MAK-90 rebuild

[safaridave]

Hey all,

I am trying to raise interest in an AK build party and I thought a good way to do it would be to start a thread about my MAK-90 rebuild. This thread will go on as I finish certain milestones.

SO... on with the rebuild diary--

I bought this MAK-90 waaaay back in 1990 from a small gun shop on Northridge, CA. I was young at the time and REALLY wanted an AK-47. This was the closest I could get to it, as was the political climate at the time.... and now... but thats another story.

ANYWAY... The MAK-90 was cool and i shot it a bit, but as young people go I get interested in other stuff, like girls and cars... and the rifle starts to collect dust in my closet. Then i was reading one day that they passed an "assault weapons ban" a few years later and my rifle is on the list. PLUS the registration period was passed by the time I learned of it. SO, possessing an "assault weapon" in CA is a FELONY and I have no choice but to cut up the reciever. Fortunately I kept the parts for all this time. Then I move here... and the idea comes to me to bring this one back to life.

So here is what I have--

mak90start.jpg (107.99 KiB) Viewed 2994 times

I will add to this thread as I demil and rebuild. I may ask for tool help along the way if anyone is willing.

[safaridave]

THE DEMIL

First thing any builder needs to do is demil the parts. You notice on the old receiver i used my bench grinder to grind down the rivet heads on the reciever tabs on the front and rear trunnions. Once you do that, its easy just to pry off the tabs using two vise grip pliers.

trunnions.jpg (117.32 KiB) Viewed 2988 times

NEXT I simply bought a cheap $10 drill bit set from The Freight and drilled out the rear trunnion support rivets. Notice I am using a punch to guide the drill bit to the center as best I can--

rear.jpg (82.08 KiB) Viewed 2988 times

Here is my drilling out the rivets--

reardrill.jpg (91.05 KiB) Viewed 2988 times

The key here is to start with a smaller drill bit than the actual circumference of the rivet, then work your way up with slightly bigger drill bits until there is not much left of the rivet. Then you simply use a punch to drive out the cored rivet. Easy as pie! If I can do it, YOU certainly can. And dont worry if you hit the trunnion side and egg it a little. The replacement rivet will fill any mistakes as it is crushed.

More to come...

[safaridave]

Here is the demilled rear trunnion with a cored out rivet--

demilledrt.jpg (132.23 KiB) Viewed 2981 times

You should try to get the rivet cored out as much as possible... it makes punching it out easier. Try to punch when you feel youre getting thin enough. if it sticks, keep going... dont go bigger than a 5/32 bit.

Here is a pic of the cored rivet..

coredrivet.jpg (136.59 KiB) Viewed 2981 times

Now I start on the front trunnion-

drillft.jpg (84.57 KiB) Viewed 2981 times

NOTICE I DONT DO THE RIVET AT THE TOP OF THE TRUNNION. In European AKs there will be TWO at the top. DONT DRILL THESE YET. You must wait until the barrel is out to do these. IF YOU DRILL INTO THESE BEFORE THE BARREL IS OUT, YOU WILL DRILL INTO THE BARREL CHAMBER AND YOUR BARREL WILL MOST LIKELY BE RUINED.

More to come...

[safaridave]

Okay, here I got antsy to use my new flat die and punches and HAD to bend my flat.

Here is my flat-

flat.jpg (114.3 KiB) Viewed 2976 times

Here it is greased up and ready to be bent in the die.

flatprep.jpg (107.73 KiB) Viewed 2976 times

And the completed reciever--

doneflat.jpg (94.66 KiB) Viewed 2976 times

More to come...

[safaridave]

Looks pretty good from other angles--

flatrear.jpg (69.76 KiB) Viewed 2976 times

flatside.jpg (89.18 KiB) Viewed 2976 times

flatbottom.jpg (125.2 KiB) Viewed 2976 times

More to come...

[Jakeiscrazy]

Nice! Look forward to seeing more!

[762]

How are you going to get the rails attached? I assume weld them in, spot welder?

[safaridave]

Yep. Spot welder is the way they did it at the factory. Its also the easiest.

[762]

My plan was to bolt/screw mine in until I had the ability to weld them. Welding of course is the best, but screwing them in will work also because it's fairly easy to fill those holes where the screws were with weld. Not the prettiest, but it'll work.

[OakRidgeStars]

For anyone planning to buy one of the HF spot welders, be sure to sign up on the HF site so you receive sale coupons via email. I was able to save $35 off the sale price when I purchased mine.

Chicago Electric Welding - item#45689

You can find links for Harbor Freight on the VGOF Sponsor page http://vagunforum.net/support_vgof.php

AK Builder still sells the replacement tongs. HF no longer carries them.

[UnderwaterMike]

Check out the thread on my MAK rebuild. Interested to know what you think.

I don't suppose you did any video or intermediate pix of the bending of the flat? I've never seen one of those done.

Eager to see the rebuild progress!

[safaridave]

Check out the thread on my MAK rebuild. Interested to know what you think.

I don't suppose you did any video or intermediate pix of the bending of the flat? I've never seen one of those done.

Eager to see the rebuild progress!

