firing pin material

[76shuvlinoff]

Folks,
I have an old Wards Hercules single shot 12 gauge from Dad that a machinist buddy made a firing pin for. I carried this thing for years when I was a kid. Touched a couple off tonight and it works fine but the question came up as to what material one should be using to make firing pins and neither one of us knows. Thought I'd ask here.

Mark

 

[Dave P]

I would use steel.

 

[Jim Watson]

My guy likes the Fatigue Proof steel from Brownells.
Their stock number 080 531 000AE for assorted sizes. Kind of expensive, but tough stuff.

 

[230RN]

Whatever is in it, have him make another for a spare. This one may last for a significant portion of forever, but just in case. After all, the other one, the factory original, may fail in the same way.*

There's a lot to be said for regarding firing pins, extractors, and springs as consumable items.

Terry, 230RN

* ETA:
On re-reading the OP, I note the shotgun in question is a single-barrel. My bad.

 

[vongh]

If I were to make one I would use 1095 drill rod than heat treat than oil quench to harden the outside.

 

[shooter1niner]

If I had to make one from material found around the garage I would use a grade 8 bolt.

 

[Steel Horse Rider]

I have made a couple firing pins for different guns over the years and I have always used O-1 tool steel. Heat treat and then draw it back at about 600 degrees. Not too hard and very durable.

 

[danez71]

I've read people modifying a drill bit, wire spring steel, and a nail.

 

[alsaqr]

For over 60 years i've used old push rods from auto engines. Tempering is not required. But most push rods will take tempering.

 

[Carl N. Brown]

Worst material for firing pin is cast steel says this CZ52 owner I ordered two spares.


230RN: "... have him make another for a spare ..."

I had a firing pin break on a Marlin .22 in the 1960s and ordered two: one replacement and one spare. Still have the spare in my parts box. I am still convinced, if I bought only one, the one replacement would have broken by now.

 

[230RN]

Carl N. Brown commented,

I had a firing pin break on a Marlin .22 in the 1960s and ordered two: one replacement and one spare. Still have the spare in my parts box. I am still convinced, if I bought only one, the one replacement would have broken by now.

That's like losing an item, looking everywhere for it including the use of magnets and bright flashlights and invoking St. Anthony, so you go out and buy another and when you get home, you trip over the original just as you step in the door.

It's called the "Perversity Of Nature" (PON) effect. Einstein was wrong. Nature is perverse.

Terry

 

[tark]

I have made firing pins for many guns over the years, including the six built from scratch firearms I have made. I use drill bit shanks. I do not machine them to size, they are too hard. I belt sand or grind them. I have never had one fail.

 

[Speedo66]

A common nail worked for years in an old single. May still be working for all I know.

 

[ljnowell]

For over 60 years i've used old push rods from auto engines. Tempering is not required. But most push rods will take tempering.

For firing pins? What about the hollow center?

 

[Deus Machina]

In any endurance application, I'm a fan of O1 tool steel. In large part because it's durable as all get-out compared to anything I had, relatively machinable before hardening, and I could harden and temper it myself with what I had in the garage.

I've tried grade-8 bolts on stuff, but it seems less durable (still plenty for a lot of stuff) and a quick way to wear down my cheaper tooling.

 

[rcmodel]

HS Drill bit shanks are as good as you can get in most Junque collections in most home workshops.

Don't over-heat them grinding them and you are GTG.

rc

 

[76shuvlinoff]

We work for a plastics factory so thru hardened pins the right diameter are easy to find, that's what he went with. I was wondering if that might be brittle but figured it was better than the one I had hand whittled out of a grade 5 bolt.

This old single had a 30" barrel with a nice bulge in it at 20" so now the barrel is 19", I put the bead back on it. Long before I existed it belonged to my wife's grandfather who traded it to my dad for a pile of scrap steel so it's just a sentimental thing. I need to strip the rustoleum rattle can paint job off it and try my hand at PermaBlue .....and there's a chunk missing out of the buttplate. It's worth about $5 but it's tight, it might get fired a couple times a year.

Thanks for the responses

 

[ApacheCoTodd]

Drill shank vote here.

If it is not over-heated in shaping the pin then no need to worry about; tempering, hardening, annealing or any of those other mystical, metal forming practices.

As with extractors and ejectors, I always make two when doing these.

Just a little "white magic" insurance - I don't recall ever needing the second one, but the number of times someone else has had a requirement for one within a year or two has been amazing.

"Hey Todd, didn't you make an extractor for your model 1922?....."


Somehow, it's considerably less frustrating to toss the extra at a pal than to try to re-visit making one just for him.

Todd.

 

[antiquus]

Any of these will work fine. The best steel would probably be S7 which is the kind of shockproof steel used in things like pneumatic chisels. But firing pins aren't all that stressed, so as several mentioned O-1, which is an oil hardening tool steel you can heat treat with a propane torch (for small parts) would work great.

Drill blanks are interesting because the end that goes into the chuck is drawn back a lot to nearly soft, while the steel gets progressively harder towards the part of the drill bit that has the spiral flutes, so depending on where you cut it from you could vary hardness and the bonus is no heat treatment required.

Other steels I'd look at are 1095, which is just a plain carbon steel but very workable, 440B & C stainless which are hardenable, and if you can case harden then about any steel including cold rolled and structural steels will work, drawn back sufficiently to give it strength.

I would say that any firing pin I would make would avoid sharp inside corners, even small fillets in the corners does a whole hell of a lot for shock resistance.

 

[rodinal220]

I have made firing pins from O-1 drill rod,1137 or 4140.

 

[Slamfire]

Why not 4340? This has nickel and that raises its toughness. Only the surface needs to be hard, the core needs to be tough for the firing pin to survive impacts. Any steel heat treated to make it super hard would be too brittle and fatigue fail in a short amount of time.

So, I would look for a material that is easy to surface harden, and at low core hardness, has a high fatigue lifetime.

 

[Kp321]

+1 for Brownells Fatigue Proof. A little tough to machine but does not require any heat treatment after fabrication. I have used 1095 drill rod but it requires hardening and tempering.

 

[jmorris]

The only ones I have ever machined were from 4140 chromemoly then heat treated for my 50 BMG.

 

[4v50 Gary]

4140 for me.

 

[redneck]

If it has to be turned to a specific profile, I would use a tool steel and heat treat accordingly. O1 is probably the easiest to find and heat treat yourself.


For really simple stuff music wire in the appropriate diameter works pretty well and is easy for a kitchen table gunsmith to work with. Also pretty cheap.