Hi guys, thought I'd share my learning with everyone. I've not setup my color case hardening facility...still practicing and will put some pictures up of my first test attempt soon!

http://www.vintageshotgun.com/

Regards,
TT

Hi folks, after a couple of tests I decided to case colour harden the first part of my Greener. I'm quite happy with it and it's not too harsh. Pictures below and more on my blog.







It's one of those things you just have to try and experiment with. I plan to do the hammers and sidelock plates next.

If you are interested and want to see more the blog has more and the pictures are bigger there.

Regards,
T

Nice Tony,


Good colors and does not look 'gaudy' as so many do......I personally like the grays and blues....a little straw is good sometimes....

2 to 1 B-C..?.......

Best,

Hi Doug, I think it was about 50/50 but I'll double check and come back to you. I actually think it's quite nice and kind of closer to what it might have looked like...I've asked Michael Greener for his view.

Regards,
T

Tony:

I have been quenching in very pure rain water and found it the best for colours....the quench tank I built has a PVC pipe aerator in the bottom with multiple holes that supplies lots of O2.......which is critical as you know.....

I have a holding tank that collects rain water for just that purpose.....

Yes, Tony, your colours do look more original than most, again, very nice indeed.....

As you know, each effort is like a "snowflake", no two are alike......and they look very different in different light....

Here's an old Marlin & LC Smith I did, Marlin made in 1895.....38-55......five or so years ago on these two......




12 Ga LC Smith 1926 .......



Best,

Doug they loook superb!! Rainwater, interesting, we have a water butt on the end of the house, will refill with this water. Did you chill the water too? When you airate how fine are the bubbles? I just shove the end of the hose of a hobby compressor at the bottom of the quench barrel..

T

Tony:

No, I do not chill the water, outside air temperature is fine....

I drilled the PVC pipe with lots of small holes and placed it lengthwise in the tank so all the bottom area is covered with lot's of very fine bubbles, it has a vertical stand pipe with an elbow and the compressor fitting on that elbow.......has worked quite well for years....

Played with different combinations of B-C and other additions, times, temps, etc., just to experiment with different colours........lot's of fun as you have found out.......

I don't spray clear lacquer on them, as I think it looks tacky...JMO.......and it also yellows later and really looks nasty.........

Here's a couple more different ones Tony.......



Best,

You are good, real good, both of you.
With kind regards,
Jani

In Birmingham many years back there was a place that did the best colour case hardening, outside of the workshop was a large water trough that was also used by the workers to pee in some say this helped the colour!! worth a try I have the old Johnsons formula for colour hardening I will see if I can dig it out

**Thank You Jani............

**Barrel Browner, I would like to see the old Johnson's formula if you dig it out sometime, thank you.......may try the pee thing, then again, maybe not....?......Send a PM if you would like, thank you........


Best Regards,

dare i say it? nahh...nobody cares anyway....

Ed,
your job here is to STFU and take notes on how its done the CORRECT (caps are for your benifit) way !


Great job Tony and Doug,the LC of yours looks like its just came out of the factory,perfect !

Very nice work....now it looks like I'm out of a job.

You will find a lot of things will affect the colors, ratios of bone wood, temp of water, charcoal size, quench temp, time at temp etc etc etc.

I started doing CCH about 10 years ago, took me about a year; lots of quenches and several dozen turn of the century books on Case Hardening to figure out what was happening.

I would take mild steel and surface grind it dead flat, then measure warpage and depth of case at different quench temps & water temps.

Right now I pretty much have the Winchester and Marlin colors down pat, still working on the Colt & Parker colors.

Have Fun

V/R

Mike

Hi, thanks for the comments. It's interesting to see how others do it. I'm quite new to this but very happy with how the greener came out. I'm doing the hammers and plates and forend metalwork on Wednesday...was thinking of bolting the plates to some 4mm plates to stop any warping..but not sure I need to.

Cheers
T

Barrel Browner I'd also like to see that formula.

Cheers
T

Tony--

Bolt the lock plates to your solid 4mm plates, providing they are completely flat lock plates using the appropriately shouldered bolts, with the appropriate holes drilled in the 4mm plates for attachment from existing holes in the lock plates.........then load and pack tightly in the crucible....you don't want them to move....at all....use caution......PLUS, the 4mm plates will act as heat sinks and collect the heat and increase the heat/temperature -(larger mass)- "that is maintained" for the lock plates throughout the process and stability as you quench, and the colors will also be improved as a result........

Most actions should be assembled when loaded in the crucible with special fixtures (that you make) bolted in place to make one solid firm unit, which retains heat better as a larger solid mass (less the internals of course), therefore cannot move and the colors are enhanced as a result ......the single mass unit retains heat much better than single small pieces by themselves.......problems occur if the parts are not properly secured in this fashion.....

Mike:

Thank you sir....your work is outstanding and speaks well of your talent and attention to detail.....

I started doing my own CCH about 25 years ago and I am always learning......like you.....it takes a lot of effort and practice runs with test pieces every time you change formula's....but it is fun......and rewarding......

Best,

Doug the sidelock (read backlock) plates are actually slightly curver up at the end so they'll be a little space at the back of these when bolted onto the plate...the majority of the plate will be flush but the ends will curl up a fraction...OK?

When I pack in then charcoal everything is tapped down solid it's like a single mass before it goes in...I thought that was the right thing to do to keep everything stable and I'm sure that helps with any warping/movement.

