Should I harden this hammer?

[Ed C.]

To make this story short, I ordered a LH 1.75" throw hammer from TOTW for my Investarm Hawken and nothing was right with it. The whole geometry was off. After about a half dozen trial and error sessions of heating and bending and finally taking a dremal to the hammer face to give it proper alignment to the nipple face and grinding metal off at the top of the neck, that was hitting the stock and preventing a full fall, it works. I was using an oxygen acetylene torch so I was able to get it very red very quickly. My concern is, with the repeated heatings and taking metal off the upper neck, is that hammer now weakened where I should try to harden it or just go with it as is. Would have been nicer to have been able to find a direct replacement LH Investarms hammer.

 

[rich pierce]

Annealed is fine.

 

[Ed C.]

Annealed is fine.

Annealed it is! So I went ahead and blued it.

 

[M. De Land]

To make this story short, I ordered a LH 1.75" throw hammer from TOTW for my Investarm Hawken and nothing was right with it. The whole geometry was off. After about a half dozen trial and error sessions of heating and bending and finally taking a dremal to the hammer face to give it proper alignment to the nipple face and grinding metal off at the top of the neck, that was hitting the stock and preventing a full fall, it works. I was using an oxygen acetylene torch so I was able to get it very red very quickly. My concern is, with the repeated heatings and taking metal off the upper neck, is that hammer now weakened where I should try to harden it or just go with it as is. Would have been nicer to have been able to find a direct replacement LH Investarms hammer.

Well, if it was hardened originally then it should be again in my opinion. I'd call the dealer and learn what the steel alloy is. It may be alright in the annealed state if it does not have one of those skinny necks like some of the flint cocks have.
I've found that when the whole hammer is annealed and left soft that they can develop looseness over time where the square and very hard tumbler head fits through the hammer purchase , a skinny neck that can easily take a bend and the nose deformed from impacting the hard nipples .
I recently checked a cock on a Muruku made flint gun and it had been strength hardened but not case hardened from what I could detect from a file test and then with a spring loaded prick punch compared to annealed carbon steel. It has a very skinny neck and needs the strengthening that hardening and temper drawing can provide.
Originals that were case colored were hardened. Folks seem to forget that the color resulting from case hardening is only a pleasant side effect. The purpose and reason for the case hardening was/is to strengthen the steel and the temper is drawn to remove the brittleness.

 

[Ed C.]

Well, if it was hardened originally then it should be again in my opinion. I'd call the dealer and learn what the steel alloy is. It may be alright in the annealed state if it does not have one of those skinny necks like some of the flint cocks have.
I've found that when the whole hammer is annealed and left soft that they can develop looseness over time where the square and very hard tumbler head fits through the hammer purchase , a skinny neck that can easily take a bend and the nose deformed from impacting the hard nipples .
I recently checked a cock on a Muruku made flint gun and it had been strength hardened but not case hardened from what I could detect from a file test and then with a spring loaded prick punch compared to annealed carbon steel. It has a very skinny neck and needs the strengthening that hardening and temper drawing can provide.
Originals that were case colored were hardened. Folks seem to forget that the color resulting from case hardening is only a pleasant side effect. The purpose and reason for the case hardening was/is to strengthen the steel and the temper is drawn to remove the brittleness.

It was not hardened originally as I did some work on it with a file. TOTW advertised it as wax cast. I did not thin the shank but did remove some of the metal at the neck right where it meets the hammer as it was hitting the stock and stopping the fall of the hammer. The bottom drive section never got that hot. It was clamped in aluminum jaws and I was able to quickly heat basically only

the section I wanted to bend which was the upper neck and hammer. But I did have to heat it about a half dozen times before getting the hammer right. That is what concerns me. I was actually concerned that hardening the hammer might wear the tumbler square if I hardened the hammer. I can heat and quench it in just a few minutes and temper it in the oven afterwards, no problem. I have no experience here at all so am relying on those that do. So I guess I'm asking, "What would you do?"

