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Discussion Starter · #1 ·
So I ditched the PSA side folder trunnion and just got a Bulgarian set. I’m gonna have to pull off the old one. The PSA wasn’t even dimpled. I’m cool with dimpling all the rivets on the receiver but one has me nervous. It’s the top left one that’s super close to the edge. This a an AKB hardened receiver. If dimpling, I’m using the ball bearing method with the jaws ooorrrrr for this one rivet should I just chamfer with a drill bit. At least the other 5/6 will be dimpled correctly. I just don’t want to crack the receiver.
 

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chamfer ≠ dimple

chamfered rivet does not create enough mechanical strength.

refer to this thread: Chamfer rivet holes?

obstreperous makes good dimple forming tool for not much money. but you do need to use a press for it. press is in general more advantageous for building. and bolt-cutter method while can work in the pinch, for more advanced building is insufficient as you already might be finding out.
 

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Discussion Starter · #3 ·
chamfer ≠ dimple

chamfered rivet does not create enough mechanical strength.

refer to this thread: Chamfer rivet holes?

obstreperous makes good dimple forming tool for not much money. but you do need to use a press for it. press is in general more advantageous for building. and bolt-cutter method while can work in the pinch, for more advanced building is insufficient as you already might be finding out.
Thanks form input.your rite, Dimpling is the way to go. I have the long rivet tool if that will also work for obstreperous but for now all I have is the bolt cutter tool and ballbearing. I’ll be using the rear trunion as backing. Should I be worried about cracking? I guess if it does crack I can get it welded and have another go no?
 

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So I ditched the PSA side folder trunnion and just got a Bulgarian set. I’m gonna have to pull off the old one. The PSA wasn’t even dimpled. I’m cool with dimpling all the rivets on the receiver but one has me nervous. It’s the top left one that’s super close to the edge. This a an AKB hardened receiver. If dimpling, I’m using the ball bearing method with the jaws ooorrrrr for this one rivet should I just chamfer with a drill bit. At least the other 5/6 will be dimpled correctly. I just don’t want to crack the receiver.
It’s a good thing you did the PSA one is garbage. I’m not a psa hater either. Here’s mine
It showed up bent and I bent it back and when I riveted it in the damn the broke right off.
Tire Automotive tire Hood Car Sports equipment

i also dimple using a 1/4” ball bearing and the Toth tool riveting jaws and they work great
I have dimpled that rivet with a press and haven’t had any problem it won’t crack on you. I never even chamfer with a drill bit or anything like that.
 

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chamfer ≠ dimple

chamfered rivet does not create enough mechanical strength.

refer to this thread: Chamfer rivet holes?

obstreperous makes good dimple forming tool for not much money. but you do need to use a press for it. press is in general more advantageous for building. and bolt-cutter method while can work in the pinch, for more advanced building is insufficient as you already might be finding out.
This. The purpose of the dimple is to draw the sheet metal into the chamfer in the trunnion, which adds shear strength. If you chamfer the hole in the sheet metal, you're merely removing material that should be drawn into the trunnion. Since chamfering the sheet metal will thin it out around the rivet, you may even lose strength.

However, some trunnions are not dimpled, and I have questioned the value of adding dimples to them. A semi auto gun doesn't really need to be as stout as a military gun that will see many thousands of rounds in full auto, so dimples may be overkill in a private build. There's nothing wrong with some extra strength though.
 
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