Gun hammer

What material should i use for the hammer on a gun

Part thickness is .156

Should it be heat treated.

Thanks

Hammer

Type of gun Semi automatic shotguns.
That's all the information I have.


QUOTE=thermite;1900295]If you do not know, or cannot be bothered to tell us WHICH 'gun', or at least the type and calibre (.25 Browning ACP?, Mk7 16"-50?), then the safest answer is possibly 'steel' and in the form of a diligently applied 12-pound sledgehammer ....so it does not become a safety hazard.

Problem solved. Sub a chocolate shake for the cola, and no salt on the fries, please.

Bill[/QUOTE]

As a rule any good tool steel. A2, O1 or D2 taken to about 55 Rc. It does of course depend on the gun. Handgun hammers are often 60 to 70 Rc as they are lighter and have a much harder attack. So are double rifles with side locks. External hammers are generally heavier and much softer because their added weight would break them if they were to hard. Many large hammers of old design should be double heat treated with a thick shell of 70 or 80 Rc and a soft core of 40 to 50 Rc to keep them from breaking and disfiguring from impact. Its not a simple science. You can have the old one tested or make an estimate from the make model and general design.

Question 1 - material selection

Question 2 - do you heat treat.



Lets go in reverse order - heat treating is used to alter the strength and hardness of a material. In this case, you probaly want to know if more hardness is needed. The answer is depends on what the hardness of the base material was. If you started with a normalized or annealed bar, chances are it will need to be hardened to keep it from bending or mushrooming in use. Hard parts are also more resistant to ware.

The comprimise is that they loose ductility and the ability to absorbe the energy from impact loading. This is why dry firing a gun is a big no no.

Semi auto and full autos go throug a lot of rounds and the fireing systems take a beating. Heat treated parts are the norm. Turn of the centrury Belgan made shotguns (hardware store specials) are often encountered with mushroomed hammers, indicating a case hardening or no heat treating at all.

Material selection -
The choice of material is a bit dependent on the application. Parts in the thickness your looking at will through harden so long as you have enough carbon in the alloy to do the job. Even a basic 1045 steel would do. The benefit to going to higher alloy content steels, like a 41 series or A2 or O1 is you can be less radical in your quenching. Parts that are cooled slowly generaly have less distortion and are less prone to cracking.

Many alloys are available in a quenched and tempered condition that is machineable. The hardness of an alloy is dependent on its carbon content, how long it was tempered and the temperature it was tempered at. Carbon content drives the maximum hardness the alloy can reach. Tempering reduces the hardness and increases the toughness.

If your quenching a small sphere, it will cool uniformly. If your quenching a part with a lot of thickness variation and sharp corners, it does not cool evenly and reducing the cooling rate helps keep it intact.

Another factor to consider is that many popular tool steels are available mail order in small quanities and in precision ground bar stock. For one off gun parts the aditional cost is small and the convienence is often worth paying for. If your making a million of them, every cent starts to count and you can afford to put a few extra bucks into your process and reduce the raw material cost.