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10/20/2017 1:01:18 AM
9/22/2017 12:11:25 AM
Posted: 9/11/2005 6:13:37 AM EDT
One of the first things a Newbie AK builder comes across is the sad fact that all trunions are not created equal. Even trunions that look the same can be a few milimeters off from one to the next, from one gun to the next.

One of you guys should come out with the "Standard Build Trunion" starting with the rear trunion. Stanardize the hole pattern. Take the guess work out of trunion hole measurment. have a:

Standard "Solid Mount" Trunion- Made for the replacement of solid rear stocks.

Standard "Underfolder" Trunion - Self Explanitory

Standard "Side Folder" Trunion

Standard Chinese Trunion &

Standard Forged Receiver Trunion.

You'd stand to make a good amount of money. Have a "model" trunion to be used with the 1.6MM receivers.

Just making the rear trunions will make you alot of money. I know I would have bought one from you. Alot of the anxiety associated with building an AK for the first time is due to the drilling of Trunion holes. I know all you have to do is use the old sheet metal as a template, but imagine if you didn't have to? No old rivets to grind off, no more measuring.

I wonder why no one has done it yet?
Link Posted: 9/11/2005 8:17:40 AM EDT
OK, I have a machine shop and have been involved in manufacturing, so I will take a shot at this.

1. There is no way that it would be profitable for a machinist to make and market standard trunnions unless he liked to work for pennies per hour. I wont debate this point. If it is not already obvious, it would take too long to explain. If you think I am wrong, buy a machine shop (or just contract with one) and execute your idea for yourself. While you are at it, make another fortune making Romanian style side folders.

2. If drilling the old rivets out is a problem, you can buy new replacement trunnions here: http://www.aa-ok.com/AK_Receiver_Parts/Receiver_Parts.html

3. Drilling the receiver to match the trunnion is no big deal. Just drill a small hole in approximately the right place and then open the hole up using a Dremel.

Link Posted: 9/11/2005 8:45:23 AM EDT
Link Posted: 9/11/2005 11:58:00 AM EDT

Originally Posted By thedukeryan:
Ozzy where are you in Ks?



EM sent
Link Posted: 9/11/2005 4:25:25 PM EDT
Link Posted: 9/11/2005 5:50:01 PM EDT
I ought 2 of the pistol trunnions from Azex arms.

There were phenominal adn installed with no problems.

Worth every dollar.
Link Posted: 9/12/2005 12:40:03 AM EDT
[Last Edit: 9/12/2005 12:41:26 AM EDT by Atreides]
As Bulldog has proven, there is a market for such a thing.

As for manefacturing costs, I understand how cost intensive it would be to produce a standardized copy of current trunions...

But how much would it cost to produce simplified blocks? In essense, that's all a rear trunion is: a block with holes drilled in it. The standardized trunions don't have to look like current trunions, all they have to do is WORK like the current ones do. Of course the side folders do need more work to produce the outside hinge: so forget them.

I think the fact that the "new" trunions don't have to resemble the factory ones has been overlooked. Make them a rectangle thats a little longer and needs 4 rivets to secure. This would offer the back of the receiver more structual strength as well.

Forget machining out the center of the block to accomodate the use of the short rivets. Now how expensive would it be to produce a drilled out block of metal? No frills, no cutouts, nothing. A Universal block trunion with the center cut out to accomodate underfolders, but with holes drilled out for use with solid stocks as well.

Of course due to the fact that these trunions no longer use the same 3 rivet patten as the stock units, a Xeroxed template would be included in each kit.

I've been talking to one of the machinists that work in the shop behind mine, and we have been talking about making a customized trunion for my Krinkov. Of course the production unit wouldn't be made like this, but mine will.

The body of the trunion will be made of billet Aluminum. The holes for the rivets will be drilled oversized to allow steel sleeves to be pressed in to give the rivets something hard to grab on to. The Aluminum block will be bolted to a iron plate that will run along the bottom of the receiver all the way to the pistol grip mount. This plate would then be riveted to the receiver from the bottom. The plate will serve as a reinforcement for the pistol grip giving it a solid base to be bolted to. This has traditionally been a weak point to the stamped receivers. We'll get around to it when the time comes.

Anyway, thanks for the input guys. And thank you for a machinests point of view OZ.

**Note: I know drilling the trunion holes is no big deal ozzy, but alot of beginners DO, and would rather have a straight foward no brainer solution to the task.
Link Posted: 9/12/2005 6:15:05 AM EDT

Originally Posted By Atreides:
As Bulldog has proven, there is a market for such a thing.



