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Posted: 3/11/2006 7:05:24 PM EDT
Anybody successfully welded the trunion to the receiver instead of riveting or screwing it?
Link Posted: 3/11/2006 7:10:40 PM EDT
THAT IS THE BIGGEST NO-NO FROM WHAT I UNDERSTAND!!
Link Posted: 3/11/2006 7:56:48 PM EDT
[Last Edit: 3/11/2006 7:58:46 PM EDT by uxo2]
TIG or MIG...
Just be sure to open up the holes to I belive a 1/4in to make a plug weld...
3 on each side work.
If you still have the rivets in them...leave them,just grind them flat to the trunnion...
Same with the rear...and weld in between the rivet gaps instead of on the rivet...
On the trunnion is where you want the weld and not on the former rivet.
Riveting is the prefered method but MIG or TIG will work JUST fine..
Besure you have a Professionla welder do it and not some shadeTree welder..
And if you do find a shop...Go with TIG or Heli-arc..
Don't walk in to a shop with a compleat rifle..Just take the reciever and Barreled trunnion and rear so it doe not look lethal weapon.
Also have everthing lined up and held togther with a C-clamp because some welders will literally throw it around...
You can dress up the welds using some fine polishing wheels or a dremil with the appropiate bit.
When it is done...It will give off the slight resemblance of a milled reciver with the center support to confirm otherwise.
And DO NOT USE STICK or GAS to weld...To much heat is generated and will nullifiy the temper of the receiver and trunnion.

Link Posted: 3/11/2006 9:05:13 PM EDT

Originally Posted By uxo2:
TIG or MIG...
Just be sure to open up the holes to I belive a 1/4in to make a plug weld...
3 on each side work.
If you still have the rivets in them...leave them,just grind them flat to the trunnion...
Same with the rear...and weld in between the rivet gaps instead of on the rivet...
On the trunnion is where you want the weld and not on the former rivet.
Riveting is the prefered method but MIG or TIG will work JUST fine..
Besure you have a Professionla welder do it and not some shadeTree welder..
And if you do find a shop...Go with TIG or Heli-arc..
Don't walk in to a shop with a compleat rifle..Just take the reciever and Barreled trunnion and rear so it doe not look lethal weapon.
Also have everthing lined up and held togther with a C-clamp because some welders will literally throw it around...
You can dress up the welds using some fine polishing wheels or a dremil with the appropiate bit.
When it is done...It will give off the slight resemblance of a milled reciver with the center support to confirm otherwise.
And DO NOT USE STICK or GAS to weld...To much heat is generated and will nullifiy the temper of the receiver and trunnion.




that and the stamped dimple mag wells, stamped X and Y pin access holes, spot welds for rails, etc.
Link Posted: 3/11/2006 9:11:55 PM EDT
RUBBISH!
I've stick welded (with 7018) about 15 with no failures. YMMV
Link Posted: 3/12/2006 12:03:42 AM EDT
I MIGGed up one and then later TIGed up one...both ran fine, at lease 1k rounds each...

The main problem is that you have to be a skilled welder...if you don't get good penetration, it will come apart and be a huge safety issue. Once it's done you have no way of knowing if the weld is good or not...

I mostly rivet everything, but for those beater kits on cheap home brew receivers, welding cuts down on the time factor.

Link Posted: 3/12/2006 2:17:05 AM EDT
i would trust a welded gun befor a screw/drivescrew build (if i knew it was done right)

you need to drill threw the rec and into the trunnion
not just a hole threw the rec
Link Posted: 3/12/2006 2:24:34 AM EDT

Originally Posted By JosephR:
THAT IS THE BIGGEST NO-NO FROM WHAT I UNDERSTAND!!



I've heard of it being done safely, but I wouldn't recommend it. Too much stuff can go wrong and the margin of safety depends on how competent the welder is. Also, you can screw up the heat treating/tempering of the receiver if you're not careful. The tools for riveting an AK are much cheaper than welding equipment would be and require far less skill, also, riveting is the tried and true factory method.
Link Posted: 3/12/2006 7:57:57 AM EDT

Originally Posted By Real_estate_salesman:
RUBBISH!
I've stick welded (with 7018) about 15 with no failures. YMMV



There is a reason that MIG and TIG and Heli-Arc welders are used....
Because stick cannot give the quality and strength of the others...
Gas welding was good too and then stick came along....

