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Robin grind-in knife reloaded

Discussion in 'Handiwork Display' started by zetieum, Jun 29, 2017.

  1. I have been spending some time in during the last weeks to improve the knife that I made during the Grind-in week-end by @Robin Dalman (see https://www.kitchenknifefora.com/threads/grinding-in-sweden-warning-very-photo-heavy.3950/). The knife I was lucky to make was a K-tip guyto, Mizu-honyaki (i.e. water quench with differential hardening). The geometry is a kind of S grind on the left-side and convex right side.
    I was (and still am) very pleased and lucky to have manage to do that in one week-end under the direction of Robin as the first knife I ever made. But the knife was faaaaar from perfect:
    • I was too thick behind and above the edge, especially in the middle of the blade
    • The finish was not perfect: some low grit marks, the Hamon was visible but not very pronounced
    • it was heavily bent, so much that it was almost not possible to sharpen it on flat stones.

    I have decided to work on these issues. I though of thinning it and progressively straighten it after thinning steps. My idea was that by removing some steel on the lower part of the blade, that is the hardest, I could maybe release some of the tension that made the blade bent and ease the straightening by having less hard steel handle. So I went through thinning/straghtening cycles.
    • To straighten, I just bent the blade in the other direction until a point I felt it was going to break. I worked pretty well.
    • Thinning was done using atoma 400. Never a fun job. I stoped at ~0.15-0.2mm being the edge, 0.6-0.8 at 0.5cm and 1.2-1.3mm at 1cm. At the end I put some convexity to improve food-release.
    • Then I refinished the blade using EDM orange stones and sand paper. I then etched the blade in ferric chloride, and sand it. This was done several time to enhance the Hamon. The on the final etch, I finished the bade using a mix of 1000 grit powder mix with some suita powder.

    And here is the result :). Much better that what I though I could achieved in all aspects: beauty, cutting performance, and FR. None of this would have been possible without @Robin

    it is almost straight: but at this point, it is not a problem anymore.
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  2. That must feel great. Pretty cool knife.
     
  3. Jim

    Jim Old Curmudgeon Founding Member

    congratulations on a fine result.

    To be able to say that's your first effort is amazing and I would think an incredibly satisfying feeling.
     
  4. Thanks guys. Indeed it feels great. And it feels great each time I reach for it to prepare something.
     
  5. Thinning a blade with an "atoma" is an hard work, i can only try to imagine your satisfaction when you finished!
    Congrats for the result!
     

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