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hair splitting edges for me?

Discussion in 'Maintenance, Tinkering & Embellishment' started by getridone, Jun 20, 2012.

  1. getridone

    getridone Banned

    320
    Dec 5, 2011
    So couple questions to those well versed on this subject matter, and those that purport to be....

    1) Is an edge that splits hair restricted by any certain geometry?....<30 inclusive...etc....
    2) Is an edge that splits hair restricted by a certain level of polish?....stropped at XXmicrons...etc..
    3) Is this edge suitible for EDC, like opening things made of cardboard, plastic and flesh?? Or does such an edge prove too fragile for said events?


    Questions submitted respectfully on this great day.
     
  2. snowreaper1

    snowreaper1 Banned

    Nov 26, 2010
    Heres a hair splitting edge I just put on my Sebenza last night. 40 inclusive. Went up to 1,000 grit diamond and than hit it with the 3.5 and 5 micron strop.
    It is not a mirror edge and actually has a good bit of bite to it. Its a very clean edge though with not a burr in sight.

    [​IMG]
    [​IMG]
     
  3. cziv

    cziv

    Nov 24, 2005
    Nice job. Waht'd you sharpen with sandpaper & strop?
     
  4. HeavyHanded

    HeavyHanded KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 4, 2010
    This my experience. Hair splitting is a lot easier to achieve with a smaller inclusive angle. Its also a lot easier to achieve as you go farther up in grit count. If its going to split with a simple push as opposed to using a bit of draw then it will most likely have to be very well refined at the apex. In many cases when stropping its possible to get a high degree of uniformity at the cutting edge but have a bevel that still shows some grind texture. Its plenty suitable for EDU, but in my experience, with common steels, loose the ability to chop hairs very quickly and require a lot of maintenance to stay effective. This maintenance might take only a few minutes several times a week but without it the edge will degrade fairly quickly compared to a less uniform apex produced at a lower grit. Its a good endeavor for improving your sharpening skills and works great for some tasks, but for low-maintenance EDU not very efficient.
     
  5. snowreaper1

    snowreaper1 Banned

    Nov 26, 2010
    Wicked Edge takes all the credit. No way am I getting an edge like that free hand ;)
     
  6. cziv

    cziv

    Nov 24, 2005
    They look very nice but the price is out of my range. I have a full array of bench stones and strops. I use them almost exclusively. I get better with each knife I sharpen. Not perfect like a WE, but I finally whittled hair with my Military about a month ago. :)
     
  7. Razorsharp-Travis

    Razorsharp-Travis Banned

    612
    Aug 16, 2011
    I can get hair splitting edges at fat angles- like 44-50 incl.

    I can get it at most grit finishes

    its about the apex and how it meets up ;)
     
  8. singularity35

    singularity35

    Mar 1, 2010
    Yep, this^^.
     
  9. Benuser

    Benuser

    222
    Nov 19, 2010
    Another factor is the steel: is it finely grained, does it support fine edges, are there large carbides, impurities...
    I guess the simplest, purest carbon steel wins.
     
  10. unit

    unit

    Nov 22, 2009
    No, but smaller angles make push cutting easier (i.e. requires less force to complete a cut) and therefore many find it easier to get fine cutting edges with lower angles.

    No, but higher levels of polish lead to a more uniform edge (i.e. there is less place to hide substandard sharpening technique with high polish) and therefore you frequently see polished edges whittling hair. In truth a WELL sharpened edge in fairly coarse grits will be able to split hairs...but the coarseness often makes for more aggressive cutting and often leads to cutting the hair instead of whittling it.

    I find them highly suitable for every day use. They should not be "fragile" but it depends on the steel you use. Many steels will rapidly stabilize to a lower level of sharpness than hair whittling, but I would not blame the sharpness as much as the alloy in question.

    In the end, it depends a whole lot on what you use and how you use it. Is it for you? Only you can answer that. Some will act as if "real men" who actually "use" their knives cannot be concerned with such matters because they are too busy working and do so with such vigor that a rusty shovel would prove sharp enough for their rugged manliness. To their point, I know of no steel that will really support a hair whittling edge for an entire day of work (or even close to it), but some steels are a WHOLE lot more fun to play with if you start them off at that level of sharpness;)
     
  11. Belker

    Belker

    25
    Aug 8, 2007
    If you ask me, hair splitting is practically a worthless measure of sharpness because it all depends on the particular hair you are trying to split.
     