T

With work like this, emphasis seems mainly on color, when do we hear about the hardening part? The receiver was dead soft after annealing, what hardness readings did you get after this work? What is the depth of carbon absorption? Too little is no good, if too deep the receiver is prone to cracking.

I was also wondering, what was the case depth you are getting?
Thanks,
Craig

Several years ago I took sample pieces that I had completed to a close friend who does military aircraft testing ....the parts were tested and showed 1.2-1.5 mm surface depth hardening and I was informed that all had passed mil spec. S-6090A which is the military aircraft spec for low carbon steel hardening.......and that is good enough for me.........

I have also hardened some aircraft parts over the years and these parts require testing and certification before return to service (paper trail from a certified testing lab).....color is not on the list of importance....depth and quality is.......these parts are magnafluxed and red dye tested as well, before certification showing any imperfections.......

Doug (PA24)

Thanks for the complements Sir,

Looks like you’ve been doing this for far longer that I, always willing to exchange ideas.

When I first started doing CCH, I built all kinds of fixtures out of stainless steel to tame warpage, one of the thing I found though, is that it’s probably not necessary; here’s my thoughts:

When you quench the part, you’ve got over 1000 deg temp change in a split second. The metal will move. Too many times I’ve removed a block/fixture only to watch the part “spring” once the fixture is removed. I also think that HEAVY blocking may actually increase warpage due to retained heat.

One of the great properties of true case hardening is that the core is still soft, meaning that the part is still quite “tweakable” , and is easily bent.

I stopped using blocking for the most part (still block receiver rails & the barrel holes in receivers). Blocking now is mostly to enhance colors.

If Color Case hardening is done correctly: reasonable temps, clean water with no additives (Salt) warpage should be minimal and easily fixed if it does occur.

Thoughts?

Mike

Nitro Express:

Incorrect......."the depth of hardening is ultimately limited by the inability of carbon to diffuse deeply into solid steel".....check with any metal laboratory or metallurgist.....

That is why for over 150 years it was called the "hardened skin"......


Mike:

Yes, I agree with your comments and observations.....I still block most parts, but do not use stainless....but low carbon steel blocking.....and as you stated......as long as CCH is done properly....i.e. temps etc......I totally agree.....

Best,

Mike, agree. Actually I didnt block the action. It's fine. Tightly packed in the carbon. For the sides I'll use carbon steel as Doug suggests.
T

Doug

Is there a reason that you don't use stainless? Reason I'm asking is that I talked with anothe gentleman who swears by cast iron for his crucibles & blocking. But he also has a local foundry that will cast for him.

I like stainless because it will last, after a couple of dozen quenches or so with carbon steel, the steel bloks are toast.

I know some folks don't like SS because it harder to machine, but since I mostly use carbide here in the shop, that's not an issue for me.

My SS crucibles & blocking have lasted a long time... some since day one.


V/R

Mike

My Canister is also carbon steel...but I let it cool naturally in the hope that it won't deform too quickly. I read mr Gaddys piece in the journal and he also used SS.

T

Mike--

The carbon steels have more carbon than stainless and I think enhance the colors......they do wear out and 'peel' as you go along, all the old timers that showed me specified carbon steels....so I just kept it up.....I know the old factories here and in Europe used carbon steel for their crucibles obviously....

Like you, I make all my own stuff, so it's no big deal to replace whatever wears out......stainless is probably better, I've not tried it...and I would have to compare and see if there is any color difference....?.......I'm not sure the extra carbon helps, but I was led to believe that it does...who knows.....we'd have to run tests 'side by side'....

Most of the folks use carbon steel I think.....probably cost...?...

Agreed. Much easier to get and form carbon steel for me. I also made the canister and it is easy to replace at the cost of about £20/$30

T

Not a metallurgist, But, only partially correct I believe. The penetration of the carbon does indeed slow the deeper it penetrates & for practical purposes there is indeed a limit of depth to be reached. However, I do believe that on a thin structural part, as for instance the side walls of a Light-weight Flues frame it would be entirely possible to achieve "Too Deep" a case leaving a part subject to cracking from its brittleness.

I have one question which I can't recall ever seeing addressed. When the part was originally Carburized it was brought up to heat in a carbon rich atmosphere & held at heat until the desired depth of penetration was achieved. Annealing the part removes only the hardening effect of the subsequent quench, it doesn't remove the carbon. Now upon subjecting the part to Re-Carburization does it immediately begin to obtain deeper penetration.

From my limited knowledge of the subject as I understand it the critical temp of a piece of carbon steel varies according to the % of the carbon, the higher the temp the lower the C'temp. It would thus seem to me a high enough temp would need to be maintained prior to the quench to harden the entire depth of the case. It would thus seem quite plausible that at some of the very low heats from which some quench to help in the prevention of warpage they might thus be achieving a very Superficial hard case with the major depth to which a declining % of carbon has attained might well remain unhardened. While this might seem desirable to minimize wrpage, it would also seem to be less than desirable for the purpose of hardening.

While true I am not a metallurgist, I did spend 35 years in machine shops where heat-treating of various types (including case-hardening, just not for color) was carried out. My experience was that any time a piece of steel was heated to above its critical tamp & quenched there was a modicum of RISK involved & that Every Time it was subsequently Re-Done, that risk grew slightly.

