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Wu Flu Quarantine Build - Hungarian FEG AK - w/ Pics

Mountain

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I don't do well in captivity and am used to being on the go for both work and personal life. In the past I had acquired an Ohio Ordinance receiver and had started to build an AK parts pile, so a project seemed like good therapy. I decided to start with American / Hungarian.

famous-hungarians-you-didn-t-know-were-hungarian.inbox1600x528.png


Yes- Gene has Hungarian roots. And like Gene, the FEG is not for everyone and a bit nontraditional- but it does like to party every day (rimshot).

Receiver was picked up for short money but needed a little cleaning up.

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Probably a good wire brushing would work but a bath seems like a good idea. Who does not know who this Hungarian is?

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I always wanted to try a DIY electrolysis tank, and the OOW receiver seemed like a good excuse. The DIY electrolysis system consists of an empty ice melt bucket, some rebar, wood, solid copper core wire, washing soda, and a car battery charger. Oh yeah- distilled water. Speaking of distilled, time for some Jack Daniels Single Barrel.



More to follow...
 
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As you all know, even more so than for AR's, AK's require special tools to break down and then build. One can spend some serious cash on setting up with the right tools. Given the quarantine situation we now have, why not make as many tools as I can?

First order of business is to have a capable press. I very much liked Boris' benchtop brake rotor press build and decided to make a version of that. Cheap 12 ton Harbor Freight bottle jack and some hardware does the job nicely.

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Rather than rotors I used some old hubs. Two of the 3/4" threaded rods are much longer so that I can move the upper 'plate' high enough to press in the barrel. The only special tool purchase I made was from a guy on Etsy who makes a barrel pin pusher, receiver support plate, and trunnion support for pressing out/in a barrel. ~$75 delivered and well worth it. Any other jig or special tool I either made or rigged up something I already had.
 
Receiver was picked up for short money but needed a little cleaning up.

a2aeXL4l.jpg
Before you started this project, I wish you went to random people and told them that this hunk of rusty scrap metal....is a gun. And needs an FFL transfer, background check, LTC to possess, etc. I think it would be interesting to see how many people you can convince that this is indeed a firearm.
 
Before you started this project, I wish you went to random people and told them that this hunk of rusty scrap metal....is a gun. And needs an FFL transfer, background check, LTC to possess, etc. I think it would be interesting to see how many people you can convince that this is indeed a firearm.

No kidding! Much more so for an AK receiver than an AR, though both are only chunks of metal.

I do like the electrolysis process. Set it up and walk away. I did a BMW 3.5L engine block years ago.

Did you use your bath tub, LOL?
 
Happy Easter to all of you who celebrate this day.

This is my first AK project, with a few minor mistakes made but no worse final result than an ugly rivet head. I can certainly see the distinction between AR 'assembly' and AK 'build'. Excepting a Compass Lake match upper and a couple other nonstandard caliber uppers, I no longer own any AR's that I did not completely assemble. I've done some other projects as well and would rank the difficulty like this:

AR << M1 Garand < M1A << AK
 
Besides the bottle jack for the DIY benchtop press and some bolt cutters that I will mention later, here are the purchased tools:

3FdcqBGl.jpg


Missing in the pic is an 8mm round nose carbide milling bit I bought off of Amazon. I used that to make rivet 'dimples' in a rivet head setting tool and bucking bar for the opposite side of the rivets.

I forgot to mention the drill guide that came with the AK tools from Etsy- it is pictured above and has spacing to allow getting the trigger guard rivets. Be sure to get good quality drill bits- cobalt or better. I've seen the usual interwebs conjecture about various AK receivers- some completely heat treated, others only by the holes, etc. All I can say is that the OOW receiver was extremely tough when drilling the 6 front trunnion holes and the 4 rear trunnion holes. Your drill press needs to be running at its lowest speed or you will get chatter and/or burn the drill points.

Other assorted tools necessary are the typical things you might have anyway- Various punches and a center punch, vise w/ non-marring jaws, drill press, BFH (big f-ing hammer). I also had some bars with clean edges for pressing against as well as a nice flat round plate to put over the bottle jack ram that is not so flat. A small round bar or a deep well impact socket can be used to push out the barrel. You also need copper or brass washers. Pennies will do in a pinch- you don't want to mar the front of the chamber when removing the barrel.

