I Tested the Edge Retention of 48 Steels

Discussion in 'General Knife Discussion' started by Larrin, May 1, 2020.

  1. jstn

    jstn Gold Member Gold Member

    Jun 27, 2012
    That makes sense. I was looking at the toughness vs hardness scale and interpreted that as edge retention. Seems Nitro-V is more marketing than anything considering it loses toughness to AEB-L without gaining edge retention.
     
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  2. WuFluFighting

    WuFluFighting

    22
    Jun 9, 2020
    In all my years of knives ive learned one thing. In a blind test id be unlikely to be able to tell much difference. I haven't used a lot of steels, but maybe 10. I can tell m390 is harder than sak steel. But in my practical use, that involves a heavy dose of inappropriate tasks, they all dull rather quick.
     
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  3. bhp9

    bhp9

    15
    May 13, 2016
    I realize I came in here rather late in the thread so here goes anyway.

    The laymen who knows little if anything about steels does want to know from a practical standpoint which factory produced knife steels would be best for him to purchase in either stainless or carbon and what if any practical difference there is in actual use. Arguing how many angles can stand on the head of pin may be an interesting subject to some but entirely a waste of time to the average consumer who just wants some clear cut answers without having to take a course in metallurgy.

    It would have been more informative if some black and white clear cut answers would have been stated as to what factory made knives being currently made in stainless or carbon (that are commonly available to the consumer) would be the best tool for the job. . Price of course is always a factor but the question is not one of price at all but which factory produced affordable stainless factory knives have the best edge retention (if properly heat treated) and factory produced knives made of carbon steel knives have the best edge retention by brand name along with heat treatment or lack there of . The laymen is not concerned with complicated explanations or hypothesis or speculation or exceptions to the rules of steel making but concerned with what is available and affordable to him across the counter at an affordable price and from the major knife makers. Whether to purchase D2 , 440a, b and c, aug 8 and 10 just to name a few of the steels the consumer often has to chose from is a question that is often asked over and over and that is "is it worth the extra money to pay more for a knife" with say aug 8 as compared to say run of the mill 440a etc. etc. In other words would the average Joe even know or see the difference or even care if all he had to do was sharpen it more often and pay way less for the product? Is one steel over another really that much better to the practical man who in most cases may use his knife once a year to gut a deer? It might make a difference to the professional chef in a restaurant or if affordable to the average house wife for use in the kitchen. Otherwise we are back to arguing over how many angles can stand on the head of pin.
     
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  4. Larrin

    Larrin Gold Member Knifemaker / Craftsman / Service Provider Gold Member

    Jan 17, 2004
    360
     
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  5. Twindog

    Twindog Gold Member Gold Member

    Apr 6, 2004
    Larrin's epic study is meant for sophisticated users, and as such can be a difficult read for beginners or casual knife users.

    If you stick to high-quality brands, pretty much all the steels they use will be fine.
     
  6. Currawong

    Currawong Platinum Member Platinum Member

    May 19, 2012
    Most knife articles online are of this sort already. Where do they get good factual info to base their recommendations on if not from sources like Larrin? Having published research is important because otherwise 'layman' articles are anecdotal.
     
  7. Fixall

    Fixall Gold Member Gold Member

    Mar 26, 2018

    “Best” is SO subjective though. The steel that is the best for your usage scenarios on a day to day basis may be completely different from what is the best for my uses. Maybe person “A” only cuts paper and values edge retention above all else (hello 15v or 10v). Maybe person “B” really likes to sharpen and keep their knives razor sharp at all times and doesn’t care about edge retention (hello super blue or similar). Maybe person “C” wants a really good balance of toughness, edge retention, and ease of sharpening (CruWear). Maybe person “D” works in a salt water environment and values corrosion resistance above all else (hello lc200n or similar). Maybe person “E” is all about toughness (3v or similar). And maybe person “F” wants a nice balanced steel for a really reasonable price (14c28n). For the undiscerning/indiscriminate customer, I imagine any of the commonly used steels from a reputable knife manufacturer would provide more than sufficient edge retention and toughness for day to day use.

    Something that I would like to see is some sort of test that helps pinpoint how much toughness and edge stability is actually needed for the average knife user on a day to day basis for EDC tasks. With a proper heat treat, I think the average user (or at least enthusiast) could easily get by with a high edge-retention, low toughness steel like 10v with little to no issues.
     
