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Thread: Sharp knife got dull with Sharpmaker.

  1. #1

    Sharp knife got dull with Sharpmaker.

    Hi,

    Just got myself a Goko knife. Like this one.
    http://www.This Site Not Allowed Her...yuto210mm.html

    Out of the box it was extremely sharp but not on the overall edge so I put it in my Sharpmaker Spyderco like with all my other knifes, carbons as VG10. After 30 or so strokes with both brown and white stone the whole knife got extremely..dull! I ran it with the 15/15 degree angle.

    I noticed it sounded more than normal when i ran it over the stones and it lost lots of metal, more than I'm used to.

    So, what's going on here and how to fix this? Shall I just continue with the sharpmaker. I have tried another 50 swipes but still I'm having a tough time getting through a normal paper compared to all my other knifes that is extremely sharp in my point of view.

    Can someone who knows more explain what might have happened?

  2. #2
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    I am guessing the edge on this knife is thinner above the bevel than your other knives, so the pressure on the edge from the rods is multiplied due to the smaller surface area in contact with the stone. You have probably rolled the edge / bent the burr to one side. Use lighter strokes, and use the flat side of the stones not the corners.

    Basically this knife is not designed to be sharpened on a device like the sharpmaker, and the sharpmaker is not designed for knives like that either. You can use it, but at the end of the day they are incompatible tools.

  3. #3
    Senior Member Benuser's Avatar
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    With all the limitations of a distant diagnosis: as far as I know the Sharpmaker is a great maintenance tool, but not the best to create a new edge. I guess you didn't reach the very edge, remained just behind it, and accumulated debris on the very edge: a huge wire edge.
    Use a marker to see where you're abrading steel. Don't switch sides until you've raised a burr.

  4. #4
    Oh, didn't know the Sharpmaker could be that destructive to a knife . I need to get myself a stone then. I have had my eyes on a King 1000/6000. Would that work better you think? At least when I have learned how to use it but I will train on some older knifes first.

    I'll try the advice with lower pressure and just the flat side until I get a stone.

  5. #5
    When I check close the primary edge look like ****. It's like a saw. No wonder it cuts bad. How can it become like this when used on a sharpmaker or is it the knife that has problems? I try to understand what's going on.

    I mean it's more dull that a 5 dollar knife at walmart and it gets no better no matter what I do.

  6. #6
    Zoom in on this picture and you'll see my problem. I only tried to sharpen it as described above. Also tried with extremely gentle force now too and only flat side of the stones. No progress

    http://i46.tinypic.com/zim008.jpg

  7. #7
    Senior Member Benuser's Avatar
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    FWIW, I'm afraid you haven't reached the very edge yet. You're polishing behind the edge. Couldn't you use a coarser grit?

  8. #8
    Did you zoom in on the picture and see the bits and pcs that comes off the edge?

    Attaching more pics for reference.

    http://i50.tinypic.com/2qbc9wh.png

    http://i49.tinypic.com/28uqq08.png

    http://i50.tinypic.com/4q55dz.png

    And this is how the sharpmaker looks after 5 minutes of strokes.
    http://i49.tinypic.com/fcjq0i.jpg

  9. #9
    Senior Member Benuser's Avatar
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    Use the Magic Marker Trick to see whether you've reached the very edge.

    http://forums.egullet.org/topic/2603...nd-sharpening/

  10. #10
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    IMO it looks like you're hitting the edge, so ease up the pressure! Only use the finest stones you have, on the flat sides. You either have a burr or chipping, both are made worse with pressure. Stropping on leather will remove / reduce the burr once you have got it to a reasonable size on the stones. The marker trick is a good idea though, just to be confident. Are you 100% sure the edge is getting worse?

    The other thing is that the knife may have bad heat treat / missed being tempered somehow, but don't worry about that now, it's the least likely cause of your problems.

    Benuser, if he isn't hitting the edge, then the edge would not be changing. Any debris would be able to be wiped off.

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