 

[Artificer]

It was not hardened originally as I did some work on it with a file. TOTW advertised it as wax cast. I did not thin the shank but did remove some of the metal at the neck right where it meets the hammer as it was hitting the stock and stopping the fall of the hammer. The bottom drive section never got that hot. It was clamped in aluminum jaws and I was able to quickly heat basically onlyView attachment 185709 the section I wanted to bend which was the upper neck and hammer. But I did have to heat it about a half dozen times before getting the hammer right. That is what concerns me. I was actually concerned that hardening the hammer might wear the tumbler square if I hardened the hammer. I can heat and quench it in just a few minutes and temper it in the oven afterwards, no problem. I have no experience here at all so am relying on those that do. So I guess I'm asking, "What would you do?"

Original Percussion Hammers were originally case hardened Iron and much later made from steel. The casehardening assured the hammer didn't wear out too fast in the square hole for the tumbler and the face of the hammer didn't batter too quickly from hitting the cap and cone/nipple.

I would ask TOTW what steel it is made from and use your furnace to thoroughly case harden it.
Gus

 

[M. De Land]

It was not hardened originally as I did some work on it with a file. TOTW advertised it as wax cast. I did not thin the shank but did remove some of the metal at the neck right where it meets the hammer as it was hitting the stock and stopping the fall of the hammer. The bottom drive section never got that hot. It was clamped in aluminum jaws and I was able to quickly heat basically onlyView attachment 185709 the section I wanted to bend which was the upper neck and hammer. But I did have to heat it about a half dozen times before getting the hammer right. That is what concerns me. I was actually concerned that hardening the hammer might wear the tumbler square if I hardened the hammer. I can heat and quench it in just a few minutes and temper it in the oven afterwards, no problem. I have no experience here at all so am relying on those that do. So I guess I'm asking, "What would you do?"

 

[M. De Land]

A decent file will cut into steel less hard than it is so the hammer can be strength hardened and still be marked by a file corner. A file check on good deep case hardening will ruin the file corner but not all parts are case hardened.
Some are differential hardened and some are oven hardened clear through and have the temper drawn back to leave a specific hardness number. The best way I know of short of a commercial metal tester is to use a spring loaded prick punch and do a test prick on the back of the hammer that won't show then do another in an annealed piece of the same kind of steel. Now compare the dent diameters and distortion with a caliper.
If you call the manufacture then ask to talk to one of the technicians who should be able to tell you what kind of steel it is . The kind of steel is important to know because each has a best heat treat protocal that should be followed for a good result.

 

[rich pierce]

It’s not made of steel with enough carbon to harden. The case hardening powders like Kasenit won’t do much to prevent impact-related deformation because the hardening is only 0.001-0.003” thick. Old time pack case hardening put a much thicker hard skin on iron or mild steel.

Kasenit and such is good for bearing surfaces.

 

[Dale Allen Raby]

First, the obvious question: if the lock was defective right from the manufacturer, why did you not return it for a replacement? Now you have voided the warranty and thrown away any chance of replacement... though I guess there is no harm in asking them about it anyway.

Now, you don't really know what kind of iron alloy the hammer is made of, so it is hard to know if you will be able to do anything with it. If you've got even a medium carbon steel alloy and you quench it from red heat, it may crack in the quenching process. There are even air-hardening steels that don't require the quench to harden. If you take a hardened hammer and drop it on a cap, it may well shatter like glass. I once had a piece of spring steel (which I had mistakenly thought was mild steel) shatter into several very hot pieces on my anvil in front of the spectators watching my demonstration. They thought it was amusing... especially when some of the pieces ignited the rubber floor mat I was standing on.

Try to get the lock replaced first. If you can't, then heat it up, bend it as needed and let it cool slowly. Don't try to harden it unless you also want to temper it. Others have given you ideas on how to test for hardness... these are not without merit. That said, you really don't want a hammer to shatter under impact a few inches from your face.

 

[Ed C.]

First, the obvious question: if the lock was defective right from the manufacturer, why did you not return it for a replacement? Now you have voided the warranty and thrown away any chance of replacement... though I guess there is no harm in asking them about it anyway.

Now, you don't really know what kind of iron alloy the hammer is made of, so it is hard to know if you will be able to do anything with it. If you've got even a medium carbon steel alloy and you quench it from red heat, it may crack in the quenching process. There are even air-hardening steels that don't require the quench to harden. If you take a hardened hammer and drop it on a cap, it may well shatter like glass. I once had a piece of spring steel (which I had mistakenly thought was mild steel) shatter into several very hot pieces on my anvil in front of the spectators watching my demonstration. They thought it was amusing... especially when some of the pieces ignited the rubber floor mat I was standing on.

