When was color case hardening first used?

[Rolf]

I've been toying with the idea of trying to color case harden the pistol lock for the long barrel pistol I'm building.
For what time periode is color case hardening proper?

Best regards

Rolf

[camerl2009]

as far back as i know is the winchester lever guns so about 1870's as far back as ive seen it on guns

[LRB]

  All imported locks from England, Germany, and I assume the rest of Europe, during the flintlock period were case hardened. It was required by the guilds in order to sell a lock. Using the old methods of case hardening, I suspect that  the colors most often come with the process.

[Jim Kibler]

Pack carburizing was of course used during any of the times being considered.  Colors are sometimes a product of this process.  Whether they were left on seems to be the question.  Examples may exist, but I don't recall seeing any 18th century longrifles with case colors on the lock.  These colors are of course fragile so they may not have survived even if originally present.  Even when looking at European and English arms, some of which are fantastically preserved, case colors seem to be more of a 19th century feature.  I guess it would be hard to say that they were never present on 18th century longrifles, but my feeling is that they weren't very common.  Personally I don't very much care for how they look on 18th century American work.  I have seen some case colors that were subdued with abrasives or brushing  that seemed a bit more appealing.

[smart dog]

Hi Rolf,
Jim is probably right.  Pack hardening has been around for a very long time but I have not seen any evidence of intentionally preserved colors left on the metal until the 19th century.  For example, in descriptions of US made military guns, color casehardened locks are not mentioned until well into the 1st quarter of the 19th century.  Of course there may be some very early examples of color of which I am simply not aware.  It seems like there are always exceptions.

dave

[blunderbuss]

 To carberize a plate (case harden without color) one packs the piece in a metal container filled with bone meal and heats red for a couple of hours. To obtain color one packs the container with leather. Many old lock plates were hardened and it would be impossible to tell if it originally had color or not.
 It wasn't so long ago that it was generally believed browning came before bluing however on reading old  advertisements and investigating undersides of some long rifles bluing was quite common. Even as far back as matchlocks and wheelocks as was some armor before that.

[kutter]

Colors can vary with the % of wood charcoal and bone charcoal used in the pack.
The quench can vary the colors also (depth, temp, distance of drop).
Furnace time, size (and even shape) of the C/C box, amount of space betw parts, etc,,

Just about everything is a variable in C/C.

You can also case harden w/o the multi colors pattern by using oil as a quench instead of water.
A dull blue gray color or just gray color usually results, but again depends on the above.

Most every gun company doing case hardening w/colors in the 19th and 20th century as a production heat treating had a pattern and color identifiable to that company. Colt colors, LC Smith colors, Parker colors, etc.

The process was eccentially all the same. What made small identifiable differences in the final results were those variables of % of mix, temperature, time in furnace, etc.
Everyone did it a bit different but replicated their our results fairly consistantly thru their own production period.

[54ball]

 From what I've read the the original color scheme of Hawken plains rifles was the following.  The barrel and trigger guard was rust blued to a satin black.  The lock, nosecap and buttplate were color case hardened.  Now the St. Louis shop was active for about 50 years if memory serves, so whether this is early or late I do not know.
 I also have read that the secret to case colors is the quench.  A mixture of oil and water was aerated.  As the part is dropped into this mixture of air, oil and water the part cools unevenly, setting the colors.  In a regular quench the part should be dull gray.
  As far as the 18th Century, I wonder if colors were accidental and undesirable.  If so should English locks be case hardened to dull grey and or polished to be correct for the time?
  The Hawken Rifles mentioned above would patina to a brown on the blued parts and a dull gray to eventually brown on the case colored hardware.  So that may leave open the possibility that case colors were used in the 18th Century.

[Jim Kibler]

As mentioned previously, sometimes colors are obtained even if using a process not specifically designed to produce or enhance them. 

Yes, as mentioned before, and based on the many surviving examples it would be hard to argue with pack hardening and polishing 18th century English locks to remove the colors.

Again, case colors are fragile so if they were present on 18th century American work, there is a good chance they do not remain today.  However in looking to an English or European precedent for colors used in a decorative fashion, it seems this didn't commonly occur until the 19th century.

[kutter]

Quench,,one of the variables.
Everyone doing case colors probably has a different quench technique.

