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Rivet build VS Screw build? Wait, what??


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Ok, so there is a prepper I talk to once in a blue moon.  He said he recently purchased a Romanian screw build AKM.  I corrected him and said "A rivet build right?"  I was wrong. Its a screw build.  Is that even safe?  Seriously? Wouldn't you always be checking to make sure that your screws are tight?  It just doesn't seem safe or even realistic.

Edited by reid17
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Properly done, a screw build is just fine. I've done them. I use high strength loctite on all screws after test firing. I thoroughly degrease, loctite all screws, then reassemble. My 1917A1 watercooled I used to have is a screw build and has had thousands of rounds through it, as has my AK build.

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Mine's stayed tight. NEVER had to tighten one screw. Done right, it's fine.

 

Like I said, even my beltfed was fine as a screw build.

 

Hell, my Ferret50 has allen screws in the upper receiver, and it a 50BMG for crap's sake.

 

Scoff if you want, I have the proof within arms reach.

 

We now return to our regularly scheduled baseless opinions.

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I don't think the million's of factory built AK's are baseless, I also don't think if done correctly a screw build is just going to fall apart for a recreational shooter. I do feel rivits provide better clamping force not to mention the swell neck rivet locations that mechanically lock the receiver and trunion. I just finished de-milling a PSL kit yesterday, I've heard a lot of people piss and moan about how hard the barrel pin and barrel are to press out but mine went relatively easy. What did shock me was what it took to remove the trunion rivets. Typically, I drill the centers and knock them out with a punch, in this case it took me almost as long to remove the four small rivets as it did to remove the barrel, the long rivet was another bugger. Note on the PSL trunion pictured, one of the short rivets on each side and the long rivet are swell neck.

 

PSL%20Trunion_zpsoelfdtz7.jpg

Edited by 6500rpm
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Back around 2003, I built a few AMD-65s on parts kits from Centerfire Systems when they were $79.  The first one was on a Vulcan receiver and three more were on Tapco 80% flat AK receivers that you had to bend yourself and weld the rails into.  All were screw builds (using grade 8 hex screws) and all but the Vulcan worked just fine. The Vulcan receiver had no hardening around the axis pin holes and the rivet / screw holes didn't match the trunnion holes.  I end up scraping that one.  I would have preferred to use rivets, but the screws worked just fine.  All are still working to this day. Drilling out the old rivets and tapping the rivet holes was the real bitch!  I probably broke (and chiseled out) a 1/2 dozen taps over 4 builds.  Those trunnions are HARD!

I still have three of those Tapco flat receivers that need to be finished / bend.

 

Macbeau.

Edited by macbeau
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Screw the screws, real men pound rivets!

 

Rivets do not unscrew, and they fill the body of the hole, screws must have clearance or they will not fit through the hole. Rivets fill the mis alignment of the holes in the pieces being joined. Screws do not, they just clamp the two pieces together, as technically a screw is just a spring clamp.

Edited by G O B
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screws were popular when complete barreled kits were coming in. you didn't have to pull the barrel, you'd just drill out the rivets, remove any old receiver scraps, and insert the whole barreled trunnion assembly into a new receiver

 

since barreled kits are all but gone thanks to the MG barrel ban, there's no reason not to completely rebuild using proper rivets.

 

once you have the holes clear and have a bolt cutter tool or press, it should take a few minutes per rivet

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I don't think the million's of factory built AK's are baseless,

 

This is a very flawed argument. 

 

Millions work using method A, =/= method B will not work. Conclusion does not follow.

 

Authority uses method A =/= method A is superior to method B. False appeal to authority error.

screws were popular when complete barreled kits were coming in. you didn't have to pull the barrel, you'd just drill out the rivets, remove any old receiver scraps, and insert the whole barreled trunnion assembly into a new receiver

 

since barreled kits are all but gone thanks to the MG barrel ban, there's no reason not to completely rebuild using proper rivets.

 

once you have the holes clear and have a bolt cutter tool or press, it should take a few minutes per rivet

 

Also affordable bolt cutter riveters are common now, and weren't then, as are plenty of guides that show each step in detail.

Let's not forget that "mil spec" = built by lowest bidder

 

And also unchanged to keep standardization despite the fact that improved parts and ergonomics have been available for decades.

 

Also built to fit a theoretical "average" soldier for a specific theory of usage. If you are that average guy of average body, intelligence, skill, vision, etc. and you plan to use it for exactly the same thing the military consensus of people with incompatible ideas settled on a half century ago, it's going to be a perfect fit. Good thing they were completely right and nothing has changed or been invented since then.

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GunFun, I think you really overthought the whole thread. It has nothing to do with missing value equations, mil spec, or anything other than common practice. When the fist AK's were  built (correct me if I'm wrong) but they were built by communist and I don't think the lowest bidder was a factor and probably had more to do with mass production numbers. To date, almost every gun I can think of is either milled with interlocking parts, welded, or riveted at heavy load points. Screws just aren't a typical method to assemble a firearm, not because they're doomed to fail but most likely more prone to failure than other methods. I'm more inclined to agree with mancat on what was going on when the market was flooded with $99 Romanian kits when the thought process of screw builds came to light. About the only guns I can think of with screws were old cowboy era, granted they didn't have Loctite back then, but missing/replaced screws are typically part of the valuation. Geeeez, both of us had roots in the paintball industry at one time...how many screws/set screws on those damn things came loose or fell out. It's just not a great option for a firearm or a method of assembly to promote. Given all the options to do it right with quality rivets, tools, or plans to make tools available I just wouldn't lead people down the path of a screw build. For those that have one I'm not belittling your build or work ethic, just realize you have other options these days, possibly revisit an old project on a cold winter day to pass the time and learn a new trick.

