Razor edge retention

Discussion in 'General Knife Discussion' started by dkb45, Sep 18, 2018.

  1. dkb45


    Dec 16, 2012
    Working edges: all the rage in the knife world. Almost all of the most popular steels rely on working edges, quickly losing the refined edge you take so long to put on. Abrasive media like cardboard is hell on edges, especially refined edges, but a few steels handle it like champions. I'm curious what all steels can hold their refined edge.

    I've found that Elmax, K390, CPM154, Cru-Wear, and ZDP-189 readily hold a razor edge under pretty intense cutting. I've found M390, S90V, S110V, HAP40, Super Blue, M4, and S35VN give up pretty quickly on the razor edge. S30V is mixed, but seems most likely to hold it if sharpened with all diamonds (diamond stones and diamond pastes to strop). CTS-XHP is hit or miss, I need a little more testing to say how it goes in my experience. VG-10 and AUS-10 aren't bad, but overall edge retention is significantly lower than super steels, and 154cm is a small step up. 14c28n holds a razor edge for surprisingly long, considering the overall edge retention, same as Acuto 440, but they are lacking in overall edge retention (compared to super steels).

    Interested in what others have found out.

    Edit: One odd standout is M4 in my Spyderco Mantra. It held a razor edge much longer than M4 usually does. Both GBs I've had, my GB 2, and a Benchmade I can't remember the name of in M4 didn't have this same razor edge retention. Possibly different HT or the efficiency of the thin stock FFG. A shocking standout was S90V on my ZT 0095, it held the razor edge almost as well as K390. I'd say it's grind, but the Native 5 in S90V that I had didn't perform nearly as well, could be ZT heat treat of S90V.
    Last edited: Sep 18, 2018
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  2. jbmonkey

    jbmonkey Platinum Member Platinum Member

    Jun 9, 2011
    m4 in my experience keeps it pretty well. surprised your experience didnt. guess it depends on what your cutting routine. m390 and the like 20cv/204p does pretty well in my experience. also xhp does quite well. d2 does very poorly at getting a refined edge and keeping it. I haven't done a list though.

    cutting ductboard kills it on every steel and very quickly. much quicker than cardboard. as little as one partial cut really, from my experience. I cut lots of that everyday so i kinda gave up on keeping the super sharp edge. gone back to geometry and ease of sharpening, more than holds it.
  3. 115Italian


    Nov 13, 2015
    What was the base line for this test? Were the knives factory sharpened or resharpened?
  4. Alberta Ed

    Alberta Ed

    Jun 29, 1999
    Blade geometry has a big part to play in cutting efficiency, too.
  5. Mo2


    Apr 8, 2016

    This guy's got a bunch of vids about what I think your looking for?
  6. Kbrasmodeler


    Mar 18, 2008
    Man, I've had the opposite experience. I've only had a few D2 blades, but they took and kept a very refined edge very well. It's always interesting to me how different people can have different experiences with the same product.
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  7. McFeeli


    Feb 13, 2017
    I've been using my K390 Urban as my one and only cardboard knife when I'm at home just to see how the steel performs. I've been pretty impressed with the steel so far, except it does seem to be a bit brittle. I chipped the edge just by shaving down a toothpick, and it sure was fun to get that fixed, haha. I still need more time with it, though.

    I would also say M390 does a good job at keeping it's shaving edge after a few boxes. I've used my mini Ritter to slice through a pile of boxes and it would still shave my arm. I've been using my Shuffler and Dom in M390 a lot lately as well and with how thin the stock is the edge really does last a long time.
  8. shinyedges

    shinyedges Unfaltering Love & Undeviating Will Knifemaker / Craftsman / Service Provider Gold Member

    Jun 5, 2012
    Probably due to what people determine is a "fine" edge. The large carbides in D2 prevent it from achieving a fine edge (also make it more prone to breaking from shock) that other smaller more evenly distributed or low carbide steels have.
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  9. Kbrasmodeler


