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Numbers
September 19, 2000, 01:32 PM
Just curious about color case hardening. Is this just a desired cosmetic result, or does something really get hardened? Aside from a beautiful appearance, is there a practical reason to do it?

Is today's color case hardening different than that of 150 years ago?


Numbers

Jim V
September 19, 2000, 04:34 PM
The color was a "by product" of the case hardening process. The parts would have been packed in leather pieces (in some cases) and then placed in a furnace. The leather would supply carbon for the case and impart the color.

There is a lot of "color case hardening" on the market today that only imparts color to the steel and no hardening.

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Ne Conjuge Nobiscum
"If there be treachery, let there be jehad!"

Gunslinger
September 19, 2000, 10:14 PM
As Jim said there are a lot of companies today that use case "color". The first that comes to mind is Ruger on their Vaqueros. The case color on these guns has received a well deserved reputation, in my opinion, for very rapid wear. All of the Italian companies making Colt clones, to my knowledge, actually case harden their guns.
If you do a search in The Smithy forum on case hardening you will find some very interesting and educational past discussions. It is a topic that is much discussed that I never grow tired of. There is nothing, in my opinion, so beautiful as good case hardening matched with a good blue job.

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Gunslinger

I was promised a Shortycicle and I want a Shortycicle!

catman
September 25, 2000, 08:35 AM
my smithy told me not to used any flitz or any abrasives to clean powder burns on color case hardening. i've got and old model 10-5 S&W (yes its pre band) and its got some color case hardening on the triger and the hammer. i guess i'm just afraid to try it because he said it will dull or mess the color up, and he's a very trusted smith and a good friend, so i'm not going to dought him. my .02

4V50 Gary
September 25, 2000, 11:45 AM
Ruger Vaqueros are not colored case hardened as this is too weak for their standards. Traditional color case hardening required the item to be placed in a sealed contained filled with ground bone and burnt leather. The container was then heated until cherry red for about 15 minutes or more (depending on the item's thickness) and then the contents plunged into water. It'll give you a nice coloring and a surface hardness of a couple of thousandths of an inch.

The Ruger hardening process consists of an acid bath followed by heat treatment. That there is coloring aftewards is a desired result of the process. It will rub off so be careful. However, the metal itself is far more durable than normal color case hardening.

James K
September 25, 2000, 04:41 PM
Case hardening was originally used on guns with iron frames (pre-1900 Colt SAA for example), since iron cannot be hardened for wear resistance by heat treatment as steel can. Case hardening need not be colored, but coloring is an added decoration and helps sell guns. Most modern colored finishes are a product of a flame coloring process; they are purely for looks. They are not durable and do not add any actual hardening. The coloring on S&W hammers and triggers is a true case hardening, and the parts are fairly soft underneath. This is the reason gunsmiths advise not to try any work on S&W triggers or hammers that could cut through the very thin case hardening.

Jim

Alex Johnson
September 27, 2000, 09:36 PM
Most of the Italian manufactures use a cyanide case hardening process for their Colt clones. I don't care much for the colors produced by this method since they are much more gaudy than the mellow colors obtained by the bone and charcoal process used by Colt. It still is a true hardening process, however. Case hardening does have some very real benefits compared to through hardening techniques. Since the core of the part remains practically unaffected by the heat treat process the exterior can be very hard. With a soft core backing it up, the part does not suffer from the brittleness that it would if the whole part were left that hard. I still consider case hardened mild steel to be preferable for many of the custom gun parts that I build.