We tried many different, with and w/o aeriation, with and w/o all manner of chemicle additives, different water sources, different temps, quench tank sizes, drop distances, etc.

Settled on R/O water @ 90F. No aeriation or additives. Use once and discard.

But everyones will be different....

[Rolf]

Thanks for the input. I'll keep the lock bright or rust blued. (All the fittings are rust blued with silver accents).

Best regards

Rolf

[Dphariss]

Using the proper ratios of the charcoals will produce color. Not using the proper ratios can screw up the finish on the part IIRC.
Back in the day it is thought the color was removed after hardening since it does not appear on the internals of locks etc.
I don't know when casehardening colors became fashionable.
Dan

[JCKelly]

Runs in my mind that Bivins had written something about case colors in the 18th century. He might have been talking about European work. Yeah that's vague & yes I agree colors weren't common in the US until the 19th century.

Bone charcoal mixed in with (actual, not BBQ briquettes) wood charcoal & a water quench is used to get the colors. I think it is the calcium phosphate in bone that makes the best colors - they are NOT temper colors.

There are other ways, in particular hardening from molten salt containing a good bit of sodium cyanide. But Colt &c used the bone + wood charcoal method.

While I personally would not want to see colors on an American-style flintlock, Oscar Gaddy wrote a two-part series on color hardening in The Double Gun Journal, Winter 1996 and Spring 1997. I have scanned copies in pdf if anyone wants them.

[keweenaw]

The steel  in the lock can also make a difference in the color.  I hardened the lock on the Beck I built and did a lock for Mark Silver in the same pack.  We're not sure who built the lock that Mark had but it wasn't made from cast parts.  Those locks came out as different in color as any two you are likely to see.  - Same pack, same temperatures, same quench . -  There was one plugged hole in one lock and the steel in the plug was radically different from the rest of the plate.  On the lock made from cast parts the pan section was obviously a different steel than the plate as it came out a completely different color - plate and cock had nice blues, the pan section was a putrid green.  Needless to say I removed almost all the color from that. 

Mark almost always removes almost all the colors from his locks.  It's easy to do with a bit of 0000 steel wool and 600 grit abrasive.  What he likes about hardening the lock even when he's going to remove the color is that the hardening not only gives a wear surface but it also changes the texture of the surface in ways that aren't possible to do by polishing and you can leave a touch of color in the nooks and crannies to give some contrast.

Tom

[dannybb55]

Don't forget that this was all done in a forge and usually with charcoal. My guess is that you don't see a lot of colour because the smith's bought good blister steel for their hardened parts and uniformally hardened the components after they were finished. Everyone knows what blister steel is, right?

[Jim Kibler]

Don't think so Danny.  The consensus is that wrought iron was used for all the parts except the springs and on occasion the frizzen face.  There have been several recent threads which discussed this in detail. 

[LRB]

  I recently discussed this with Jerry Huddleston. He said that all the 18th. c. locks he has seen or worked on were case hardened wrought iron. He also said he saw one broken spring that appeared to also be cased wrought iron. Yes, I believe most of us know what blister steel is, but why do you think it was good? If it was all that good, shear steel and cast steel may not have happened. Either of which beats blister steel. It was cast steel that allowed for accurate time keeping in clocks, as best I recall.

[rich pierce]

I've had a couple blister steel butcher knives and they were nothing special.  But the ones I had were trade level knives.

[Dphariss]

Don't forget that this was all done in a forge and usually with charcoal. My guess is that you don't see a lot of colour because the smith's bought good blister steel for their hardened parts and uniformally hardened the components after they were finished. Everyone knows what blister steel is, right?

If you think they used high priced blister steel for lock plates you have been reading different material than I have.
Iron or at least low carbon steel was common for lock parts well into the 19th century.
Read "The Gun" by W. Greener 1835.


Note even when steel is mentioned it only for sears and tumblers. Not plates and bridals. If you look you will find that a number of locks, high end ones included, have steel faces on the frizzens.

