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Discussion Starter #1 (Edited)
1919a4 rivets installed a.jpg

For some time now, many people have been asking for a Riveting guide. I've hesitated to create one because, frankly, there are a lot of people here with a whole lot more experience than me at riveting. What the hell. If it looks OK, maybe the admins can make it into a sticky.

To start, I always refer new builders to the tutorial ( https://1919a4.com/content.php?5-tutorials ) to get a general idea of how these things go together, and Lobo's build sequence ( https://1919a4.com/showthread.php?421-Build-Sequence-Checklist ) to minimize stupid mistakes. I reference these rather than recreate them because I am philosophically opposed to reinventing the wheel, and Corona beer (life's short, drink good beer).

As far as riveting goes, this is how I started (finally found it hiding behind the MSDS file). Below is a 2006 post by a long standing board member named TANKER. Before beginning my first 1919a4 build, I practiced riveting on scrap bar stock using these basic techniques and ideas reprinted below. I've only modified it slightly in an effort to improve flow, added some benign commentary in bold, and omitted the portions in which he pitches his own competing riveting products.

This was a response to a question about riveting:

Riveting is so simple yet so complex. The final look of the rivet depends on a multitude of things ... diameter of the rivet, length of the rivet shaft you leave protruding, and how soft or hard the rivet is to start with, your air pressure and riveting technique, your particular rivet gun, etc.

The most important variable seems to be the length of the rivet shaft you have to work with. If the protruding length is too short, you won't get a good head to form before the tool bottoms out. If you leave too much protruding, the rivet head will form a nice dome ... but then you have to keep on with the air tool to get the rivet completely set. That's a trick!!! What I do is to oscillate the rivet gun to keep it from making a ring on the rivet. You sort of move the rivet gun in a circle ... leaning it all the while. This will keep that ring from forming as the rivet punch is allowed to smooth the rivet head as it forms. Envision rubbing your cupped hand over a bald man's head ... hehehe (after I graduated from Airborne, complete with buzz-cut head, girls would just walk up to me and...). If you have to do this, watch the edges of the rivet punch to see that the punch doesn't make a "smiley" on the plate rail as you wobble the rivet Punch over the dome head. I go SLOW with my air tool, just barely letting it tap ... tap ... tap ... tap. It sort of makes a little growling sound instead of a "brrrrrrrrpppp" sound. It's too easy to mess up with the ripping sound. I have my air pressure at max for my compressor, which is 125 PSI. But because the air tool uses so much air, I sometimes have to wait a bit for the pressure to build back up. It's a 5hp. dual cylinder, 30 gallon tank, Craftsman brand. I think that when it's operating in the 80 to 90 psi range it's working at its best.
If everything is just right ... rivet length, diameter, rivet tool size, etc. it seems that you just have to hold the rivet gun up straight and let it do its work. But throw in one of the variables and you have to compensate in one way or another. Going very slowly and looking at the forming rivet often, will let you know what you need to do. You may find that the rivet is "leaning" one way or the other. You can use the punch to "steer" the rivet back up straight. Usually before doing a rivet on the gun, I'll do a couple of practice rivets to see what length to leave in order to form the best rivet head using the rivets, and rivets set, I'm working with. Most often this will be somewhere in the 5/32" range (this, +/- 1/32", is good gouge). You can usually adjust the length of the rivet shank to match the rivet punch concave for the best size, without too much metal being left over ... or not enough metal to form a nice head. It is possible to really screw up a rivet ... but then go back and rotate the punch over the mess and end up with a very nice domed rivet. One other variable is the diameter of the rivet hole. I helped on a 1919 with a friend, and his kit was demilled in a way that left some very large diameter holes for the rivets. His BrandNam rivets just didn't have enough length to fill up the big holes and then have any metal left over to make good domed heads (which is why some of mine are longer than Mil-spec.). We had to go to a larger rivet diameter and redrill his holes for a tighter fit on the larger rivet. You don't want the rivet too loose in the hole or the compression of the rivet shank will shorten the overall length, and you won't have enough metal left to form a head.

So, to sum it all up ... I don't think that it's the air pressure, so much as it is the rivet length as compared to the rivet punch concave depression size. You do need enough pressure to smash the rivet, and as the rivet compresses, it will work harden the more you mash it. The closer to finished that the rivet gets ... the harder the metal becomes ... all the molecules get crowded together like people in a phone booth. This is when you wait on the compressor to get back to max.

I hope this helps. If I can be of any further assistance please let me know.
Thanks, TANKER

P. S. I think I'll publish this to the How-to section. Names will be changed to protect the innocent. All suspects are considered innocent until proven guilty in a court of law. You Rivets have the right to remain silent while we beat the crap out of you.

This is obviously directed at setting the rivets with an air tool. I have always used similar techniques while holding a 3-1/2" setting tool by hand, and striking it with a 3 lb hammer. My experience with hydraulic presses is limited to that necessary to validate the designs of the materials I offer.

I did a good bit of experimentation to determine what size concave will produce a proper looking head for the 1/8, 5/32 and 3/16 inch and #7 rivets used to assemble the 1917a1, 1919a4 and Colt Commercial machine guns, and those are what I have available.

Smiley faces happen. But if caught on the first strike, I've found they can be whisked away with a sandblaster.

As I have the opportunity, I'll expand on this thread. Maybe I'll even take pictures during my next build. If others of you have tried and true techniques, please feel free to add them. MSG

1,303 Posts
I rivet with an air rivet gun as well...

Didn't even see a mention of what I feel is the most important thing. SOLID backup. if you have the rivet backed with a fixture to hold it tightly in place and then the whole weapon on a solid surface; all the energy of the air hammer goes right into forming the rivet. Then it will only take a couple pops. I like to clamp the weapon to a heavy solid table in addition to clamping the rivet in place when ever possible. It really makes riveting far easier.

Oh, and the second most important thing. Buy your rivets from MSG :)


6,355 Posts
#1 -- Need good rivets
#2 -- Need good advice
#3 -- Need proper tool(s)
#4 -- Need a helper to hold tool
#5 -- Need solid work surface
#6 -- Need to take your time
#7 -- Need MSG's connection
#8 -- Need to understand it's not hard
#9 -- Need to make this a 'sticky'

Carry On!
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