My first AK-47 build
In the beginning, there was a cut up Romanian AK-47 kit. There are plenty of them on the market right now ('right now' is Summer of 2007). They practically can't give them away. The bore of my kit looked brand new, unfired, the receiver was cut up, the wood looked okay. This was one of the kits I ordered from Classic Arms (by the way their service is great and I am very happy with them). The kit came with a TAPCO single hook trigger group. I also ordered a US manufactured pistol grip and gas piston on gunbroker.com
After several evenings of grinding, drilling, tapping, screwing, hammering and so on, here is what all that work resulted in:
For the 922 compliance (must use no more than 10 import parts when assembling an assault rifle from foreign parts kit) the following US manufactured parts were used:
- reciever (NDS-3)
- fire control group (counts as 3 parts)
- slant muzzle break - in appearance it is pretty much exactly like the original
- pistol grip (tapco)
Here is a nice detail of how the wood came out:
The receiver is NoDak Spud Economy (NDS-3) and it came in blued finish. The plan was to shoot a few rounds first and then paint the whole gun, receiver and barrel, everything, with Duplicolor Hi Temperature engine paint.
De-mill the Kit
The first step in building the AK kit into a rifle is the demilling of the parts kit. This includes the removal of the receiver stubs left over from the barbaric torch-cutting, drilling or knocking out the old rivets, separating the trigger guard from the receiver stub. Detailed instructions on how to do this can be found here.
For those who like adventure, this also includes the removal of the barrel pin and the barrell. I tried this once. On the first kit, I was unable to remove the pin with a 20-ton press, and I damaged the rear sight and gas block (this is a picture of what not to do):
In order to fix this, I had to completely strip the barrel (good experience) and then bend the gas block back into shape. I then filled the irregularities in where the bend occurred with "JB WELD" and polished it flush with the rest of the rear sight/gas assembly block (now I have to paint the rifle, simply blueing won't do).
If you cannot remove the pin with a 20 ton press, you can either drill it out, or just leave it in there. In the factory set position. For a screw build you do not need to pull the barrel. Yes, tapping the holes in the front trunnion is easier when the barrel is not there, but in my opinion is not worth the headache of removing the pin and the barrel.
Tap the trunnions
Drill out the rivets in the front trunnion. Do not drill them deeper than 3/16".
If you deciede to leave the barrel in, you really will need all three kinds of taps. They are all 10-32 taps: a regular tap (the kind with a tapered point), bottoming tap (no tapering at the point), and plug tap (kind of in between the other two kinds).
You will quickly learn that the regular tap does not do much for the front trunnion holes (if you did not remove the barrel). The tapered part is too long to lock in the shallow hole in the trunnion. Start with the plug tap. Use plenty of oil (walmart 3-in-one works great). Turn the tap 1/2 turn, then 1/4 back, then 1/2 again... take it out frequently to clean. The key is to go slowly.
Attach Trunions to Receiver
For my first build, I used a 100% receiver from NDS. Mine had the trunnion holes pre-drilled but they didn't match exactly. They had to be 'egged' by using a dremel and a diamond grinder bit. On this picture you can see where I marked which direction the holes needed to be expanded:
Install the trigger guard using screws and really small nuts:
Install the rear trunnion. The receiver now looks like this:
Next, install the front trunnion with the barrel, drop in the fire control group and reassemble the rifle:
The wood cleaned up nicely, using the following technique:
- paint stripper, let it soak in (read the directions), then rub it off
- metal paint scraper - carefully (I think this step is very important)
- 60 grit sandpaper
- 150 grit sandpaper (I used my finish sander during this step. Some dirt has penetrated into the wood quite deep, and a finish sander won't really hurt the wood, so this is a time saver)
- 220 grit sandpaper
- for the upper hand guard I also used bleach because the dirt (glue??) was just not coming off with hand sanding or with a finish sander.
- 0000 steel wool
- tack cloth
- tung oil finish, let try overnight
- 0000 steel wool
- tack cloth
- tung oil finish, let try overnight (repeat this until you see that the tung oil is not going into the wood anymore; for me this is usually 4..6 applications)
- you can now either be done, or put some sort of polyurethane finish coat (I did), it's harmless and it protects your tung oil finish.
At the end of the finish process I like to do a "fingernail test". If I press a fingernail into the wood and it does not leave a mark, I am happy. If I was not too impatient and let each coat dry well, you will not be able to scratch it with a fingernail.