hardening question

[flaming canvas]

Probably need a mechanical engineer or metallurgist to answer this one.

How would you harden an L6 steel? I have an old sawmill blade that I made some knives out of. I took these to a place in town and had them hardened and they turned out great. I think he said that they were 54 Rockwell. I want to try making a couple of small knives and some firesteels but I don't want to pay $30 a piece to have them done.

My first guess is heat them to red and quench in an oil bath heated to 160 degrees or so. he knives will probably need to be drawn back by baking at 350 for an hour or so. The steels could be used as is.

Any input greatly appreciated.

 

[musketman]

I would suspect it would be much like hardening a frizzen, then here is a good thread that...

Frizzens

 

[flaming canvas]

I saw that one, MM. I imagine this is a different alloy.

 

Every steel is different so you might want to check in over on the Knifenetwork Forum http://knifenetwork.com/forum/forumdisplay.php?f=37 and/or
Bladeforums http://www.bladeforums.com/forums/forumdisplay.php?f=741
Both are great places for fledgling or expert knife makers.

 

Machinery's Handbook says L6 hardening temps are 1450-1550 F and 350-1000 for drawing. Range of hardness runs from 45-62 Rc. A value of 54 is in the middle of the range so you would need to temper around 675.

 

[Charles/NM]

L6 is probably one of the best high carbon knife steels. Harden it by heating it until it won't attract a magnet. You only need to harden the blade and back to just into the handle area so it won't bend with use. Then quench it in room temp olive oil. Temper immediately. You can temper L6 two ways. One is to polish the black coating from quenching off and heat the cutting edge to get a brass color on the cutting edge, the back can go to dark blue for a more springy back. You have to be careful, heating the back of the blade and watching as the color approaches the cutting edge. Stop sooner than you would expect as the heat travels for some distance after it's removed. The other way to temper it is to put it in a toaster oven that you have preheated to around 375 to 400 degrees. Leave it in for an hour or less and let it air cool. L6 doesn't really need the one hour temper like O-1 does but it won't hurt the blade. You should wind up with a blade hardness of around RC58 to 60. That's hard enough to keep a good edge but still soft enough to field sharpen.

 

[Bushwhacker]

First you should anneal by heating to a cherry red and place in a box of lime until completely cooled down, this makes it more workable. When you are ready to reharden, heat up to a cherry red and quinch in a light oil. Next re heat to a straw color and let cool on it's own. this process "draws" it back so it won't be toooooooooo hard :redthumb:

 

[flaming canvas]

Well, I got striker made. There was a little piece left from cutting out the knives last time about 3/4 wide and 7 inches long. I got about 3 inches on 1 end to a medium red using two torches. I would have liked to have it about 50 degrees hotter, but that was all she wrote. Quenched it in transmission fluid, unheated, maybe 40 to 45 degrees. Sparks as well as any firesteel I ever bought.
This blade mikes .180. I have another one that is thicker, maybe .240, that I haven't cut into. That's a little thick for practical usage.

Many thanks for all of the responses.