And to quote ...TheNorm
The main problem is that you have to be a skilled welder
..
That is the truth.
Link Posted: 3/12/2006 5:41:40 PM EDT

Originally Posted By socandyman:
i would trust a welded gun befor a screw/drivescrew build (if i knew it was done right)




Yep I totally agree. The more screw builds I see the more leary of them I get. There is not enough thread engagement to trust it. I have been quiet about the whole screw drive thing. I don't like it at all...I think people are getting more excited about an easy method than really thinking about how that fastner could fail under use. I also think the reason we don't see a lot of guns failing is that a lot of people don't shoot them that much...the few that DO shoot them a lot I think are really risking things in these sub-standard methods.

Link Posted: 3/12/2006 6:54:16 PM EDT


Yep I totally agree. The more screw builds I see the more leary of them I get. There is not enough thread engagement to trust it. I have been quiet about the whole screw drive thing. I don't like it at all...I think people are getting more excited about an easy method than really thinking about how that fastner could fail under use. I also think the reason we don't see a lot of guns failing is that a lot of people don't shoot them that much...the few that DO shoot them a lot I think are really risking things in these sub-standard methods.



Okay, I'm not trying to be a smartass: I'm genuinely curious. Say a screw/drive screw build fails. What exactly happens? Do the screws shear off? Back out instantly and catastrophically?

I'm having a hard time picturing what would actually occur.
Link Posted: 3/12/2006 8:25:25 PM EDT
[Last Edit: 3/12/2006 8:26:13 PM EDT by Bob1984]

Originally Posted By skywarp989:


Yep I totally agree. The more screw builds I see the more leary of them I get. There is not enough thread engagement to trust it. I have been quiet about the whole screw drive thing. I don't like it at all...I think people are getting more excited about an easy method than really thinking about how that fastner could fail under use. I also think the reason we don't see a lot of guns failing is that a lot of people don't shoot them that much...the few that DO shoot them a lot I think are really risking things in these sub-standard methods.



Okay, I'm not trying to be a smartass: I'm genuinely curious. Say a screw/drive screw build fails. What exactly happens? Do the screws shear off? Back out instantly and catastrophically?

I'm having a hard time picturing what would actually occur.



My guess is that they would begin to fail slowly by shearing off, with the trunnion/barrel sliding forward slightly out of the receiver every shot, most likely you'd get some failures to feed at first from the resulting gap between the magazine and the feed ramp then you would eventually have the front half of the gun fall/fly out. You'd also likely have the receiver cover and possibly bolt carrier fly off, too. The cover and carrier are what is most likely to injure you if the gun fails.
Link Posted: 3/12/2006 8:33:05 PM EDT
So it's the shear strength of the screws/drive screws that is under question? Rivets are stronger in that regard?
Link Posted: 3/12/2006 8:41:33 PM EDT

Originally Posted By skywarp989:
So it's the shear strength of the screws/drive screws that is under question? Rivets are stronger in that regard?



Most likely, considering the direction of the forces of being fired are acting on the weapon. Back to front (force pushing forward), not side to side.
Link Posted: 3/12/2006 9:48:56 PM EDT
Imagine a thin piece of metal and a screw in it...then let the fastener fail due to too few threads...basically the threads fail, either on the screw, the trunion or both, not because the metal is weak, just because there is not enough of it to hold.

The rivets probably are not any stronger than decent screws...in fact I would venture to geuss that a good bolt has more tensile and shear strength than a good rivet...but either one installed incorrectly (and IMHO minimal threads for screws and improperly smashed rivets (drive screws) are such things), can fail.

As said above, I think the failure would be in sliding action between the trunion and receiver and eventually some very funky play in the components... it could get ugly.
Link Posted: 3/12/2006 10:53:59 PM EDT
[Last Edit: 3/12/2006 10:59:19 PM EDT by Journier]
just finished doing a weld together job. Turned out really decent.
Link Posted: 3/12/2006 11:38:20 PM EDT

Originally Posted By Journier:
just finished doing a weld together job. Turned out really decent.