Try to get the lock replaced first. If you can't, then heat it up, bend it as needed and let it cool slowly. Don't try to harden it unless you also want to temper it. Others have given you ideas on how to test for hardness... these are not without merit. That said, you really don't want a hammer to shatter under impact a few inches from your face.

Now we get into the longer version of this story. On the new gun I needed to move the hammer inboard and forward for a more proper strike on the nipple. 1 out of three shots was a misfire. I was afraid to try any bending on the factory hammer so I deepened the lock inlet which took care of the side to side problem and dremeled the cup wall on the hammer and that barely clears the cap going forward and now it goes bang so I'm still good on the warranty. Having bought several Italian BP revolvers I've gotten used to the idea that something will need to be fixed or adjusted on new guns which I'd just as soon do myself rather that going through the hassle of sending it back. In the meantime I did want to play with fitting a hammer for the experience so I ordered the hammer we are talking about as a learning experience. It was good for that requiring several sessions of heating and bending and grinding the hammer face at an angle to square up with the nipple. The shape is now very functional. Question is, have I softened it with all the repeated heatings and if it is mild steel (I do have an inquiry in to TOTW) not much I can do anyway. I only have a torch and my kitchen oven to work with. Would heating and quenching in used motor oil with ground up charcoal do any good or just be a waste of time? And yes, I'd rather have a hammer that fails by bending then shattering in front of my good eye. Thanks for you prospective on this.

 

[Ed C.]

A decent file will cut into steel less hard than it is so the hammer can be strength hardened and still be marked by a file corner. A file check on good deep case hardening will ruin the file corner but not all parts are case hardened.
Some are differential hardened and some are oven hardened clear through and have the temper drawn back to leave a specific hardness number. The best way I know of short of a commercial metal tester is to use a spring loaded prick punch and do a test prick on the back of the hammer that won't show then do another in an annealed piece of the same kind of steel. Now compare the dent diameters and distortion with a caliper.
If you call the manufacture then ask to talk to one of the technicians who should be able to tell you what kind of steel it is . The kind of steel is important to know because each has a best heat treat protocal that should be followed for a good result.

I have started an inquiry to TOTW. Past that I don't know who manufactures the hammer. I like the pin punch idea for checking hardness. That seems like a good tool to have. I only have my torch and kitchen oven to work with so I am limited to just a crude heating and quenching with some 3-400 F tempering afterwards.

 

[Dale Allen Raby]

Now we get into the longer version of this story. On the new gun I needed to move the hammer inboard and forward for a more proper strike on the nipple. 1 out of three shots was a misfire. I was afraid to try any bending on the factory hammer so I deepened the lock inlet which took care of the side to side problem and dremeled the cup wall on the hammer and that barely clears the cap going forward and now it goes bang so I'm still good on the warranty. Having bought several Italian BP revolvers I've gotten used to the idea that something will need to be fixed or adjusted on new guns which I'd just as soon do myself rather that going through the hassle of sending it back. In the meantime I did want to play with fitting a hammer for the experience so I ordered the hammer we are talking about as a learning experience. It was good for that requiring several sessions of heating and bending and grinding the hammer face at an angle to square up with the nipple. The shape is now very functional. Question is, have I softened it with all the repeated heatings and if it is mild steel (I do have an inquiry in to TOTW) not much I can do anyway. I only have a torch and my kitchen oven to work with. Would heating and quenching in used motor oil with ground up charcoal do any good or just be a waste of time? And yes, I'd rather have a hammer that fails by bending then shattering in front of my good eye. Thanks for you prospective on this.

If it is mild steel, no amount of heating and quenching will do anything to it as far as hardening goes. You could potentially use a product called Kasenit (not sure of spelling) to case harden your hammer. This is a long process involving hours at high heat. If you have a coal furnace, a box forge and/or a kiln, you could potentially do this, but if it came from the manufacturer not being hardened, then there is no need. If it was case hardened when you got it, then you could potentially quench it in oil or something to re-harden it at the risk of cracking it. Case hardening of parts like this is mostly color case hardening and done only for decorative purposes.... sometimes it isn't even real case hardening.

Personally, I would leave it as it is now, install it and use it.

Some years ago I was at a blacksmithing exhibition with another smith who was then in his late eighties. Someone brought a heavy draw-bar that was bent like a pretzel. It was about four inches wide and maybe an inch and a half thick. He wanted us to straighten it.

