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Usuba bocho and shiseiji bocho

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Hesparus, Nov 2, 2012.

  1. Hesparus

    Hesparus

    Oct 31, 2004
    A while back I posted about wanting to make an usuba bocho. I had enough steel left on the bar to make two of them, so I did. Here they are, picture with a couple of other knives I'm working on:
    [​IMG]
    They were both looking pretty good, but after HT I started to wonder whether I really needed two of these. On a whim, I reground one of them to FFG (still single-bevel):
    [[url]http://sphotos-b.xx.fbcdn.net/hphotos-prn1/65445_395763167160072_86310547_n.jpg/img][/url]
    Here it is finished:
    [img]http://sphotos-b.xx.fbcdn.net/hphotos-ash4/416876_403443999725322_624654361_n.jpg
    It occurred to me that this modification makes it sort of a cross between an usuba and a nakiri: it has the thickness and single-grind of an usuba, but with cutting geometry more similar to a nakiri. So I decided to call this a "shiseiji bocho" which (according to an online japanese dictionary) means "bastard knife." It's also sharpened 95% on only one side.
    After finishing it up last night, I did some cutting with it. The edge didn't end up quite as fine as I had wanted — about 0.01" just behind the edge — but it still slices very nicely (the edge thickness is actually the same as my JA Henkels "Zwilling" chef's knife, but with a thinner spine). I'd like to try to get this down closer to 0.005" on the next one. It is a very different feeling for me to cut with an edge that is almost perfectly flat but I'm enjoying it so far. After cutting up an apple (and immediately washing again), this is already developing a nice patina at the edge.

    Specs:
    steel: 1/8" 1084
    overall: 11-3/16"
    blade: 6-5/8"
    blade width: 1-13/16" at base of blade
    handle: "walnut" dymondwood w/ nickel pins
    weight: 7.60oz

    To reflect the dual heritage of this knife, I used slightly different materials for the two scales. Here's the other side:
    [​IMG]
    Okay, so what actually happened is that screwed up on one of the scales and had to replace it with one cut from a piece of dymondwood from a different manufacturer, but I'm sticking with my original story.

    I finished the usuba last night, as well:
    [​IMG]
    The dimensions are almost identical on both of these knifes.
    I haven't sharpened this one up yet. I may actually need to regrind the bevel, since it came out thicker than it probably should be (0.006") — and since the back of the blade probably isn't as flat as it needs to be, I may regrind the whole thing into another shiseiji bocho. Or I may just sharpen it up as it is and see how it goes. These are both experiments anyway.

    I've got a few more blades in progress that are cut from similar cloth as these. Hardcore Japanese knife enthusiasts are probably cringing at these, but I'm having a lot of fun with them and I think they'll turn out to be great in the kitchen.

    Thanks for looking. Comments and suggestions are always welcome

    - Chris
     

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