BK knife has soft spine ?

Discussion in 'Becker Knife & Tool' started by dingy, May 12, 2020.

  1. dingy

    dingy

    Feb 19, 2008
    Hi you all. today i stripped my well used BK7 , and what i found is that my BK7 has a soft spine , what i mean is that the spine on knife is softer than the edge. is it normal?

    thanks
    dingy.
     
  2. 1066vik

    1066vik Gold Member Gold Member

    Nov 28, 2009
    maybe?
    kabar or cam?
     
  3. dingy

    dingy

    Feb 19, 2008
    my beloved 7 is a kabar
     
  4. 1066vik

    1066vik Gold Member Gold Member

    Nov 28, 2009
    interesting.
    my understanding is that those are supposed to be through hardened, not differential.
    OTOH, as long as edge retention is good, it shouldn't hurt anything.
     
  5. DunkEm

    DunkEm Gold Member Gold Member

    Dec 9, 2013
    How could you tell it was softer?
     
    th3ug1y0n3 likes this.
  6. th3ug1y0n3

    th3ug1y0n3 Basic Member Basic Member

    78
    May 22, 2019
    I am not to knives as a buyer, but technically savvy far from it. However, I would like to know more on the technical side. How do you know or test for hardness?
     
  7. dingy

    dingy

    Feb 19, 2008
    I used stripper and a stainless tiny shovel (spoon like ) to to remove the paint on the knife ,when scraping paint with tiny shovel which contacted with knife tang ,spine and edge , i can feel the hard ness diffrence , cause i can scrap tiny tiny steel fillings from the spine of the knife , but i can not do so with the same shovel on the edge.
    so i can tell the hardness diffrence on the knife that the spine is obviously softer than the edge.
     
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  8. daizee

    daizee KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 30, 2009
    interesting.
    How far does the bevel does the softer steel go?
    Differentially hardened blades are often desireable, if done right. Super tough.
     
  9. Xr6x

    Xr6x Gold Member Gold Member

    Sep 17, 2015
    I thought I heard a while back KA-BAR was now using the differential heat treat process on all their current knives. Maybe not?:rolleyes:
     
    Last edited: May 14, 2020
  10. DunkEm

    DunkEm Gold Member Gold Member

    Dec 9, 2013
    Might be able to draw out a cool hamon line
     
  11. dingy

    dingy

    Feb 19, 2008
    my old bk5 (there are stamp marks on both sides of the knife , so i thought my BK5 is a older than my bk7and 9 which has laser marks .) has hard spine and the hardness on spine as hard as the edge .

    you guys may do a test by youself with a steel file,

    and my 5 and 7 both have soft tang.

    i have not polish both knives , so can not found out the clue of hamon line.

    [​IMG]
     
  12. MolokaiRider

    MolokaiRider Gold Member Gold Member

    Sep 13, 2017
    Soft spine or soft tang?
     
  13. MolokaiRider

    MolokaiRider Gold Member Gold Member

    Sep 13, 2017
    Or are you saying the spine and the tang?

    It’s possible that is the case, although I have no idea if on purpose. If it is, that’s actually kinda cool as the blade will resist snapping better, and the edge will still hold an edge.

    Many outdoor knives are treated this way. Anyone know if Ka-Bar does this on purpose?
     
  14. dingy

    dingy

    Feb 19, 2008
    what i found is that my bk7 has soft tang and spine,and my bk5 has hard spine and soft tang.

    [​IMG]
    [​IMG]
     
  15. daizee

    daizee KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 30, 2009
    Inneresting.

    Hardening requires rapid cooling to complete. It might be possible to cool the blades at an identical rate that would allow the lower-mass BK5 blade to harden fully, but not the thicker-spined BK-7. And tangs carry a lot of mass. Or they could do them differently. And things may have changed over time. Curious how they're going about it these days.
     
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  16. zzyzzogeton

    zzyzzogeton

    Feb 17, 2013
    Maybe @OFFICIAL_KABAR can get us the straight skinny?
     
  17. OFFICIAL_KA-BAR

    OFFICIAL_KA-BAR Moderator Moderator

    546
    Aug 3, 2011
    How long have you had the knife for? Some of the early versions had a full heat treat to mid-handle. It shouldn't impact the performance.
     
    Tanker 1/66 and daizee like this.

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