Miller; all makes sense to me.
T

PA24, you are incorrect..... see 2-piper's reply reference thin cross sections of the receiver, trigger mounting plate, opening lever and small parts. If you look at enough re/cased receivers and parts you'll start seeing cracks. And may I ask where you took your degree in metallurgy??

What does that mean ed ?

Miller

Yes you are correct… in that annealing does not remove the carbon, but it does disperse the carbon a little more and a little deeper. A hypothetical example; SAE 1010 case hardening steel, case hardened, then annealed may change the carbon content of the steel from .10% to say .12%, which is still within the “safe zone” for case hardening steels (less than .25% carbon).

Steels with greater than .25% carbon are usually considered thru hardening steel, where there is enough carbon present for the steel to harden all the way thru.

For very thin parts this may be a problem, An example of this is if you have a very thin area say .005 thick of low carbon steel (SAE 1010, with .10% carbon) and you case harden to a depth of .002, then anneal the part, you have probably increased the carbon content so that piece may be equal to 1020 or 1030 with .20-.30% carbon, too much resident carbon to be safely case hardened.

Case hardening is certainly not a no risk endeavor. There are way to mitigate the effects such as reducing the soak time at critical temp, reducing the quench temp below the critical temp etc. But the bottom line is that the case hardener needs to have the experience to make that judgment call.

There have been several times that I’ve turned down work, and have refused to case harden a part, the risk just wasn’t worth it.

But on the OTOH, I have seen some folks that would color case just about anything.

Hi Mike, interesting stuff. Actually I think your last two comments there make a lot of sense. For me it was the excitement coupled with just wanting to extend my gun smithing skills. I Admit I've bought a Greener which some say is not worth the risk, but actually, it's a nice little hammer gun that I really wanted to see if I could replicate somewhat it's earlier days...it didn't cost me a lot so it's my risk.

The big thing I've taken from this thread is that it is very true that one shouldn't CCH everything and that some guns should just be twinkled up a bit and left...V true.

Regards,
T

Nothing is without risk.....

In over 25 years of CCH, I have never observed so much as a microscopic crack in any of the parts that I have quote "re-cased".....and I have always magnafluxed (if you know what that is) all my parts through a relatives aircraft crankshaft shop.......

But surely you and Miller know more than the rest of us......and since I do only my own personal guns and parts, I really don't care what you or Miller think or read......both of you need to go out and get some fresh air IMO...........


**Tony: Don't let these people throw water on your great new beginning's......you've done a super job.....

Thanks Doug, I always listen and read peoples views. I'm the type of person that will of course go my own path

Tony, I suspect you won't know if you have warpage until you try to fit the barrels. It would have been nice if you had measurements pre and post. Just cause I'm weird that way. Feeler gage type measurements.

The only place where I can see an embrittlement issue on an action would be when an action had been recased several times. Not common, yet. Most recasing soak parameters are necessarily well within range.
At the met lab sections are routinely cut, polished and reviewed. Case depth takes time. Non-linear time. So, excluding the multi cased action, there is considerable leeway, within the conditions normally used, trained in, and passed along. In cases like these,where destructive testing isn't possible, you just want a procedure that keeps you between "too little, and too much".
Not everyone is comfortable just doing as they are told. Some of us like to know exactly what the range is we can get away with, and what effects our little flourishes leave behind.
Some believe in magic, some in science. It's all good.

Note: I survived being blown up by an annealing furnace. Very surreal event.

Hi Clapper, I've put it to the barrels and it appears fine, I cannot see any difference gappage than prior to my CCH. However, I have to say I've only researched and gathered my data unscientifically. It's very interesing to read what you say about tolerances. I have to say also that I did crap my self the two times so far that I have dropped the parts into the water. Keep it coming!

Great info all round.

T

Very well said CZ.....

Best,

Tell us about that annealing furnace...you scare me now...am I going to blow myself up? /wink

I'm no expert on these things.
My best friend is. Right down to jury rigging a forge and re-caseing a bale spike in our friends barn. In general,I send him the stuff, his people heat treat it. In the last 30 years I have seen carefully controlled science replace the voodoo.
It shows in the consistancy and quality of heat treated parts.

I suspect, that if we start out with a shotgun that weighs enough to be confortable to shoot, it has enough steel in it to be somewhat forgiving of our secondary manufacturing treatments. Which isn't the same set of determinants as effects fuel economy and highway safety. Or, rifle safety for that matter.
Just a viewpoint.

CZ....Yup, 100 + years ago it was "black magic" and nobody talked about it, all hush-hush.............voodoo is a good word.......


Tony....tell us about crapping your pants when you dropped the parts in the quench....!......