All He has proven is there is a market for pistol trunnions, which nobody ever denied.
People will pay for a pistol trunnion, because none exist.
How many are going to drop $50 bucks for a rifle trunnion, when they already have one?

It is a lot more than just a block with 2 holes in it.
It must be machined for the recoil spring Assembly as well as the ears that engage the upper rails.
Link Posted: 9/12/2005 6:38:04 AM EDT
What the heck are you talking about? If you think the rear tang has lots of frills, you need to look again. You can't just drill out a block of metal and use it. It has a shape and the shape has a purpose.


Originally Posted By Atreides:
I think the fact that the "new" trunions don't have to resemble the factory ones has been overlooked. Make them a rectangle thats a little longer and needs 4 rivets to secure. This would offer the back of the receiver more structual strength as well.

Forget machining out the center of the block to accomodate the use of the short rivets. Now how expensive would it be to produce a drilled out block of metal? No frills, no cutouts, nothing. A Universal block trunion with the center cut out to accomodate underfolders, but with holes drilled out for use with solid stocks as well.

Link Posted: 9/13/2005 12:08:19 AM EDT
[Last Edit: 9/13/2005 12:16:13 AM EDT by Atreides]
You're missing the point Jim.

Yes, the stock trunion DOES have the center cut out, with curves here and there, but all those things are not nessesary to do the trunions job. The trunion caps off the recievers end, and helps with the structual strength because the sheet metal alone would prove too weak to stand alone. That's it's purpose. If a softer metal like aluminum were to be used, the more material actually used the better.

A functioning trunion does not have to look like a stock one to work.

I hear you maxx, maybe I over simplified my description, but in essence my trunion will be a Block. If the plans go through OK I will post a pick of mine when it's done. My friends gonna use 'cut offs' (scrap billet pieces) to make mine. I'm gonna engrave my shop logo on the back too time permitting.
Link Posted: 9/13/2005 5:12:30 AM EDT
I await the pictures and the cost figures, this should be educational.
Link Posted: 9/13/2005 5:29:03 AM EDT
Just so everyone knows, the part that is called the "trunnion" is the block in the front of the gun that the barrel goes into. No other part on a gun is called a trunnion (If you want to be correct!)
Link Posted: 9/13/2005 5:46:32 AM EDT
Thanks, what do you call that thingy at the back?
Link Posted: 9/13/2005 8:17:02 AM EDT
[Last Edit: 9/13/2005 8:19:04 AM EDT by terma-nator]

Originally Posted By Texxut:
Thanks, what do you call that thingy at the back?


There's no "official" name. But most people call the part in the back that they mount the stock to a "tang" or "rear tang". If it's a folding stock a "sidefolder mount"......

Only thing that gets to be called a "trunnion" has a barrel going into it. Anything else is not a trunnion. If it's a milled receiver, then the whole receiver is considered a trunnion.

The only people who call it a "rear trunnion" are those that don't know any better.
It's like calling the exhaust pipes on a car the "rear carburetors".
Link Posted: 9/13/2005 8:30:08 AM EDT
I guess I am because I still don't know what you hope to accomplish with this.
You keep saying you're going to make the tang a block, bigger than it is now. Ummk. Where do you plan to add material? To the bottom, so everytime your tang is used, someone will have to cut the stock down, effecitively weakening the wood? To the top, so it interferes with the recoil guide rod (never can remember the right name)? You can't bulk up the sides because the receiver is there. You can't bulk up the front, you'll get into the trigger and bolt/carrier area. You could add material to the back, but then you're just cutting on your stock again.
So, where do you plan to add material and what will you give up to add it? And will the perceived cost savings outweight the labor involved in cutting down the stock or whatever?


Originally Posted By Atreides:
You're missing the point Jim.

Yes, the stock trunion DOES have the center cut out, with curves here and there, but all those things are not nessesary to do the trunions job. The trunion caps off the recievers end, and helps with the structual strength because the sheet metal alone would prove too weak to stand alone. That's it's purpose. If a softer metal like aluminum were to be used, the more material actually used the better.

A functioning trunion does not have to look like a stock one to work.

Link Posted: 9/14/2005 11:12:39 AM EDT

Originally Posted By terma-nator:
Just so everyone knows, the part that is called the "trunnion" is the block in the front of the gun that the barrel goes into. No other part on a gun is called a trunnion (If you want to be correct!)



While technically you are correct, it is really a stock tang, I gave up trying to correct people long ago.
Just like the folks who insist on calling mags clips.
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