Torch Heat treating

[DanCrabtree]

Hey. Ive been heat treating all my knives with a torch but now im questioning my method. Here it is. After I heat the blade up to non magnetic and quench it in vegtable oil I take it to the grinder and clean it off. I then take a torch and heat up a 1" section of the blade spine first. I wait for the golden color to get to the blade edge then quench in water. Doing this the spines oxidization is a grey color the middle is blue and the edge is gold. I do this through out the whole blade. Heat up 1" quench... Heat up 1" quench... Is this the correct method for torch tempering?

[Ray Rogers]

I've never heard of it being done quite that way but it is intereesting. The biggest draw back that I can see to that method is that you don't get the soak time that you should have according to the steel manufacturers.

I think a more common way of doing it would be to heat treat and quench in oil or water according to the steel's requirements. Then temper in an oven (kitchen oven will do) at 350 - 500 degrees (again, according to that steel's manufacturer's requirements) for at least two hours, and usually do this at least twice. Then put the blade in a pan of water to cover as much of the edge as you want to have hard and then torch the back with the edge in the water. The edge stays hard and properly tempered, the back is as soft as you want it to be, everybody's happy.....

[DiamondG Knives]

I agree 100% with Ray, an oven will heat much more evenly and with more control and you get the soak time he was refering to with much less hassel, and much better chance of repeatability. Are you heating your blades in the forge or with the torch? Just wondering, Using your forge may take a little more practice, but it's a lot easier to get a good even heat with a forge verses a torch. Clay coating may be up your ally also, just a diffrent way to skin the cat. Just my $0.02

God Bless
Mike

[DanCrabtree]

im using a torch

[Quenchcrack]

Put a good sized chunk of steel plate in your forge and heat it to a good cherry red. After the blade has been quenched, pull the plate out, put only the spine on the plate and let the heat diffuse from the plate through the spine, up the blade. Quench when the edge starts to turn golden.

[rhrocker]

First of all, this is a very old post. 2nd, I'd like to try this method for the fun of it. QuenchCrack, what if there's a curve to the spine of the blade? The spine will only be touching in 2 places on the cherry red heated metal bar that you mentioned. Would you pull the blade back and forth in an attempt to keep the entire spine in contact with the metal bar, thus heating it evenly? Quench in H2O afterwards? I use a Evenheat for my tempering, but like experimenting and learning some of the other ways.

[mete]

I would prefer Ray's method.It gives a good thorough temper to the edge And to the spine too. Further torch tempering with edge in water and playing the torch along the whole spine would be more thorough and uniform......Sorry Mr Q...

[rhrocker]

Good, thanks Mete! Am I shooting for a blue spine color? Blue = spring temper.
Robert