In big casting operations, sand casted parts go through shakers on mesh belts. Sand wears stuff out. The parts also run through annealing furnaces on long time controlled belts. A furnace can be 100 feet long or longer. All about time, temp, and flow.
We were changing the shafts and pillow blocks on a shaker. The shakers are adjacent to the furnace lines for minimum handling of parts. Normal maintenance. Standard 4" GM spec shafts and bearings. Every GM plant uses the same shaft size and bearing set.
Well, suddenly I saw a flash, felt a wave lift me in the air, and then the world was all orange, and then black as the deepest mine shaft. I could not breath. I was engulfed in fire, but it was not very hot.
Then, I was sitting on my arse in the blackness. Then Orange embers began to fall like a firey snow storm. A whirlwind of orange sparkly embers in the pitch black. Then, like stars on a cloudy, moonless night, the sodium vapor lamps 50 feet above, began to show through the blackness. Their glow increasing with each heartbeat, and the settling of the ash.
I stuck my face into my shirt to try and catch a breath in the dust and fire. The firey soot settling all around me.
Light finally returned enough to move. You can't run when you can't see.
I looked for my partner Dave. He was in the shaker at the blast.
Dave's a very sober guy. Smooth as Hubel's glass. He was looking at me.
He say's to me, "You alright kid?" I check myself for damage, just a few dents. I shake my head yes. "Go on and take alook for any meat around by the control office, them's the kind that kills people." I stumbled across the pile of pump castings and cinder blocks over to the control booth. There was no one inside. No....meat to be found at the blast site. Just mangled chainlink, refractory cement, and cinder blocks.
I looked across the aisle to the furnace. The gas fueled annealing furnace had had a gas build up of un burned fuel, and had blown a 30 foot section of the tunnel out. Directly across the aisle from the control booth, which disintegrated and rained parts and block at Dave and I. Well, mostly I.

The operator came running down the aisle to find Dave and I. We were OK. He'd been on break. Or he'd have been the meat.
His office was destroyed. A direct hit, that saved my life.
The fire was the carbon rich gas burning in the atmosphere. The cinders, the accumulated soot and ash that was blasted off the ceilings, beams, and machinery during the blast. It was ready for paint after the soot fell.
Within an hour, division level GM managers were in the plant interviewing us.

Sometimes it's better to be lucky than good.

Well I thought this was an open discussion of case hardening. I thought in fact I "Asked" more questions than made Statements. One or two did provide some answers, which certainly sounded reasonable.

I am not trying to "Throw Water" on anyones endeavor. I do think anyone who wants to attempt case hardening though needs to fully understand it is not as casual a feat as for instance Rust Bluing & should definitely be interested in learning all they can about the process.

I suppose if someone asks a question, to which you have no idea as to the answer, just "Attack" the questioner is a viable tactic. Well for my part you just totally lost all my respect. As this thread started I was actually thinking you were a good source of some things I wanted to further learn on the subject. Missed That One BIG time.

PS; I have seen a case hardened part so full of cracks one had absolutely no need for a microscope, or even a magnifier for that matter to see them. It was a non gun related part & newly made, not an irreplacable antique.

PPS; Yes I am quite familar with Magna-Fluxing. This part didn't need it though to show up the cracks.

An old Mule trader once took some Black Polish & shined up an old decreptid mule. He then sold it to an unsuspecting Green Horn. Next day Green horn comes around & tells him, You know that mule you sold me Yesterday, He died last night. Old Mule trader says "Well, He Ain't Never did Nuten like Dat Afore.

OK, well it goes like this Doug...I was standing there and....

Actually...better not..:)

Miller:

Well, for my part, you lost all my respect about one and one half years ago, maybe one year ago on a similar thread regarding CCH......you came in with your same machine shop scenario and began an essay on critical temperature.......everybody else was wrong, but you were right.......that is the way it read......

I think you belong to a group that believes: --"if I have not experienced it, then it probably has not happened"........?.......Could be wrong, but your posts sure read this way.........

Sorry, but I think the information you seek is available at most libraries, electronic or otherwise and then you can complete your book or whatever the use is for the information you are gathering.....

Best,

We don't progress if we don't study and learn.
Disagreements should be settled as possible by facts. By evidence.
I'll ask Smith tomorrow about double heat treated parts and carbon migration. He's only heat treated a few Billion dollars worth of parts.
My guess at this time would be that for thicker parts, GM doesn't care. Samples are tested, accepted, rejected, or accepted and sent out for rework.
But I will definately find out.

A better discussion would be how to control colour pattern.

I'm glad for any feedback personally. I'm quite new here so suck it all up. I'd also be interested to hear about how to change pattern at some point.

Right now, I'm happy with my results. It looks like if I find guns to restore myself that any pattern changes are good! And as long as I find things that haven't already been re-coloured I'm in with a good set of tolerances ready for re-colouring.

Of course thing's could go wrong but I'll have to take that as it comes!

T

Doug;
I guess I just don't "Treat" the "Heat Treatment" of structural parts of a gun quite as casually as many do. I certainly have not "Claimed" to have all the answers. I personally do not consider "Myself" qualified enough to attempt to re-color harden a gun frame of my own. Questions I have raised are simply things I would like to know answers to prior to allowing anyone to do one of mine. I thought perhaps You had some of these answers, definitely appears I was Wrong Big Time on that.
Machinery's Handbook recommends a higher temp for for hardening than many today are using for color hardening, so again I ask;
What affect does this have on the hardening of the case?? I assume you do understand that when the part is carburized via heating in the carbon atmosphere to a temp above its critical temp, the deeper into the metal you go the lower the % of carbon added is. Charts are readily available, Done by Metalurgists which state the critical temp for carbon steels of varying carbon content, this is nothing I did or imagined. So I ask again "IF" you have carburized a part to a total depth of .010" & you subsequently heat & quench from a temp that has only reached the critical temp of the first .002" of that carburized depth, what portion of it will be hardened? Also what affect does this have on the integrity of the part.
My own personal knowledge is simply not enough to answer all this, So I "ASK" & then all I get for my troubles is a Personal Attack for asking. I guess essentially that tells me what I need to know, "You Don't Have a Clue" or you would have answered rather than attack the asker.

Miller-

I would guess you read ALL the previous posts, not sure......?...

