AK build questions.

[tomfoolery]

so how hard is it to first...

drill out the rear trunnion rivets on an ak...then second, reinstall the new trunnion and rivet it in.

or should i go the screw route?

suggestions?

[grahamstein]

The rear trunion wont be you problems. You have to grind off the heads of the rivets at the front. Then press out the barrel pin. Then press out the barrel. Then remove the rest of the rivets. Then rivet the trunion in the new receiver. Then press the barrel back in. Then headspace the barrel and pin it in place.

Just for the front. And thats the abbreviated version.

At the rear, with a small bit drill through the center of the long rivet, and the short ones, then knock them out with a punch. Then rivet it into the new one. There are a few more small details to pay attention to, but yeah thats the jist.

[tomfoolery]

im not totally re building....just taking a side folder trunnion out and putting a full stock trunnion in. so i dont have to sweat all that work up front

i have the heads ground off...im just waiting for my buddy to bring my drill press back.....

[blefferd]

there is a little bit more involved to it than that, granted i have never built an AK. there is a video series on youtube that shows you how its done.

[Rocket6R]

Originally Posted by tomfoolery

so how hard is it to first...

drill out the rear trunnion rivets on an ak...then second, reinstall the new trunnion and rivet it in.

or should i go the screw route?

suggestions?

What AK are you doing it on (Romanian, Polish, etc.)? Hope the new trunion lines up with pre-existing holes in the receiver.

Please don't go the screw route! Screws were not meant for shear force.

[AZXD]

Tom,
Have you done very much riveting ??
It's not that hard, but does take a proper technique and some practice. If not, locate someone with the tools to do the riveting in a fashion kind of like using an overgrown pair of pliers with special jaws, or find someone who does sheetmetal repair to help you.
Honestly, having repaired aircraft in the service, I notice a lot of write-up on building AK's that go to more trouble than needed. The drill all the way through method (small bit) of rivet removal is much better than using a hydraulic press, but still is overkill. (No offense grahamstein)

Example:
Use a bit that is one to two sizes smaller than the rivet shank, drill the head until you are just shy of the receiver's surface, take drill bit out of drill and use back end of drill bit to pop the head off the rivet by just bending the bit to the side in a quick motion.
Then use a pin punch that is as close to the rivet diameter as possible and a hammer to drive the rivet out.

I've done thousands of rivets this way over the years, and just like putting them in, there is a technique to it.

A hint Jdavionic threw out the other day works very good. Find a pin punch that will fit a rivet gun and use a pneumatic hammer to drive the old rivet out.

ETA: Re-read you first, go with rivets. If you can install them correctly, they are the proper method of dealing with the stresses that are imparted upon the trunnion/receiver when operating the firearm.

[einheit 13]

If you've ground the heads off all the way to the receiver, then you just drive them out. If this is for your AMD, everything should line up just fine. Make sure that the top cover fits nice and tight before you mash the rivets on the new trunnion, not all parts are the same spec, and you don't want a loose top cover-they tend to smack you in the face when they pop off from poor/loose fit. The only downside is that a notch will be left in the right side of the receiver on the AMD.

[jdavionic]

I'm working on build now that is a Romanian AK. As AZXD mentioned, I ran into some real frustration getting that barrel pin out...until I got an air hammer. I got a punch that fit the air hammer and went from banging the snot out the thing to finishing the job in less than a couple of minutes. I was amazed. I would guess you could knock out the rear trunnion rivets using the same idea.

WRT screws versus rivets, I did some digging and I think there are pros & cons with both. For me, I've decided to go with a screw build. I have never heard of anyone incurring failures due to sheared screws. But then again, I'm still learning. From what I found, if you use locktite, a screw build is just as effective as a rivet build. The big difference is aesthetics, as best I could tell.

Since you're only working on the rear trunnion, you don't have to endure the barrel pin fun. If you don't use an air hammer, then you'll likely need to drill them out. The biggest challenge with the rear trunnion that I found was getting it set up right to drill out the rivets without having the drill walk into the trunnion hole. I took the heads of the rivets off with a .250 end mill in my drill press. I thought it would be easier to control than trying to grind them off. The process went very well. I got the heads off and didn't damage the trunnion or even the old receiver. I would think you could get the heads off, use a center punch, then start drilling with a small drill bit, working your way up to .125 dia. GO SLOW! I didn't do it, but I recommend drilling from both sides only half way in from each side, versus trying to go all the way through from one side.

Make sure you use a drill press with a vise. Use cutting oil and pull the bit out often. And in case I didn't emphasize it before, GO SLOW!

[tomfoolery]

i appreciate the suggestions....

i think i may have encountered my problem though....im not worried about drilling into the trunnion by mistake because i dont want to use it anymore (side folder, switching to full).

my concern is that the new trunnion will not match the holes in the reciever already.

is that a legit concern or are they standard across the board.

[AZXD]

Originally Posted by jdavionic

I'm working on build now that is a Romanian AK. As AZXD mentioned, I ran into some real frustration getting that barrel pin out...until I got an air hammer. I got a punch that fit the air hammer and went from banging the snot out the thing to finishing the job in less than a couple of minutes. I was amazed. I would guess you could knock out the rear trunnion rivets using the same idea.

WRT screws versus rivets, I did some digging and I think there are pros & cons with both. For me, I've decided to go with a screw build. I have never heard of anyone incurring failures due to sheared screws. But then again, I'm still learning. From what I found, if you use locktite, a screw build is just as effective as a rivet build. The big difference is aesthetics, as best I could tell.

Since you're only working on the rear trunnion, you don't have to endure the barrel pin fun. If you don't use an air hammer, then you'll likely need to drill them out. The biggest challenge with the rear trunnion that I found was getting it set up right to drill out the rivets without having the drill walk into the trunnion hole. I took the heads of the rivets off with a .250 end mill in my drill press. I thought it would be easier to control than trying to grind them off. The process went very well. I got the heads off and didn't damage the trunnion or even the old receiver. I would think you could get the heads off, use a center punch, then start drilling with a small drill bit, working your way up to .125 dia. GO SLOW! I didn't do it, but I recommend drilling from both sides only half way in from each side, versus trying to go all the way through from one side.

Make sure you use a drill press with a vise. Use cutting oil and pull the bit out often. And in case I didn't emphasize it before, GO SLOW!

In effect you and others are IMO correct. A screw can be effectively used as a replacement for a rivet. However, you must ensure that the shear potential of the screw head is equal to, or exceeds the shear potential of the original rivet. Using locktight stops loosening, which would accelerate the shearing of a screw head. But ultimately it is the shear of the head that would cause a problem, IMO. What'cha think ??
Stay away from those low profile screwheads!!!