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Discussion Starter #1
Good morning,

I had trouble forming a nice rivet head on the long trunnion rivets that are towards the top of the weapon near the front sight. Using Plinker's rivet fixture which worked well on everything else. Using MSG rivet kit. I am considering peening them flat and grinding them flush like the bottom rivets near the pintle attachment.

Are the domed head finish more appropriate for the weapon or do many of you just grind them flush?

Thanks,

Brian
 

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I'm at the same spot with my M2 build, I believe originally they where domed. I am making making a special fixture to dome them cause I have many more M2 to build. Heard some people just do them by hand
 

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Pictures I posted are factory rivets with domed heads at top of gun. Someone else with experience with forming them can chime in... Calling Toolmanm203, lucky13, Greaser.. They are the pros to talk to
 

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The domed head in front of the bracket is a mf-er to do with the press setup. Had to make some custom tooling to do it. Also, new made brackets are a little thicker up front than ww2, which makes it harder. The top 2 are easy.
 

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PhD in Over-Engineering
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A few years back, when toolman was first putting out the Plinker's Jig for the M2, I did some R&D on making it work for that rivet that is right alongside the BHP Bracket. I sent him the specs for the extra pieces needed, and he started making the fixture just a bit taller to allow for the space required. It revolves around clearing both belt holding pawl brackets, so his first generation- a copy of the Plinker 7.62 original- did not provide for this. On mine, I had to mill a clearance on the base of the fixture, and so he accommodated the extra length on the subsequent generations of the tool. A longer forming mandrel also was required.

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Discussion Starter #7
Wow!! Thank you all for the excellent pictures and advice. I'll have to go back and look at my fixtures and press pins to see what I can come up with. Rolin, thank you for the pictures of the modified fixture and the custom spacer. I may have to make up a similar setup. A lot of work for one rivet but it bothers me how they look now so why not go the extra mile.

Thank you all again and I will update you once I get these reset. Unless it looks horrible then I might be showing you a picture of ground flush rivets!!😬

Brian B
 

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That was the first generation 30/50 combo and as Lucky mentioned I had revised it after the first run. I have had good luck doing them by hand and with an aircraft riveter but it helps to have two people to accomplish nice rivet domes. Sorry I did not chime in sooner I missed this thread all together. The trunnion rivets have always been a bear and I prefer to do the initial set with the jig then finish them by hand FWIW.
 

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PhD in Over-Engineering
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Which Rivet Jig are you using? Plinkers 30 or 30-50 combo Jig? By any chance can you post picture..
That was the first generation 30/50 combo and as Lucky mentioned I had revised it after the first run. I have had good luck doing them by hand and with an aircraft riveter but it helps to have two people to accomplish nice rivet domes. Sorry I did not chime in sooner I missed this thread all together. The trunnion rivets have always been a bear and I prefer to do the initial set with the jig then finish them by hand FWIW.
Thanks for chiming in, toolman. Yes, that's the first gen 30/50 combo. As I stated earlier, that was exactly as Plinker originally made it. What I did was simply figure out a way to make it work with the extra width needed for that one darned rivet. So those pics were taken for toolman so he could make adjustments for the second generation, and supply the extra tooling required to accommodate that rivet without having to mill a clearance in the fixture base, as I did on mine. Call it Revision -1, lol.

Brian B, glad I could help!
 

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They are supposed to have domed heads on both sides. The actual Mil-spec long Trunnion rivets have a head just like the rivets used along the bottom of the Trunnion - a round head countersunk head:

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Those rivets in my current set are a commercial round hear rivets. If you truly want to duplicate the factory look, chuck the rivet in a drill press and hold a file against the head at a 60 deg. angle. It takes a minute or two per rivet. Those of you with a metal lathe can do it in a much more civilized manor. I'm setting up a run of long Trunnion rivets for the M2/M3 based on the Mil-spec. and should have them available in the next couple months. Just part of the continuous improvement program. MSG
 

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PhD in Over-Engineering
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Excellent, MSG. I have been using the file method on not only the occasional dome head rivets, but on 90 degree ones to get them closer to 60. Looking forward to your new Mil-spec offerings.
 

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Discussion Starter #13
I have the early Plinker 30 and the 50 jigs. I'll see if I can pull them out tomorrow and upload a couple of pictures. I ruined one of the locating pins and made up a new one a few weeks ago.

Thanks Toolman for the additional insight. I hadn't thought of starting them in the jig and then finishing them by hand. Any chance I could purchase the additional tooling needed to complete these rivets?

MSG, Thanks for the insight on the rivets. I have couple of sets that I purchased from you. I have some of the long trunnion rivets left and I will try to modify them per your suggestion and use them. The two I tried to use with the jig didn't quite work out. The already formed head smashed a bit flatter and it seemed that I didn't have enough extra on the opposite side to form a full round rivet head.

I'm going to revisit the whole process and incorporate all the excellent feedback and suggestions from all of you. Let's see if I can make another run at these three rivets and have the desired outcome. I'm probably the only one who will notice the not so perfect three rivets but I want to do it right.

Thanks again everyone and Happy Memorial Day!!

Brian B
 

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Always willing to help Brian just shoot me a PM. Have a great weekend. Russ
 
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