Rookie Question - Firing Pins

I was asked by a former professor to turn a new firing pin for one of his antique shotguns. If memory serves he said it was made in the mid to late 1800s. My question is what material should I be using to turn the pin out of? Are there any post-turning processes that I should be performing on the pin? Thanks fellas.

Nick

FarmallMan,it's been a long time since I made anything to do with a gun but I'll chime in.The last firing pin I made was for an antique shotgun.Beleive it or not I made it out of a piece of old lawn mower blade.I Used to be able to get a brand of blade that was fairly hard(took them forever to wear out).I used a die grinder to cut it out and then shaped it on a regular bench grinder.I also used a Dremel for final shaping.It was a flat type pin so doing it this way posed no problems.I blued it when I had enough jobs to warrant firing up the tanks,installed it,tested, and gave it back to the old fellow that owned it.If it,the one you're working on is round,I'd use one of the air or oil hardening steels.It may need to be HT'ed.If so you're on your own as I can't offer any assistance in that area.

A few quick thoughts.

1)When I have rockwell tested old shotgun pins they have been soft!, off the C scale, so I would not get too excited about material. Pick something moderately hard and tough and go with it. Also, we have all seen cheep external hammer guns with mushroomed fireing pin heads. This indicates that soft pins were common on old guns

2) Asses the condition of the piece. No point makeing new pins for a gun that can only be safely used as a wall hanger.

3) A university prof should have access to a rockwell scale. Have him check the hardeness of the original pin if its availabe. That should provide some guidence.

Just a word of advice: find out if the gun has damascus steel barrels. A great many of these old damascus guns are rusty and pitted in the bore. An ironclad policy in my shop is to never restore to firing condition any weapon that is unsafe to fire, and it's my call not the customer. Remember, liability falls on the last person in the chain, and if you do repairs, it'll probably be you. I would think twice before making that firing pin. Here endeth the lesson.

It's a firing pin, not a jet engine vane. Use mild steel and case harden it.

Don't take this firing pin business too lightly on those old shotguns with the big nose on the pin and no transfer bar to keep the pin from coming out the back. I was rather fortunate when I had a primer blow. When it blew it recocked the hammer and the hammer deflected the pin but parts of the primer broke my glasses and one part of the primer was imbedded in my forehead. The surgeon said it was in over 1/4". If the firing pin would have hit me instead of that little lightweight piece of brass this report would be done by the coroner. Sicero

Thanks for the responses guys. I haven't seen the shotgun itself, but he showed me the old firing pin. Someone had ground the end that strikes the primer to a point and the other end was severely mushroomed, which is why he's looking to have a new one made. As far as firability goes, I trust in his judgement. He is an avid shooter and in my estimation knows what he's doing, he just doesn't know how to run a lathe. Also, for what its worth, this job will be paid for with coffee and lunch.

I was told by the fellow who runs the student shop that he has made pins out of drill rod in the past. Any thoughts on this? Thanks again guys.

Nick

Some people consider drill rod to be too brittle. The stock recommendation is 4130/4140 annealed or plain mild steel case hardened. The one advantage of 4130 is you can't get it too hard.

Farmallman;
im with mr Gaskill on this make sure you have a radius on the striker side of the firing pin.

ahall;
yeah just about every college proffessor i know has a couple of Rockwell Hardness Testers laying around ...jim

drill rod should be fine under general circumstances but you will have to know how much - if any - to harden it. this would depend on the design of the gun and the apparent wear and peening on the existing pin. a too-hard pin can eat up the cavity in which it rests by peening the material around it too much, it can chip itself or cut away the supporting material, it can break at some inopportune place or time. a too-soft pin can suffer the same problem as the one you have and probably a good many other failure modes. now is where you get to earn your pay - you have to figure out if that one you have is the original and if it is too soft or what. it could be the factory item that just plain got worn out - so now is a very good time to see what else is worn around it. test the pin with a steel file to see if it was case hardened or hardened at all. examine the parts that held it and see what their wear condition is. to make a replacement one you can probably use oil or water hardening drill rod in its spheroidized state where it is somewhat harder than mild steel but certainly not real dam hard, it can still be cut with a hacksaw and high speed steel tooling. in speroidized state it may be off the bottom of C scale but still well on the B. when hardened it can go right up to 63 plus on the C - much too hard for the pin. test a sample piece of this rod unhardened and see if it is close to same hardness as the one you have and go from there. even if you make the pin and harden it - you can still draw the temper way down. same caveats about the condition of the rest of the arm apply - dont even think about working on a dangerously worn or damaged gun to make it shootable.

YMMV, use some tests and trials to figure out what you have there and then you will have a fair idea of how to build the right part. without knowing more about the arm and it's condition , there is no answer that is always going to be correct. Drill rod is just a general purpose tool steel of a couple of different types and certainly there are many other sources of material that would work just as well. I too like saw blade and mower blade steel for general purpose flat carbon steel but its harder to work with than factory rod when making round parts. carbon and even some tool-grade steel is available in lots of places for the taking (recycling from old parts that is, not borrowing from the neighbor's mower), you just have to learn what folks built out of it and then go find and use it accordingly. I made a list one time for a nephew wanting to make a knife out of recycled steel and he couldnt believe how much there was all around him.

Let me say again thank you all for your responses. The more I'm thinking about it, the more I think a hardness test on the orginal might be in order. I'm sure I can find someone with a hardness tester somewhere on campus. I know the guys that run the on-campus shops, so it shouldn't be too hard to find one.

Next week is spring break, so if this happens, it'll be sometime next week. I'll keep you guys posted. Thanks again guys, I really appreciate your help.

Nick

I've made a few firing pins for old shotguns, to replace ones with broken tips from dry-firing....and just turned them from the shank of a grade 8 capscrew....or, in a couple of instances from the so-called 'grade 9' high strength capscrews.

I suspect, but couldn't be certain, that the originals were just mild steel, and case-hardened.

I really don't know exactly what the steel and heat-treat spec for a grade 8 capscrew is, but its machinable, and seems to be suitable for the purpose....or at least it worked nicely enough for the ones I did.

If you happen to have a bit of small-diameter mill-hardened 6150 on hand, that would probably be the best choice.

cheers

Carla

made more than a few for "liberated " pieces after WW2 ..always out of w-1 drill rod ,hardened & drawn to a full blue ( spring temper ) ...dont remember any complaints....be careful of protrusion & radius on point ...therein lie the blown primer probs....on single shots ,routinely bushed for a smaller diameter mann neidner variation to solve the blow out possibilities(rear shoulder on firing pin )

best wishes
docn8as....