Edited by 6500rpm
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I've always wondered if anybody back in the days of those complete kits tried hardened steel pop rivets. They can fill in a shitload of material. I suspect they would've worked better than even loctited screws. 

 

any way, at least it's not this

 

002-63.jpg

Edited by mancat
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Post #22 is awful. 

 

 

don't get me wrong above. I don't think a screw build is the best way to go, but I also think it can be done fine and result in a safe, reliable gun. I just think it tends to be a bandwagon. AK purism is rather tiresome to me, because it is such a self contradictory mentality more often than not.  The AK is about making a gun which meets your needs as cheaply and simply as possible. It is a machine of compromises. The lauded milled guns were a compromise and a stop gap, and every version since has been an attempt to improve shortcomings or get around costs. It's bizarre to see people celebrate that on one hand and jump on someone who does the same thing in their circumstances with the other. I don't really see the same degree of dogmatic obstinance with any other weapon platform.

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Post #22 is awful. 

 

 

don't get me wrong above. I don't think a screw build is the best way to go, but I also think it can be done fine and result in a safe, reliable gun. I just think it tends to be a bandwagon. AK purism is rather tiresome to me, because it is such a self contradictory mentality more often than not.  The AK is about making a gun which meets your needs as cheaply and simply as possible. It is a machine of compromises. The lauded milled guns were a compromise and a stop gap, and every version since has been an attempt to improve shortcomings or get around costs. It's bizarre to see people celebrate that on one hand and jump on someone who does the same thing in their circumstances with the other. I don't really see the same degree of dogmatic obstinance with any other weapon platform.

Trust me.  It was not the preferred way even back when it was more popular.  There just weren't a lot of options for the home builder and there weren't many professionals doing it either (Red Jacket was one, But Will was up to his ass in back orders and pediphilia.  Jim Fuller and Rifle Dynamics came in on the tail end of the craze..).  Remember, this was before the sunset of the '94 Assault Weapons Ban.  There weren't even a lot of tools, jigs or parts to do it right.  I remember sitting up one night reading up on how to modify some bolt cutters with two spare sets of heavily modified jaws to make (grind and file) a rivet crunching tool.  There just weren't a lot of options if you wanted an AK from one of these AWESOME kits.  Given civilian usage and the cheap cost of parts kits and receiver flats then, the screw build method had a lot of appeal.  I built four and all but one are still working just fine today.  I am not sure where people get the idea the the screws loosen over time.  It's not like you could run the screws down with your fingers then just give a few tugs with an "L" allen wrench.  They were work to get started and I had to use a power driver (with grey loctite) to get them in.  And I at least welded the rails in.  Many builds used screws to attach those too.  They weren't the best by any means.  They work, are safe and I sure did learn a lot about AK construction.  That alone made my 1st Saiga conversion a snap.

On a side note:  I had considered using stainless steel pop rivets, but the grade 8 screws I was using were much harder.  The receiver in reply 22 above looks like the old Vulcan I had problems with.  The back is even cut out for the AMD-65 side folder.  The hammer marks on the side were probably to get the FCG area to line up with the axis of the bore / bolt.  Yeah - Those were horrible receivers.  The Tapco's flats were much better, if you could get them bent correctly. Used to have "bend parties" where guys with flats would congregate at the house of a guy who had a 20 ton Harbor Freight press and a bending jig.  The law states that YOU can build your own gun / receiver, so you couldn't just send it off and have someone else do the bending...legally.  

One of the nicest things about building it yourself on an 80% flat?  No serial number...  No form 4473... No marking at all...

 

Macbeau...

Edited by macbeau
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I have 50 years or more experience in reparing broken machinery. Many of those machines broke where two or more pieces of metal were joined. I will say again that I would NEVER trust a screw build, unless I did it myself,as I have NEVER seen anyone do one right. To do screws right takes MORE time and tooling than rivets!

Axial motion - where the fastener is in shear requires that the fastener has an interference fit - for screws that means that the  the fastener must be larger than the holes by .001-.0001". That is after the holes have been dressed with a precision reamer to a precise size and PERFECT alignment, then  the fastener STILL needs to be pressed into place.

The body of the fastener must fill both pieces (if we are doing sheet metal) and the body DOES NOT INCLUDE THE THREADS! The threads need to outside of the pieces being fastened. That means the nut or tapped hole must have a few thread or two removed to allow it to be tightened. The nut or tapped hole then needs to be deep enough to have enough threads to match the diamater of the fastener. (1/2" bolt must have a nut with 1/2' OF THREADS on the bolt when tightened).

 With rivets, the holes need no special treatment or even accuracy. The holes do not even need to be perfectly aligned - they only need to be close enough for the rivet to flow into them completly when you brutally mash the rivets!

 

 Real men pound rivets!

Edited by G O B
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I've always wondered if anybody back in the days of those complete kits tried hardened steel pop rivets. They can fill in a shitload of material. I suspect they would've worked better than even loctited screws. 

 

any way, at least it's not this

 

002-63.jpg

Ugly as sin... but I bet it shoots

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