Tag Archives: front trunnion

Setting an AK’s Internal Front Trunnion Rivets with the AK-Builder rivet jig

It’s pretty straight forward really.  You need to insure the rivet jig is sitting on good strong steel cross plates – don’t use wood.  I’ve seen guys try so don’t laugh too hard.  For the record – that one I never tried – I used 1/2″ steel plate from the get go.  Wood is not your friend under high pressures.

Be sure  to use the right rivets – AK-Builder sells the best rivets and tailors them to what you are building.  Lay them all out and identify what rivets are for the front, the swell neck rivets for the lower back of the front trunnion, etc.  A rivet should stick out 1.5x its diameter – that’s it.  Just for example and to keep the math easy for me, a 4mm rivet should only stick out 6mm.  If you go further, you are going to have problems.  As you get experienced, you can buy rivets in bulk and use rivet trimmers but you might want to save that for down the road.

Make sure the rivet and your receiver are all nice and square and that the little cup is under the rivet’s head to support it.  Make sure everything is nicely supported too.  If you don’t you will bend the receiver.  When I make cautions, it’s usually because I did it the wrong way already at some point 🙂

Only extend the rivet arm the minimum amount necessary.  The longer it sticks out, the easier it is to bend it.  I’ve done that and you may too.  If you do, just bend it straight again by pulling it out of the jig, supporting it by steel block and press it straight.

Now go slow.  Speed will only help you mess up faster, especially if you are new to this.  Extend the little set screw enough to squish the rivet and clear the trunnion walls.

Do not go crazy with the pressure.  You want to squish the rivet, not start bending stuff.  The rivet swells inside the hole and and the end caps it – that is all you need to accomplish.  Too much pressure and tooling starts to bend.


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