My AK Build

Comrades,

I'm doing some engineering math.

The solid rivets we use in the AK builds are 5/32" in diameter, made of 18-8 stainless steel. The 18-8 stainless will shear at 45000psi, so using the cross-section calculation, r^2*pi*Ss where Ss is shear strength, we get (0.078)(3.14)(45000)=862lbs of force needed to shear the rivet. With a safety factor of 0.4 we get 345lbs.

A grade 5 bolt in 10-32 would be calculated as follows: minor diameter of 10-32 is. 0.15 and the shear strength is 90000psi. 0.075*0.075*3.14*90000=1590lbs. With a safety factor of 0.4 we get 636 lbs allowable shear force.

A grade 3 bolt in 10-32 would be calculated as follows: minor diameter of 10-32 is. 0.15 and the shear strength is 57000psi. 0.075*0.075*3.14*57000=1006lbs. With a safety factor of 0.4 we get 403 lbs allowable shear force.

A 5/32 stainless steel blind rivet from McMaster lists a shear strength of 650 lbs. With a safety factor of 0.4 that comes to 260lbs allowable shear.

A 3/16 stainless steel high strength blind rivet from McMaster lists a shear strength of 1650lbs, 660 with safety. Similar zinc plated high strength blind rivet is 1050lbs absolute and 420lbs safe.

Now the twist here is that Grade 5 bolts are listed to have Rockwell C hardness of 25 to 34, higher than 1080 steel. Unless you are hardening the entire receiver, the bolts will "eat" through the sheet metal once they vibrate loose and the load is place directly on the threads. Grade 3 bolts are much lower, they may actually be ok given the shear rating.

Another conclusion is that if you pick the right high strength blind rivet and set it correctly, it will match the performance of the solid rivet.
 
Why does yield strength matter in a shear condition?

Also- once you crush these rivets during the build (an assumption on my behalf, I apologize) their material lattice will change substantially. Do you know if the SS rivets will maintain their material properties like a carbon steel does once under compression? I don't know this answer... if you do, please share.

Carbon steel is very ductile. SS might be enough. Then again, it might be tough to compress as well due to its heightened hardness. Food for thought.
 
It doesn't, I meant shear strength.

Without getting heavily into the physics of riveting, the SS rivet at the shear joint will maintain its mechanical properties. Stainless WILL be more difficult to compress, you will most likely need one of the heavy duty blind riveters rated for stainless. The hand-held riveters usually specify "not for stainless". I'm not going in that direction anyway, but for anyone who may stumble on this later on.
 
So I decided that **** screws. Although I can use properly designed shoulder screws and such, it's just not worth the hassle of doing that over rivets. Would anyone with a press and jigs like to lend them for a build? I'm willing to pay in vodka.
 
I'm not dead, just for a variety of reasons I've had to put the project on hold for a long time. I will come back to this and it will be epic. In the meantime, I'll repeat my request - does anyone have a press that I could use for the rivets? Will renumerate for the favour.
 
Bolt cutters work for the short rivets.

A hammer and punch will work for the rest.

But, if you can't find a press, you can use a large bench vise and a cheater bar, too.

You can be creative.

Or you can post this request with an actual "area" where you live, because asking if anyone has this magical press is useless. Many people have them. But where you live? Who the **** knows. I don't have one as far as everyone is concerned so don't ask me.

Jesuslove contacted me and talked like he had a hydraulic press, but he's now banned so there's no easy way of getting back into contact with him.
 
I got the bolt cutter tool and the trigger guard tool . I took care of my long rivets with advice from Boris and Atillia mix of vise and hammer with a punch think I made to round then over.
 
I don't do much so I'm flexible. I can lend you my stuff or you swing by and we do it here etc . I'm in Tewksbury .

I don't have the long rivet tool I just used a vise a hammer and some thing I made to round the rivet head.
 
Last edited:
flintoid said:
Bolt cutters work for the short rivets.

A hammer and punch will work for the rest.

But, if you can't find a press, you can use a large bench vise and a cheater bar, too.

You can be creative.

Or you can post this request with an actual "area" where you live, because asking if anyone has this magical press is useless. Many people have them. But where you live? Who the **** knows. I don't have one as far as everyone is concerned so don't ask me.

Jesuslove contacted me and talked like he had a hydraulic press, but he's now banned so there's no easy way of getting back into contact with him.
Click to expand...

flint have you tried using an air hammer to form the heads on the long rivets? It gives great control in forming them. I leave the radius a little shallow so you can roll the head over nicely.
 
akma said:
flint have you tried using an air hammer to form the heads on the long rivets? It gives great control in forming them. I leave the radius a little shallow so you can roll the head over nicely.
Click to expand...

There is this friend of mine who claims the same thing. As soon as he gets some free time, we're going to crack some tall boys, drink some brown liquor, and give this theory a shot.

Personally- I can't ****ing wait for this day. I got two russian beauties of a kit to try this out on. **** it.
 
flintoid said:
There is this friend of mine who claims the same thing. As soon as he gets some free time, we're going to crack some tall boys, drink some brown liquor, and give this theory a shot.

Personally- I can't ****ing wait for this day. I got two russian beauties of a kit to try this out on. **** it.
Click to expand...

plz post DEM RESULTS. can't wait to see your stuff put together and how this method works. not that the bolt cutter adapter doesn't work outstanding though.
 

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