I looked at the other smith and said, "I hope you brought a heavy hammer."

As it turned out, neither of us had anything heavier than a three pound cross-peen. We got the heaviest anvil we had, heated the draw bar up and team-hammered it until it was straight. We laid it on the concrete floor to cool. Then the question of hardening came up. In the end, we figured that it had never been hardened in the first place or it would have broken rather than bent.

Before the owner left with his draw-bar, I advised him on the use of a clevis to prevent the drawbar from turning in the three-point-hitch arms.

We charged him $40.00 for the work, The advice was free.

 

[ZUG]

Leave it be --- just use it as is. Muzzle loading parts from early times were made of IRON and the parts were SOFT so they case hardened them. The STEEL that our parts are made of NOW are MUCH harder and tougher than of the past. USE AS IS

 

[Ed C.]

"A little knowledge can be a dangerous thing!" Thanks for all the advice that is making this decision easy now. As much as I would like to have a properly hardened hammer, without knowing the carbon content of the steel, me not really knowing what I'm doing, and having only my torch and the kitchen oven to work with, it seems I'm much safer not trying to put it through a hardening attempt. So I'll consider this project done. I did grind a hardware store screw driver, heat treated it and tried to anneal it but I guess not good enough as it finally shattered on a tough screw.

 

[Dale Allen Raby]

The process to harden and temper steel is as follows:

1. Heat to cherry red.
2. Quench in either water or oil, depending on the carbon content... oil is easier on the metal but will burn, so be careful.
3. Polish metal until it is silver.
4. Slowly heat it starting, in the case of the screwdriver, at the handle end. Colors will form on the metal, it looks kind of like a rainbow. You want to stop heating it shortly before the tip becomes straw yellow. You can quench it, but I usually like to stop early and let it cool slowly so that the colors remain afterwards. If you quench, the colors may sort of flake off.

This is a very simplistic version of the procedure. Hardening is relatively easy, tempering, not so much.

 

[Ed C.]

TOTW did respond. Said it is most likely 8620 steel.

 

[LRB]

A good steel for a gun hammer. Its tough and ductile with low carbon but has good manganese, chromium, nickel, molybdenum and is a good choice for case hardening if you ever wanted.

 

[Phil Coffins]

TOTW did respond. Said it is most likely 8620 steel.

8620 was developed for case hardening of parts made from it. You will get years of use without case hardening it but better if case hardened. I’ve done this many times but having the back ground and equipment makes it easy.
AA0149F3-4E50-45BB-8CAC-B4D4D9909E96 by Oliver Sudden, on Flickr

 

[M. De Land]

To make this story short, I ordered a LH 1.75" throw hammer from TOTW for my Investarm Hawken and nothing was right with it. The whole geometry was off. After about a half dozen trial and error sessions of heating and bending and finally taking a dremal to the hammer face to give it proper alignment to the nipple face and grinding metal off at the top of the neck, that was hitting the stock and preventing a full fall, it works. I was using an oxygen acetylene torch so I was able to get it very red very quickly. My concern is, with the repeated heatings and taking metal off the upper neck, is that hammer now weakened where I should try to harden it or just go with it as is. Would have been nicer to have been able to find a direct replacement LH Investarms hammer.

I've done quite a bit of case hardening after study of Oscar Gaddy's writings on the subject along with the Brown shot gun family of England. Coupled with my own experience of case hardening gun receivers with bone and hard wood charcoal I have garnered a pretty fair grasp of what and how things work and what to expect.
Mauser smokeless guns were equivalent 10 series steel alloys with some manganese and silicone added for strength and machine ability if memory serves but were designed as case harden-able alloy.
Julian Hatcher's book has good details on the heat treat protocols.
Mauser case depth for 48K pressure level was a nominal .012 on average where as case color depth is generally no more than .003-.005. Colors start south at about 1400 F. from my experience.
This is quite adequate for black powder and low smokeless pressure but wholly inadequate as the pressure goes up.
To get in the .012 case depth one needs 1550-1600 F. with a quench in oil as water will often crack them at this heat.
Now that I've glazed your eyes over with boring facts let me finish by saying case color heat treat depth is fine for the hammer in question and should be applied for best result. Original locks,hammers and cocks were hardened!