Tag Archives: sheet metal

Converting a milled M70 receiver stub to a stamped receiver front trunnion using plug welds

I miss building AKs – I never have the time any more.  At rate, some years back I wound up with two Yugo M70 front milled stubs, and then decided to convert the rifle to a stamped receiver because I liked working with AK-Builder flats.  So, in the spirit of trying something new, I decided to convert a stub to a trunnion and plug weld it in place vs. trying to machine the rivet seats inside.

Yes, I’ve heard tons of people say not to weld them together and that rivets are better.  Yes, rivets are better and I have done many of them.  Have I ever had problems with a weld build where I filled plugs, stayed away from the locking lugs and was careful with the heat?  No, I have not had any problems.  I have an AMD-65 with tons of rounds through it that still runs fine.  My thinking is that I am not firing full auto, not using grenades, don’t use this in combat … I’m not really stressing it.  What would I use for a reliable build vs. a test like this?  I’d use rivets.

This was almost eight years ago.  I found the photos and thought you might like to see them.

Here are the front stubs.

When you look at the front stub, you can see readily it could become a trunnion.

Here’s a Hungarian AMD trunnion next to it.

Here are the stubs from a couple of angles.  I already used my bandsaw to cut the top one

Ok, time to make some chips.  It’s secured an I’m milling the OD under the top shelf of the trunnion that sticks out over the receiver:

I didn’t have anything to cut the slot with for my mill so I clamped a straight edge and then ran a Dremel wheel down it over and over until I got the depth and width needed for the stamped receiver to to slide into:

My theory was that by drilling holes and filling them via plug welds that I could lock the receiver into place.  Thus, I drilled holes for the plug welds both in the stamped receiver and into the newly made trunnion:

The plug welds were done with a Harbor Freight 220V MIG running ArCo2 gas and .030 wire.  I let it cool down after each weld and was careful not to pour on a ton of heat.  Notice the relatively big weld area to distribute the load.

I then sanded it all down with a flap sander.  The back was just a regular M72 rear trunnion that I found at R-Guns. I never had problems with cracking, etc.  The experiment seemed to work for a casual use semi-automatic rifle.

That’s all I have as far as photos go.  I hope maybe it gives you some ideas.

Writing this makes me wish I had time to build another AK but it’s back to our grips and handguards 🙂

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Build Your Own AK (Vol. I): Headspacing & Virgin Barrel Population (Kindle Edition)

Got an AK Parts Kit? This ebook shows you how to build it right!

The AK-47 and its variants are world-renowned for being simple, rugged and nearly indestructible. But if you wanted to build your own Kalashnikov rifle there was no good single source of construction information—until now.

This new ebook series dives deep into proven techniques of home-built AKs. Profusely illustrated with numerous photos and diagrams, these manuals will show you exactly how to assemble your AK parts kit step-by-step. Your build will go easy using our techniques, recommended tools, and veteran builder tips/tricks…all with a critical focus on both safety & quality.

Volume I covers both headspacing procedures and the population of the barrel components in a non-original barrel or virgin barrel AK parts kit. Both AK-47 and Ak-74 build procedures are described in the first book.
Topics include:
– Measuring the barrel journals
– Cut extractor relief on chamber end of the barrel
– Cut the clocking notches for the lower hand guard retainer
– Strip bolt, in preparation for headspace check
– Align, and press front trunnion onto chamber end of barrel
– Headspacing
– End mill/ream barrel pin notch, and set barrel pin
– Install, and drill/pin Rear Sight Base
– Locate, and cut lower handguard retaining notch
– Gas Port location
– Install Lower Handguard Retainer
– Install, and align the gas block
– Drill and pin the gas block
– Install, and align the Front Sight Base
If you have been waiting for the ‘definitive AK assembly guide’ before building your AK, wait no more.
Volume II (coming this Fall) will continue the journey, showing every step to complete your Matching or Newly populated AK parts kit into a complete rifle.

By (author):  Guy Montag, Nicoroshi

List Price: Price Not Listed
Kindle Edition: Check Amazon for Pricing Digital Only
buy now