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Posted: 2/23/2006 3:47:43 PM EDT
I wrote this post for a non-gun message board, so if the language sounds basic, that's why. this is a cut and paste.

First the standard disclaimer. Don't try this at home without adult supervision and have someone else pull the trigger for the first few shots.

here is my second AK that i built from a flat piece of metal. the first one is on the chopping block. there are enough flaws with it that i would rahter chop up a $12 flat rather than have it associated with me.

this AK is for a buddy who served a couple tours in Iraq and wanted something similar to what he carried. I had him come over and actually bend the flat on the press so he would be considered the "manufacturer" and i would merely be the assembler by riveting and pressing in the barrel.

We start out with a 0.050" flat sheet of 1050 steel which is in the shape of a rolled out AK receiver.


Next we mount it to a 3 piece male fixture i made. It is made with two sides and a middle piece. You are looking at the bottom where it is secured with a piece of barstock.


We put the male fixture into a female die that i made from scrap angle iron and 3/8" bolts. The entire piece is put in the 12 ton shop press.


Apply pressure and bend it.


Remove it from the press and you are ready to bend the upper rails.


Top rails are bent to a 90 degree angle with a ball peen hammer.


We now flip it over and peen the bottom corners so we get a nice 90 degree bend.


We're ready to remove it from the fixture. You can now see why it's 3 pieces. If it were one piece, the dimples in the mag well would make it impossible to remove w/o bending it.
So we pull out the center piece and the sides come out easily.


Now we have our receiver shell.


We need to heat treat the pin holes that secure the trigger and hammer on the receiver and the also the ejector. We do this by heating to cherry red with MAPP gas and quenching.


If you stop there, the metal is too hard and brittle. We need to temper it by heating to 700 F. This is easily done by surrounding the parts with burning break fliud which burns around 700


it also keeps ya warm on cold February evenings.


Now we need to attach the rails. This is done by using a spot welder from Harbor Freight with modified tongs so they can reach in the small areas of the receiver.


Now we need to attach the trigger guard. This is done using the 12 ton press. Once again, i made a fixture.


Mounted it in the press.


Finished with the trigger guard.


Now we have a receiver w/trigger guard and need to parkerize it. Ideally i would have waited until i built the whole gun, but my blast cabinet is too small.
We first degrease then blast it.


Now we're ready to parkerize. Unless you're single (or want to be), I'd suggest not doing this in the kitchen.


From rear to front: Heated Simple Green degreasing solution, Parkerizing Solution, Hot water to pre-heat the parts.


With all the different AK variants available, i had to make a couple extra receivers. :angel:


O.K., now we have our receiver and parts kit.


Next step is to add the front trunion. This is riveted in place. The easiest way to do this is with a "rivet squeezer". It's a modified bolt cutter.


We need a backing plate to keep the round heads from getting crunched. I made it from bar stock and drilled some partial holes.


Rivet squeezer in action.


The rear trunion rivet is one long rivet and you can't use the bolt cutters. For it, I used my bench vise.


Time to put the barrel in. The barrels are press fit. I could have used the 12 ton press to do this, but keeping it lined up and not canting is tough w/o making a fixture. Instead, I did it by using 1/4" threaded rod. This method uses a nut which pulls against the bolt carrier (minus the bolt) which in turn exerts force on the front trunion.


Slowly turning the nut at the front pulls the barrel into the trunion. Anti-seize helps here.


The barrel is secured with a barrel pin.


Once again, i used the vise as a press. I shaped a socket to fir the contour of the trunion. That way it pushed evenly.


Once the barrel is fixed in place, we have our AK complete. It is basically in a field stripped condition. All we need to do is add the fire control group, furniture and do any final fitting of the rails so the carrier goes smoothly.



I can't take credit for any of the innovative tools or methods described in my build. I learned from fellow enthusasts on various message boards.

Thanks
Caspian
Link Posted: 2/23/2006 4:32:07 PM EDT
STAUNCH!!
Link Posted: 2/23/2006 4:52:32 PM EDT
Great post!
Link Posted: 2/23/2006 6:01:08 PM EDT
Excellent pictorial walk-thru. Thanks for sharing.
Link Posted: 2/23/2006 6:17:36 PM EDT
Bardzo dobry AK
Link Posted: 2/23/2006 6:54:34 PM EDT
Nice find-Could come in handy
Link Posted: 2/24/2006 1:40:06 AM EDT

Originally Posted By KnobCreek1:
Excellent pictorial walk-thru. Thanks for sharing.



Hey Charlie,

I built up the Yugo UF. I'll post picts on your site later.

Thanks
Caspian
Link Posted: 2/24/2006 4:41:31 AM EDT
How did you start with a standard flat and end up with a receiver for an underfolder?
Is it hard to locate those holes?
Link Posted: 2/24/2006 4:46:22 AM EDT

Originally Posted By POLYTHENEPAM:
How did you start with a standard flat and end up with a receiver for an underfolder?
Is it hard to locate those holes?



no. i used center punches to line up the holes. basically, i lined the rear trunion on the back of the receiver and transfered the center of the holes. they were easier to line up than my Romy since the back trunion is bigger and easier to visualize how it sits.

