Homemade Case Hardening???

leeblackman

I know the theory behind it, and it seem's pretty simple. You heat the metal up, and then dip it in oil.

I was thinking of trying this out on a gun. Or should I say a part of a gun. Is there anything I really need to know. Has anyone else tried this. Or should I just not bother.

If I'm wrong please correct me, I won't be offended.

The sound of a 12 gauge pump clears a house fatser than Rosie O eats a Big Mac !

woodsrunner

What you describe is hardening not case hardening. I'll explain the difference. When you heat a piece of high carbon steel to a cherry heat and quench it. It becomes hard as glass. Pretty useless in most cases. After this step usually you would temper the metal. You would reheat the metal to a known temperature and allow it to cool. This would relieve the stresses in the metal and give a known level of hardness, with a degee of toughness combined. An example of what I describe is a knife blade. Hardened alone it would be very easy to sharpen to a razor edge, but, wouldn't have any flexibility. It would snap in half with very little effort. Temper it and it gains a bit of flexibility and loses a small ammount of it's hardness.

To Case harden you put mild steel inside a metal or ceramic box (known as the case). In addition to the metal you fill the box with a substance with a high carbon content. This substance could be bone, charcoal, coal, etc. You then heat the case in an oven at a known temperature for a given length of time. What happens is the metal absorbs carbon from the material around it. The carbon source is also what gives us such beautiful "case" colors. The advantage of case hardening is it makes the outside of the metal hard while leaving the interior of the piece in a mild state. This enables a hardness that would be otherwise too hard on the outside, while leaving the inside with a level of toughness.

In application case hardening is used where the part doesn't flex and is ridgid. While the metal loses it's flexibility it keeps it's ability to take a blow without breaking. This is what made it's use in gun frames so popular. More modern steels have made the process unneeded in modern guns. That's why you see more blued frames than case colored.

Can you do it at home?? Sure I've done both. Springs are easy to make once you get the hang of it. Take a piece of spring wire bend it to shape then harden it. Place it in a sardine can with a 1/4" of 30wt oil and heat it until it catches fire. When it catches put a piece of sheet metal on top of the can to extinguish the flames 75% of the time you'll get a good spring. A good blacksmithing book can teach you to temper by colors, if you want to make knives or something similar. If you decide to try larger gun parts keep in mind the old low numbered 03 springfields. They were hardened with the techniques available to the home hobbyist.

A couple good books to read before you try this are:
Edge of the Anvil by Jack Andrews
Country Blacksmithing by Charles McRaven

I learned to make springs from Brownells Gunsmith Kinks.

I hope I helped without boring you too much. I've been playing blacksmith since high school and Working in machine shops on and off for 17 years. Metal working is one of my pet activities after guns and gardening.

Woods

leeblackman

Wow, that helps out alot. Thanks for the book titles. I really appreciate your time and help. I think for now, I will wait, cause apparently its not as easy as I thought, but I will get as much information on it as I can because later I may have the resources to attempt it.

If I'm wrong please correct me, I won't be offended.

The sound of a 12 gauge pump clears a house fatser than Rosie O eats a Big Mac !

robsguns

woods,
That is going to be the info. that keeps me from doing anything like that for now, but it sure was good info. I'll keep in my brain housing group.

SSgt Ryan E. Roberts, USMC

jo-dan

Hey Lee,
I've been experimenting with a little scout rcvr,
a neycraft heat treat furnace and various carbon
containing materials for about the last year.
I seem to be able to either get good colors and no case,
or a good case and no colors. I can tell you
that the temperature and the time exposed are the critical
factors. I'd be happy to scan you a photo of my latest
endeavor if you like. It's very time consuming since it
takes me several hours of hand polish between tries but
it is enjoyable to me. Don Menk of color case will do the
job for you for about $100 and his results are out of this world.
good luck
joe

laissez les bontemps rouler

pabooger

I work in Heat treat at Cutco/Kabar Cutlery in Olean Ny. On most of our cutlery it is made of stainless steel, the knives are blanked out of stainless then they are ran through a furnace, at approx 2400 degrees as an annealing process this varies depending on the material. This is done in a furnace that contains an atmosphere of Hydrogen and Nitrogen which is oxygen free, as oxygen is destructive in the heat treat process. Basically what happens if the oxygen enters the atmosphere in the oven, the knives will flake apart like several layers of paper. When the blades come out the other end they are put into a freezer at a temperature of minus 180 degrees for several hours, this is called chryonics, basically what it does is realign the molecules in the metal which gives the blade more strength. The blades are then put in another oven and tempered to gain the rockwell hardness that they are required.
We also produce some carbon steel blades such as your marine corp knives and such, they go thru a different process similar to what was mentioned in the post above. They are quenched in oil.
Carbon steel blades do hold an edge longer than stainless blades!
Hope this helps some! Oh and by the way we have been known to heat treat a government job or too on occasion. But you didn't hear that from me. L.O.L.

Alpine

I would caution anyone against attempting to harden a barrel. If a barrel were hardened, and then failed, it would shatter scattering metal like a frag grenade. If a barrel fails you want it to bulge, on a minor failure, and only split on a major failure.

"If you ain't got pictures, I wasn't there."

pickenup

You just never know what a person might learn, reading the posts here.

The gene pool needs chlorine.

v35

If you want to case harden, buy some Kasenit and follow directions. If you want the colors as on an old SAA Colt then you have to use animal bone and cook the parts with it in a box at high temps followed by a quench. The actual details are a closely guarded secret but I'm sure it can be researched or empirically determined.

BlueTic

The case with the part and bone/carbon material needs to be heated to 1400F for the amount of time it takes to absorb the carbon from the material (or burn off the bone meal). A good kiln that holds a steady temp is a must. Remove the case and quench the part in a 1/2 water 1/2 oil mixture. You get better patterns if you run an air line in the quenching tank (an old aquarium pump and airiation stone - bigger bubbles give better results), something to do with the reaction of the oxegen on the metal surface as it is quenched. The biggest problem, as you can guess, is warping in the material.

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