Casehardening mild steel still makes very nice lock internals and is best for lockplates since it need not be drawn back after hardening. A blister steel plate hardened will be too brittle for use unless drawn back to 450 degrees or maybe more. This will result in a softer surface than a traditional case hardening process will provide. Case hardening makes the plate slicker and more rust resistant. Its fairly easy to obtain .005" thick carbon skin with traditional methods. But I would not want to be the apprentice pumping the bellows if done in a forge. Since it takes time to get this penetration.
I would also point out that an engraved lock plate will loose some of its sharpness unless heated in a controlled atmosphere so even doing the heat as would be done for a spring may seriously damage the engraving. Pack hardening, properly done will not damage the surface.

Dan

[dannybb55]

Correct me if I am off here. Is blister steel case hardened iron? It is described that way in my older blacksmithing books.

[Jim Kibler]

As to the mention of steel tumblers only being used for the best locks a few years prior to 1835;  I guess it would be safe to conclude 18th century export locks were not in this category.  So with the exception of springs and the occasional steel faced frizzen I think it's safe to conclude the remaining parts were wrought iron on most 18th century longrifle locks.

[dannybb55]

Don't forget that this was all done in a forge and usually with charcoal. My guess is that you don't see a lot of colour because the smith's bought good blister steel for their hardened parts and uniformally hardened the components after they were finished. Everyone knows what blister steel is, right?

If you think they used high priced blister steel for lock plates you have been reading different material than I have.
Iron or at least low carbon steel was common for lock parts well into the 19th century.
Read "The Gun" by W. Greener 1835.

 point taken


Note even when steel is mentioned it only for sears and tumblers. Not plates and bridals. If you look you will find that a number of locks, high end ones included, have steel faces on the frizzens.

Casehardening mild steel still makes very nice lock internals and is best for lockplates since it need not be drawn back after hardening. A blister steel plate hardened will be too brittle for use unless drawn back to 450 degrees or maybe more. This will result in a softer surface than a traditional case hardening process will provide. Case hardening makes the plate slicker and more rust resistant. Its fairly easy to obtain .005" thick carbon skin with traditional methods. But I would not want to be the apprentice pumping the bellows if done in a forge. Since it takes time to get this penetration.
I would also point out that an engraved lock plate will loose some of its sharpness unless heated in a controlled atmosphere so even doing the heat as would be done for a spring may seriously damage the engraving. Pack hardening, properly done will not damage the surface.

Dan

[Dphariss]

Correct me if I am off here. Is blister steel case hardened iron? It is described that way in my older blacksmithing books.

The processes are similar but blister steel comes out heavily blistered since the process is long enough to burn away the charcoal and allows oxygen in to cause the scaling and blisters. The temp is also higher than for casehardening. Nor is the charcoal the same as for casehardening.

Dan

See parts one and two.



Part two is "blister and shear steel part 2" I think

[JCKelly]

Fascinating, first time I've seen blister steel.

The blisters do come from carbon diffusing into the wrought iron, and reducing the iron oxide component of the slag. This makes carbon monoxide (and iron, of course) and that gas is what raises the blisters.

His spark testing showed that the surface was high carbon.

In the old days, when they thought the metal had "cooked" long enough (about a day),they would draw one bar out from the pack and water quench that bar. Then notch & break it. The appearance of the fracture shows "the depth of steeling", i.e., how deep is the carburized case. The carburized layer will get hard when quenched  & break differently than any low carbon core metal which might remain. Specifically, the carburized metal will break with bright shiney crystalline facets, if any soft iron is left in the center of the skelp it will break in a fibrous manner.

Mid-eighteenth century a guy named Reaumur (same guy who patented, if not invented, the process for making malleable cast iron) experimented with different additions to the charcoal, in an effort to speed up the carburizing ("steeling") process. His conclusion was that additions of sea salt & pigeon dung helped. For reasons both of metal surface finish & the health of your liver I would not recommend these additions for case hardening iron lock parts.

[smart dog]

Hi,
I was just reading a chapter in Neal and Back's "Great British Gunmakers 1740-1790"  and discovered the following passage on page 48:

"William Bailes of Russell Street, Bloomsbury, was a maker of great repute, known for his many improvements in the art of gunmaking, who worked in London in the 1760's as a contemporary of Twigg.  In a curious little book written by Sir Thomas Frankland in 1801, entitled Cautions to Young Sportsmen, he refers to Bailes, giving him credit for the invention of the iron rib which held the ramrod in a half-stocked gun and also for the case-hardened tinted surface of his locks, which would be the equivalent of bone-hardening today."

dave