If a metal lab inspects my parts and says the hardness depth averages 1.2 to 1.5 mm, then I believe their findings to be correct and valid, their x-ray and micron microscopes are quite accurate I think, since they inspect for hidden voids, blisters, structural integrity and the like, not only surface variation and hardness......and since all the parts pass mil spec S 6090A at the temperatures that I am using there is no further information that I require...... all the parts are approved for return to service, guns included, as per the lab......I don't know of any gunsmiths that use a lab for CCH, do you....?....I use it because it is owned by a close friend......

Since you appear interested in some more data, I suggest you take two Flues receivers that you mentioned, case one and run destructive tests on both receivers. You would need to crush both receivers in a press with meters and gauges attached. This would give you the 'structural' comparison testing you seek........A against B.....both from the same manufacturer, same alloy, same size etc......Or you could load both weapons to extremes with gradual increases until they explode and measure the results....Or you could just saw them in half and study the loop.......

Since you have NO clue what temperatures I am using, you therefore have no way to reference this information against your machine shop handbook and your charts and graphs........and since you have "never cased" one single part yourself, I don't think you understand what is involved....maybe as an observer....?.....Maybe your machine shop did not have a high tech aircraft metal lab.....?......Maybe you should read some books on aircraft inspection parameters first, then read your machine shop book.....?.........

Everyone has a different risk tolerance.
Investments to old guns, we are all different.

This is from the horses mouth. I trust him with my life.

Carbon is a solute in the steel solvent. It migrates above a certain temperature along a concentration gradient. If the temp is too low it doesn't migrate from the carbon rich pack through the carbon poor steel. As temp is raised, it migrates along a curve that looks like a hockey stick. Relatively fast for the first .025 and then ever more slowly across the cross section.
At 1650 degrees F, (his most common carburizing temp) he said we are talking hours and hours of soak time to allow, not push the carbon atom to migrate only a little further into the steel. Thousandths, not inches.
When asked about the effect of multiple annealings and carburizings, he said " The carbon equalizes above temp with the surrounding environment. So, if packed in a carbon poor environment for annealing, carbon atoms migrate toward the areas of lowest concentration from highest. Both a little deeper (as soak time permits) but mostly outward toward the low concentration packing chips."..."This leaves residual carbon atoms in the case, but they cannot be driven deeper until critical temp is reached in a carbon rich environment. There is not enough carbon in the surface to create the gradient necessary to allow the migration deeper. They will go "out" just as likely as "in" in this case. Leaving a piece of steel with a very low concentration of carbon in it. (Soft)

But wait, there's more.

The time gradient is different for thick or thin parts.
Here is the common ground for the bickerers.
Small parts can much more easily be hardened through with successive heat treatings. Leaving them brittle. They are easier to allow carbon to migrate through, and the distances are smaller. So, less time to equilibrate.
How small parts are packed and processed, he believes, should be different that the larger forgings.

Well, what about an action that was repeatedly heat treated?
In the annealing, the equilibration lowers carbon content to a low level. The next heating in a carbon rich environment slowly raises the carbon content from the outside in, and starts the gradient migration all over. It would take hours and hours to add a slight increase in depth from the prior state.
So, first the annealed part has to reattain where it was before, and then follow the time gradient to let carbon migrate a tiny bit deeper. Up until that moment, carbon atoms are as likely to migrate outward, as inward. The gradient favors outward until the previous percentage is attained.

Now here is where I blend in what Dr. Gaddy told me.
"Color hardening is very very thin."
"Microns thin."
That suggests to me a thin case on the part, and a much shorter time of soak than what Smith has been talking about.
Achieving a color case for decorative purposes does not allow carbon atoms to migrate very deeply into an action. Even if done multiple times. The times at temp are either too short, or temps too low.
Again, deeper for thin parts.

So, as a guy that doesn't have a kiln, I am guessing that most colorers bring a part up to a temp pretty quickly, soak it a relatively short time, and then quench it. Leaving a micron thick film of oxides, which is more decorative, than strengthening. A wear surface. Not strengthening.
The implied conditions followed don't allow for very deep penetrations. But, for all I know, you guys are soaking these actions for days and days, just in case. It doesn't seem to be necessary in order to create a decorative skin.

So, what do you think? Am I full of it?

You can always cut up an old action and look at it under a loop to determine case depth necessary. But I suspect that information is already out there.

Yikes. Didn't really intend for this thread to become quite so heated! (forgive the pun).

Actually all interesting stuff. It's fair to say what I am doing is surface colouring. However, due to the fact that my annealing is for 1hr also I think that's why I'm not so phased with warpage...I'm not going deep at all.

T

I think you are correct Tony.
The conditions you have suggested you are working at wouldn't seem to promote deep carbon migration.

Why don't you case a piece of 1020 an inch thick or so, and then cut it in half with a grinder? Bandsaw would toast the blade.
Then you could see with a loop how far in the carbon specks have migrated. Just for fun.

Nice idea I've actually got a square piece I put as a water displacer ahead of the parts..actually...hmm its still at the bottom of the tank...cheers

Wow, leave for a little while and come back to the set of the family feud

Thought we were having a decent discussion about Case hardening…so what happened?

Bottom line is that Case Hardening is really not voodoo, hasn’t been for a bunch of years.

Back when I first started CCH, those who knew how to do it…wouldn’t talk about it; and those who thought they knew…would tell you a bunch of crap.

