What diameter rivits are used on the rear trunion?

[6500rpm 670]

Can anybody tell me the diameter on the long and short rivits used on the rear trunion? I'm going to pull the sight rail and think I can just mill the head off the one shared by the rear trunion/rail and re-form with what's left, but it's good to have a back up plan. If nothing else, there was a thread earlier that got wondering if they're the same as most typical AK rivits or larger?

[HillBilly2 9]

Can anybody tell me the diameter on the long and short rivits used on the rear trunion? I'm going to pull the sight rail and think I can just mill the head off the one shared by the rear trunion/rail and re-form with what's left, but it's good to have a back up plan. If nothing else, there was a thread earlier that got wondering if they're the same as most typical AK rivits or larger?

 

The long one is .173 x 1.650 end to end. The short ones are .157 x .406 end to end. Thats measuring what they sent with a bulgy side folder kit. btw, they get larger near the head, more of a taper that a swell neck.

[6500rpm 670]

Is this specific to the S12, just what the Bulgarian folder uses, or one in the same?

[floytt 0]

So, what are the specs on the standard AK trunion rivits? I think that the string that got 6500 thinking about this is mine. I won't have my new trunion 'till late next summer, but if they're different I need to know soon so that I can start figurin' out how to replace them. can anybody mic up standard trunion pins and tell me?

 

thanks, Hench

Edited February 24, 2009 by Henchman

[6500rpm 670]

FWIW, I removed the sight rail tonight. The short trunion rivit looks to be .180" diameter (measured with calipers after the rail was removed). You have to remember that this rivit had already been set to hold the rail in place, I just milled the head off and removed the other two rail attachment rivits and pulled the rail leaving the rest of the rivit intact. I have .149" of protrusion to form a new head.

I have no idea of the diameter of the long rivit, probably the same, but it would be nice to know. Hench, they vary just a bit- the AK Builder (AKM) Long rivits are .170" dia, Short (swell neck and standard) are .151" dia as measured w/ calipers.

***Now this was a little concerning-the original rivit has a small gap (big enough to run a pick around) between the rivit and hole in the receiver. This gun only has about 50 rounds through it at this point. I would imagine there would be plenty of clamping force when the rail was installed, but I thought the diameter of the hole would have been smaller. I think I'll give all of them a bit more squish before I'm done.

[floytt 0]

FWIW, I removed the sight rail tonight. The short trunion rivit looks to be .180" diameter (measured with calipers after the rail was removed). You have to remember that this rivit had already been set to hold the rail in place, I just milled the head off and removed the other two rail attachment rivits and pulled the rail leaving the rest of the rivit intact. I have .149" of protrusion to form a new head.

I have no idea of the diameter of the long rivit, probably the same, but it would be nice to know. Hench, they vary just a bit- the AK Builder (AKM) Long rivits are .170" dia, Short (swell neck and standard) are .151" dia as measured w/ calipers.

***Now this was a little concerning-the original rivit has a small gap (big enough to run a pick around) between the rivit and hole in the receiver. This gun only has about 50 rounds through it at this point. I would imagine there would be plenty of clamping force when the rail was installed, but I thought the diameter of the hole would have been smaller. I think I'll give all of them a bit more squish before I'm done.

 

Hey 65, I think I will try to get a pin set from tula too, if I can. .015" differance sounds like a lot. between the Ak buider and the stock S-12 pins. oops .180" minus .170" is 010" duh, but still, too much no? I still havn't taken pics.

Edited February 25, 2009 by Henchman

[6500rpm 670]

Hopefully Tony or one of the Builder/Business members will pick up on the thread and verify. The bolt carrier on the S12 has a bit more mass so I can see the need for bigger rivits. Curtis at AKBuilder.com probably knows, but he likes to talk.....a lot sometimes

Rule of thumb for a good dome when forming a head is the length needs to be about 1 1/2x the diameter. I got extremely lucky since I formed this one to match the other side which is flat with just a slightly tapered edge. Ended up with a head diameter of .259" and visually just a nats ass shallower. I'm good, good luck with your project. Every day's a learning experience.

[floytt 0]

Hopefully Tony or one of the Builder/Business members will pick up on the thread and verify. The bolt carrier on the S12 has a bit more mass so I can see the need for bigger rivits. Curtis at AKBuilder.com probably knows, but he likes to talk.....a lot sometimes

Rule of thumb for a good dome when forming a head is the length needs to be about 1 1/2x the diameter. I got extremely lucky since I formed this one to match the other side which is flat with just a slightly tapered edge. Ended up with a head diameter of .259" and visually just a nats ass shallower. I'm good, good luck with your project. Every day's a learning experience.

 

Still hopin' that the lil' woman comes back from Russia with a factory set along with a new trunion in July. thanks for the good luck wishes, because I have so much to learn, luck my play a large part. Tom and I are starting with those home made tools you sent me on that link. I do not think that I can adequatly express my gratitude for all your help and information with this project. thanks.

Edited February 25, 2009 by Henchman