• James Watson
    2
    Hello all.
    I was wondering how you all go about differentially tempering your blades? Ive never had to in the past but Im having a go at making a big chopper out of O1, so I thought Id give it a go....

    Would this sequence work ok?

    Harden
    2 tempering cycles in the over
    Submerge the cutting edge of the blade in water and heat up the spine and tang with a blow torch to soften.

    All help would be really appreciated.

    Best wishes,

    James
  • JR Knifemaker
    15
    Hi James- I’ve seen Alec Steele do just this. Might be easier with 1070/1095 steel? Just because it’s a simpler steel to work with!
  • Rix Raven
    8

    My latest knife I did a diff quench. I assume it gives same end result if done right. But maybe there is more control doing it in temper?
  • Matt Brookes
    31
    I think you'd need an oxy torch or something similar to get a good even heat across the spine. I do an edge quench where you heat the whole blade but only submerge around a third to half of it in your oil, wait for the spine to lose colour then turn the blade over to cool the spine. Then temper as normal.
  • James Watson
    2
    Thanks everyone for your replies and advance! I'll let you know how I get on!
  • Matthew Lee
    2
    so from everything I’ve heard if you are after pure performance and durability for a hard use knife a differential temper (full blade is quenched and spine is tempered to ~gray oxide or just below ~I think it’s 1000 degrees or so) is far superior to a differential quench like the oxy torch method on the edge and/or shallow oil quench) because tempered martensite is springy and strong in the fully quenched blade and unquenched steel retains more of a malleable “annealed” characteristic (due to the fact that there is not as much martensite formation). ABS bend test knives are generally differentially quenched because they have to be able to give under pressure but that’s not necessarily the best characteristic for a real working knife. Those differentially quenched knives would be way out performed strengthwise when it comes to lateral or prying forces as compared to differentially tempered.
    That being said I love differentially quenched knives and hamons (essentially just a fancy one lol) because they look awesome! Even my first forged knife was a differential quench!

    As far as the actual differential temper, the two favorites seem to be water and wet sand (possibly with water up to the surface of the sand) will work well as a heat sink.

    Hope it went well if you already went through with it James!
  • James Watson
    2


    Thanks Matthew for your reply! Not done it yet, but I like your tip about yet sand! :-)
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