*** ***

The 1/8" bit was used to start drilling through the old trunnion rivets on the scrapped receiver sections. Other drill bits for the appropriate size rivet. Even with a drill guide it was challenging to get the bit centered on the old rivets for removal. I used an angle grinder to grind down to the receiver to make the rivet extraction easier.

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Given the long rivets on rear trunnions, they are known to be a huge PITA to remove. After fighting them long enough and running out of conceivable curse word combinations, I decided to punt and get a new rear trunnion for $20. Next projects I won't even try to recover a rear trunnion. This also presents an opportunity to use a USA made part for 922R compliance if one needs that for a particular build.

The front trunnion only has short rivets which are much easier to extract. No cursing necessary.

A small request not to derail the thread into 922R & AWB debates. I'll leave it at this: I am following the rules and will end the project with a 922R compliant and Mass AWB compliant build per the actual MGL's. Though I don't believe 'letters to the editor' are legally binding (it's a Massachusetts thing) this receiver was made ~2012 or 2013- thus pre-dating the notification that has everyone scratching their heads. Finishing touch will be EFA10 registration once the 'go switch' is ready. Rulz are rulz for me. Please look them up for yourself and if anyone wants to debate these things, do so in another thread, please! :)

Now for some Easter time with the family.
 
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Because the holes should be positioned for whatever trunnions one uses, DIY AK receivers typically do not come with trunnion holes predrilled. There's a 'sticky note' trick that worked OK for me, though backup measurement with calipers is well advised. Basically you very securely tape the sticky note to the trunnion and mark the position of the holes. I did this with the trunnions inside the old receiver sections. Slide out the trunnion and reinstall it into the new receiver, then mark the hole positions. Glad I verified with calipers, because one of my holes would have been off. I strongly suggest using a center punch before drilling. Once I drilled through one side I used the trunnion to guide the drill bit to the other side and then continued drilling. Some mark and drill from both sides, which seems to me overly complicated and presents greater risk for a mistake.

As before mentioned, the steel for this OOW receiver is very tough and was difficult to drill. No doubt the receiver will be durable in use.

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OK, now time to start setting the rivets in the new receiver. To utilize the Frankenpress for the rear trunnion rivets I made a bucking bar and a rivet head forming tool. Scrap hunk of steel for the the bucking bar and the rivet head form from a large socket head bolt. I don't have a lathe, so I chucked the bolt in a drill and ground the head to shape with an angle grinder as the bolt rotated. Once I had the taper and dimension I wanted, I used a ~1.5mm thick abrasive cutting blade for the angle grinder and cut while the bolt head was rotating. Divots to form the rivet heads were cut with that 8mm carbide round end mill. A little bit of a lip squished out on the lower rivet but still a nice round head. Other one came out near perfect. These are the largest diameter and longest rivets, therefore taking some force with the press.

I was given a tip to start the heads of these rivets with a hammer for a much better chance of forming a good head with the press. Tapped round and round on the rivet ends to get them evenly started. Worked well- they don't look bad for a first attempt ever with this type of rivet and they are perfectly centered.
 
The front trunnion rivets take a different approach. They are short and must be set in tight quarters. I liked the idea of using a modified Harbor Freight 24" bolt cutters to do this. There are a couple sources for some nice pre made special bolt cutter jaws, but they cost ~$90 and I figured I could make my own. The bolt cutters were on sale, so I was only out $16 if I needed to start over. Back to the angle grinder to do a little off-hand 'machining' until the jaws look like this-

quFFvdvl.jpg


The inside heads of the front trunnion rivets must be set very flat so that they won't interfere with the barrel when it it pressed in. I think before I use this 'tool' again I'll cut a little deeper hook in the upper jaw for better clearance. However, as is it worked pretty good for all six rivets.