I couldnt get video or an interim pic because both my hands were needed to pump the handle after lubing.

I can tell you this-- It was incredibly easy... the flat started to bend a little after some pressure was applied. It seemed to go slowly as I applied more pressure, then all of a sudden you hear this POP as the punch quickly seats into the die... and the flat is bent perfectly. My wife was looking on and said "Is it supposed to make that sound?"

Here is my takeaway from the bend-

1) tighten the alignment bolts in the punch as tight as you can BY HAND.
2) apply pressure SLOWLY as it bends. Once the POP is heard and the punch is seated in the die... STOP. Any pressure after that will just stress the flat, the die and your press.

[safaridave]

I think the trigger guard is possibly the worst part of a demil. Its best done with a dremel tool and small-size barrel sander.

You will probably need more than one barrel sander-

guarddremel.jpg (88.21 KiB) Viewed 2889 times

I started on the rear rivet, since I was dreading doing the sides..
Your best bet is to relax, go slow and let the dremel do the work. that way you can minimize scratching the guard itself.

guardrear.jpg (98.6 KiB) Viewed 2889 times

Dont forget the other side... it makes it easier to loosen the guard out of its rivet

guardrrivet.jpg (98.79 KiB) Viewed 2889 times

[safaridave]

Once I got the other side of the rivet out, using a punch I popped out the rivet with ease...

guardreardone.jpg (85.13 KiB) Viewed 2889 times

Now its time too do the sides...

guardside.jpg (75.93 KiB) Viewed 2889 times

After grinding the underside of the rivet..it got a bit of attention with the punch...

guardsidepunch.jpg (82.1 KiB) Viewed 2889 times

Lather, rinse, repeat with the other side.

[safaridave]

So the trigger guard should come off easily when all of its rivets are ground down, and/or punched out

but there is still the selector stop.

sstop.jpg (87.99 KiB) Viewed 2888 times

Use a screwdriver to GENTLY pry it up a little

sstoppry.jpg (94.26 KiB) Viewed 2888 times

It should either come up off the receiver or start rotating around any leftover rivet material like it did here...
I used a punch to knock out the last remaining part of the rivet and the selector stop came right off.

sstopalmost.jpg (84.89 KiB) Viewed 2888 times

Dont pry too much on the stop or it will bend. If it resists to the point of almost bending STOP.. figure out why its not coming off. This stop was made of pretty thin sheet metal.

[safaridave]

And now I have a nicely demilled trigger guard and selector stop.

guarddemil.jpg (122.96 KiB) Viewed 2888 times

FYI-- demilling your kit at home is best because you don't want to waste time demilling at your build party. The only reasons i can think of demilling anything at the party are these-

1) something is not demilling right and you don't want to break it
2) you dont have the right tools for the job

Another thing you can do is ask someone on this board who is near you to help *before* the build party. For example, if anyone needs help before the BP I am trying to get together, I would be more than willing to help them demil at my place a few days before.

More to come...

SPOILER-- I am going to pull off/replace the Front Sight Block (FSB) and the Gas Block (GB) off the barrel... I just need to wait for my tools to arrive.

[762]

I could use a press to demill a kit. I have a cut barrel with the components on it still. I couldn't get out the barrel pin or the RSB pin. I thought a press would be way easier than beating the crap outta them with a hammer. The smaller pins came out without issue.

[safaridave]

I'd be more than happy to let you use my press to do it. You may need a tool to pull off your FSB/GB/RSB... The one I am waiting on fits Yugo m70s and chinese barrels. If you have steel bar stock that we could use to pull off the barrel parts.... that may work. Do you have a tool to press out the RSB and barrel pins?

[chuckyzfr1]

That all looks great so far - I'm not so sure about the part where you use screws on the bolt guide rails though....and I'll tell you from personal experience that you want some serious penetration when you weld them in - the first AK I built the rails popped out when I went to heat-treat the receiver, and I had to go back over them and re-weld them in. What I did was drill a series of holes in the receiver in line with where the lower guild rails went, and then I used small vice grips to hold the rails in place (using the proper width drill bit for alignment/spacing purposes) and then used a Miller MIG wired for 220V and set on a pretty high heat setting, and plug welded the rails in, and didn't let up on the trigger till I had burn-through on the inside of the rail, which I needed to dremel down a little bit to get the action right. But it'll be a frosty day in hades before those welds let go! I used the same procedure on the remaining 3 AK's I've built, and it has worked great every time. Drill fairly large holes too, btw, just smaller than the width of the rails, so that you don't wind up with messy weld slag on the inside of the receiver. Let me know if you'd like to see pics, I have a few I took with my phone that show the process at least a little bit. Good luck!
Chuck

[safaridave]

Now for the barrel repop. Here is what I am starting with-

barorig.jpg (103.04 KiB) Viewed 2737 times

At the factory the AK is assembled on its side with the charging handle UP... than means you must take out the pins from the opposite side.

gb.jpg (98.44 KiB) Viewed 2737 times

I am simply using a hammer and punch to get them out.

fsb.jpg (111.13 KiB) Viewed 2737 times

Once the pins are out I can press out the GB and FSB.