    Last edited: Jul 5, 2020
  8. me2

    me2

    Oct 11, 2003
    The first thing the layman needs to do is decide the job. Then learn to sharpen or decide to pay for sharpening. Before those issues are addressed, steel choice is irrelevant.
     
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  9. Broos

    Broos

    Jan 10, 2005
    Wow awesome, best ever testing with a catra machine. I haven't read it yet but I am looking forward to it! Thanks again for sharing Larrin!
     
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  10. Karl H

    Karl H

    85
    Apr 24, 2020
    I think that when most people talk about "loosing initial sharpness" they are probably referring to microchipping at the apex, causing the apex to become wider and rougher, without any visually apparent change (edge rolling or macroscopic chipping).

    I would assume that a Brubacher Edge Sharpness Scale (BESS) and a microscope could be used do a study on this? A methodology similar to this study seems like it would work. The applied stress to the edge would need to be low enough that macroscopic plastic deformation and chipping would not occur. I think that one would want to use a non-abrasive material to minimize loss of sharpness due to abrasion.

    Alternatively, it seems like taking the derivative of the CATRA cut distance vs. cut # curve (for only the first two or three cuts) seems like a way that you could analyze this without doing any additional testing.
     
  11. Larrin

    Larrin Gold Member Knifemaker / Craftsman / Service Provider Gold Member

    Jan 17, 2004
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  12. Twindog

    Twindog Gold Member Gold Member

    Apr 6, 2004
    If I remember correctly, the idea that high-wear steels quickly lose their initial sharpness started with the early batches of S30V, where micro-chipping was a real issue because of slow quenching during the heat treat. S30V makers have overcome that problem, but the conventional wisdom remains.

    Nonetheless, most high-alloy, high-hardness steels are not very tough; so in real world use, micro-chipping can be an issue, depending on the knowledge and skill of the user.
     
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  13. hardheart

    hardheart

    Sep 19, 2001
    Great job all around. Sorry about those costs, but at least you have your own catra now.

    Really great how you further confirmed your model's ability to predict cutting performance with real world repeatable and verifiable tests open for anyone to actually try themselves. Catra testers are out there in use, just ask. Lots of people have already done it. Just not *this* well.

    Maybe one day it will be enough to satisfy the questions and criticisms. Or not. Knives are all about the magic and mystery.
     
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  14. TRfromMT

    TRfromMT Gold Member Gold Member Basic Member

    Jan 4, 2016
    @Larrin - can you point me to some more complete information on K390? I see very little mention of it in this paper (good night, what an undertaking! Thank you!). It seems one of a few you did not get test for toughness (quoting: . I have tested the toughness for all but 7 of the steels: Z-Max, BD1N, K390, S125V, S90V, S60V, and Vanadis 8.) I'd like to see how it stacks up compared to some other high end carbon steels. Purely anecdotally from my PM2 in K390, it seems pretty tough and holds a great edge.
     
  15. Larrin

    Larrin Gold Member Knifemaker / Craftsman / Service Provider Gold Member

    Jan 17, 2004
    I would expect K390 to have similar toughness to 10V. But Bohler claims improved toughness over 10V so there is a chance it is somewhat better.
     
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  16. Mrs_Esterhouse

    Mrs_Esterhouse

    100
    Apr 9, 2019
    I read in your article about the history of M390 where you wondered why Bohler used more expensive tungsten instead of upping molybdenum to the same effect. Why do they keep using tungsten vs. upping the molybdenum even in K390?

    K390
    [​IMG]
     
  17. Centuriator

    Centuriator Gold Member Gold Member

    370
    Jun 7, 2020
    Thanks for this research.
     
  18. Larrin

    Larrin Gold Member Knifemaker / Craftsman / Service Provider Gold Member

    Jan 17, 2004
    My guess is they attempted to differentiate from 10V to make the grade more “patentable.” The 10V patent had expired but some unique nature must be demonstrated, or at least claimed, to patent the steel. You can read the original patent to see if you think their reasoning makes more sense than mine: https://patents.google.com/patent/EP1382704A1/en
     
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  19. Blues

    Blues Lapsed SuperMod / Cattle Knife Rustler Staff Member Super Mod

    Oct 2, 1998
    We need to find a way to incorporate "upsidaisium" into these steels.
     
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  20. Sigifrith

    Sigifrith Gold Member Gold Member

    798
    Jan 18, 2004
    Larrin I joined your Patreon today to say thanks.
     
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