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    Science of Sharp

    scienceofsharp.com · Personal blog · on HN since 2019

    Science of Sharp reports lab tests of knife sharpening, using electron microscope images to examine burrs, stropping, honing rods and blade materials.

    Visit blogRSSHN submissions
    Science
    What HN says

    HN commenters call it a great, contemporary source on how sharpening works and what it looks like under a microscope.

    Stats for nerds
    16HN people shared it
    8linked in comments
    25story points
    May 2025last shared
    2020people per year2025

    Top posts on HN

    1. 1
      Honing rods analyzed with an electron microscope – Scienceofsharp (2018)
      2 people · 9 points · first shared 2025 · 1 comments on HN
    2. 2
      Scienceofsharp
      6 people · 5 points · first shared 2020 · Discussion on HN
    3. 3
      Sub-surface damage when sharpening steel
      1 person · 5 points · first shared 2019 · Discussion on HN
    4. 4
      What Does Stropping Do?
      2 people · 3 points · first shared 2022 · Discussion on HN
    5. 5
      Misconceptions About Knife Burrs
      1 person · 3 points · first shared 2024 · Discussion on HN
    6. 6
      Home
      2 people · first shared 2022
    7. 7
      Amp
      1 person · first shared 2022
    8. 8
      Ceramic blades
      1 person · first shared 2022
    9. 9
      Simple straight razor honing
      1 person · first shared 2020
    10. 10
      What is a burr part 2
      1 person · first shared 2022

    What HN people wrote when they linked it

    • carpdiemOct 2022

      These ideas are mistaken.

      "Sharpness" is related to the physical size and radius of curvature of the apex of the blade, combined with the angle of the terminal bevel. [1][2][3]

      Chipping of any sort almost certainly tends to erode the sharpness for many reasons, not least of which is that a sharp edge is a very low entropy state (compared to a dulled / chipped / etc edge...).

      VG-10 steel is considered "entry level" in terms of high end steels. [4] It was first introduced in production knives in the mid-90s, almost thirty years ago! [5] And there has been significant progress in materials since then.

      Almost all mid- and high-end knives these days are cut from blanks via an industrial laser or waterjet cutter.

      -----

      [1] https://scienceofsharp.com/2014/01/25/quantifying-sharp/

      [2] https://scienceofsharp.com/2014/08/18/definitions-of-sharp-and-keen/

      [3] https://scienceofsharp.com/2015/03/24/sharp-and-keen-part-2/

      [4] https://www.bladehq.com/cat--Best-Knife-Steel-Guide--3368

      [5] https://forum.spyderco.com/viewtopic.php?t=87185

    • ZakOct 2022

      Ceramic knives are so prone to chipping that they effectively have micro-serrated edges even when freshly sharpened. A micro-serrated edge on a razor pulls hairs and cuts skin.

      I don't doubt that in your experience ceramic knives cut food better than metal ones, but I suspect you have not used a well-sharpened knife. Mass-produced knives are typically sharpened using belt grinders and do not cut as effectively as knives hand-sharpened by someone skilled at it.

      https://scienceofsharp.com/2018/02/24/ceramic-blades/

    • KozmoNau7Aug 2020

      Abrasion absolutely happens when stropping, however it is very mild compared to other sharpening/honing processes.

      This is by far the best resource I've found for explaining sharpening and the concepts of sharpness vs. keenness: https://scienceofsharp.com/

      I don't go nearly to that level of effort in sharpening, as I only sharpen pocket knives, kitchen knives and various tools, I don't bother with straight razors (or any razors at all, but that's a different matter).

    • esaymAug 2020

      I think the trick with straight razors is to finish the blade with a denim strop with abrasive compound. I only have two stones, a 2k and a 5k. From there, I strop with a strip of denim that I put a little bit of automotive "swirl remover" (it's like car wax with a bit of abrasive in it, but the point is almost any kind of "polish" compound will work.)

      This blog describes why denim works so well: https://scienceofsharp.com/2016/04/14/simple-straight-razor-honing/

    • OGWhalesOct 2022

      For those interested in the SEM images and looking for more, check out this site: https://scienceofsharp.com/home/

      The site focuses mainly on sharpening razor blades and is full of SEM images of blades in various conditions. Very cool to see.

      This page about burrs has some particularly cool images: https://scienceofsharp.com/2015/01/13/what-is-a-burr-part-2/

    • diab0licJun 2022

      I find the best way to think about a honing steel is that you’re micro beveling the edge. [0] The images there help develop an intuition of what angle will work well. That said it may be irrelevant if your universal sharpener is doing the trick. :)

      [0] https://scienceofsharp.com/2018/08/22/what-does-steeling-do-part-1/amp/

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