doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com Hardening cheap hammers

I have a CZ Hammer Classic, made by Huglu, for shooting steel and after making a few modifications (lightening triggers, opening up the tight pistol grip to POW) I have been happy with it. However, the hammers are poorly hardened. The left barrel stopped firing some time ago due to slight peening of the original hammer's nose, and now the right hammer has peened and only dents the primer. CZ-USA cheerfully sends replacements and I am waiting for the new one.

I am wondering if I should try to harden them. I have hardened a few screws with a propane torch, but am otherwise inexperienced. I know nothing about the steel.

Advice, please? Many thanks.

Kutter probably has a better way, here is my way.
Make sure the new hammers fit. Heat the new hammers to a bright red, quench in oil.
May be 4140 castings. Check hardness with a file. If hard, polish bright and reheat to a blue.
If soft after quench, caseharden the hammer nose with Kasenit, Cherry Red, Hard-n-Tuff (what ever you can get) according to the instructions.
Should hold up better. Different process for hammers with sear notches.
Chuck

Wish we could know if the factory corrected the mistake on the first hammers. If they fixed the problem messing with them now would not improve anything. I guess I would compare the hardness of the new ones by filing on an out of sight area. If the replacements are no harder, what to do with an unknown steel is a problem.
If a spark test maybe on one of the old ones might indicate the carbon content. If it is low carbon steel case hardening may improve things.
These 2 recent threads in a machinist forum maybe helpful:
https://www.practicalmachinist.com/vb/gu...ccesses-384163/
https://www.practicalmachinist.com/vb/ge...estions-383361/
In the past I have sent tools out rather than mess with case hardening. Even with an oven now I still have sent case hardening work out.

Chuckster's plan is not a bad one. I would do a file test in an out of the way spot just to be sure a known problem was not already fixed. So many ways to skin a cat.

Take some advice from a long-time Journeyman welder- propane by itself won't achieve the heat for hardening, case or through--Propane with oxygen, like the scrap yards use for rough cutting, is OK- but nothing beats acetylene and oxygen- delivery pressure and tip size, even up to a rosebud in size, is always your best call- You mentioned the hammer faces "peening"-- and light strikes on the primers-- Huglu--?/ Turkish mfg.. How about the firing pins, especially the face where the hammer face makes contact. Are the fp holes rough or out of round>Are you shooting factory new shells, or reloads? Just wondering is all. RWTF

Thanks all for the good advice.

When I asked CZ USA about hardening the hammer, they said it might be a good idea, so they are aware of a QC problem. Foxy, the firing pins and holes are fine, it is the hammer noses that are peened. It has been happening with both factory shells and reloads.

When I pull up photos of these guns it appears that the complete action is casehardened, as I can see the colors on the action. The photos, however, are not close-up enough for me to be able to tell for certain if the hammers are, but they look to be. If so, it makes me wonder if something like Kasenit will help the problem, and what heating to cherry red will do to the existing colors.

How many rounds does it take to get the hammer peened to the point that it is unusable?

SRH

This problem is a trip back to the 1970s for me, remembering those low price not so good Spanish doubles that hit the shops here. The steel used was a little like toffee, so it was either the strikes turned into Mushrooms or the hammers had deep indentations where they hit the striker top.
My cure for the hammers was simple with them being soft I would file a recess in them at the striker position, then hard solder a piece of HSS (high speed steel) into the recess and grind to shape. A word of caution if the striker steel was not up to a decent standard you would end up with mushrooms in time, so I did replace the strikers as well to stop a return problem causing more work. But striker replacement in this case may not be necessary. In the way of gun faults this is a simple fault needing a simple repair.

"Cheap' gun hammers and internal parts in general are usually case hardened low carbon steel. Usually a very thin case.

Check an edge on the part with a not-so-good file and see if you can file thru a thin case and into the soft core. If you can then there's your Case Hardening.

If the part had been made from through-hardening steel to begin with, the red heat and then cold quench needed for the C/Hardening would have 'through hardened' the part and you would have not found a Case.

If proper steel for and then through hardened and then possibly drawn back too far leaving it too soft for the job,,it would be just that,,too soft over all and no 'case' would be detectible on the surface,,thin or otherwise.

I usually just reshape the part if possible and then re-case with Case-n-ite.
Wonderful stuff, hard to get now. But the Cherry-Red case hardening powder works the same way. But I'm told by those who actually understand these things that Ch/Red hardens by using a Nitride (?) instead of a carbon infusion.
Makes the planet safer.

The CH on many of the inexpensive guns parts, and some of the not so inexpensive gun's parts, is very thin.
It's OK for sliding surfaces, but when battering takes place it simply crumples inward and is not of much help in keeping the surfaces shape.

A deeper case helps and you can get one with the above simple methods, but you need enough heat to do so.
Plain propane will do on small lightwt parts like a firing pin, screws, ejectors, sears ect.
A hammer starts to be too much for the small flame and you can't keep the part at red heat over all while the powder melts on the surface very well.

Oxy/Propane will do nicely for this.
O/A no problem but just be carefull you don't let the temp get too high and that bundle of melted powder with your part inside gets a little too brite in color/temp. It can melt away in an instance due to inattention.

The powders are also nice in that you can harden a specific area on a part (sear nose & pivot area for example) by just letting the powder adhere and melt onto that area.
The rest of the part (sear arm in this example) will remain in the soft state if that is what you desire.