Caspian
Link Posted: 2/24/2006 5:04:46 AM EDT

Originally Posted By Caspian45:

Originally Posted By KnobCreek1:
Excellent pictorial walk-thru. Thanks for sharing.



Hey Charlie,

I built up the Yugo UF. I'll post picts on your site later.

Thanks
Caspian



Looking forward to seeing that....hope you liked the kit.
Link Posted: 2/24/2006 12:03:20 PM EDT


Great tutorial.....
Link Posted: 2/24/2006 7:23:12 PM EDT
Great job. I understand the need to have a few extra receivers around. On an underfolder if you use a uni-bit it is very easy to make the required holes, just use the rear trunion to locate them an drill to the proper size. Only takes a couple of min. Measure twice drill once :)
Link Posted: 2/24/2006 8:13:26 PM EDT
nice, im working on my Romy build as we speek, haveing a hard time figureing out how to crush rivets with out a press (trigger gaurd)
i like the barrel press idea
Link Posted: 2/24/2006 8:17:06 PM EDT
Link Posted: 2/25/2006 1:09:52 AM EDT
Nice work!
Link Posted: 2/25/2006 4:15:07 AM EDT

Originally Posted By Caspian45:

Originally Posted By POLYTHENEPAM:
How did you start with a standard flat and end up with a receiver for an underfolder?
Is it hard to locate those holes?



no. i used center punches to line up the holes. basically, i lined the rear trunion on the back of the receiver and transfered the center of the holes. they were easier to line up than my Romy since the back trunion is bigger and easier to visualize how it sits.

Caspian



Thanks for the information. Your rifle looks great.
Link Posted: 2/25/2006 6:23:29 AM EDT

Originally Posted By Parabellium:
nice, im working on my Romy build as we speek, haveing a hard time figureing out how to crush rivets with out a press (trigger gaurd)
i like the barrel press idea



Before i had my press, I used a piece of barstock steel, drilled a couple dimples (use yur trigger guard as a template). these dimples will support your rivets so they don't get flattened.

I then used a big ass flat punch and big assed hammer and carefully pounded them flat.

good luck,
caspian
Link Posted: 2/25/2006 11:09:09 AM EDT
[Last Edit: 2/25/2006 11:15:12 AM EDT by Parabellium]
the problem im haveing is im useing a 100% receiver and i cant get a straight wack on the rivets, any suggestions?

Link Posted: 2/25/2006 5:27:33 PM EDT

Originally Posted By Parabellium:
the problem im haveing is im useing a 100% receiver and i cant get a straight wack on the rivets, any suggestions?



I had one where i put the center post in prior to the trigger guard. I could still wack them in with a hammer/punch, but it took some lining up and a lot more time.

Your only other real option is to remove the factory post, install your trigger guard and then put in an "aftermarket" post and rivet. I think the removal process would be the biggest time taker.

good luck,
caspian
Link Posted: 2/26/2006 3:40:47 AM EDT
thanks for taking the time to put this post togeather
Link Posted: 2/26/2006 11:58:58 AM EDT
This is one of the best build threads I've seen in a long time. Thanks for posting it. I know constantly stopping and taking pics is a PITA.

Galland
Link Posted: 2/26/2006 1:05:25 PM EDT
[Last Edit: 2/26/2006 2:31:33 PM EDT by Caspian45]

Originally Posted By Galland:
This is one of the best build threads I've seen in a long time. Thanks for posting it. I know constantly stopping and taking pics is a PITA.

Galland



shit, you guys are making me blush. It's kinda lacking now that i look at it. i left out a few things that may help a nubie. Things i can think of that i skipped include:

Demilling
spacing the front trunion
Locating the trunion holes
More detail on the long rivets
Making your own centerpost

If there is anything you want more detail of, now's the time to mention it. I can take more detailed pictures while i'm actually doing it.

I'll edit this and add to it some of the steps i skipped over as i do some of my other builds. The receivers/guns won't always be the same, but the info is universal so it'll be fine.

I'll edit the heading when i have it 100% complete.

Thanks for your interest,
caspian
Link Posted: 2/26/2006 1:55:14 PM EDT
Great work!!
Link Posted: 2/26/2006 2:39:43 PM EDT
I am speechless...thank you. Can this be posted as a permanent feature on the website?
Link Posted: 2/26/2006 2:52:53 PM EDT
this is a result of 3-4 weeks of searching ak.net, gunco, ak files, etc and saving/printing off any related build info. I then made a binder with the info organized into chapters so i could reference it while i was in the garage.

NONE of the ideas or techniques are things i came up with. I incorporated the methods for which i had tools. You'll recognize Socandymans trigger guard fixture, 555th jig, "Soup to nuts" heat treat brake fluid trick, etc.

I only deserve credit for compiling it and snapping pictures.

