Center support rivet

1436 Views 20 Replies 11 Participants Last post by rigore, Apr 6, 2010

rigore

Discussion Starter · Apr 2, 2010

I am about finished with a Romanian non-g AK, except for a couple last things. One of them is the center support rivet. What is the best way to install these? I used the bolt cutter method on the front, the long rivet jig on the rear, the trigger jig (almost the same as AK-Builder's) but kind of at a loss on the center support rivet. The rivet I have has somewhat of a larger and flatter head on it (still dome shaped though), to clear the selector. Unfortunately I won't be able to finish this build as I carelessly forgot to order a rivet for the gas piston. Any help would be greatly appreciated.

P.S. Did quite a bit of looking around for a tutorial of some type.

1 - 20 of 21 Posts

sjohnson

· #2 · Apr 2, 2010

You can use a hammer to set the rivet (tapping it, not wailing on it) and make a rivet head bucking bar to shape the head, again with hammer taps.

The gas piston rivet can easily be made from a common carpentry nail. Just find one that fits the hole and form the mushroom on both sides, then grind it smooth.

Mr_Posthumous

· #3 · Apr 2, 2010

I have used two different methods... First, after jacking up the long rivet that came in a rivet kit, i went to a hardware store and got an appropriatly sized one of those screws that have a flathead/phillips head on each side, but one part is male, the other female, and one screws into the other. I like this way, because you can screw/unscrew the bolt to whatever it needs to be to have the bolt carrier slide nice and easy. Like if your receiver is a bit wide, tigthen it up and it pulls the wals together a little bit.

The other way was I took one of the bushings from a rivet kit, used a 10/24 tap, tapped the bushing, and used half inch 10/24 hex screws in each side, which are low enough to let the selector clear. I tried the rivet once, but after the hammer hitting it a few times, it started warping a bit, which is totally due to me messing up the installation of it most likely.

in AK building fashion, I would say go with what you want the type of build to be. I totally dig the random nuts and bolts and having to tap and make your own stuff, because its just awesome how you can use damn near anything to make an AK work. If you're looking to make a really nice professional looking rifle, then i would go with a nicer way....

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Bradrock

· #4 · Apr 2, 2010

I just support the rounded side with a dimpled piece of steel & then mash the other side flat with a body hammer. Tap...Tap...Tap.. until snug.

kernelkrink

· #5 · Apr 2, 2010

Yep, use the pre-formed head on the side opposite the selector and just flatten the other end until it clears the selector, supporting on a steel backer plate. Look at a factory AK, that's how they're done although I assume they have a jig and mechanical hammer to flatten it.

1/8" hole drilled through the gas piston and use a shank from an old Dremel grinding stone. Perfect size, smashes easily, and most Dremel owners have a pile of them.

Coils

· #6 · Apr 3, 2010

Which long rivet jig do you have? I think the one I got from Plinker has a former for doing the center support rivet?
Though everything said about using a hammer works too, pick and choose

hcpookie

· #7 · Apr 3, 2010

For the center support rivet I use a normal long rivet and chuck it up in the vise. Use a big file and shape the head to a smaller flatter shape. Then drill out the center support hole to fit the rivet and install from the right side. Cut to fit and shape the head on the left side with a hammer like sjohnson said.

Use a metal tubing sleeve like automotive brake line which you can buy in small sections from places like NAPA.

rigore

Discussion Starter · #8 · Apr 3, 2010

Thanks everyone for the great information. I have never used a bucking bar to form a rivet, don't know what it is??? What I did do is make a support for the rivet heat to sit in while I peen the other side. Here is a picture of the rivet I am using.

Picture from: AK building from soup to nuts

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sjohnson

· #9 · Apr 3, 2010

rigore said:
Thanks everyone for the great information. I have never used a bucking bar to form a rivet, don't know what it is??? What I did do is make a support for the rivet heat to sit in while I peen the other side. Here is a picture of the rivet I am using.

