o1 heat treat with a propane torch

kile

kile

Joined
Mar 19, 1999
Messages
620
I have read everything I could on these and other forums about heat treating 01 at home, I took a test piece today to practice on before I tried any of the knives I have made so far. I hung the test peice by a coat hanger from my garage ceiling, I then took a propane torch and started running it up and down the three inch section of steel, after about ten minutes, I never changed the color of the steel much past blue,brown black color, when i took the torch away, the steel looked like I hadn't done anything to it. I then held the torch on one section of the blade, and didn't wave it around at all just to see if I could get that little section hot enough, and I couldn't get it to turn red, after another ten minutes or so. My question is does it take longer then ten minutes to bring the steel up to temperature? Do I need a different torch, if so what kind? or was it that my garage which is very drafty, was way to cold,(30 degerees Fareheit). Any help would be appreciated.


Also here is my plan for the heat treatment procedure, any advice about whether I am going about things properly or not would be greatly appreciated.

step 1 heat blade with torch until it becomes red

step 2 drop into pot of olive oil that I previously warmed up on the stove until it is cool enough to touch,

step 3 throw it in the oven which is preheated to around 450 all the blades are 1/8" so i took a saw and cut a peice or 3/4 wood with a bunch of 1/8" slots in it, I figured I would put the blades in the slots spine down, so that they would heat more evenly,(can I just lay the blades on a cookie sheet, or is that bad)

step 4 while first blade is in the oven, start heating blade 2 with torch, quench, put in oven next to blade one.

step 5 once all blades(4-6) are in the oven let sit in there for about 30 minutes, turn off oven and open the door and slowly let the blades cool,

step 6 once blades are cool enough to touch, put them in my other preheated oven at 450 for about 30 minutes, take out and let cool, and put blades back in the first oven for 30 minutes at 450.

Am I doing everything right, will my wood block burn up in the oven? I need help guys, these are my first knives, and they kind of suck so I don't want to pay anybody to heat treat them for me, because they would laugh at my horrible grind lines, but I think I can make decent using knives out of them, and I would like to try. thanks in advance for any help, and sorry this is so long.
Kyle Fuglesten
 
Get a magnet and a couple fire bricks. Place the blade on the brick and torch away. The brick helps keep the heat in. You definately need the magnet to be sure you are at critical. Be sure to test the blades for hardness. Brass rod test is best. Good luck

Try this link for heat treating info.
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The Edge


[This message has been edited by exsanguinate (edited 03-24-2001).]
 
Your main problem seems to be able to heat the metal to the critical temperature. A magnet is definitely needed for that. A temperature about 50 deg. higher is preferred so it may need to go just a little more and then quench in oil. O1 has about 10 seconds to cool without becoming soft. ALWAYS check the steel with a file to make sure it got hard. If it didn't and the steel has a smooth appearance, chances are that you didn't get it hot enough to start with. Do it again until it is "hard".
For tempering O1, a temperature of 375 to 450 will usually take care of the tempering range {hard (375)to soft (450)}. I like the time of 2 hours per tempering cycle with a cooling to room temperature between the first and second. If you don't go over the tempering temperature for an extended period of time, it will not harm the blade. After the last tempering cycle, the blade should be ready to check on the 1/4" brass rod for chipping or edge deformation.
 
well now..hmmmm do you have access to a forge or aceteline torch?
I use mainly O-1,this is how I do it,it may not work exactly the smae in your shop but should be close enough!
-mix 1/3borax with 2/3 water bring to boil, put CLEAN! knife in and out of the boiling mix abou 5 or 6 times and let dry.
-heat veggy oil to 130 degrees keep at 130
-heat blade slowly and evenly till the mag doesn`t stick,then heat just a bit more(bring it up about 50 more degrees)
-quickly plunge blade in 130 degree oil, leave in till you can grab it with fingers.
-temper imediatly at 350 degrees for 2, 1 hour cycles.
58 to 59 rockwell(in my conditions)
Have fun
feel free to e-mail me with any more questions!


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i keep grinding and grinding and it is still too short!!
 
Kyle as you already know propane alone does not get hot enough. I tried plain mapp gas with an extra hot tip and it does not really get it either unless it is a small blade. Best bet is a forge, oxy acetylene (I use that now) or try one of those $50 plummers torch sets that have mapp gas and oxygen together. I believe that will be sufficient for average size blades posibbly. I have heard of others using one of these though I have never. Adding the forced oxygen with the gas makes it alot hotter. Cory

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"I am a shootist."
Clay Allison
"Does this mean we are bladists?"
McAlpin Blades
http://www.geocities.com/mcalpinblades
 
I'm with exsanguinate. I think your problem may be heat dissipation. I think you need to trap the heat that is escaping into the air.

One maker's book (it might be Goddard's) that shows a quick & dirty heat treater using firebrick and a propane torch. His shows a firebrick with two holes bored in it. You stick the blade in the long hole and the burner in the other. It works for small, thin blades.

I'd buy 7 or so firebricks and build a small "house" - two on the bottom, one on each of the sides, one on front, one on back and one or two for a cover. You may want/need to bore a hole in one for the nozzle of the torch - wear a dust mask for that work.

That's about a $6 expense that might work depending on the blade size.

If the blade is long, you may chose to let the tang stick out of the house.

Or simpler, use a vegetable can filled with dirt! Check this out - http://www.primitiveways.com/pt-knives-1.html

A magnet would certainly tell you if the temperature is right. The other suggestions, such as MAPP and oxy/propane or oxy/acetylene would help, too.

My $.02,

Mike

[This message has been edited by Michael Bennett (edited 03-28-2001).]
 
Michael is right, I also build a small enclosure with several firebricks. In addition I bought two handheld propane torches with the jumbo flame tips. They work much better than the pencil flame tips. I then put just the blade in the enclosure, edge up, in a way so that I could heat both sides of the blade evenly (holding a torch in both hands). In this manner you can heat treat small blades to non-magnetic in just a few minutes. The trick is trapping the heat and only heating the portion of the blade you want to harden.
Thankfully since I built my propane powered freon tank mini-forge I don't have to mess around with those torches anymore, bu they do work for small blades. -Guy Thomas
 
Kile, you can try something like this with several torches. It will get hot enough with propane.
View

 
Peter Nap,my brother and I point the torches in the front opening, facing toward the back. The back is closed off with kao-wool, the heat has to come back out the front. The blade goes in between the flames. This heats the air that heats the blade, I think this heats the blade more evenly.
 
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