Hardening 1084 steel cheaply

S

ScottEnglish

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Apr 11, 2020
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I intend making a knife a little over 6" long, about 1 1/4" wide, and about 3/32" thick.

For hardening it I could buy a single burner propane forge from Devil Forge in Lithuania. I would also need to buy a gas cylinder plus propane to fill it. However, the total cost is more than I want to spend.

Alternatively, I could buy a blowtorch with MAPP gas. Would this be adequate for heating up my knife? Would I need some firebricks too?

Thanks.

Scott
 
ScottEnglish said:
I intend making a knife a little over 6" long, about 1 1/4" wide, and about 3/32" thick.

For hardening it I could buy a single burner propane forge from Devil Forge in Lithuania. I would also need to buy a gas cylinder plus propane to fill it. However, the total cost is more than I want to spend.

Alternatively, I could buy a blowtorch with MAPP gas. Would this be adequate for heating up my knife? Would I need some firebricks too?

Thanks.

Scott
Click to expand...
weed burner would be better choice .With some bricks you can make open channel and use burner from top and back side ........knife inside with spine UP
WCEZDMM.png
 
If you are just making one or two knives, yes that is an acceptable method for 1084. A welding torch with a brazing or rosebud head, or a plumber's torch with MAPP gas will work just fine.
The important thing to remember is that it is the edge that you want properly hardened. It is not important that the tang or spine get as hot as needed, but overheating the edge is not desirable ... so pay attention to evenly heating the blade while watching the edge. It is easiest to play the flame up and down the spine area and watch the heat travel toward the edge.

Here is a simple torch HT regimen:
Hold the tang with long handled pliers.
Heat the blade with the torch. If you have a couple firebricks, stack them in an "L" to make a backsplash for the flames.
Place a welding magnet or other magnet near the blade (or use a pick-up magnet on an extension rod).
As the blade starts getting red, check the temperature with the magnet often (just touch it to the magnet). It will stick until it is just above 1400°F, and then suddenly stop being attracted by the magnet.
When the blade becomes non-magnetic, heat just a little redder to around 1475-1500°F and quench in a gallon of canola oil.
Let cool in the oil for at least 10 seconds and remove. If the blade has a warp, you can straighten it with gloved hands or a wooden mallet on a board for the next five or ten seconds. After that stop any straightening or the blade will break once it reaches 400°F.
Clean the blade up and place in an oven set at 425°F. Bake for 1 hour. Remove and cool in running water and return to the oven for a second hour.
The blade is now hardened and tempered and ready to finish.
 
A good alternative would be to put "looking for HT in UK" in the title and get it HTed properly by a knifemaker in UK. There might even be someone willing to ro you a favor and harden your blade for the price of shipping. Professional HT in EU runs for about 10-15 Euros per blade.
 
Stacy, i assume the blade should go point first into the oil if the container is tall. I have never done HT at home because I normally use stainless steels and i have no proper equipment so I have it done professionally. Can the blade be put into the oil in its length.
Should the oil be preheated. I have read so many things and there are so many opinions out there but no all are based on sound physics.
Thanks
Mike
 
Thanks Natlek for the drawing.

Thanks Stacy E. Apelt for the step by step procedure for heat treating the blade. Especially straightening warped blades. Very helpful.

Thanks FredyCro for your suggestion.
 
ScottEnglish, thanks for asking the HT question, I am going to attempt heat treating this steel myself soon so it came at just the right time for me too;).
Sorry that I hijacked your thread with my questions to Stacy but I figured that everyone that needed the info could benefit from a reply.

Good luck with your project.

Mike
 
miden said:
Stacy, i assume the blade should go point first into the oil if the container is tall. I have never done HT at home because I normally use stainless steels and i have no proper equipment so I have it done professionally. Can the blade be put into the oil in its length.
Should the oil be preheated. I have read so many things and there are so many opinions out there but no all are based on sound physics.
Thanks
Mike
Click to expand...
Blade should be dipped tip first if you are using a vertical oil container, some even dip just the blade and not the tang as to leave the tang softer for drilling and/or shock resistance. Canola oil needs to be heated, for engineered or synthetic quench oils follow the instruction of the supplier/producer, most are used at room temperature.
 
I do not like horizontal quenching (edge down in a long pan of oil). The best method is tip first straight down in a tall container.
Most quench oils except Parks #50 should be heated to between 120°F/50°C and 130°F/55°C.
 
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