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Thread: Bevel Grain

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    The Great & Powerful Oz onimaru55's Avatar
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    Default Bevel Grain

    Don't attribute anything magical here just something pretty that happened whilst honing.
    Was working this Case Red Imp wedge on a Jnat & noticed something I have seen on occasion but never succeeded in photographing with my cheapo USB m'scope.
    The bevel shows a grain pattern close to end stage of polishing. I understand some carbon steels will show this alloy banding effect when etched or polished but I thought this one was particularly cool & looked a bit like wood grain so thought I'd share with my fellow honeristas.
    The last 2 pics are at the higher end of mag. which is supposed to be 200x but the lower end shows up the effect better I think. And no it's not my fingerprints
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    Last edited by onimaru55; 10-27-2011 at 06:40 AM.
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    Bondservant of Jesus coachschaller's Avatar
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    Very cool! The pics are good as well.

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    Very clean, crisp bevel. Would you mind sharing your honing process pertaining to stones and technique?

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    The Great & Powerful Oz onimaru55's Avatar
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    Quote Originally Posted by FriedLiverAndOnions View Post
    Very clean, crisp bevel. Would you mind sharing your honing process pertaining to stones and technique?
    Stones & technique are really secondary to razors with good geometry. A clean, crisp edge bevel is ALWAYS a reflection of the spine.
    IIRC I used my Shapton Pros 1k - 12 k to rebuild the edge after the restoration. If you mean the polish I just spent a bit of time on it testing a stone I may buy.
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    Senior Member jeness's Avatar
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    Looks like damascus or wootz pattern, very interesting. I have only seen this on a few blades while polishing, never on the edge.

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    It does kind of look like wootz but is really alloy banding, or grain banding. I bet everyone honing with a microscope is going to go wild looking for this stuff on their blades now.

    Now you have to polish up the spine and see what you get there...(not like you needed more work to do).

    I'd be curious to know if the makers of Red Imps could possibly have overlapped with the use of shear steels? Those can have a subtle lamination look to them. Another possibility would be the use of some Sheffield crucible steel because that could also produce some of this kind of crystalline appearance.
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    Thanks for the pics, that is interesting to say the least, nice bevel btw, as if you didnt know.
    It is easier to fool people than to convince them they have been fooled. Twain

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    The Great & Powerful Oz onimaru55's Avatar
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    Quote Originally Posted by jeness View Post
    Looks like damascus or wootz pattern, very interesting. I have only seen this on a few blades while polishing, never on the edge.
    I first came across it after etching a tanto a few years back. I'm unsure but think the knife was 52100 steel. Next I saw it was on the edge of a Harner razor after honing it.

    Quote Originally Posted by Mike Blue View Post
    It does kind of look like wootz but is really alloy banding, or grain banding. I bet everyone honing with a microscope is going to go wild looking for this stuff on their blades now.

    Now you have to polish up the spine and see what you get there...(not like you needed more work to do).

    I'd be curious to know if the makers of Red Imps could possibly have overlapped with the use of shear steels? Those can have a subtle lamination look to them. Another possibility would be the use of some Sheffield crucible steel because that could also produce some of this kind of crystalline appearance.
    Mike, would you mind expanding on the visual difference between alloy banding & Wootz. I know steelmaking processes can vary but what about the appearance & actual structure . Very different ?

    Ooh no,not touching the spine. Just wanna smooth the edge out a little



    Quote Originally Posted by nun2sharp View Post
    Thanks for the pics, that is interesting to say the least, nice bevel btw, as if you didnt know.
    Kelly, the grind's not under my control. I wish they all came out like that one tho.
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    Mike, would you mind expanding on the visual difference between alloy banding & Wootz. I know steelmaking processes can vary but what about the appearance & actual structure . Very different ?

    Ooh no,not touching the spine. Just wanna smooth the edge out a little


    I hope this isn't too much.

    alloy banding or grain banding is the segregation of the various types of crystalline products in a bar of material. This is not a phenomena unique to steel. It occurs in non ferrous alloys as well. Banding is the formation of different colored streaks across the polished surface. Carbon generally averages evenly throughout a billet. What you are seeing in the bands is the minor alloying elements that were not uniformly distributed even though they were dissolved in a 40 ton lot in the melting ladle.

    Industry likes a uniform, fine grained alloy mixture. Steel is stronger, e.g. tougher, when the alloy distribution is uniform and the crystalline structure is smaller. Hence the efforts to produce as homogenous a mixture of alloying elements and grain size from the very beginning of the process. This resulted in the crucible particle metallurgy products.

    During the making of steel, the crystalline structure gets oriented along the long axis of the big damn bars they roll out of the mill (4 inch by 24 inch by 20 feet long). Good austenitizing can overcome this problem, but an incomplete soak can accentuate it.

    It is not generally considered to be a good thing, performance-wise in knife blades, except in wootz because that's what gives it the special look. In ordinary use (meaning the risk of some fool using a knife as a crow bar) the crystalline structure is aligned with the long axis of the blade, formerly the long axis of the mill bars, and does not perform optimally with lateral forces. This means that grain banding risks weakening the material.

    Higher concentrations of other alloy substances, can make the metal weaker and more prone to cracking, not to mention affect the look of the metal significantly. Alloys like chromium are greedy when it comes to acquiring carbon in chromium carbides. They increase rapidly in size. Large grain size means large grain boundaries and more places that are easier to fracture. Hence the reputation for stainless blades cracking easier. You can't see it as well but the separation is still there and some of those alloys can accelerate banding and retard it.

    A knowledgeable smith can manipulate this grain structure and have it take on a pattern just like wootz or pattern welded steels. I think it looks pretty cool too when it's done that way. But no one in this century invented it (especially not one particular resident of Texas) and it's not the best way to treat a steel for a blade, and it's definitely not wootz. Everyone of us heaters and beaters has, at least once, made some of this stuff in our shops accidentally, and some deliberately. There is one steel supplier who apparently bought a large lot of material from some steel mill and nearly every bar of their material has banding in it. That has been frustrating for some folks. If steel is not heated sufficiently, all the alloying products that form carbides may not necessary dissolve completely (okay you heat treaters, this is why soak time is so important!). This is why thermal cycling can both increase banding and eliminate it. Time at temperature rules in this place.

    This does not imply that this razor is a bad one, or the steel is bad in some way. There are a lot of blades out there that have an interesting, some times lesser some times better heat history and no one will ever know unless they try to develop the surface to where it can be seen like this. Until Oni polished it who knew? It was hard enough to shave, it sharpens well. Banding does not affect performance. It's now an interesting feature. Unless, he plans on using it to open paint cans or something....

    Not going after the spine? Ah you're tough sir, here I thought that would be an easy thing to tempt you.
    Last edited by Mike Blue; 10-30-2011 at 08:28 PM. Reason: added discussion
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    The Great & Powerful Oz onimaru55's Avatar
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    I hope this isn't too much.
    To quote Goldilocks ~ " Just right"

    Not going after the spine? Ah you're tough sir, here I thought that would be an easy thing to tempt you.
    Weeeeell, I would hate to tempt Murphy's law & have to reset another bevel if there was a mishap. These Case razors are damn hard, alloy banding & all
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