    Mar 18, 2008
    I totally get that. We're talking about relatively "large" carbides, though, right? It seems to me that they are still mighty small, on a macro scale, though. I had a Queen Canoe (sadly lost) with D2 blades, that I convexed with sandpaper and stropped on green compound. Thing would cut cardboard all day. Years ago,I had a customer come in, after I had been cutting cardboard all day (packaging and shipping orders) to pick up some product. He was trying to tie it down in his trailer in our shop. Now, keep in mind, his rope had been in the trailer, while it was raining, and was not only wet, but loaded with sand and grit. He wanted the rope (about 1-1/2" synthetic) to be shorter, but his razor knife wouldn't cut it, so he was snipping strand by strand with a pair of side-cuts. I offered to cut it with my Queen. He declined, and struggled through the rope, finally getting all the way through.
    He said "My razor knife wouldn't even cut this."
    "This will. I guarantee it," holding out my Queen canoe.
    With a disbelieving look, he held out the rope, challenging me. That D2 spear point whispered through the synthetic, grimy, wet, gritty rope like it wasn't there. Not even freshly sharpened, but it just felt like a really fine edge, and it lasted all day through cardboard.
    I don't know if Queen did something in processing their D2 that made the carbides smaller, or if that is normal D2 performance. However, I get similar performance from my Composite Kershaw Leek. Maybe I just got freak blades.
  10. shinyedges

    shinyedges Unfaltering Love & Undeviating Will Knifemaker / Craftsman / Service Provider Gold Member

    Jun 5, 2012
    Significantly larger in size than other steels, so large that carbide tear out occurrs. Which is why people always say it keeps it's toothy cutting edge for a very long time. Now, I'm not an expert on metallurgy, this is just my understanding of it.

    I've had knives in D2 as well and found it got "razor" sharp and I actually enjoyed sharpening it which some people apparently have issues with.
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  11. Twindog

    Twindog Gold Member Gold Member

    Apr 6, 2004
    All super keen edges will show a quick drop in sharpness, followed by a slower decline as the apex recedes and becomes wider.

    That rate of decline is driven almost entirely by the steel's wear resistance, unless the edge is being pushed beyond the steel's ability and the decline is speeded by rolling or microchipping.

    If an edge seems to lose its keeness too fast, it's almost certainly because the edge was improperly sharpened, usually by leaving a burr.
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  12. GatorFlash1

    GatorFlash1 Gold Member Gold Member

    May 28, 2012
    The knife that I have that holds a razor edge the longest is a Spyderco Manix 2 with Maxamet steel blade, probably because of it's hardness. However, my EDC GB1 holds the edge I like the best for working around the shop and yard.

    If shaving arm hair is a turn on for you then check out this video.

    Last edited: Sep 18, 2018
  13. jbmonkey

    jbmonkey Platinum Member Platinum Member

    Jun 9, 2011
    on d2 I should clarify if I sharpen them toothy they stay that way a long time. if I put a very fine edge on them, they dont.
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  14. Alberta Ed

    Alberta Ed

    Jun 29, 1999
    There is a difference in D2 between various makers, maybe due to heat treat. Benchmade's D2 seems finer grained, for whatever reason; my Cabela's Grippie and 710 in D2 take and hold a very fine edge. (Same for my BM Mini-Rukus in S30V.) My Dozier K1 General Utility seems a bit different, maybe due larger grain, but it cuts like a chainsaw and holds an edge all day.
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  15. marthinus

    marthinus KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 10, 2006
    Are we just talking personal experience or actual metallurgy?

    Personally I have gotten everything razor sharp and all lose their sharpness the same way and within a day needs to be resharpened.

    Metallurgy speaking, the smaller the carbides and distrubution the finer the edge.

    Check out https://knifesteelnerds.com/ and the article on edge stability.
  16. BTGuy

    BTGuy Gold Member Gold Member

    Jul 5, 2016
    I've become more of a fan of slightly toothy edges (600 - 1000 grit finish) than highly polished and "smooth" edges (5000+ finish). It seems most steels with that super refined cut dramatically less freely after a few minutes of usage. The edges will then still push-cut paper fine and all, but lose the ability to slice through materials thicker than paper as well as a less polished edge. D2 is a good example of this with the few knives I've used with that steel. It basically came down to sharpening time versus duration of cutting for me. I find I get the same or more life from an edge for less than half the amount of time spent sharpening.
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  17. eKretz


    Aug 30, 2009
    52100. The end. :D It is very good at holding a fine edge in my experience.
  18. Wowbagger


