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"Hello Knife People" To Convex or Not
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Thread: "Hello Knife People" To Convex or Not

  1. #1

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    "Hello Knife People" To Convex or Not

    Polarisation Convex - Flat Bevel
    I used to do all my sharpening on an Edge Pro Pro so all my edges were flat beveled although it is possible to convex using using incrementally different bevels from the cutting - micro bevel through to the thinning bevel then stropping them out.
    i recently started using bench stones which I am fortunate to be able to use ambidextrously .
    I started aiming to achieve flat bevels so as to discipline my control . Then I realised that even when trying to achieve a flat bevel there is some degree on convex in it .
    I have experimented in various blade shapes as inspired by Virtuovice (Hello Knife People) making many knives asymetric and of course convexing.
    I read that some advocates of flat bevels really are anti convexing even though it would appear that blades have been sharpened this way for centuries possible more so than flat bevels.
    If I wish to get to say expert level in sharpening should I be doing both types or shall I say compound convexing so thinning bevel convexed say around 8-10˚//10˚-12˚then a micro bevel say 14-15˚ perhaps topped with a minuscule asymmetric micro bevel say of 25-30˚ to strengthen the main edge.
    It seems that a blade can have a combination of both flat & convex bevels.
    I thinned and sharpened a small ceramic paring knife the other week using DMTs and this was a turning point I discovered that it is very hard to maintain a flat bevel on such hard material so I intentionally convexed both the thinning bevel and the edge the result was awesome it has never been that sharp it probable took x10 in time over steel to do this .
    The question I am really seeking an answer to is would a convex bevel be correct for a Fugubiki and what would be considered correct for any Honyaki knife ?
    I am awaiting delivery of a budget Honyaki Nakiri Takagi I have read that the Yanagi Takagi needed thinning out of the box and the result although arduous was worth while so I am half expecting to need to do this since it is rare that a knife is truly sharp out of the box and therefore do not necessarily expect the edge bevel to indicate what bevel is correct .
    Indeed is there even a correct bevel for these knives (convex or flat).
    One of the main reasons why i particularly want to know is if someone were to give me a Honyaki to sharpen is there a recognised correct bevel?
    So far I have not been able to find any information to support either as yet unless I look at Shuns which appear to be flat bevelled out of the box where as Globals are convexed as far as I know.

    The stones I am using apart from DMTs are Bamboo & *** and Shapton Glass

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  3. #3

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    I have my answer from CKTG forum
    "For a Honyaki, it will depend on the maker and what they left the edge at. I have a 240mm Blue #2 from Konosuke and the blade grind is nearly flat, and almost down to the edge itself and a very small bevel. It would be almost impossible to tell if the bevel was convex or flat on the edge and honestly, with the thinness behind the edge, won't matter at all".
    So with a micro bevel done only with the finishing stone it is pretty easy to produce a virtually flat micro bevel since the micro bevel will be so small.

  4. #4
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    I don't think that answer really means much of anything at all. The larger the bevel, the greater the effect of its geometry. For tiny bevels, the difference is not noticeable. For large bevels, it is quite significant. In general, you would ideally want a tiny bit of convexing on a large bevel. Exactly how much you want is to some extent, personal preference.

  5. #5
    Senior Member Baby Huey's Avatar
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    Welcome to KKF. I am sure your question will get answered with this crowd.
    It only hurts til the pain goes away........

  6. #6

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    Thank you yes I understand that the most important part of the blade is the thinning behind the cutting bevel when I first started to sharpen using an Edge pro it took me a while to realise the important of thinning a knife correctly many knives are not the correct shape to begin with unless they are to be used to chop wood .( one possible draw back of guided systems is that it is often hard to set a low enough angle without hitting the device hardware)
    When the cutting bevel is hardly visible the knife is likely to be sharp that is provided the entry to the edge from the spine is sufficiently fine and yes I see now that providing this is so it does not make a lot of difference if it is convexed or not this is a minor detail. Many people seem to like bevels they can see they faces in virtually which may look good but it will not function well.
    I write this to clarify the importance to others of the need for a blade to be adequately thinned I have even read of people lowering the spine of a knife to further thin the blade I have not as yet gone that far but many of my own knives i have thinned almost as high as three quarters of the way up to the spine or possible more .

  7. #7
    jklip13's Avatar
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    welcome

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