24hourcampfire.com
24hourcampfire.com
Previous Thread
Next Thread
Print Thread
Hop To
Joined: Aug 2006
Posts: 983
M
muddy22 Offline OP
Campfire Regular
OP Offline
Campfire Regular
M
Joined: Aug 2006
Posts: 983
I need to make 2 new firing pins for my Husqvarna Mod. 20 16 gauge SXS as the originals are nearly as sharp as nails on the points and occasionally punch primers. They are simple all round units and should be easy to make. Could anyone tell me what type of rod to use to turn them from as my only tools are sharp files, mic & caliper and a 1/2" drill in a vice for a lathe. I will then harden them but I need to know of an easy machining rod that will "harden" w/heat and quench. Thank you all-Muddy

BP-B2

Joined: May 2003
Posts: 3,274
Campfire Tracker
Online Content
Campfire Tracker
Joined: May 2003
Posts: 3,274
Get someone to help; someone with a lathe. Use S-2


+Professional member American Custom Gunmakers Guild
Joined: Jun 2001
Posts: 19,029
S
Campfire Ranger
Offline
Campfire Ranger
S
Joined: Jun 2001
Posts: 19,029
Buy some oil quenching drill rod from McMaster Carr. You really need a lathe though to do a decent job


If God wanted you to walk and carry things on your back, He would not have invented stirrups and pack saddles
Joined: Dec 2004
Posts: 10,340
B
Campfire Outfitter
Offline
Campfire Outfitter
B
Joined: Dec 2004
Posts: 10,340
Listen to Kobe.

Joined: May 2005
Posts: 16,554
Campfire Ranger
Offline
Campfire Ranger
Joined: May 2005
Posts: 16,554
If I was going to that much trouble I'd go with a shock resistant steel like S-2 or S-7. But common tool steel like O-1 or W-1 would probably be fine and are noted for not so critical heat treating. Could do the drill and file thing, anything is possible, but so much better and easier on a lathe. And you don't mess up your drill bearings, they're not designed for heavy lateral force.


The key elements in human thinking are not numbers but labels of fuzzy sets. -- L. Zadeh

Which explains a lot.
IC B2

Joined: May 2006
Posts: 430
B
Campfire Member
Offline
Campfire Member
B
Joined: May 2006
Posts: 430
Where you located??? Retired from gun smithing but have all the tools. You could stop here and I'll drink coffee while you make the parts.

Joined: Aug 2006
Posts: 983
M
muddy22 Offline OP
Campfire Regular
OP Offline
Campfire Regular
M
Joined: Aug 2006
Posts: 983
BT, 2650 miles West, 100 mi. NE of the fires that burned Pateros, WA. Thanks I really do appreciate it. I lived/worked the family ranch (not big 400 pairs) for 50 years I have made small parts before. A lathe would be great but a $50 drill that I use for the same thing on a weekly basis doesn't bother me to burn up. Delta Gun Shop is 5 miles away but I lean on Jim waaay too much as it is (he is the greatest!). If I could buy new ones I would but as they are simple round objects they should be easy to make and as I have made barrel band sling bases w/a file before I should be able to do this. My first thought was to heat and draw a suitable sized drill bit, form, heat, quench and polish but I don't know what I would end up with. BT funny you should offer that as Jim said the same thing when I was cutting relief grooves in orig. X bullets w/the drill in 250 gr. .338 and a lathe tool in ViceGrips . Any way thanks to all-Muddy

Joined: Oct 2012
Posts: 233
T
Campfire Member
Offline
Campfire Member
T
Joined: Oct 2012
Posts: 233
Muddy, years ago, I bought a ol' Knickerbocker double. Both firing pins were broke. I found drill bits, the size I needed, cut the shanks to length, and turned them to dimensions.

Joined: Aug 2006
Posts: 983
M
muddy22 Offline OP
Campfire Regular
OP Offline
Campfire Regular
M
Joined: Aug 2006
Posts: 983
toes, my HVA was made in 1904-Thanks-Muddy

Joined: Oct 2004
Posts: 24,634
Campfire Ranger
Offline
Campfire Ranger
Joined: Oct 2004
Posts: 24,634
La Salle makes a steel called "Fatigue Proof" that's just wonderful for firing pins. You can machine it on the lathe, and you don't have to heat treat it, it can go right in the gun. I found out about this steel from a guy who worked at Purdey's; told me that was the steel they use for all of their firing pins.

You can find La Salle Fatigue Proof from most large steel suppliers, or you can get it from Brownells. It's expensive from Brownells, but it's worth is. Best firing pin material I've ever used.

Other than that, O-1 drill rod is darned good to use, but you'll need to heat treat and oil quench when done (which isn't a big deal).

IC B3

Joined: Mar 2013
Posts: 156
M
Campfire Member
Offline
Campfire Member
M
Joined: Mar 2013
Posts: 156
After heating and quenching O-1 (which will work fine btw), you need to draw it back to a spring temper. Test the hardened steel with a file to be sure it's fully hard, polish bright, then play a flame on it (or put it in a little sand on a thin piece of metal...piece of soda can works), and draw it through straw, then plum, and stop at the bright/light blue...there's your spring temper.