Pics ? I haven't seen many pics posted of welded builds.
Link Posted: 3/12/2006 11:42:34 PM EDT
basicly its like this
the ak has a built in system to stop it from firing without the bolt being locked in
if the bolt isnt locked in then the hammer cant hit the firing pin

if your joke of a push pin rivet allows the barrel to move forward
the rifle can fire the bullet in the rec still outside the barrel
and you can say bye bye to the use of your left arm

thought i would add ive been called an elitest an im really not
i was undecided about the drive screws till a few days ago when i saw 1
i coulda pulled that rifle apart with my hands
Link Posted: 3/13/2006 7:24:57 AM EDT
[Last Edit: 3/13/2006 7:26:48 AM EDT by TheOtherChris]

Originally Posted By Bob1984:

Originally Posted By Journier:
just finished doing a weld together job. Turned out really decent.



Pics ? I haven't seen many pics posted of welded builds.



Pic of my welded Romy before refinish. (I hadn't even attached the TG yet as you can see by the machine screw)
I TIG'd the receiver (TAPCO flat) to the rivet stubs and plug weld the lower rails.
I have over 1k through it with no signs of failure.

Refinished in GunKote and it has a nice slick side appearance.

My problem with welding was that I don't own a decent TIG so I have to make special arrangements to use one in a place that isn't as private as I would like.
I now rivet and spot weld in the garage.
It was nice not having to pull the barrel or drill the rear trunnion rivets though.

TheOtherChris

Link Posted: 3/13/2006 10:08:09 AM EDT

Shear forces breaking through screws and drive screws? Hmmm...I doubt it.

Screws getting loose and backing out? Ok, I can go with that.

Only case I can see for u-drive screw build being unsafe is if the loaded barrel, trunion and bolt, fell out of the receiver and landed on the firing pin. Not likely, but still scary to think about.

Link Posted: 3/13/2006 10:36:34 AM EDT
[Last Edit: 3/13/2006 10:40:55 AM EDT by MNGuns]
Read this post, got inspired, went out to the shop and MIG'd a receiver. Tried it first on a older cut receiver to get the settings right, and I was unable to seperate the receiver from the block I welded it to. New DCI receiver to Romy trunnion went way easy. Just a little grinding to do to clean it up, as the plug welds are just slightly above the surface of the receiver. Now that was a fast build.....

ETA: I used the original rivet holes in the DCI receiver, and drilled the rivets out perhaps 1/4" deep so the weld had a good place to fill.
Link Posted: 3/13/2006 10:50:21 AM EDT
Those welded receiver pics look slick! Makes it look like a milled receiver.

Unibodied cars are just welded together and hold up incredibly well in high speed crashes. I might try one. I guess you could always add a couple of screws if cracks appear.
Link Posted: 3/13/2006 11:06:06 AM EDT
Shear forces causing drive screws or screws to fail? I call BULLSHIT. It should be obvious to anyone that the drive screws and the grade 8 screws used in screw builds have more shear strength then a rivet you can crush with a boltcutter. What are the chances that all 6 screws or drive screws will fail all at once? And Candyman, if you saw a drive screw build that you could pull apart with your bare hands, either you are a lot stronger than I think you are or the guy who did the build did a shitty job.
Link Posted: 3/13/2006 11:24:02 AM EDT

Originally Posted By dalesimpson:
Shear forces causing drive screws or screws to fail? I call BULLSHIT. It should be obvious to anyone that the drive screws and the grade 8 screws used in screw builds have more shear strength then a rivet you can crush with a boltcutter. What are the chances that all 6 screws or drive screws will fail all at once? And Candyman, if you saw a drive screw build that you could pull apart with your bare hands, either you are a lot stronger than I think you are or the guy who did the build did a shitty job.



