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What Grit

Discussion in 'Maintenance, Tinkering & Embellishment' started by Aerosmith101, Dec 3, 2018.

  1. Aerosmith101

    Aerosmith101

    32
    Oct 28, 2018
    What grit should I be sharpening my EDC knives to in order to get a hair popping edge right now I'm finishing with a Shapton Kuromaku 2000
     
  2. CableGirl

    CableGirl

    72
    Aug 19, 2018
    Your results may vary but if I want to cut a rope Id stop at 2k but if I wanted a scalpel I usually go to 12k. BTW, 12k isn't always good at cutting everything.

    Other comments will follow.
     
  3. 'Hair-popping' is more about fully apexing the edge and, to some extent, making sure the geometry is relatively good for it. In other words, edge angles at/below 30° inclusive make it much easier, although it can still be done at pretty wide edge angles (the finish needs to be nearly perfect). It'll never happen if the edge isn't fully apexed in the first place, no matter how polished the bevels. It's generally accepted that apex width needs to be somewhere at/below 0.5 - 1 micron for shaving or popping hairs to happen reliably. That's why fully apexing is important.

    It can happen at most any grit finish between ~ 200 (sometimes lower) and anything higher. Assuming a full apex, it gets relatively easy to accomplish at around ~ 320 (ANSI) and higher. See if you can make it happen at your first grit stage, then enhance it as you go higher.

    True shaving edges are generally finished higher in order to make shaving comfortable on the skin by reducing or refining the edge's toothiness; but shaving and popping hairs can start happening much earlier in the grit sequence.
     
    Last edited: Dec 5, 2018 at 10:17 AM
    Mo2 and Lipripper like this.
  4. Lipripper

    Lipripper Gold Member Gold Member

    62
    Oct 15, 2017
    What David said is entirely factual. That's your answer.

    I often stop at 600 grit and a 'hair-popping' sharpness is achieved. I will say that it's easier to form a bigger burr at a lower grit though, so if you do stop at a lower grit, you have to be careful about making sure that burr is as gone as possible. You can then strop a bit if you prefer that, but getting the apex clean before that is by far the most important part of the process... always will be :thumbsup:
     
  5. Wowbagger

    Wowbagger

    Sep 20, 2015
    Some of my woodworking hand plane blades are as wide as 54° inclusive; that's 27°per side if it were a double bevel knife (It is a single bevel / chisel type edge).
    I take those to 8,000 Norton Water stone using a jig and the edge is extremely satisfying as far as whittling hair; hair popping goes without saying. So . . . geometry isn't all that critical for the result you are looking for. I would strongly emphasize that jig sharpening is going to get you there ever so much easier (I would say faster at least at first).

    That said . . . sure shallow angle knives like my Little Monster White Paper steel kitchen knife that is running around 20° inclusive certainly stays whittling / hair popping longer.

    Here's a link about me banging on about just how long.
    https://www.bladeforums.com/threads/razor-edge-retention.1611756/#post-18410257
     
  6. Alberta Ed

    Alberta Ed

    Jun 29, 1999
    Depends a lot on the steel, too. Steels with large carbides work great for cutting coarse(r) material; low carbide steels often will take finer edge.
     

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