    Sep 20, 2015
    I would have to beg to differ in the M4. Big time.
    HAP40 , though I have none, it would surprise me if it didn't keep some shave, shave for a while.
    I get stellar results with M390 . . . pretty shavy compared with that funny high vanadium stuff.
    But I regress and will now pop out of the rabbit hole to create my own.
    I wrote much of this and took these photos before reading this post.
    Nutty ?
    Well yeah . . . but I knew it was going to be all about the super steels. In that regard the only super steel I am enamored with, for cutting abrasive stuff and difficult paring / trimming is M4. It does EXACTLY what I need it to do week in and week out and then goes on to surprise me in it's ability to come back from shave sharp to hair whittling with a few simple hand held strokes of a Spyderco Ultra Fine Triangle rod . . . sound of gavel hitting anvil . . . done deal . . . why would I even LOOK at any other steel for the things I cut. Although there was that flirtation with K390 that drew my eye but there was no actual contact, it was infatuation from afar . . . Sal I am glaring at you with frustration and longing for what MIGHT have been. (Pattada in K390). :mad: :( :)

    Anyway . . . he shakes his head like a person who has just been body slammed . . . he walks it off for a while . . . stumbling . . . trying to focus . . .

    The Little Monster !
    That's what I am here to talk about. Even RANT . . . in a good way.
    You've al heard me go on about it. A year and no sharpening with daily kitchen use.
    Shave sharp and hair whittling AS LONG AS I USE THE GOOD PLASTIC CUTTING BOARD.
    Well . . . here we are at one year and six months. I have been thinking about sharpening it. Should need it by now right ?
    I will let you be the judge.
    There are no chips. The only thing I feel when I draw the edge across my thumb nail is fear . . . THAT THE THING IS GOING TO CUT THROUGH MY THUMB NAIL, MY THUMB AND CUT THE CORNER OFF THE FRIGIN’ KITCHEN COUNTER.
    . . . did I mention this thing is a monster ?

    Shaving edge : (true it isn't whittling hair these days) ? ! ! !
    Before edge test

    Whoa dude . . . no prob
    sorry for my poor i-Pod camera; most of the hair stayed on my arm in a little pile after it was shaved off.

    Then to the kitchen. The Chef left out some oatmeal to cool and now I need to cover it and put it back in the fridge. I save the scrap cut off this to cover my Ti spoon for lunch tomorrow.
    . . . hmmmm how to trim this off ? ? ? I could use the kitchen scissors or . . . lets try The Little Monster . . . does he have anything left after all that hair shaving ? ? ?

    YES ! He easily draw cuts the delicate plastic. When it is hair whittling sharp it will push cut the plastic. By the way this is something that was COMPLETELY beyond the capability of my Manix in S110V right off the Edge Pro . . . 0.030" behind the edge ? ? ? PLEASE ! ! ! that is geometry for lumber jacks not pocket knives o_O.

    Here is a test that shows the edge is ready to go to work off the Edge Pro.
    The Little Monster can still pass the test after a freaking year and a half of daily use ! ! !
    Can it hang on the skin of a tomato, apple . . . or in this case the only thing to hand . . . a grape. Grapes and blue berry soya yogurt for breakfast / lunch. Hey . . . I have to keep my figure for all that underwear modeling / photo shoot this after noon. :rolleyes: Oh wait . . . I'm lying again but only about the photo shoot . . . :D
    All this knife edge stuff is real. :cool: :thumbsup:
    Is it the superior Japanese White Paper Steel ?
    Is it the superior white plastic cutting board ?
    Or is it the highly trained hand that wields this fearsome weapon of mayhem and destruction ?
    I leave it to you, dear reader, to decide.
    Last edited: Sep 18, 2018
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  19. Wowbagger


    Sep 20, 2015
    . . . and
    AND !
    . . . another thing
    " "

    I just wanted to say that maybe , just MAYBE, that whole idea about edges deteriorating significantly from rust . . . well that just might . . . maybe . . . might . . . be nonsense.
    See the rust on the blade ? I never oil it; I wash it under the faucet, give it a quick wipe on a damp towel and toss it (well gently place it with reverence) on the cutting board to stew in the awful juices of the kitchen water tap left on the blade.

    huh . . . some how it has retained a shave sharp edge for a year and a half, only recently lost it's hair whittling edge
    . . . I'm just saying . . .
    Last edited: Sep 18, 2018
  20. Wowbagger


    Sep 20, 2015
    wow . . . I'm speechless. (don't you wish)
    Almost sounds like the start to a hyperbolical insult monolog :
    "Why you would chip up if you even tried to shave a tooth pick . . . " and all like that.

    Lets hope it was just some steel fragments imbedded in the tooth pick after an environmentalist spiked a tree. :D
    Go Hayduke !
    Of course my M3 blades would have cut into the steel fragment and been completely unaffected but that's another story.

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