  12. unit

    unit

    Nov 22, 2009
    While I agree that it is highly subjective, I think it is a few standard deviations away from practically worthless.
     
  13. KennyB

    KennyB

    Jan 19, 2010
    It's useless to the degree that it generally devolves into a ____ measuring contest. Fill in the blank on your own...

    Splitting hair is useful in one regard: It shows you how easily the apex of your edge will cut into the very narrow diameter of your hair. Hair is also a good test material because it's about as hard as copper at that diameter--or so I've heard. In any case, there's just not a lot of material that is as thin and pliable as hair is, so an edge has to be very keen to actually bisect it, rather than simply push the hair aside or skate off of the surface.

    Past that it doesn't do much to tell you how sharp an edge is, because like you said hair varies so much. On top of that though, your hair is different from one place on your body to the next, and the humidity and moisture content of it changes every day, etc. There's just a ton of variables in that realm to where I think that once people get into the semantics of "tree toping" vs "hair whittling" vs "hair hanging tests" and all this, that they're really just getting far too concerning.

    In my experience, an edge that is hair whittling... That is, will carve little splinters of a hair held outstretched and unsupported like a stick. This type of edge is going to degrade from that level of sharpness immediately. There's no point in trying to reach this level of sharpness, because once you've shaved your arm a couple of times, cut up a few pieces of paper, it's not going to be as sharp. That's just my experience working with a lot of mild steels, or steels with large carbides like S30V though.

    Anyway, I think I said it somewhere once before... But I think that all this talk of "hair splitting" and "hair whittling" and "tree topping" and "hair popping"... It's all up in like the 99th percentile of how sharp one can get an edge, and there's not even that big of difference in practical use between any of them. Once you get an edge up to this level of sharpness, unless you're actually shaving with it, then the blade geometry behind the edge is going to be the bottle-neck. You can take an edge from sharp enough to shave, to so sharp it will make the air bleed, but it doesn't mean it's going to cut through anything you actually need to cut through any better. Unless you're talking about razors and actually shaving, there's no real discernible performance increase when going from one level of hair-splitting sharpness to the next.
     
  14. singularity35

    singularity35

    Mar 1, 2010
    I find that getting hair splitting(whatever kind of human head hair) serves to tell me that my sharpening technique is along the right path.
     
  15. DNAIEL

    DNAIEL

    22
    Jun 17, 2011
    I agree completely. When I was able to whittle my first completely free hanging hair I felt like I had reached a more-than-acceptable level of freehand sharpening skill. If you can whittle a hair with a knife you've sharpened be it freehand or on a jig, you know your're on the right track.
     
  16. HeavyHanded

    HeavyHanded KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 4, 2010
    I find it is just one way to prepare an edge, and in some respects getting the most from a coarser edge requires more ingenuity. I can get a refined edge to tree-top so much hair it piles up on the blade with one pass, but that same edge is not a good fit for EDU IMHO. Getting them to a high level of refinement will help freehanding overall, and whittling my first hair certainly felt like an accomplishment, however its a milestone not a pinnacle, and one that most users of edged tools will have no need to achieve.
     
  17. That's how I view a hair-whittling edge. Assuming it's a real clean apex and not just a very thin burr/wire on an otherwise imperfect edge, it's one way to gauge one's technique and abilities, if taken that far. It's fun to achieve, but doesn't really hold much value in terms of the real-world cutting chores it may be tasked to do (aside from actual shaving). As mentioned earlier, on an EDC knife, it's fleeting anyway. The quality of the working edge left after the razor is gone is really what matters.
     
  18. KennyB

    KennyB

    Jan 19, 2010
    Yeah, I think this is the right way to look at it as well. It's great to reach those milestones and "chase the dragon" in how much sharper you can get an edge, but the only real point is to get a sense of your abilities.
     
  19. HoosierQ

    HoosierQ

    Feb 9, 2010
    Well I am fixing to go another way with one of my knives. I plan to give it a very course edge (it's an ESEE-5) and then strop it. See what toothy does for me on a beastly blade like that. I also have a real Khukuri and hair splitting edges on those are pointless.
     
  20. parbajtor

    parbajtor

    Nov 24, 2010
    I'm not anti-semantic, some of my best friends are words :)
     

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