+1
Link Posted: 3/13/2006 11:31:28 AM EDT
I didn't realize how strong the opinions are on this topic. Will we get the flaming folder?
Link Posted: 3/14/2006 8:48:00 AM EDT
So far all three of my builds have been miged by me , I am a collision repair tech and weld alot. My first was a pistol and has more than 3000rnds. down the pipe. The second was a romainian 700rnds. My third is a polish underfolder about 1000rnds. I have had no problems a all. a lot of people really like the way they look. I have had offers of $500. & $600. for my pistol. I have started a 4th, AMD-65. I was going to rivet this one but it took five months to find a global receiver and in that time i lost my rivets so I think i'll take it to the shop and mig it. Any way heres a few pics of my underfolder it has not been refinished yet I just put gun blue paste over the welds....
http://i49.photobucket.com/albums/f260/223burner/IM000455.jpg
http://i49.photobucket.com/albums/f260/223burner/IM000459.jpg
http://i49.photobucket.com/albums/f260/223burner/IM000460.jpg
Link Posted: 3/14/2006 8:53:35 AM EDT
Link Posted: 3/14/2006 12:55:25 PM EDT
I only wish I had asked the question myself earlier. Been dragging feet trying to decided on rivets, drives, screws, etc. I may have thirty minutes into the Romay I did the other day. Needs only blast, blue, and wood work. Had to order two more kits to celebrate....
Link Posted: 3/14/2006 3:50:57 PM EDT

Originally Posted By uxo2:

Originally Posted By dalesimpson:
Shear forces causing drive screws or screws to fail? I call BULLSHIT. It should be obvious to anyone that the drive screws and the grade 8 screws used in screw builds have more shear strength then a rivet you can crush with a boltcutter. What are the chances that all 6 screws or drive screws will fail all at once? And Candyman, if you saw a drive screw build that you could pull apart with your bare hands, either you are a lot stronger than I think you are or the guy who did the build did a shitty job.



+1



+2 He must have had his wheaties that day.
Link Posted: 3/14/2006 4:08:54 PM EDT
musta

i wasnt trying to start a fight

i was just sharing my views on them
Link Posted: 3/14/2006 4:40:54 PM EDT
I TiG most every day at work and home and was wondering about doing an AK that way. Are those receivers you all are using bent and heat-treated when you get them? Was the drill and fill method used for the rail install too? Also, are the flat ones pre- heat treated as well? I have access to a good brake and that would save some bucks, too. Great job guys, those guns look real solid!
Josh
Link Posted: 3/14/2006 10:36:08 PM EDT
Va Gun nut, The other Chris And223 Burner those welds look great! So smooth and clean. I wish I lived near to you so you could weld mine up! nice work guys rvn6869(moses)
Link Posted: 3/15/2006 2:40:00 AM EDT

Originally Posted By Yaash:
I TiG most every day at work and home and was wondering about doing an AK that way. Are those receivers you all are using bent and heat-treated when you get them? Was the drill and fill method used for the rail install too? Also, are the flat ones pre- heat treated as well? I have access to a good brake and that would save some bucks, too. Great job guys, those guns look real solid!
Josh



I used a 100% DCI on mine, rails already attached. I imagine you could drill and fill the rails if you cared to. From what I've read, the flats have to be heat treated after you bend them. I looked at doing it that way myself, and figured after the price of the jig, and the potential oops factors, I'd just buy finished receivers. Glad I did, makes life way easy.....


Link Posted: 3/15/2006 6:41:03 AM EDT

Originally Posted By Yaash:
I TiG most every day at work and home and was wondering about doing an AK that way. Are those receivers you all are using bent and heat-treated when you get them? Was the drill and fill method used for the rail install too? Also, are the flat ones pre- heat treated as well? I have access to a good brake and that would save some bucks, too. Great job guys, those guns look real solid!
Josh



Mine was a TAPCO flat, so "No" it was not heat treated.
I ground the rivet heads off the trunnions, leaving the stubs flush with the old receiver. Popped the receiver pieces off which left the rivet stubs 'proud' of the trunnions. I used a jig to bend the flat, matched the receiver holes to the rivet stubs and welded the stubs to the new receiver (about 45amps). Then lined up the lower rails with the front trunnion and installed the center support and pin (I used a framing nail) to help keep everything in place. Then I drilled through the receiver and into the lower rails. TIG'd everything, including the center support pin in place and heat treated the ejector and FCG pin holes. Finally, I dressed the welds with an abrasive flap wheel, blasted with silica, sprayed with GunKote and heat treated in my gas barbeque.

Have fun and be safe.
Link Posted: 3/16/2006 10:07:44 AM EDT
Those welded receiver look great , I need to get myself a good MIG setup .
Link Posted: 3/26/2006 9:11:43 AM EDT
Excellent postings. I think I want to weld one and see how it holds up to occasional firing.
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