Riveting pcb holes - engineering type input sought!

[HankMcSpank]

Long time no post how you all doin'?!!! :-)

I need your input!!

I've a little widget that I used to make ...basically a pcb with 2 x m3 holes tapped into it ....it's looking like that I'm going to have to dust it down & start selling again (sigh).

Problem: Tapping M3 holes directly into 1.6mm thick pcb is not strong enough (especially since I use paper based FR2 board vs. fibre glass based FR4...this is because FR2 is a whole lot cheaper & presents a far nicer grade of dust for inhaling when I mill it!) .....at the moment I tap the m3 holes, & put nuts onto the screw behind to reinforce the hole - not ideal). So I need a more robust way of reinforcing the holes in the pcb.

These self broaching nuts initially seemed a good option....http://www.rapidonline.com/mechanica...-of-50-33-3802 .. except the hole has to be 4.2mm to receive those nuts ....and they have to be a couple of millimetres away from the board edge (not sure I understand their "Min. radius thickness from sheet edge" ...is that to the edge of the nut or the centre of the nut?) ...this last bit is the deal breaker (I can't move the holes, and with a 4.2mm hole to receive those nut, it'd be too close to the edge of the pcb...it'll probably crack when inserting the nut under pressure).

ok, second option, re-inforce the hole with a rivet, so I was looking at these copper rivets...

http://www.aliexpress.com/store/prod...271034053.html

their hole is 2.5mm diameter ...bearing in mind I need an M3 tap, that seems in the ballpark, but I then worry how much of the rivet would even left after the M3 thread was tapped inside it??

My main problem though is how do you even crimp something like that? (it'd need a die /punch of some kind or other, but I can't even begin to work out where I'd source one from?!!)

Cheers in advance!