That’s about when I started building my “Library”. I bought every period (1890-1920) book on case hardening/heat treatment of steel that I could find. I’ve got over a dozen books on the subject. Back then case hardening was a well understood process. Lots of research/data into depth of case correlation with carburizing temp /time /materials.

When carbon rich materials (in our case Wood/Bone charcoal) are heated, they begin to off gas carbon in the form of carbon monoxide and carbon dioxide. When steel is heated, it will absorb this carbon. Steel will begin to absorb carbon well below its critical temps, and can be hardened when quenched below its critical temp.

To me, the true “mystery/voodoo” is in the colors, Winchester v. Colt, Marlin, L.C.Smith, Parker, etc

V/r

Mike

Mike...

There are just so many people in this hobby that just don't understand this, of course all of them have never actually hardened a piece of steel........they probably never will and love to argue numbers and inject negatives....with a firm belief that we are somehow structurally weakening old gun receivers......and making them brittle, the most common phrase you hear from the uninformed.....

I don't think I have ever heard of an action that failed from bone/charcoal "re-casing"--(not counting the 'El Torcho method')--, there may be some out there done poorly and over heated that failed, I am just not aware of any in my travels......as long as the temperatures are kept within the envelope, the risk is held to a minimum IMO....

So, from a safty standpoint......there are many, many more shotgun barrel failures that are the result of grinding out the chambers and forcing cones and bores by the "barrel butchers" who actually remove lots of metal in different places.........IMO........

CZ...

"Well, what about the action that was repeatedly heat treated"...?....."It would take hours and hours to add a slight increase in depth from the prior state"..........

Very correct......at the temperatures we operate I think it would take quite a few re-casings before the molecular anatomy of an old gun receiver was destroyed.....and as you previously mentioned...most guns receive 'maybe one' re-case in their entire lifetime......

Best,

Mike, indeed!

Actually the thing is for me is that I get very excited about learning something new. My friends often think I'm a bit mad...I'm the guy that pulls out the 1911 20 bore at a clay shooting competition and shoots 20 out of 50 and people snigger...I don't care! I thoroughly enjoyed shooting that little gun. I had restored it and I loved doing it...I've got mates that won't pull out a gun because they might get laughed at with their score...how can one possibly learn if you don't try?

Anyway..I've researched and will continue to learn from people here Like doug, Mike, CZ and others...bring it on...I only hope people can see I'm trying to enthuse my passion...even though it might make some cringe..

Regards,
T

Tony:

And VERY WELL SAID....!........The people that don't take risks are the ones that stay "on the ground"........

Best Regards and Keep It Up Mate.......!.....

Cheers Doug. Actually sometimes people have some authority to taking a W.W. Greener and trying it first. That was a mistake...but hey...I've learnt from it and I've literally just turned of the kiln that is annealing the last of the parts. I'm meeting Graham Greener on Friday at the CLA fair here because he's been super helpful with the dating and how things should look...now if he says it's looking good I've GOT to be happy.

Doug thanks for the continued learned statements:)

T

Doug;
I relly don't know why you even thought I was making a personal attack on "Your" work, I did not intend to come across that way. I did indeed read that post & the depth you said you acheived. Now 1.2-1.5 mm depth is indeed good depth. I was in fact hoping you would come in & give us some more detail as to just how you acheived this. Also if perhaps with the connections you had if you had by any chance had an original part tested as to what was there before anything was done.
As you said I have no idea from what temperature you quench to acheive this depth of case. All I have ever seen on the subject is that in order for a low carbon steel to absorb the carbon it has to be above its critical temperature & that to harden any steel has to be quenched from above that temp. As it absorbs the carbon & the case acquires a higher % the critical temp is lowered. Now I have read accounts that "Some" doing color casing drop the temp prior to quenching, which supposedly assists in prevention of warping. Note I did not say you did this, or actually even state it was an improper method. I simply asked the Question "If" this would in fact result in hardening of the entire case or if it would only give hardeness to a very superficial layer of it.
I still want to know the answer to that. As the process adds the carbon from exposure to its surface it makes sense to me that the deeper into the case you go the lower the % of carbon will be.
I am thorughly convinced that re-casing a gun frame is a job that needs to be done "Right" or not done at all. Nota Bene (Note Well) I am not accusing yours of not being Right.
From your posts on this I felt you could likely answer some of my concerns, but rather than attemt it you just chose to make a personal attack on me. I Pounced Back, for this I do appoligize. Perhaps we can still act like men & have a meaningful discussion on this from which All can benefit.

No apology necessary Miller, thank you though sir.....like the Bible passages we all interpret words differently and I am sure I misread your postings.....?.........I took it as a personal attack (which appears all to common on this BBS) connected to Nitro's smart remarks.....probably my error......and my apology is probably more in order than yours.....so you have it.....

If you take a piece of low carbon steel (at or less than .03wt%C) and pack it in a rich solid carbon atmosphere of your choice and heat for a few hours you will easily attain a carbon depth hardness of about 1 mm.......so from there you, Miller, can work out what is necessary for a slight increase in dept.....

I think the original factories ran CCH at higher temperatures than most of us re-case today, key word here is re-case, therefore the original carbon depth already exists at about 1.2 mm or a little more IMO......I personally do not lower my temps prior to quench and find a lowering of temperature would be detremental to the whole process.....also detremental and key is to lower the crucible and drop the parts into the quench at the shortest possible drop height as the 02 rich atmosphere directly impacts carbon and colors........this is also another reason that I do not lower the temperature prior to quench......and have built special crucibles with an emphisis on this step..........the more 02 in the quench water the better.........