Picture from: AK building from soup to nuts

A support for the rivet head IS a bucking bar

Liar! :rofl:

Seriously, you're on the right track. Take it slow and it'll come out pro.

hcpookie

· #10 · Apr 3, 2010

One thing, though, I wouldn't use a rivet for the hammer axis pin :rofl:

rigore

Discussion Starter · #11 · Apr 3, 2010

lol guys!

zoom6zoom

· #12 · Apr 4, 2010

I got the correct size tubing in bulk from Aircraft Supply, cut it to length and heat treat, works great. Irks me to pay eight bucks for a center support and rivet no matter how good they are.

hk22045

· #13 · Apr 4, 2010

how do you hold the tubing in place

i get the idea of using the tubeing as a center support, but how do you hold the tubing in place? do you put a rivet thru it?

hcpookie

· #14 · Apr 4, 2010

Yes the "typical" center support is a piece of tubing into which the rivet is inserted. I've got a cut section of a Bulgarian receiver and its obvious that's what they did. They crimp the tubing flat on top to A) clear the carrier and B) keep the tubing from moving. Heck on my brother's AK we did it so good that he shot a few hundred rounds through it without a center support

I bought a 3' long section of 4130 thick tubing that does NOT let the carrier clear, so whenever I need another center support I drill it out, cut it down, then chuck it in the drill press or lathe and file/sand the outside down to a thinner section. Lots of work.

The brake line repair section tubing is IMO the easiest way to do it. My dad got a small section for his and my brother's AKs and it works like a charm. Just don't go crazy with the hammer - this piece doesn't act as a load bearing surface like the rivets do, so the ends only need to be peened down to hold it in place.

The good thing about tubing vs. those commercial center supports is that if you need to widen the receiver due to heat issues when you spot weld the rails, it is a trivial matter to do so by using a slighly wider center support. ANd as you may know the faster you spot weld it together the more likely it is to warp during cooldown and give you an inwardly-tapered receiver. Answer - wider tubing to compensate. Simple!

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shotgunner

· #15 · Apr 4, 2010

I normaly use the support rivet & tube that comes in the rivet set.
The large head goes on the right side (selector side) that is why the head is so flat.
You can use your long rivet jig to mash the center support rivet just turn over the bucking bar, and use the flat on the back to rest the rivet head.
For the gas piston rivet you can use a small finishing nail and hammer it in to get the head to swell to fill the hole, file & sand then finnish.

allesennogwat

· #16 · Apr 4, 2010

Measure the inside trunnion width and subtract the thicknesses of both lower bolt rails. They are usually different widths from each other but not always. That's the length of the center support tube.

rigore

Discussion Starter · #17 · Apr 4, 2010

I stock 5/16" x .035 wall hydraulic tubing for my customers, so since the rivet does not have to fill the void in the tubing it should be fine? I found this info. on another post for center supports:

Here are some center support specs.

The Inner Diameter (I.D.) needs to accommodate a 3/16" (or 4.5mm) rivet shank. The material I used:
5/16" O.D. 4130 steel tubing
0.065" wall thickness
0.183" I.D.

the length varies and is usually around 1.150" but you should cut them long and trim, file or grind to proper length for each build.

rigore

Discussion Starter · #18 · Apr 5, 2010

kernelkrink said:
Yep, use the pre-formed head on the side opposite the selector and just flatten the other end until it clears the selector, supporting on a steel backer plate. Look at a factory AK, that's how they're done although I assume they have a jig and mechanical hammer to flatten it.

1/8" hole drilled through the gas piston and use a shank from an old Dremel grinding stone. Perfect size, smashes easily, and most Dremel owners have a pile of them.

The Dremel shank idea worked great! As they say the kernel is always right!
Now on to the center rivet.

Thanks

rigore

Discussion Starter · #19 · Apr 5, 2010

Center rivet done! Assembly of the bolt and install the trigger and then off to test fire.

Thanks again.

zoom6zoom

· #20 · Apr 6, 2010

Another tip is to make sure your rivet diameter matches the ID of the support closely; if it's much smaller it will tend to collapse inside the tubing when you try to peen the ends. Tapco ones used to be really bad about this.

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