Using a torch to harden/differentially heat treat 1095 steel

Lerch

Well-Known Member
Hi all,

well i was thinking about trying to use a blow torch to get a smoother hamon on my differentially hardened 1095 blades. when i use the satanite clay i get a good temper line but it is usually a jagged line and not always predictable. I thought if i was able to harden with a blow torch like i have read in some Fowler books i might get a more even and smooth temper line. From my understanding i would heat the desired portion of the blade until it became non magnetic and then quench.

My questions would be how to test the non magnetic point , as in what kind of magnet to use
How long does the blade need to be held at this temp? (in my evenheat i hold 1095 at 1475deg for 5 min)


anything else anyone can think of that i might need to know would be very welcome, i plan on trying this tomorrow if it all works out

thanks
steve
 
The non-magnetic point will not give you the carbon solution required for a good blade. Non-magnetic is 1414°. Your heat process with the oven is perfection with 1095. I would suggest you continue to work it all out with the oven and your present heating process. You may have to decide if you want a nicer hamon, or a good blade. Hamons are only cosmetic, and do nothing to help blade quality.
 
Sort of like Wick said.......... There is a lot of misinformation associated with magnets and heat treating. 1095 is fairly easy to get a wispy hamon, however, although visually appealing, they don't mean much unless you are making a long chopper style that needs a softer back spine (e.g. Samurai sword, mega wood chopper, or some futuristic zombie slayer).

Forget a magnet. Magnets only tell you when you have reached or exceeded the Currie point. In days gone by, I heat treated several knives using a torch. Problem was that I had no real idea of what temp the blade was (except for the dreaded magnet).

I must state here that many makers use a torch for heat treating and the end results is sometimes amazing. Its just not my way of doing things........ Been there, done that, and got lucky most of the time, however, to me it was a guessing game.

My advice (which is worth absolutely "Zip") is to go with accepted heat treating practices based on your particular steel and make the best knife possible with the knowledge and tools you have available.

Robert (who is old as dirt and set in his ways)
 
You might also consider edge quenching. You will have to put something in the bottom of the quench tray to limit how far the blade sits into the oil and you might have to be kind of quick with rocking the blade to get the point in and then the rest of the edge but it might be something that you can work out. Just an idea.

One thing on heating the edge of the blade with a torch is concerned. You might want to try spotting decalesance in the steel. Watch for the shadow to pass in the steel on the edge and point of the blade and try to keep it away until you quench. Other than that all I can say is what has already been recommended and that's to try to improve with the clay quench technique.

Doug
 
I use a torch for O-1 and I use just a plain old magnet on a string. I take the blade to when it is non magnetic, heat it just a tad more and then quench. I would look up the color chart for temps and shoot for that and test it with the magnet. Tangerine Orange is ~1500 degree F.
 
Ideally speaking, using a torch for 01 HT is a poor practice. You will not get the benefits 01 offers without a controlled heat source that will allow a soak time to get a better solution of the alloys in it. You could use a cheaper 10XX steel and get as good or even better results.
 
Lerch,
Hamons are dictated by the steel, not so much the clay, as Doug said, edge quenching will most likely give you a straight line, but that isn't what hamons are about. When you use Satanite, it gives you the ability to make the clay thicker and thinner which gives different effects. On small knives, I will agree that it's a cosmetic thing, AND the maker showing off his/her ability to make a hamon, BUT! Like Mr. Dark said, on larger knives, choppers sized blades, a hamon shows the buyer that it is differentially HT'd. Chopper sized blades have to withstand a lot of shock when slammed into a log or whatever, it's this type of "abuse" that makes a hamon worthwhile. That is the purpose of a differential HT, the hamon, which takes an incredible amount of work to polish out is all asthetics, which to me gives the blade a unique quality. A finger print if you will.

The main thing you want in a hamon is that it be about half way up the blade and not down on the edge. I have yet to have a hamon follow the clay, but once it's polished out, it is a thing of beauty! Like everything some folks won't like it, but I believe that most customers will LOVE it, and that's what matters the most. If your applying your clay in a straight line, drag some down a little ways toward the edge with a toothpick, but make sure it is thin, almost watery. You'll start seeing some different hamon lines that are really sweet! If I can help at all feel free to ask anything, Rex
 
Another thing to consider , try and make sure your steel is on the low side as far as manganese content . I try and stay below .30 . A hamon is basically a surface feature and too much mang and it will harden through . Trying some low mang steel will really see a more visible hamon and with more activity . Aldo has some great low manganese 1075 and w-2 and maybe some 1095 . Of course that does not me you cant produce a good hamon but as Rex says "its the steel" good luck
 
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