Shoot straight, shoot often
Joined: May 2005
Posts: 16,554
Campfire Ranger
Offline
Campfire Ranger
Joined: May 2005
Posts: 16,554
Temper embrittlement? I've had blue tempered plain carbon tool steel be surprisingly subject to breaking on impact. Looking it up (ain't the Innanet wonderful?) I found that steel, alloy in particular, looses impact strength (permanently) if tempered between 250C and 400C. I temper outside that range if I'm gonna hit it. Last time I tempered (W-1) in the kitchen oven, ran it up to 450F (232C), let it cook for about an hour, and let it cool with the door closed. You can't cook too long when annealing.

But all I know, beyond that damned blue tempered thing breaking when it shouldn't have, is what I've read. Google "temper embrittlement" and get confused. wink Here's a Link with a nice graph.

So how impact resistant do you really need it? Dunno, but for a SxS or O/U firing pin I'll take all I can get.


The key elements in human thinking are not numbers but labels of fuzzy sets. -- L. Zadeh

Which explains a lot.
Joined: Mar 2013
Posts: 156
M
Campfire Member
Offline
Campfire Member
M
Joined: Mar 2013
Posts: 156
The impact toughness of quenched steel after tempering at 250-400�C is lower than that obtained on tempering at temperatures below 250�C. If brittle steel tempered at 250-400�C is heated above 400�C and transferred into a tough state, a second tempering at 250-400�C cannot return it to the brittle state. The rate of cooling from the tempering temperature within 250-400�C has no effect on impact toughness.

From your site you linked. That 250-400 degree range is in the straw heat range, which I was always taught was 'knife' hardness, 58-60C Rockwell. The steel will then darken through the blue/plum colors then get a vibrant bright blue then going to a lighter blue...that's where I stop. I've made new hammer springs for revolvers (flat spring) this way and they've held their power and certainly weren't brittle. You need to draw the harness back and it will give you the 'toughness' or basically impact resistance yet still have enough hardness against deformation.


Shoot straight, shoot often
Joined: May 2005
Posts: 16,554
Campfire Ranger
Offline
Campfire Ranger
Joined: May 2005
Posts: 16,554
Not the most clearly written article but the graph was nice. This one is a little better Link. "The low temperature phenomenon is called 'tempered embrittlement' and it is irreversible except by reaustenitizing and repeating the entire heat treating cycle."

Apparently the graph was made from impact testing data. All the articles I read agree that the phenomena occurs in plain carbon steel though maybe to a lesser extent. Nevertheless I avoid the low areas on the graph for impact, not springs, and don't worry about it. Metallurgy is not an easy subject and I don't claim to understand it. (You don't hammer on your springs, do you?)

(For readers, light blue tempering color translates to about 321C. A nice chart Here. )



The key elements in human thinking are not numbers but labels of fuzzy sets. -- L. Zadeh

Which explains a lot.
Joined: Mar 2013
Posts: 156
M
Campfire Member
Offline
Campfire Member
M
Joined: Mar 2013
Posts: 156
Ah hah, I was confusing Farenheit with Celcius... Hmm, interesting. I related toughness to the same brittleness the article speaks of.... Maybe I will have to treat a piece of O1 and give it a whack or two, although I did make a couple new firing pins for that POS Mossberg O/U shotgun they sell and I know they've survived the last 3 years of shooting trap, over a few thousand rounds now I imagine. That's better than both factory firing pins at this point. Oh, and that's a very handy chart!

Last edited by msalm; 07/29/14.

Shoot straight, shoot often
Joined: May 2005
Posts: 16,554
Campfire Ranger
Offline
Campfire Ranger
Joined: May 2005
Posts: 16,554
Yeah, there's the big question, just how good does a firing pin need to be anyway? In Dunlap's book he tells of making firing pins out of several steels when replacements were unavailable after WWII. They pretty much all worked though he recommended going with a factory replacement when you could. I've seen factory pins break in O/Us, don't know if it was a design/tolerance problem or just that heavy hammer strike on the little pin with not much to absorb energy before it bottoms out in the hole. Thinking the latter, I want to err on the side of impact resistance just because I don't really know.

Blue embrittlement in plain carbon steel is a bit controversial. In fact the cause of the phenomena was and may still be not precisely known though there are a lot of theories. One article related it to impurities in the steel (plain carbon) which varies by melt which may be why sometimes you see it and other times not so much. Like I said, read the articles and get confused.


The key elements in human thinking are not numbers but labels of fuzzy sets. -- L. Zadeh

Which explains a lot.

Moderated by  RickBin 

Link Copied to Clipboard
YB23

Who's Online Now
645 members (1badf350, 09wingates, 2003and2013, 007FJ, 160user, 67 invisible), 2,627 guests, and 1,171 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums81
Topics1,187,601
Posts18,398,282
Members73,817
Most Online11,491
Jul 7th, 2023


 







Fish & Game Departments | Solunar Tables | Mission Statement | Privacy Policy | Contact Us | DMCA
Hunting | Fishing | Camping | Backpacking | Reloading | Campfire Forums | Gear Shop
Copyright © 2000-2024 24hourcampfire.com, Inc. All Rights Reserved.
Powered by UBB.threads™ PHP Forum Software 7.7.5
(Release build 20201027)
Responsive Width:

PHP: 7.3.33 Page Time: 0.191s Queries: 14 (0.005s) Memory: 0.8667 MB (Peak: 0.9801 MB) Data Comp: Zlib Server Time: 2024-03-28 13:27:18 UTC
Valid HTML 5 and Valid CSS