Hey Cranky, check out this FUBARed barrel threading job.

[WLJ]

http://www.thehighroad.org/showthread.php?t=653582

[RecoilSensitive]

That's bad. Real bad.

[ssracer]

I would be beating the "smith's" ass on that one

[Ian]

Holy crap... Could of gotten someone seriously hurt.

[guncrank1]

Well actually you can weld up and rethread some barrels
I would have at least tried to redo that.
Everybody makes mistakes, it is how to fix them that names the craftsman.

[g19]

Horrible job this smith sucks.

[guncrank1]

I read the responses most seemed to cut barrel or replace
But you could weld and recut the threads
I was shown that by Bill Sanders ,Sanders Custom Gun Service, one of my FFL Manufactor /Gunsmith clients that I did stockwork/ finish work for.

[Ulwembu]

Wouldn't you have to dis-harden en reharden the barrel after welding over the threads??? I would never have someone weld on my barrel. Soldering fine but welding? No way.

[guncrank1]

Wouldn't you have to dis-harden en reharden the barrel after welding over the threads??? I would never have someone weld on my barrel. Soldering fine but welding? No way.

Well if you weren't told you would never know

A barrel is not a harden piece of metal.
I have the piece of barrel off Kyswede M/N.
I will post pics of it later when I test it with my Brinel scale hardness tester.
Mr Sanders would TIG weld up 1917 and 1903a3 barrel and recut threads for Mausers and did so for years.

I have MIG at low heat and re-threaded FUBARed AR barrels for customers that other smith have worked on.

[guncrank1]

And in the USA the only BATFE , legal method of attaching a barrel extension is by hard solder/silver braze and welding
The silver braze method require a heat of 1400 F which is red heat.
And red will remove all temper from heat treated steel.
A 14.5 barrel is not reheat treated, but reparked after hard soldering.

[Ulwembu]

OK, so not hardened (except hammer forged barrels maybe?) but you'll change the hardness on the end you welded for sure. I'm curious to the results of your testing

At the company I work, they weld cheats of metal into pipes that get cut into rings. A welded pipe always has to go through an oven to get the hardness of the weld and the pipe at the same level before cutting. The same was done with cylinder heads at the overhaul company I worked at. If a head needed welding, the whole head would go into an oven to get the metal back on spec.

As a reaction to the soldering you mention: if it gets upto 1400 F it's likely to have the same problem. However, with soldering the temperature moves up slower then welding. Still, I'm interesting in your hardness test results. Might change my vision to welding on a barrel.

[guncrank1]

OK, so not hardened (except hammer forged barrels maybe?) but you'll change the hardness on the end you welded for sure. I'm curious to the results of your testing

At the company I work, they weld cheats of metal into pipes that get cut into rings. A welded pipe always has to go through an oven to get the hardness of the weld and the pipe at the same level before cutting. The same was done with cylinder heads at the overhaul company I worked at. If a head needed welding, the whole head would go into an oven to get the metal back on spec.

As a reaction to the soldering you mention: if it gets upto 1400 F it's likely to have the same problem. However, with soldering the temperature moves up slower then welding. Still, I'm interesting in your hardness test results. Might change my vision to welding on a barrel.

Actually with hard solder the heat is over a great area and for longer time. With a Mig weld the heat is in a smaller area and for a less amount of time.
The more heat at longer time means more less hardness than more.
So soldering is less "harsh" than welding.

[guncrank1]

The welding done at plants is a different technique than I do.
A MIG is a also called a wire feeder.
When I weld up a barrel I weld in short time and not at once and over a long time.

[son of liberty]

While no expert at gun smithing I have a very good knowledge of steels , and heat treats.

Guns are heat treated , but only to minimize visual exterior damage to the steel of the weapon itself. Most often the carberized depth is very shallow, a hardness test will not tell you what depth the steel is hardened to, well not without some serious lab skills. In fact a Hardened barrel would be rather dangerous as it would be brittle how brittle would depend on the temper cycle , but again the act of shooting the gun would again temper the barrel reducing the hardness in relation to thtemperaturere of the barrel. Most AR15 type barrels use 4150 or 4140 alloy steel, the alloys provide thwarere resistance no matter thtemperaturere uuntilll you reach the very low end of forging heat, much hotter then MOST barrels get. A barrel can get so hot it just cooks off rounds and while the bullet will forge out thriflingng the barrel will remain intact. Thats not to say that a barrel is dead soft or that its heated and quenched, a barrel is normalized or allowed to cool at rootemperaturere before the exterior of the barrel is carberized. Forged barrels are not harder or softer, the act of forging when done correctly reduces the size of the grain analignsgs the crystastructureor of the barrel better then some other methods.

A very simple waydemonstratingting this would be a hand grenade and a cannon. The cannon was made of brass "Very soft" and the grenade Cast Steel "Very hard" The effects can be seen in there use.

Now thats not to say that Particular parts such as trcontrolstrolls , hamfiringireing pins, are not heat treated, in fact most are.

[son of liberty]

TIG would be the ideal method of welding but MIG would do fine, Its my understanding that its not how hot you get steel but how fast you cool it, bringing basic carbon steel up to 1550 and sticking it in wood ash will slow the cooling and the steel will be dead soft, bringing it to 1550 and quenching in water will make it so hard it wants to snap and will shatter if dropped. Even if the weld created to much heat you could just cool it slowly with a torch and fix the problem. The hardness of the welded area will also depend on the welding rod or wire. Heat cycles actually refine the grain of the steel doing nearly the same thing as forging.I'm
Im no expert so take it for what its worth.

[guncrank1]

As SOL guns have some parts that are heattreated , some are surface hard
Some are carbuziened

I do have some knowledge of metallurgy.

[son of liberty]

My post was not really directed at you cranky, and the accuracy is based on my limited knowledge and as anyone who has some knowledge of metallurgy will say, there is a boat load I don't know.


But its neat

[guncrank1]

My post was not really directed at you cranky, and the accuracy is based on my limited knowledge and as anyone who has some knowledge of metallurgy will say, there is a boat load I don't know.


But its neat

No offense

[guncrank1]

It is about 8:45 and I will go to shop and post a YouTube vid on that barrel piece

SOL you knowledge base is fine
Even "experts" learn
That is why the expert are experts

[guncrank1]

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Part one

[guncrank1]

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Part Two

[guncrank1]

So the sample barrel was 30 Rockwell "C" scale
Not very hard
Wicki says a knife blade 50 or so

[guncrank1]

Anyway this topic is way OT

The proper way to repair is to cut , crown and rethread
And this time use 60% thread cutter , correct offset on cross slide and correct technique.

[Ulwembu]

I would like to thank you both for your thorough explenation. I've learned something tonight. Thanks!

And I fully agree with your last comment Cranky. ALthough welding is possible, if the barrel is still long enough cutting and rethreading is the best option

Thanks again guys!