Quantcast
Softening spine with a torch
+ Reply to Thread
Results 1 to 3 of 3

Thread: Softening spine with a torch

  1. #1
    Marko Tsourkan's Avatar
    Join Date
    Feb 2011
    Location
    Westchester, NY
    Posts
    4,088

    Softening spine with a torch

    Is there a practical reason to soften a spine on a knife? Is this done with a torch while the edge of the knife is immersed in the water? Can it be done with a portable torch?


    Marko


    "If there’s something worth doing, it’s worth overdoing.” - An US saying.

    If my KKF Inbox is full (or not), please contact me via Email: anvlts@gmail.com

  2. #2
    Senior Member rockbox's Avatar
    Join Date
    Feb 2011
    Location
    Longhorn Country
    Posts
    393
    I assumed that differential heat treat was so you could have a super hard edge and still have some flex for strength. The same reason for san mai. What I never understood is why people do it for kitchen knives that have under 63 hrc since you can make knife with that hardness through out without any strength issues.

    I have no clue what the proper way to do it would be but I think it would be easier to put the edge between some quenching plates versus water assuming you heat treating before grinding.
    "Insanity: doing the same thing over and over again and expecting different results." --Albert Einstein

  3. #3

    Join Date
    Mar 2011
    Location
    Bangor Maine
    Posts
    339
    Yes it can easily be done with any torch, even propane. My experiance is only with high carbon and not stainless steels. I dont think it would do much on a blade that was differentially hardened because the spine should already be a mixture of pearlite and martensite and much softer than the edge. However if you did a full quench on a high carbon steel, you can temper the whole blade at whatever temp you choose for the edge, then put the edge in water and bring the spine up to whatever temp you would like to temper it at. Quench plates would probably work but a pan of water allows you to keep the edge under the water and if you feel that you are getting to hot on the spine you can give it a quick dip to cool it off.

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts