I wonder of some sharpening technique can reduce chisel efficiency, so maybe after giving the chisel a nice cut it worth re-hardening it so it will last a longer in time.

I know I can heat it and then put it in water/oil but I wonder if water must be cool, shall I re-heat a bit the blade after ?

Is there a standard procedure ?

  • 2
    Why would you want to re-harden a blade? Generally it requires fairly well controlled conditions. You're more likely to cause more damage than improve things.
    – user2
    Mar 17 '15 at 15:31
  • 1
    @GlenH7 Some sharpening methods give the blade temperature, so I think in time the blade get less effective with weak edges. My father use a grinder on one of his chisel he use for almost everything.
    – Nelstaar
    Mar 17 '15 at 15:39
  • Hi, welcome to Woodworking.SE! Your statement about cool water and reheating was a little confusing -- could you edit your post and clarify what you meant?
    – Ana
    Mar 17 '15 at 15:43
  • I would say that although this is an interesting question, the subject matter is not something that would be common to woodworking. Most woodworkers might not know about metallurgical methods to harden steel. Mar 17 '15 at 19:45
  • @PeterGrace I agree, I think my question is more about blacksmithing.
    – Nelstaar
    Mar 18 '15 at 9:45

Not all steel is quench hardening. I do not know that HSS or High Speed Steel (common wood tools) is easily hardened by this method. Typically, the cobalt and vanadium content makes this difficult. It can be done, but only by a controlled heating between 1260-1280°C, controlling the quench (or thoroughness of the heating) and then rapidly cooling, usually in oil. The difficulty in this, is without a controlled induction unit, you end up heating the ENTIRE tool, which would make it brittle and unusable.

If you are going to do this, I would consult someone with at least some blacksmithing skills, and definitely do not use any prized or favorite tools.

TL:DR I would not get into this without EXTENSIVE research and investment in the proper equipment. But by then, you could have just bought hardened tools with a differential temper

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