can't detect it.

    So my questions, after a very long preface:

    - how do I know if I'm successful in removing the burr, i.e. if I can't feel it with my fingers?
    - is my deburr technique proper and sufficient?
    - if not, what can do I deburr?

    THANK YOU!

  2. #2
    Senior Member UglyJoe's Avatar
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    I think what they might be talking about, and what you are talking about isn't burr removal, but removal of the mythic wire edge. Dave would have a lot more to say about this than me, because I'm not sure I've ever been truly successful in removing the wire edge without micro-beveling. What I would tell you is that if your edges are holding up as long as you feel like they should be, don't worry too much about it. If you are experiencing what seems to be early edge failure, then you've probably removed the bur, but you might still have a wire edge. The easy way to get rid of that is to micro-bevel on your finest stone, but that is at the cost of having the sharpest possible edge.

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    I discussed this with Dave some month back, he told me that over the years he developed the ability to feel burrs even from high grit stones. I have the god-given talent to feel even the burr created by the 12k SS, so I can not tell you how to detect it using other methods.
    Dave told me that his ultimate weapon is to deburr, by felt, wood, cork or what else, after each successive stone. Using this approach I never had problems with bitchy burrs on my Global G-2. To me the "micro bevel on highest grit stone" approach that Jon introduced is a good way as it let's you get rid of the micro burr, decreases sharpness slightly but adds some strength to the edge.

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    Magnification is going to help at every level of sharpening, so add one of those $10 loupes to your kit annd checl your work along the way. If you've been successful at de-burring at 500 and 1.2k, it won't be an issue on the next stones, especially with better quailty steels. So it comes down to 'foundation' work on the 500 and 1.2
    After deburring, go back and do multiple trailing edge passes on one side, and see how quickly and how large the burr is if it comes back. If you haven't done a good job at burr removal or have the wire edge, it should come back fast and feel pretty large. If you have a tough burr, or the wire edge, you'll have to flip it back and forth a number of times before it will let go.

    Personally, after raising a burr on both sides, I'll do a trailing edge countdown (c-dawg style?), i.e 6 strokes on the front, 5 on the back, 4 on the front, etc until I get to 1,1,1,1,1 - then I'll de burr on fely, then go back and do alternating side countdown again, but maybe with a lot less pressure.

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    My method:

    When you finish, cut some paper and a tomato. Then slam the knife edge-first on a cutting board. Then slice the paper and tomato again. It won't be as sharp as before, but if it seems dull like before you sharpened, it's a honking wire edge.

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    I have always thought that a burr was the same as a wire edge. What is the difference?
    Spike C
    "The Buddha resides as comfortably in the circuits of a digital computer or the gears of a cycle transmission as he does at the top of a mountain."
    Pirsig

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    Senior Member Cadillac J's Avatar
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    They are pretty much one in the same, as a wire edge is that bit of weakened metal that will remain behind if not taken care of...it can feel sharp, but won't last long at all.

    I've used Dave's felt w/ diamond spray for over a year now, and to me it is the ultimate burr removal tool. Between each stone I cut into the felt a few times, then power strop on the felt, then cut a few more times. I've never had an edge fail using this method.

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    A wire edge is a knife sharpening term, a burr is a metal deformation, and the concept is universal throughout all metal-working trades.

    I've always considered knife burrs to be spots of bent steel from damage/inaccurate sharpening. A wire edge is a burr consistent enough to cut with, but it is weak, because it is just a straightened out burr, and not a continuation of the structure supported by the rest of the blade/bevels.

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    Senior Member UglyJoe's Avatar
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    Quote Originally Posted by johndoughy View Post
    A wire edge is a knife sharpening term, a burr is a metal deformation, and the concept is universal throughout all metal-working trades.

    I've always considered knife burrs to be spots of bent steel from damage/inaccurate sharpening. A wire edge is a burr consistent enough to cut with, but it is weak, because it is just a straightened out burr, and not a continuation of the structure supported by the rest of the blade/bevels.
    Basically this; I've always thought of "burrs" as loosely held metal that's not consistently attached across all of the edge. It's almost like shreds of steel that are holding on "by a thread" so to speak. Pulling the edge through cork/hardfelt/etc. will pull this deformation off pretty easily. However, with tough steel and working at a shallow angle especially, you can (and will) form a very thin and ultimately week layer of steel just in front of the edge. Unlike what I consider burrs, this "edge" is consistently attached across the whole edge of the blade, and simply pulling through cork, etc. will not remove it. It has to be abraded away. When you add a micro bevel, especially at a higher angle like Jon advocates in a lot of cases, it's kind of like folding a piece of paper across a tabletop edge and then tearing it off. This does remove the wire edge, but also it means the final edge of the knife isn't as acute as it can be. Some people are morally opposed to this, and if that's the case with you, you need to experiment with ways of telling that you have a wire edge and that what you are doing to get rid of it is actually working.

    The frustrating thing for a lot of sharpeners is that I really think you only start to get a wire edge when you are working with good steel and your technique is well developed. With weaker steel and/or wobbly technique, I think you tend to form burrs mostly and very little wire edge. Especially with wobbly technique, as your edge angle isn't consistent enough to get that one smooth consistent strip of steel that is the wire edge. I think it frustrates a lot of sharpeners, because they start off with cheaper steel, they work with wobbly technique, and they achieve an okay edge after they finish - an edge that I and many others thought was wonderful because we had never really felt a great edge before. You then get better knives with better steel, your technique improves, and suddenly you start generating wire edges that are sharp as a mother, but the edge fails after a few sessions cutting with the knife, and you begin to be upset, thinking that you suck at sharpening or that the knife you spent a lot of money on sucks, etc.

    Wire edge removal is the hurdle that moves you from beginner sharpener to good sharpener. Once you learn it well, you'll see a dramatic increase in your edge quality and endurance.

  10. #10
    Senior Member heirkb's Avatar
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    Quote Originally Posted by UglyJoe View Post
    Wire edge removal is the hurdle that moves you from beginner sharpener to good sharpener. Once you learn it well, you'll see a dramatic increase in your edge quality and endurance.
    Is the removal of a wire edge only possible with a microbevel then?

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