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Best way to shorten a firing pin

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04 September 2020, 23:32
RogersGunWorks
Best way to shorten a firing pin
I need two Mexican Mauser firing pins (M1910/1936). The front of an original pin is a non-safety type like a Swedish 96 and the rear is like an M98. Could the front end of an M96 firing pin be joined with the rear portion from an M98? Of course, things would have to adjusted to correct length. What would be the best way to join the two sections of firing pins? Sleeving, where one section is bored out for a tenon turned on the other then either soldered or threaded together? Welding with a simple butt joint.

Sounds like a lot of work. But these parts don't seem to be available, & modifying two existing firing pins sounds easier than turning a whole new part from scratch. Those of you who have shortened actions should find this question easier to answer. Thanks.
04 September 2020, 23:54
kda55
See the classifieds
05 September 2020, 03:21
metal
I would do it like you described, sleeved or spigot joint and 45% silver solder (braze).
05 September 2020, 16:13
Russ Gould
Firing pins have to be specifically heat treated, and any brazing or welding is going to require that you redo the heat treatment afterward. Exactly what is required is beyond me. If all else fails, heat treat it like a spring.


Russ Gould - Whitworth Arms LLC
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05 September 2020, 16:43
slivers
I'm about certain Mauser firing pins are case hardened. I've seem a pile of 'um with beat-up a cam. Gotta' have high carbon steel to make a 'spring'.


05 September 2020, 18:58
dpcd
I make them out of O-1, it's easier to make the whole thing than to extend one.
Quench the tip.
Old Mauser pins might have been case hardened but that is not what we want to do now, and if it was spring steel, it wasn't case hardened anyway.
05 September 2020, 19:58
slivers
SARCO (usually junk dealers) offers repro '98 pins that they claim are made of 4140HT. I would suspect that most modern made rifles have their pin made of the same. Modern firing pins can be cut with a file, so they're not that hard. Don't know which would be easier, make one or alter 2 to make one. If I was to make one, I believe I'd use prehardened material to avoid any possibility of deflection during quench.


06 September 2020, 01:50
metal
quote:
Originally posted by metal:
I would do it like you described, sleeved or spigot joint and 45% silver solder (braze).


Of course use proper heat control methods, don’t anneal the ends.
Can’t see a problem.
06 September 2020, 02:05
dpcd
Speaking of SARCO, I have used many of their 98 firing pins without issue. They come bright, as machined so no heat treat was done on them; they are not hard, but seem very tough.
06 September 2020, 02:52
slivers
quote:
Originally posted by dpcd:
Speaking of SARCO, I have used many of their 98 firing pins without issue. They come bright, as machined so no heat treat was done on them; they are not hard, but seem very tough.
4140HT isn't hard, it can be cut wit a file. Usually 28C-32C from the mill. The same stuff some CM barrels are made of. Not "bearing hard", but tuff. We used to machine it with HS tooling before carbide became readily available and we could increase speeds and feeds. 4140HT can be bought straight from the mill. Steel suppliers everywhere have it in stock. Machined, it comes out 'bright', just like any other steel. So, the only real way to know if it's HT is to put it under the Rockwell Tester. Before SARCOs' new web site, their repro pins were described as "made of 4140HT", if I recall correctly. 4140 annealed or HT doesn't weld well. It can become brittle, so not a good option for a welded connection on a re-worked firing pin, but if I was to have to make a firing pin, that's what I'd use. 4150HT would be another option, but it's not as readily available.


06 September 2020, 04:11
J Wisner
I just pulled two M98 firing pins and checked the hardness of them.

One is a CZ and so marked, the other is a FN, in the middle of its length on one of the flats, they ran 25 - 28 RC.
The CZ still has the temper colors on the tip back to about 3/4" behind the flange, up as close to the flange I can test it ran about 36 RC.

So that one was heat treated in select areas and tempered in select areas.

I would cut the firing pin in half, lathe turn a short stub, and drill a matching hole in the other end.

Then use some Harris Safety Silv 45, which is a low melt ( about 1050 degrees ) 45 % silver solder to join the two half's, once they have been lined up.
Clean the joint and use it.

J Wisner
06 September 2020, 19:11
slivers
^^^^^^^ there's the plan I'd try first.