Recommendation? Sharpening angle?

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Diego_B, Aug 23, 2020.

  1. Diego_B

    Diego_B

    25
    Aug 17, 2020
    Hey guys so I’ve got two knives that I’ve recently forged and I’m about to move on to grinding the bevels and so on. But there’s one thing that I want to make sure these knives are and that’s sharp, I want them to be knives and not butter knives. So my question today is what angle should I be sharpening at for a general use knife? I’ve thought of just at 25 degrees which seems standard but could it be bumped down to say 22 degrees? Not sure if I’m just asking for chipping at a 22 degree angle, but that’s why I’m asking you guys to see what are your thoughts. The steel I’m using is 1084 by the way.
     
  2. Hengelo_77

    Hengelo_77 Basic Member Basic Member

    Mar 2, 2006
    2 x 20
     
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  3. Hubert S.

    Hubert S.

    481
    Dec 14, 2019
    I don't think there is an easy answer to this, otherwise all knives would use the same magic angle. A lot will depend on the heat treat and what the knife is used for. There are some great articles on Larrin's website: Sharpness vs Cutting Ability and What is Edge Stability Part 1 and Part 2.

    There is a test that I have seen recommended here called the brass rod test that may be helpful in determining whether the edge is prone to chipping or rolling. You can find a lot of posts with a search on blade forums and there are some youtube videos as well.
     
  4. DeadboxHero

    DeadboxHero Triple B Handmade, Custom Knives Knifemaker / Craftsman / Service Provider

    Mar 22, 2014
    15-20dps is the sweet spot you want to play with. Just try it out and see what works best for your knives and sharpening.

    Thicker= durability at consequence to cutting ability and sharpeness

    Thinner = increased sharpeness and cutting ability but is more fragile.

    End of the day, put less stock in EXACT angle and more in consistancy of whatever angle is held.






     
  5. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    My technique is to go thinner and if it doesn't hold up in testing, re-sharpen thicker. You can easily and quickly increase the angle, but it is much more work and makes more TBE if you go down.
    I start around 12-15° per side. It may end up at at 20° per side when the testing is done.
    I start from a blade that has the main bevel (sides) taken to a nearly sharp edge in grinding and sanding. The edge thickness id below .005".
     
  6. Diego_B

    Diego_B

    25
    Aug 17, 2020
    I like the idea of that actually. Yesterday while I was browsing through these forums I found another person doing the same at least with his kitchen knives and taking them to nearly zero and sharpening from there. But I think the reason as to why some of my knives aren’t as sharp as I would like is because of the thickness behind the edge. I have become aware now of how important thickness behind the cutting edge is now to your final product in the end. So from here out I will get close to a a zero edge and sharpen and see how that goes. As of the brass rod test how reliable is it? I’ve seen people on YouTube doing it and have heard of others doing it as well. I have yet to attempt to do it but I’m not entirely new to it either, I know the basic idea of it. I’m just curious of its reliability and what are your thoughts of it?
     
  7. N.W. Gean

    N.W. Gean KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    157
    Oct 10, 2018
    So far, the brass rod test has frustrated me. I have yet to heat treat a knife that will pass it without the edge rolling away. It's a good ballpark test, but it'll tell you the knife is bad in a hurry if it's bad (good but very upsetting :D)
     
  8. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    I understand the brass rod test, but never use it except for demonstration purposes. Testing is how you will know the edge is right. If you start with the thinnest possible edge (near zero) you will be starting in the right area. You can always make it thicker if needed by sharpening it back or at a higher angle.

    The other reason people don't seem to get a sharp edge no matter how they sharpen is they don't remove the wire. There is a super thin "flap" of metal created when sharpening called the "wire". After sharpening, I lightly buff the edge on a charged buff and then cut about six times down a piece of card stock ( light cardboard). Buffing a sharp edge is dangerous if you are not trained, but a half dozen strops on a charged leather strop does the same thing. On the first cut or two down the cardboard the edge seems to be dull ... then all of a sudden it is screaming sharp. That is because the wire has broken away and exposed the sharp edge.
     
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