Note that the rearmost front trunnion rivets are 'swell neck' rivets. To accommodate these I 'punched in' the edges of the receiver holes into the trunnion hole depressions and also countersunk the holes just a touch. Pic below shows the profile of the swell neck rivets-

oHkfHG.jpg


Some folks swear by just using standard rivets and not bothering with the swell necks. No idea if that's truly OK, so I used them as designed. Perhaps someone with AK building experience can weigh in? Worth noting that I sourced the rivets from AK-Builder.com . Quality and function of the rivets was excellent and so was their service.
 
The front trunnion rivets take a different approach. They are short and must be set in tight quarters. I liked the idea of using a modified Harbor Freight 24" bolt cutters to do this. There are a couple sources for some nice pre made special bolt cutter jaws, but they cost ~$90 and I figured I could make my own. The bolt cutters were on sale, so I was only out $16 if I needed to start over. Back to the angle grinder to do a little off-hand 'machining' until the jaws look like this-

quFFvdvl.jpg


The inside heads of the front trunnion rivets must be set very flat so that they won't interfere with the barrel when it it pressed in. I think before I use this 'tool' again I'll cut a little deeper hook in the upper jaw for better clearance. However, as is it worked pretty good for all six rivets.

Note that the rearmost front trunnion rivets are 'swell neck' rivets. To accommodate these I 'punched in' the edges of the receiver holes into the trunnion hole depressions and also countersunk the holes just a touch. Pic below shows the profile of the swell neck rivets-

oHkfHG.jpg


Some folks swear by just using standard rivets and not bothering with the swell necks. No idea if that's truly OK, so I used them as designed. Perhaps someone with AK building experience can weigh in? Worth noting that I sourced the rivets from AK-Builder.com . Quality and function of the rivets was excellent and so was their service.
My build I didn’t press a countersink in the hole for the swell neck rivet. Have never had a malfunction but would do it right next build. Use a ball bearing with a bucking bar with a divot on back side. There is a tool someone is making out there also.
 
I do like the electrolysis process. Set it up and walk away. I did a BMW 3.5L engine block years ago.

Not sure if you noticed when you picked up your safe last year, but I had an electrolysis tub in my driveway that I'd put random pieces of steel/cast in. Mostly cast iron pans when Ms. 76Too would f*** up the seasoning and cake some ungodly shit on them.
 
My build I didn’t press a countersink in the hole for the swell neck rivet. Have never had a malfunction but would do it right next build. Use a ball bearing with a bucking bar with a divot on back side. There is a tool someone is making out there also.

I had some bearings and tried them, but they must not have been hardened. They just squished into the holes and didn't deform the receiver. Had to use some tool steel to make a sort of punch. Receiver made from some tough stuff.

Lunchtime edit-

I'm not such a big fan of the AK trigger guard design but it does serve its purpose. I know, "Rifle is fine!" For this I made a close fitting 'U' shape jig with the four divots to support the rivet heads and clear the trigger guard as well the mag release rivets. Nothing complicated about that, but the bucking bar or 'shoe' to reach the business end of these four rivets took some work and fitting. Back to the angle grinder to rough one out of scrap steel via my off-hand 'machining'. In the below pic to the right you can see how this bucking bar has clearance for all the crap on the inside walls of the receiver plus a cut-out to clear the cross support that is above the front two rivets. All four rivets are set at the same time with this tool. Worked well and they were uniformly mashed flat. I mashed the hell out of the rear rivet to ensure there is no interference with the trigger group.

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VCdVAHXl.jpg
 
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My build I didn’t press a countersink in the hole for the swell neck rivet. Have never had a malfunction but would do it right next build. Use a ball bearing with a bucking bar with a divot on back side. There is a tool someone is making out there also.

If you have ever tried pulling apart an unriveted countersunk hole receiver and trunnion you can see how difficult it is. Probably not necessary to have because the rivets won't fail.
A drywall screw properly supported works like a 1/4" ball bearing too if you like.
 
So now all the front trunnion rivets are in, and all are flush against the inside of the trunnion. Time for paint. For such projects I like to use ultra-high temperature exhaust manifold paint. It's basically a poor man's cerakote, so long as you only need black. After application of a couple coats, I do a quick low temp cure with a heat gun. A couple hours later I come back and give it a high temp cure. It looks a little hazy when cured but that buffs off with a clean cloth. The surface is very durable and looks appropriate for the receiver.

