Screwing trunnions?

meatgrinder42 · September 23, 2011, 09:08 AM

I've been looking around at AK builds and have been seeing a lot of guys tapping their trunnions and bolting them into the receiver with 10-32 bolts. Is this safe to do? I mean they were riveted from the factory for a reason weren't they?

jaguarxk120 · September 23, 2011, 03:31 PM

Riveting is for ease of manufacture.

Think about the tooling and extra labor required to drill/tap/install the screws. Insert rivets, place in press hit the cycle switch and your done.

The screws should work fine for what you want to do.

meatgrinder42 · September 24, 2011, 08:54 AM

Thanks for responding, I kind of figured it was because rivets are easier to mass produce but I was just making sure.

Harry Bonar · September 24, 2011, 09:22 AM

Sir
I have long advocated on these "pressed in barrels held with a pin" that the trunion be threaded, and the barrel (of sufficient diameter) be threases and screwed up properly to the trunion like Remington does the 760 and 740 rifles, at some others!
Pressing barrels in with a pin holding them is a very poor way to do it!
Harry B.

guncrank · September 24, 2011, 12:05 PM

Screws work
The buttonhead screws look better IMO

Gunplummer · September 24, 2011, 06:14 PM

Screws are O.K. for what you want to do (Use lok-tite). The rivet situation was not always for ease of manufacture. We had a terrible time with M-60 receivers coming loose because the rivets were too hard. Welding was tried and made the situation worse. Finally annealed (Softened) rivets were used and the issue resolved. Screws used on a M-60 (Hard or soft) would have come loose.

meatgrinder42 · September 27, 2011, 03:03 PM

Okay next question, will this also work on a PSL? Since the PSL fires a heavier round would that snap the bolts?

And is red loctite enough or do I need to go Green?

chack · September 28, 2011, 01:10 AM

I've never liked screw build AKs, although they do work. My concern is that the screws would come loose. I've seen it happen.

I've also seen rivets come loose, but I think they weren't installed correctly.

Welding the trunnion to the receiver is a good. cheap home build method, but has the down side of not being able to reverse. It is plenty strong though and has worked for H&K and CETME for decades.

Riveting is the best way I think, but to really be right, the trunnion needs to be riveted to the receiver without the barrel installed in it,

September 23, 2011, 09:08 AM	#1
meatgrinder42 Senior Member Join Date: July 1, 2011 Location: Good Ol' Wisconsin Posts: 327	Screwing trunnions? I've been looking around at AK builds and have been seeing a lot of guys tapping their trunnions and bolting them into the receiver with 10-32 bolts. Is this safe to do? I mean they were riveted from the factory for a reason weren't they? __________________ When I die better bury me deep, two .45s layin' at my feet, An M16 across my chest, tell Chesty Puller I did my best

September 24, 2011, 08:54 AM	#3
meatgrinder42 Senior Member Join Date: July 1, 2011 Location: Good Ol' Wisconsin Posts: 327	Thanks for responding, I kind of figured it was because rivets are easier to mass produce but I was just making sure. __________________ When I die better bury me deep, two .45s layin' at my feet, An M16 across my chest, tell Chesty Puller I did my best

September 24, 2011, 09:22 AM	#4
Harry Bonar Senior Member Join Date: December 5, 2004 Location: In the Vincent, Ohio general area. Posts: 1,804	pressed barrels Sir I have long advocated on these "pressed in barrels held with a pin" that the trunion be threaded, and the barrel (of sufficient diameter) be threases and screwed up properly to the trunion like Remington does the 760 and 740 rifles, at some others! Pressing barrels in with a pin holding them is a very poor way to do it! Harry B.

September 24, 2011, 12:05 PM	#5
guncrank Senior Member Join Date: July 15, 2006 Location: Fern Creek ,KY and Metro Louisville at large Posts: 430	Screws work The buttonhead screws look better IMO __________________ Republic Arms and Armaments 07 1-502-231-1118 Machine Shop and Finishing Services to the trade and public

September 27, 2011, 03:03 PM	#7
meatgrinder42 Senior Member Join Date: July 1, 2011 Location: Good Ol' Wisconsin Posts: 327	Okay next question, will this also work on a PSL? Since the PSL fires a heavier round would that snap the bolts? And is red loctite enough or do I need to go Green? __________________ When I die better bury me deep, two .45s layin' at my feet, An M16 across my chest, tell Chesty Puller I did my best

September 23, 2011, 03:31 PM	#2
jaguarxk120 Senior Member Join Date: February 28, 2008 Location: Michigan Posts: 2,620	Riveting is for ease of manufacture. Think about the tooling and extra labor required to drill/tap/install the screws. Insert rivets, place in press hit the cycle switch and your done. The screws should work fine for what you want to do.

September 24, 2011, 06:14 PM	#6
Gunplummer Senior Member Join Date: March 11, 2010 Location: South East Pa. Posts: 3,364	Screws are O.K. for what you want to do (Use lok-tite). The rivet situation was not always for ease of manufacture. We had a terrible time with M-60 receivers coming loose because the rivets were too hard. Welding was tried and made the situation worse. Finally annealed (Softened) rivets were used and the issue resolved. Screws used on a M-60 (Hard or soft) would have come loose.

September 28, 2011, 01:10 AM	#8
chack Junior member Join Date: May 24, 2011 Location: dixie Posts: 477	I've never liked screw build AKs, although they do work. My concern is that the screws would come loose. I've seen it happen. I've also seen rivets come loose, but I think they weren't installed correctly. Welding the trunnion to the receiver is a good. cheap home build method, but has the down side of not being able to reverse. It is plenty strong though and has worked for H&K and CETME for decades. Riveting is the best way I think, but to really be right, the trunnion needs to be riveted to the receiver without the barrel installed in it,