Stupid Simple Heat Treat

[JTknives]

well my search for a simple heat treating process that even people that live in apartments can do. this process does not use a forge or a bbq gril. First you need to get your self a propane torch, the one i have is the JTH-7. if you try to just heat the blade with the torch you will never get the blade up to temp unless it it a blade that is very very small like the size of a tooth pick. you cant even get a pocket knife blade up to temp this way. so to combat this problem most people use this torch to power a forge but i wanted to find another way. so wht i did was put my blade on my kitchen stove ellement, cranked it up to high. i let it sit there for around 5 min then i started up the torch and started heating the blade that was on the stove. with the heat from the stove and the torch i could get the temp up to allmost white hot. i then just droped ther blade unto my quentch tank which is just a quart jar with a quart of oil in it. this makes a super hard blade and seemes to be very good.

 

[Bufford]

Okay now your blade is hard and it needs to be tempered. Turn on your kitchen oven and temper the blade. Find out what kind of steel you are using and then set your oven's temperature for tempering. Soak the blade in there for a couple of hours. Your blade will then be ready for finishing.

 

[LRB]

Use an oven thermometer, kitchen ranges are notoriously inaccurate

 

[butcher_block]

might want to rethink the glass jar it might not like the heat and cool thing too much
i might be over thinking but an old 50 cal can works great for oil storage and quenching

 

[Old CW4]

JTknives:

When you heat high carbon steel "white hot" and quench in water or oil, the result is an almost glass hard piece of metal which will snap in a heartbeat if any side force is applied.

We gunsmiths buy annealed (softened) spring and other types of hardenable steel stock to fabricate springs and parts. We bend/shape/machine the softened steel into the desired shape. Then it must be first hardened and then tempered, two separate steps. First I do like you described---heat the metal really hot and quench in water or oil. Now it's glass hard and must be tempered or "drawn" so it will function as a spring, firing pin, or whatever. Here's two quick methods to temper your hardened steel, in your case your knife blank.

1. Sand and oil. Put an inch of so of dry sand in a bread pan large enough for the knife blank. Saturate the sand with 30 weight motor oil and use your propane torch to set it on fire (it's hard to light). You could do this outside in your barbeque grill or anywhere the smoke won't bother someone (and there isn't a lot of smoke). When the oil soaked sand in the pan (poetic, huh?) is burning well, lay the knife blank on it, sift a bit more sand over the blank and perhaps add another small squirt of oil so it's all burning. Let this burn until it burns out then cover with a piece of wood or sheet metal and let it cool several hours. You now have your knife blank heat treated to a near perfect spring temper. It will take an edge and still be resilient. The 30 weight oil and sand mixture burns at between 800-900 F, hence the resulting spring temper.

2. Second method and ONLY to be done outside or in a VERY well ventilated area so you don't breathe fumes is to use molten lead which will also provide an excellent spring temper. Use a camp stove or grill to melt enough lead in an old frying or bread pan so you can submerge the knife blank completely it it. The steel blank will float on top of the molten lead like a cork on water so you have to use something metal to hold the blank down and keep it submerged. Keep the blank submerged in the molten lead until the lead stops sticking to it. I like to go at least five minutes. That's it, you now have a spring tempered blade. When you remove the blade from the lead lay it down on a piece of wood and let it air dry. I like to cover the item with an old dry shop towel when it's cooled enough so the wood is no longer smoking and the towel won't catch fire. Let it cool for several hours covered up.

WARNING! Make DOUBLE DARNED CERTAIN SURE WHATEVER YOU MELTED THE LEAD IN IS NEVER USED FOR ANY OTHER PURPOSE AND ESPECIALLY NOT FOR COOKING!!! Best thing is to leave the cooled, solidified lead in the container for future use or give pan and all to a buddy who molds bullets or fishing sinkers. Also make ABSOLUTELY sure no moisture of any kind gets into the molten lead! One drop of saliva, perspiration, or a single raindrop will cause the most violent explosion you've ever been close to! I kid you not! It's hard to believe how far ten or fifteen pounds of lead will spatter if one single drop of water gets into it. Be warned. The oil/sand is the safest method but the lead works great also provided you're careful and stay downwind from the fumes.

The methods I've described don't equal what's obtainable with a heat treat furnace used by an expert but they do work and work well. I'm a gunsmith with a lot of years in that trade. I have MANY old guns out there that have functioned for years with springs and other critical parts I've made using the above methods.

BTW, a shiny non stainless knife blank tempered with the burning oil method comes out gorgeously blued. This can be left or polished off.

 

[LRB]

Spring temper is a bit soft for most knives, but yes, the lead bath is great for a spring.

 

[Old CW4]

LRB: You're right and thanks for comment but it still makes a serviceable blade and is sure better than a super hard---and soon broken blade.

I should have continued on a bit but try not to write "books" for my posts. A good technique for tempering a knife in molten lead is to grip the tang with an old pair of vice grips so the blade is horizontal with the edge up. Then lower into the lead but not all the way. Leave the blade area sticking out a quarter to half inch or so. Result is a blade with a harder edge and more resilient back. Would appreciate Your thoughts on that since you know about the lead method. Best regards

 

[JTknives]

this does not make sence, 800-900f for O1 not possible. you have to bring the blade up to non magnet temp which for O1 is 1300-1400f. then cool in oil that is why it is O1 the O stands for oil. to test this out but a small blade on the stove and let it get to around 800-900f and cool in water or oil, there will be no difrince in hardness. the steel has to be brought up to the temp where the carbon gets desolved into the steels matrix, then when its cooled the carbon forms into the steel making it hard.

 

[Stacy E. Apelt - Bladesmith]

JT - You missed the part where he had already hardened and quenched the knife.The 800F stuff was the tempering.

 

[JTknives]

O ok, then it make perfect sence. i thought that was doing the harding as well. sory i miss understood

 

[Dan Gray]

to temper the O1 800 degs is a wee bit way a tad over kill rrr and not to mention more money to do so. I quench at 1550F
and temper at around 430F depending on what the knife will be used for.

you can edge quench for a differential quench
or you can draw the spine back several different ways for a differential temper
or full quench and full temper for a very simple HT..

I use the lost art of water tubing the edge to protect it..once it's HTed I now can draw the spine at will with out fear of over heating it.
but I practice most all the ways to suit the customer..I've been
messing with o1 for about 33 years now it's still a VERY popular steel for knives making..you've chousing :thumbup:

 

[Daniel Prentice]

One can take two pieces of firebrick.... one flat and one on it's side and use a Mapp gas kit from your local hardware store. The bricks are in an L shape and will help reftact heat back to the blade. Also since the blade is flat the grind lines will be setting off of the brick and this can give you nice quench lines just from contact and raised areas of the blade. We show this in the videos we make..... Mapp gas will limit your blade size, but you can do up to 4" blades..........

Check out my site.... www.dpcustomknives.com and you will see the pic of the brick and the blade on the vidoes section....

Daniel

 

[hp2spare]

I have a one brick forge that would work quite well on the back pattio of an appartment. You can run it with your JHT-7 (that's what I run in mine).