Now time to press in the barrel. The extra length I built into the press works very well for this. Some anti-seize or very heavy duty grease is needed for this. I used anti-seize which worked well, but as usual proceeded to get that sh!t all over everything. I do not know what is more pervasive- anti-seize or stripper glitter. When all this is over, I shall conduct an uncontrolled experiment to settle this question- for science of course.

tzOq7hTl.jpg


Sorry for the busy background in the pic. Maybe I could find a better way to attach the crossbars but duct tape worked fine for this upside down job. You can see how that purchased jig supports the receiver. It rests on the back of the front trunnion and allows clearance for the barrel as it is pressed in. You can see the silver anti-seize where the barrel is being installed.

Lining up the barrel to press was done via eyeball and straight edge method. I should have immediately raced to the nearest open convenience store for a lottery ticket because I got it right the first time. Once it was close to original position, I used a bright headlamp to inspect as I slowly inched it into position so that everything lined up for the pin to reinstall. Don't forget to support the muzzle with some type of softer metal. In my case a permanently attached brake was involved but I still used some aluminum to keep it from being dinged.

Replacing the barrel pin is the simple opposite of removing it and uses the same tools. One difference is that I applied a couple layers of masking tape to the aluminum support plate so that I did not mar the paint job on the receiver.
 
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If you have ever tried pulling apart an unriveted countersunk hole receiver and trunnion you can see how difficult it is. Probably not necessary to have because the rivets won't fail.
A drywall screw properly supported works like a 1/4" ball bearing too if you like.

Great tip- thank you. [thumbsup]
 
So here's the 'Learn from My Mistakes' post and some comments regarding final fitting of the moving parts:
  • Use extra caution measuring, marking, and finally drilling the holes for the trunnion rivets. I didn't make a mistake on this, but would have if I had not triple-checked.
  • When setting the rivets, go very carefully and ensure that both sides of the rivets are well centered and stable in your tooling. One of mine cocked sideways a little which is what caused the 'smile' mark on a rivet, coming from the edge of the setting tool.
  • When checking the fit of the bolt carrier along the rails, there was significant interference from the right side rail at the very front, along the trunnion. Seems to be a common issue to have a rail sticking up a little more than it should. I've read that some recommend getting out the BFH for this but that seems a bit extreme for me, maybe it was a joke. I have a diamond file that is good on hard metal and leaves a smooth finish, so with that I removed a little of the rail at a time until the carrier would slide smoothly over that area.
  • Now it's time to see how the carrier + bolt work. No issues there, once I smoothed down that rail.
  • Before installing the trigger group, I checked to see how it would chamber a round. Damn- some interference. Though I stacked a couple copper washers to protect the barrel when pressing it out, they did mash quite a bit so it's possible I made a little ding at the edge of the chamber. Also possible that the parts kit has had a little rough handling at some point in its shipping history. By marking the bottom of the cartridge with sharpie I could see where the ding was catching. I have a rubber bonded fine grit dremel stone that I used to polish out the edge with the sharp spot going very slowly and checking often so that I stop as soon as it chambers smoothly.
  • One clear mistake that I made was not checking the fit of the magazine catch. Only after the trigger guard was fully installed (Duoh!) did I notice very excessive front to back wobble for the magazine. Apparently this is a very common problem for AK builds and sometimes variation in the mags is the culprit, but usually it's variation in the mag catches. This may have been the wrong trigger guard for the build. I'll replace the catch with a longer one later and for a quick fix I used some JB Weld to put a metal shim on the mag catch tab. Locks up great now. This 'fix' will hold up indefinitely- remember that this tab is plastic on P-mags.
So no huge SNAFU's and everything appears to be working now.
 
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Finally, here's a pic of the finished project! [party]

ILbEHCsh.jpg


Not your traditional AK but I do like the look. Bore looks perfect and everything seems well fitted so it should be a good shooter, but we'll see. The stock is actually made in the USA by Choate and counts as a 922r part. I may play Barbie dress up later and put on some nice USA-made wood furniture. I finished this on a vacation day a few days back and registered the EFA10 but am just now catching up on posting the progress.

Range report TBD.
 
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