[hotbarrel]

each time I replace the gas piston I need to replace the rivet and I do not find them for sale. I guess this is a good thing because it has forced me to come up with a good method to make my own. I have done two methods and both have worked well for me.
both require the rivet removed properly. you have to locate at least
one side of the pin that holdes the piston in. use a pin ounch and mark
the center on the rivet head this is to keep the drill bit centered
when you start drilling. I then use a 1/8" drill and drill enough to just
remove the rivet head. then you can punch the rivet out. do not drill
all the way through
1 I will start with the simpelest method first. Start with a nail and grind the edjes of the head down till it looks like a rivet. leave the head a tiny bit bigger than the countersink in diameter and thickness. this is so you can hammer it in tight. I have used finish nails for this and common nails. I think 8p or 10p nails. they should be just under 1/8 inch diameter. I have just used a sideing trim nail in my last build gust grind the head a tiny bit. next is to put the rivet through the hole in the carrier and cut it off. it has to be LONGER that it looks. I cut it off with about 1/4 inch sticking out the other side. NOW THE RIVET IS DONE. by done I mean ready to install, installation is the same for both method made rivets and will follow.
2 The next method starts with a straight rod. I had to do this with one of my polish kits because the carrier is polished. I did not use a nail due to the fact that I wanted it to be stainless steal. this way it would match the polished carrier . I bought I piece of 1/8" stainless welding rod at welding supply for cheap money.. I got a piece of 1' square stock about three inch long and a piece of 1/2" X 1" again about three inch long. THIS IS THE BASE. I drilled two holes through the base and into the 1" block. One hole at each end. Then I tapped the holes in the block 10/32. next drill the base holes oversize so the screw will slip through. This will allow you to screw the base to the block. The next step is to countersink the two holes in the base. this is so you can use flat head screws and they will alow the block to sit flat on the base and not sit on the screws. Now take the base off and drill a 1/8" hole all the way through the 1" block and countersink the top of the hole enough to form the head of the rivet. realy it is a very simple tool to make, most of the measurements are not too critical. just two screws holding a base to a block with a hole in it.
Now to make the rivet. take the stainless rod and cut it about 1&3/16" long. that is 3/16 longet than the hole is deep. Just drop the pin into the hole and it will stop on the base. again you will have about 3/16 sticking out this will form the head. I use a frameing hammer to form the head. USE safty glasses :rockin: I hold the block on my anvil with one hand and tap the pin down into the countersink to form the head with the other hand.
It is very important to watch the pin with each tap. as the pin moves, bends, flexes, and crushes into the countersink you can see it move each tap. you will need to tap in differant directions to keep from just folding it over. Once it is down you can work the metal around to fill the countersink again by tapping in differant directions. You will be able to see each impact to the head by watching closely. You will see how each blow is affecting the head and what you need to do to get what you need. Tap the head tight into the countersink, but leave it mounded up some so it can be tapped into place later. all that is left is to take the two screws out of the tool and you will have to DRIVE the new formed rivet out of the block. flip it over and drive it out with a punch.
this hammering metal into the shape you need may sound difficult, but it is not after you do a few. plan on a few OOPs. It is better to OOPs here that when you are installing the rivet. but either way you can remove the rivet and start again even if you have to drill and punch it out. I REALY ENJOY THIS METAL FORMING. Actualy hammer forming a real useable part,, NOW THAT IS . Once you see and get the feel of the metal moveing you will enjoy it too, and get the pride of TRUE hand formed :rockin: parts

 

[hotbarrel]

now for install
first you need the piston installed in the correct place. I measure the old piston length from the front of the carrier before removel. If you have no measurement then screw it all the way in then back it off 1/2 th 3/4 a turn. the piston MUST be loose "wiggely" not tight.
starting the rivet you need the hole through the piston, and to have the hole centered in the countersinks of the carrier. I center the holes by drilling half way through from each side NOT all the way through from one side. The hole in the piston should be a few thousandths larger than the rivet diameter. this is to keep the piston loose. Push the rivet through the hole and it should extend about 3/16 out the other side. trim to fit. I put the protruding end into a hole in my anvil and tap the head into the countersink filling the countersink, leaving it high is fine as long as the hole is filled. now flip the carrier over and tap the rivet to form a head and to fill the countersink. this is exactly the same as described in the above post to forf the head. keep tapping and CAREFULLY looking at how the rivet is reacting to each blow till the entire countersink is filled. It is important to tap enough to fill the countersink but do NOT tap so much to tighten up[ the piston. if the piston dose get tight you can try to loosen it up by turning it ever so slightly. Do not bend it. After you are happy with the rivet then use a small file and file off the high sopt of the rivet head. try not the file the carrier but this is for looks only . now I put a drop of blue on the rivet heads and the sight rivet should go away. if it is a polished carrier and a stainless rivet then skip the blue. rivet installed :rockin:
any one with additional info please feel free to add to the post and it will be togeather.

 

[machman]

That is some great information. And good timing, too. I am in on the Tapco Group buy on the other site and it won't be long until they will be shipping them out.

Thanks for taking the time to post that info.

 

[7.62x39]

Good info, HB.

Thanks for sharing.

 

[Toten Kopf]

Great info 'hotbarrel', this goes into my keep file.

Thanks