edge hardening

B

bjalongi

Joined
Oct 23, 2006
Messages
640
Been around a while, but haven't posted much.

I don't have a forge and only use simple shop tools, the kitchen oven, etc to make knives in my free time.

Is it possible to harden the edge by using a torch and doing an edge quench? All I have is a butane torch. Will that work, or do I need to upgrade?

I generally make fixed blades under four inches for personal carry and hunting.

Oh, and the metal I use is generally old files or leaf springs.

I'm a 30 year old who's back in school full time for another degree, so I'd rather not buy any tools if possible.

Thanks.

Brook
 
I doubt you can get a big enough flame to get the whole edge up to temp at the same time with a butane torch. Could be wrong, but it would take a lot of fuel and be difficult to do evenly.
A propane torch would probably work ok, especially if you had a fire brick or two to help hold the heat in. I know you don't want to buy new tools but a snap start propane torch is only about $30. I bet you can get one of the old manual torch heads for about $10 and a bottle for it will only cost $2.
Soft fire bricks can be had for a dollar or two apeice if you can find them locally. Check around with building supply places.
 
I have read on these forums of people heat treating small blades using only a torch for the heat source. One thing to keep in mind is that you can build a forge really easily and cheaply. Search for one brick forge or for small forge and you'll find lots. You can get the supplies from Darren Ellis at http://refractory.elliscustomknifeworks.com/.

Charles
 
Wow, do I sound like a doofus.

My torch is actually propane, but for some reason I typed butane.
 
You can try this out and see how it works for you..Lay a hard or soft (much better) fire brick on a heat proof surface, then lay your blade with the edge in contact with the fire brick (use vice grips not your fingers) and start moving the flame back and forth along the edge keep most of the heat towards the ricasso so you don't over heat the tip..when it is glowing red and wont stick to a magnet quench it in 120 degree oil..you have to be quick so you dont loose too much heat in the tip..Then temper in the oven at about 375 for 1 hour twice....good luck!!
 
rocketmann said:
Then temper in the oven at about 375 for 1 hour twice....good luck!!
Click to expand...

When you say twice, do you mean to heat it to 375 for 1 hour, cool it down, then heat it back up to 375 for another hour? Just want to clarify.

Thanks,

Charles
 
Charles,

I don't believe you can produce enough heat quickly enough with butane or propane, unless you add some oxygen. You have to move the flame along the edge fairly fast to get the entire edge heated at one time. If you know someone with an O/A outfit that will work.

Fred
 
It depends on the torch. I have a heat shrink torch that blows about a 4" flame thats about 3/4" in diameter at the base. With a couple bricks on either side to help direct the heat you can heat a 3" or so blade fairly well with it.

In the long run its alot easier to just make a small forge though.
 
I have used the bursamatic TS8000 with great results..It is the hottest torch out there..it is even hotter if you use Map gas (yellow cans).It will get the job done!!:thumbup: As far as the tempering "you got it"!
 
thanks guys.

I bought a few fire bricks at a local fireplace shop. After a few hours of dinking around with configurations, I decided I couldn't get it up to temp.

I stopped into the local thrift shop and found a single electric burner for $4. With the burner on high and my propane torch, I was able to get an even bright red glow. I was able to anneal my 1/4 thick bastard file blade very easily. I made my latest knife, then used the above technique to edge harden the blade.

It's curretly tempering in the oven.

Thanks.

I'll post picks of the finished product.
 
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