If time, temperatures and various mixtures of solid carbon rich additives are all monitered carefully, some very vibrant colors and uniform hardness can be achieved.....since most of us do not have extreme annealing times, most of the original carbon has not been removed IMO....of course, should you anneal for far too long, then most of the carbon would out gas as a result.....

Most of us keep records and know all our times, mixtures, temperatures and various patterns which satisfy the end result.........various experiments are tried to achieve different colors, but remember, each alloy of steel is different from manufacturer to manufacturer , what works for one, may not work for another....(records, records and more records)...and these alloys also can change from year to year even with the same manufacturer, CCH has and always will be like a snowflake....no two are alike............. this is truly the beauty and fasination of CCH for me........

Consistency on the hardness issue must be and is very consistent on re-cased items in my opinion.....some people I know heat small parts and quench these in a carbon rich medium, like various cyanide compounds........I personally do not like that process or the colors it achieves......I firmly believe in bone/charcoal and some secret sauces.....unless originally cased using the cyanide process, like Sterlingworths after 1912 or so, Savage, Sears, later Ithaca's etc....the cyanide process uses a lower temperature and the carbon layer will seldom exceed 1 mm and is not as uniform as the bone/charcoal hardness.........IMO........

I don't publish my times, temps and propriatary information that took me over 20 years to tweak, sorry, but I hope this helps in what you are looking for.....

Best,

Anyone ever cover the water with an inert gas flood? Argon, Nitrogen? You could open the crucible into an inert atmosphere.

I have not, but I would like to try it, probably with Nitrogen...or another inflammable gas that is heavier than air.....Very good suggestion CZ......

The drop is quick....but an inert gas cloud intrigues me.....Nitrogen will not freeze easily, or you could make it 'visible'.....a real fog.......

Best,

Very interesting but I don't have the means to do it. However I DO make sure that the quence water is as close to the bottom of the metal plate as possible so minimise air. We plunge extremely quickly by yanking out the slide plate...and make sure that their is plenty of carbon/bone charcoal around the pieces to case them as they drop in.

T

Actually that would be quite easy; Use Dry Ice (Frozen Carbon Dioxide).

Carbon Dioxide is Inert and heavier than air. I Thought about it a few times, but unless you are having problems with "flash" or oxygen gettig to the part before it's quenched, don't see much benifit.

V/R

Mike

One other curiosity I have is the effect of tumbling the coloured parts into the tank. Let them fall, and roll down an incline within the quench.

Figuring out traditional hardening patterns is a great curiosity to me. Like deciphering a recipe. Unearthing closely held secrets is part of the fun. Like a membership at a club. Oscar had a knack for it.

Marlin produced a silent documentary about their factory, circa 1922. Here are a couple of captures of the CCH process.









Pete

One of the issues when trying to “decipher” period case hardening is the very few pristine examples left to review.

Take Winchesters for example; I’ve been collecting pictures of “minty” (80% or better) Winchester case hardening. I would say that I have possibly 80-90 pics, of nice guns with lots of visible, original CCH. The pics are of models 1873s, 1876s, 1890s, 1886s, etc, kind of a mish mash.

But if you look at the numbers; if I had 80-90 pictures of just the Winchester Model 1886, Winchester produced 160K of those rifles alone, that 80-90 example would be less than ½ of 1% of total production. Not statistically relevant by any stretch of the imagination.

Guess what I’m trying to say is that most folks will see just a few minty guns, then try and compare, or mimic their work to mirror those few examples.

Occasionally I will get the customer that wants “real” Winchester colors …like they saw in some book. Really irritates me. For those customers, I will e-mail pics of some originals that are so different you would swear they were done by two different companies. I also have pics of guns where one side of the frame is almost barren of colors, straw with a few hints of blue… the other side looks like Picasso puked; full of reds, greens, blues, all factory original.

I will then ask the customer which colors he wants me to replicate; usually at that point they get a clue, for those that don’t, I generally tell them that I cannot meet their expectations.

V/R

Mike

........."Look Mom, NO GLOVES".........

Those receivers appear to be model '94 Marlin's with the small loading port and minus the bolt which was factory blued..........

I like his period silk backed vest and I like his hat too.....good CCH garb don't you think.....?........First cabin 1922.........

Yes no gloves.Yikes.

Intersting pictures thanks for those...do you have the video??

T

Hi folks, getting ready to CCH the rest of the Greener parts tomorrow! Latest blog has pictures and my latest commentry...

http://www.vintageshotgun.com/?p=618

Regards,
B

Hi folks, I've just completed my second and final case colour hardening for the W.W Greener. I've created a video which also has pictures of the final results. I'm EXTREMELY happy with the results of this one.

What is absolutely clear is that bolting parts to thick 4-5mm steal as a blocker/packer makes a huge difference to the quality and colour of the hardened pieces...tremendous difference...

Please take a look! Oh and no funny comments...I'm the guy sitting down at the table. I've just had leg surgary, in fact, lost my leg so that's why I'm doing the easy part...for now..

http://www.vintageshotgun.com/?p=630

Regards,

T

Yes, I have it. I purchased it a couple of years ago from the Marlin Collectors. Here is the contact I had at the time,
if any one is interested, Harvey Frakes MFCA 217-585-3454 between 6pm & 10pm CST

The CCH process is a small part of this silent 2 reeler (about 25 minutes total running time). They go through all the steps for making a Marlin at the factory. It is fascinating to watch.

