Metal for firing pin

[leadchucker]

I have an old gun with a broken firing pin. No replacement is available anywhere.

I have a metal lathe, and it would be fairly easy to turn out a firing pin of the same shape as the broken one, but I'm in some doubt about what kind of steel would be best for this application, and I know little about heat treating metal.

What kind of steel should I use?
Will the part have to be heat treated?
If so, is heat treating it something I could do fairly easily?

 

[RSVP2RIP]

Just really guessing here but if you had some 416SS and had someone treat it to Rc52 you would be in the ball park. As far as treating it I'd call around to some of the gunsmiths that do custom built guns or local machine shops would be able to tell you where they get their stuff done. There are inexpensive ovens that some tool and die shops would have on hand to make their own bits and they could most likely be able to do it for you.

 

[Jim K]

It depends on what you want to do. If you just want a replacement for a few shots, almost any steel will do, even a nail if there is one handy of the right size.

But for a durable firing pin, I would use tool steel drill rod, which is readily available and easily machined and hardened. Brownells has it in 18" lengths up to 1" diameter. Not cheap, but will do the best job.

I might be able to help more if I knew the type/make of gun involved.

Jim

 

[mag1911]

A friend repaired a Star PD firing pin by facing off a small flat, drilling a hole and inserting a piece of decapping pin which happened to be the same dia.

 

[gunplumber]

I use "fatigue proof" steel from www.brownells.com and have never had to replace any I built. Very good stuff for f-pins.

 

[earlthegoat2]

O-1 drill rod

Amazon sells it for less than Brownells in longer lengths. Not saying you need more rod but it will still be less money in the end.

Wholesaletool has it for even less.

You will want 1/16" wider than your widest part on your firing pin you wish to replace.

 

[1SOW]

I never do anything the easy way, but:

depending on the gun your talking about, a titanium firing pin is lighter, stronger and "faster". It would be fun to make one if it was mine.

One small rod shouldn't cost 'that much', and just think of the 'bragg'n rights'.

 

[Jim K]

Except lighter might not work and you could get misfires or blanked primers. I would stick to the material used in the original.

Note that we still have not found out what gun this is for, only an "old gun".

Jim

 

[earlthegoat2]

Make sure you harden the ends of the finished firing pin too.

 

[leadchucker]

The gun in question is a Star PD. I've already replaced the recoil buffer once. This old thing shoots really well, and I would like to keep it going.

Firing pins have sporadically been available for them, and there are couple of places that claim they have them, but after calling and emailing, I haven't been able to find anyone who actually had one in stock.

 

[Jim K]

As you say, that is a pretty simple firing pin. You will want to harden the back end so it doesn't spread from the hammer hitting it, but the rest doesn't need much hardening at all; in fact making it very hard could make it brittle. Make sure you radius any sharp angles. Length control is critical; I am not sure if that firing pin is the inertia type or not, but it would be a good idea to make the replacement that way.

Jim

 

[exospex]

I've made a bunch of them for a local company. We've used O-1. It's a little tougher to machine but gives a good final product. overall I'd say your best choice is 4140. It machines well and it can be flame hardened without getting too brittle.

 

[Mac's Precision]

4140

Heat to critical and quench

Heat to 450 or a blue color to anneal like a spring

Your done.

Alternately you could use mild steel and case harden with Kasenite.

No need to be using tool steel or drill rod for firing pins.

Cheers

Mac