AK Stamped Receiver Build Question?

[starkadder]

I have a question about AK-47 builds, I know that almost all of them are riveted together and that some people are doing the "screw build" method. My question is why doesn't anyone weld them. There are several types of rifles that are welded together, HK's CETME'S are the first to come to mind, so why couldn't you MIG or TIG weld the trunions into the receiver using the rivet holes as anchor points then welding the entire front and rear edges of the receiver stamping to the trunions, and maybe even a few spot welds on the inside, I can't see where that wouldn't be as strong as rivets. Your thoughts?

Thanks


This is this! It's not something else, it's this!

Don't pull it if you don't plan to use it, and don't use it if you don't plan to kill!

ALWAYS REMEMBER OUR MEN AND WOMEN OVER THERE!

 

[THE DARK KNIGHT]

Not to be a jerk, but if it ain't broke, why fix it? Rivets have worked just fine in stamped builds for 62 years now, why change it now.

 

[starkadder]

Because not all of us who bought a box full of kits when they were dirt cheap have a press or the expertise to use one, or don't trust screws that can strip or work loose. And just becase it ain't broke don't mean you can't make it easier or faster.
Besides, when we quit asking why, we are no smarter than animals.


This is this! It's not something else, it's this!

Don't pull it if you don't plan to use it, and don't use it if you don't plan to kill!

ALWAYS REMEMBER OUR MEN AND WOMEN OVER THERE!

 

[JHansenAK47]

Warping. Annealing. An alternative that doesn't require capitol to develop or a lot of time to research.

 

[nalioth]

Rivets are soft steel and are designed to "give" slightly as the weapon heats up and the dimensions change, or if it's dropped and a shock is given to it.

Screws are "okay" if you keep an eye on them. They are usually made of a more hardened steel and not designed to "give" at all.

Welds are "okay" if it's for your gun, and you never plan on selling it. You see, a screw build can be unscrewed and riveted, but a weld build is only as good as the welder who did the work - which is something you can't see. Also, once it's welded, it's potentially ruined from any "rescue" (as with the screw build) due to heat treat issues, etc.



If you have a kit to build, find a build party in your area and go build it the right way

There are build parties here at least once a month.

 

[Ian]

If you have the expertise and equipment for welding, you might be better off getting a milled kit and repair plates. I don't know if it's still true, but for a while the milled kits were a good deal cheaper than stamped, because most folks were looking for rivet builds.

 

[dfariswheel]

People DO make welded AK builds.
Most of these are best done on receivers that are only hardened around the trigger and hammer holes and left soft everywhere else.

Welding "works" but just isn't as good as properly riveted or even screw built rifle.
There is a danger of problems with heat treated parts like the ejector and receiver rails, and the barrel trunnion.

 

[justashooter in pa]

a properly welded AK is miles ahead of a screw build, and hundreds of yards ahead of a riveted gun. the russians chose to rivet the early AK because they had lots of steam powered factories full of fat women in black babushkas who were qualified to press rivets. rivets are 19th century technology used in poor countries that can't afford welding process assembly.

i have built many AK by welding SMAW and FCAW, including those with new sheet metal receivers, rewelds of original receiver stubs with center section donors from bent flats, and milled guns that had receiver stubs. every one of them works as good as the day ot was first built.

for stamped AK you should bevel the vertical front corners of the front trunion by 3/16" and apply weld in the bevel to the sheet metal of the reciever, using a copper backing plate. then reach up inside and weld the underside of the trunion just a bit. then reach inside and weld the trunion tails. on the rear trunion a few welds in the flats on the interior is all you need ohio ordnance receivers work best for weld builds because they have no rivet holes.

but then, i'm just a certified welder and CWI and welding engineer.

 

[bobotech]

I would not do a weld build. My buddy is a decent (not awesome) welder and he got impatient and welded his AK and has issues ever since. It came apart once, the rear trunnion weld cracked while shooting. Nothing catastrophic but still very disconcerting.

The only weld build I would do would be a milled side plate repair.

Unless you are someone like Justashooter above me, doing a weld build isn't the smartest thing.

 

[Shadow 7D]

If you got a flat receiver blank and welded the trunnions Etc. before you bent and heat treated it, after annealing the welds, used similar metal wire for the weld and the receiver, I would think that as long as your engineering was good it would work, but you might want to check on a build site like weaponeer.

 

[briansmithwins]

The real problem is that the AK was engineered for rivets, not screws, not welding.

Other weapons, like the HK G3, Uzi, or AR18 were designed to be assembled by welding. Emphasis on design.

Obviously, rivets are used to join metal together, like welding or screwing. However they work differently from screws in the way that they accept tension and sheer loads. Rivets are strong in shear and weak in tension, which is the exact opposite of how screws fail. On a AK receiver there isn't any tension load on the rivets, all the stress is in shear.

http://en.wikipedia.org/wiki/Rivet
Because there is effectively a head on each end of an installed rivet it can support tension loads (loads parallel to the axis of the shaft); however, it is much more capable of supporting shear loads (loads perpendicular to the axis of the shaft). Bolts and screws are better suited for tension applications.”

http://en.wikipedia.org/wiki/Screw
“Screws and bolts are usually in tension when properly fitted. In most applications they are not designed to bear large shear forces.”

http://en.wikipedia.org/wiki/Welding#Quality
Bunch of details about welding quality and what effects it.

Welds are also stronger on shear than in tension. The problem with welding AK rifles is that the steel the trunion and receiver are made of wasn't selected for welding. How does the heat affected zone of the weld affect the strength characteristics of the trunnion? I have no clue.

My AK pattern rifles are assembled by riveting. BSW

 

[tju1973]

I am not knocking rivet builds, but due me worrying about f-ing it up, I probably will go the screw build route-- I have access to good taps, and a former coworker has a jag for flats---

I think still I can build one with my limited skills for under $300....

 

[nalioth]

I am not knocking rivet builds, but due me worrying about f-ing it up, I probably will go the screw build route-- I have access to good taps, and a former coworker has a jag for flats---

You are more likely to "f' it up" with screws than with rivets.

Find a build party in your area and do it right.

If you're in Houston, I can advise you of the next build party.