Pete

Amen, only way to go with the small parts Tony....they look super, great job there Mate........

The thick plates act like a 'heat sink' and help transfer-retain heat to the smaller pieces.....

So which 'barn' are they moving you to.........?.........

Best,

Thanks Doug! Really pleased with the results. We live on a farm so have 3 to choose from. From the wifery perspective probably the farthest away!

Will post the pics here too when I get a moment.
T

T-

If you have any more pieces to case, or on the next gun, since you live on a farm, try adding a little 'hoof' material here and there in your crucible.....evenly spaced pieces top to bottom.....I think you may like the results.....?......

Best,

Doug, very interesting. Marie my wife has two horses...can we take the clippings when it's next shod and add those in? sounds intriguing. Is this what you are suggesting?

T

T-

Yes, horse clippings are good, three or four golf ball size chunks cut in half would be good for your size cannister/crucible......for more substantial pieces you could go to a cattle slaughter house if one is nearby or dairy farms that have some dead cows.....?.....The material keeps for a long time obviously......


Best,

I've read that some gunmakers would urinate on the bone and wood charcoal pack in their crucibles before it went into the furnace. Supposedly this enhanced the colors. Have you heard of this or tried it?

A word of warning though... When I worked in a blast furnace years ago, sometimes someone would piss in the coke dust that lined the iron runner. When the molten iron hit it, the resulting odor from the superheated human urine was worse than a herd of skunks.

Yes Keith, Barrel Browner in the UK mentioned it on page one of this thread.....above is that posting......

Best,

I have a new toy to CCH....I've added a new post to that effect..

T

I live in cattle country, and have a few horses. I have tried hooves, raw bone, leather, etc; they will all work, …. Just some thoughts:
One of the issues with using raw products is the fats, oils and waxes that can cause havoc during CCH.
Hooves have a lot of crap in them…literally. Also imbedded grit, sand stones etc.
Burning raw materials will smoke and stink to high heaven. A smell that you will not likely enjoy nor forget so do it outside, downwind.
As I stated earlier, I talked with quite a few folks with lots of ideas/opinions: leather, horn, use only pig bone, urine, peach pits, …eye of newt etc. I could go on and on. Bottom line is that they were either clueless or were leading me on a wild goose chase.
In my humble opinion, the material needs to be well charred to remove any of the fats, oils, waxes etc, at that point the material is charred enough, and it becomes charcoal, and is basic carbon.
Again, I’ve been doing this for about 10 years, the conclusion that I have come to is that, you can get acceptable repeatable results with just bone & wood charcoal by varying the bone to wood ratio, quench temp, blocking and quench water temp.

Hello Tony, nice background music!!

tunes

Mike, I've had pretty good luck with hoof material as a 'supplement', it does indeed stink because it is a natural carbon material....I didn't find the smell that radical though....(not like Auschwitz or anything).... I did clean it, saw it and place it properly against the outside walls of the crucible.....JMO.....

The leather and horn are old recipes like the hoof material, the other stuff you mention are all over the top I think.....

Best,

Mr.Hunter is correct about carbonising natural materials for CC Hardening.

Preparing hoof and horn parings, leather and bone for colour case hardening can really make you very unpopular with the neighbours. The stench can be abominable.

I have managed to get around this by packing the material into a short (6-8 inch long) length of steel pipe threaded both ends and fitted with cap ends, one of which has a 1/16" hole drilled in it's end. A Plumbers Supply Co, should have varying diametres of pipe nipples and cap ends readily available.

The loaded pipe(s) are put into a hot woodburning stove (or an old modified caravan sized gas bottle (usually available at the local dump) fitted with a door, a tall vent pipe and air holes near the base) a fire is kindled and permitted to get burning well. Soon the volatile gasses are being given off and pass out of the pipe(s) via the small hole. The flames ignite the gasses which burn freely. The stove pipe carries the burnt gasses mixed with those of the burnt wood into the atmosphere.

If you use a sweet scented wood like pine for the fire, no one knows there is anything untoward going on. When the fire has burnt out remove the pipe and let cool, or better, leave it in the stove until the following morning, then empty the pipes contents into whatever metal container you are using to store the carbonised material. If your using a none metalic storage container, make very sure the carbonised components are stone cold.

Use the largest diam. pipe you can get(that will fit easily into the stove). It's surprising how little carbon there is after the carbonising process is complete. The larger the pipe the more material you can process at any one time.

Harry.

Interesting chaps. Are you saying one should burn/heat the hoof material prior to putting it in with charcoal. These ideas are definately for my testing actions first off

T

Hello T.

The idea is to soak the parts you want to colour case harden in an rich Carbon Dioxide gas. Heating previously prepared carbonised items such as wood, bone, leather, horn and hoof material will provide such a carbon rich gas.

Using unprepared or none carbonised components in the crucible, will upon heating, produce a great many different gasses, some of these may be beneficial to the CC hardening process, BUT, some will not.

Perhaps it's best to go with the traditional methods of CC Hardening.

Having said that, as the Bard said, 'You pays your money and takes your chances'

If you want to experiment, by all means do so.

Harry

Interesting Harry. Will give this a try...live in the middle of nowhere with no neighbors so will just burn it:)