Anyway, if it is to become permanent, let me finalize it by adding more pictures and steps.

Thanks,
caspian
Link Posted: 2/26/2006 2:53:09 PM EDT

Originally Posted By garum:
I am speechless...thank you. Can this be posted as a permanent feature on the website?



Agreed, the screw method to pull the barrel into the trunion is worth tacking up if you ask me. Haven't seen that done yet but it's a great idea if you dont have a press or want to beat it with a ten pound hammer.
Link Posted: 2/27/2006 7:50:07 AM EDT

Originally Posted By NHG21:

Originally Posted By garum:
I am speechless...thank you. Can this be posted as a permanent feature on the website?



Agreed, the screw method to pull the barrel into the trunion is worth tacking up if you ask me. Haven't seen that done yet but it's a great idea if you dont have a press or want to beat it with a ten pound hammer.



No doubt. I have four builds sitting here just waiting for receivers. I have a press, but pulling the barrel in, I never thought of that. Nice. Now to go get some more hardware from the surplus store.
Link Posted: 2/27/2006 9:02:32 AM EDT

Originally Posted By Lonerunner1:No doubt. I have four builds sitting here just waiting for receivers. I have a press, but pulling the barrel in, I never thought of that. Nice. Now to go get some more hardware from the surplus store.


One thing that i will put in my edited build directions will be the addition of some sort of bearing between the front nut and the barrel muzzle.

see, when you twist the nut to tighten the barrel in, the spinning of the nut exerts force on the barrel slightly canting the barrel. You have to stop 1/2 way through and gently twist the barrel back into alignment. Using a bearing would prevent this.

Caspian
Link Posted: 2/27/2006 9:12:14 AM EDT
Link Posted: 2/27/2006 9:16:08 AM EDT

Originally Posted By me223:
Caspian45, let me know when you are ready and I will add to this Instruction thread tacked up top. Good job, BTW.

Mike



Thanks, Mike.

I just ordered a 3 piece ball bearing for the barrel installation. It was $6.24. Well worth it since you won't have to use a crecent wrench to torque on the rear sight assembly.
Link Posted: 3/3/2006 10:08:54 AM EDT
Great post, that threaded 1/4" rod trick is brilliant!

As I'm not an AK guy I gotta aks - are those flats purchased like that or do you have dies & jigs to punch the holes and make the dimples?
Link Posted: 3/3/2006 10:40:42 AM EDT

Originally Posted By Caspian45:
We need to heat treat the pin holes that secure the trigger and hammer on the receiver and the also the ejector. We do this by heating to cherry red with MAPP gas and quenching.
www.precisionforensictesting.com/images2/mapp.jpg

If you stop there, the metal is too hard and brittle. We need to temper it by heating to 700 F. This is easily done by surrounding the parts with burning break fliud which burns around 700


it also keeps ya warm on cold February evenings.
www.precisionforensictesting.com/images2/ejburn.jpg


So do you just let the fluid burn itself out or what? How much fluid do you put the parts in?
Link Posted: 3/3/2006 11:40:41 AM EDT
update: I bought a thrust bearing hoping that the force of the twisting nut would not affect the barrel. it didn't work as planned. it didn't hurnt anything, but it certainly didn't cure the problem.

It's not a huge deal. Having the gas piston in place helps give you a sense of alignment. if th barrel twists a little, you gently twist it back with a crecent wrench on the gas block. key word there is gently

to answer your question, the flats come with the holes and dimples.

I let the brake fluid burn itself out. I covered the parts with the liquid. It burned for about 15 minutes. I slowly and gently poured mineral spirits on top of the break fluid before lighting the fluid. The mineral spirits acts will help get the break fluid started. the break fluid isn't very combustable. you won't be able to light it with a lighter or matches. I used the MAPP gas torch to get it started.

Later
caspian
Link Posted: 3/4/2006 6:12:40 PM EDT

I have a question about this...

If you have matchin part numbers, and you pushed the barrel out, riveted receiver and then pressed it back in and used the same barrel pin, does the headspacing need to be adjusted? It should end up what it was originally shouldnt it? Isn't there a drilled recess for the pin in the side of the barrel?

The reason I ask is that I am trying to decide whether to go with rivets or screws for my first build... I think I can get away without worrying about head spacing if I have a matching kit and dont remove the barrel... but that means I can't use rivets in the barrel trunion.

I guess if I can find a cheap go/no-go headspacing device it's a non-issue. I realize it's a good idea to check anyway... but how many of you haven't?

-tom


Link Posted: 3/4/2006 6:55:12 PM EDT
Matched number kits should headspace after barrel removal and installation. It is always a good idea to check headspace on any firearm before firing!!



How about some pics of the underfolder tunion hole fabrication. I have done it, would like to see how you did it.
Link Posted: 3/5/2006 4:49:50 AM EDT

Originally Posted By Thealien:how about some pics of the underfolder tunion hole fabrication. I have done it, would like to see how you did it.


we'll do. i have to wait until i do my next build b/c i forgot to take pictures of that process.
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