casehardened frames, function or cosmetic?


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Alex
February 21, 2003, 02:30 PM
I do quite a bit of work on percussion revolvers and lately I've started to get interested in engraving. I'm thinking of engraving a pair of 1860 armys since I can obtain Piettas relatively cheap in my area and so they make ideal practice guns to work on. I'm interested in having them plated afterwords but wonder if it would be necessary to have them re-casehardened before this is done. With the abundance of brass frame revolvers in use I don't know if this step would be absolutely necessary, was a casehardened steel frame really all that essential for BP loads or would the soft steel have worked well enough since it would already have been considerably stronger than the brass frames. Something tells me it might have been done for cosmetics as much as function and I'm curious if any of the plated models were ever casehardened prior to being plated. Does anybody have any insight into this?

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dfariswheel
February 21, 2003, 07:08 PM
Color case hardening has no real effect on strength. It does provide for a hard non-wearing surface, but is mostly for appearance.

Most original BP guns used iron frames, so casehardening was originally to help with wear resistance and appearance. When steel frames became common, color case hardening was a tradition, so they continued to offer it.

If you can remove or breakthrough the coating to engrave the surface, there is no need to reharden the frame.

As to were some guns color cased before plating? Probably, since most companies run frames through a production process, and it actually costs more to put some frames through a different process. In other words, it just cost less to pull special frames out at the end of the entire process for plating.

In any event, this would be nothing more than to ease production, not for any reason concerning strength.

Old Fuff
February 21, 2003, 07:53 PM
Originally soft iron or steel was sometimes case hardened to resist wear. A by-product of the process was a mottled oil-slick look, which was strictly cosmetic. Now days, when parts are usually made from tool steel a different process is often used which duplicates the look of case hardening but not the hard surface. Colt used to ship their revolvers to engravers “in the white” (unfinished and unhardened) to make engraving easier. Then the finish was added after the engraving was done. One problem with color case hardening is that you can’t tell how the parts will look until the work is done. Consequently Colt (and probably others) would salvage bad-looking-but-otherwise-good parts by plating them – nickel, silver, gold or whatever.

Many of the Cap& Ball reproductions have colored but not hardened frames. These should not be difficult to engrave. You might also consider copies of the “New Model” Remington – which like the original are blued and easy to refinish after engraving.

Then too, many people - then and now - think plated finishes look particularly good on an engraved gun.

Jim K
February 21, 2003, 09:34 PM
They did the case hardening in a cyanide bath; for color, they bubbled air through the bath, which is why the colors are totally random. If you wonder why folks don't much use color case hardening today and why it is very much in the "don't try this at home" category, check out that word "cyanide". As in gas chamber. As in poison. As in breathe the fumes and you're dead.

Jim

jrhines
February 23, 2003, 06:14 PM
There are several methods of case hardening that are available to the home worker, if what you want is a hard, wear resistant surface. The process involves cooking added carbon into the low-carbon steel. It is the reverse of what sometimes happens when hardening a spring. If a carbon sparse flame is used (a propane torch for instance) you can cook carbon out of the steel and make it softer and weaker.
Guy Lataurd, in his excellent series of books "The Machinists Bedside Readers", gives some detail on color case hardening using a carbonized bone mixture, packing the parts in it and firing at the appropriate temperature. He emphasizes that this technique is solely for color and should not be relied upon for added strength or toughness. During the quenching, I do believe he recommends that air be bubbled through the oil quench to enhance the random colorization.

Alex
February 24, 2003, 07:12 PM
Thanks for all the information, I should be able to start my project now.

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