Riveting pcb holes - engineering type input sought!

[HankMcSpank]

Whilst not the same project at all, this guy has the same challenge & you can therefore get a flavour...

http://www.cycfi.com/2014/08/neo-base-boards/

...mine will be a similar shaped pcb to that - and one of these covers goes atop ..... http://www.themusiczoo.com/product/1...-Covers-White/ )

The logic of using the rivet is that it probably sits proud less than 1mm on the top surface (ok, so I said in my former post that the enclosure butts up against the pcb.....indeed it does, but at the perimeter only, there's probably about 1mm of 'head' clearance where the holes are)

[mekanik]

I know you don't have a lathe so this is probably not going to help but i think the best solution would be a top hat type of insert drilled and taped 3mm the flange could be 0.5mm thick so minimal protrusion, clearance hole in the board to locate it while soldering top hat in place.
Regards
Mike

[mekanik]

http://www.theinsertcompany.com/bras...or_plastic.php

[HankMcSpank]

http://www.theinsertcompany.com/bras...or_plastic.php

thanks but they looks broadly similar to the nuts I referred to in my opening post...

http://www.rapidonline.com/mechanica...4658e0d0b4ee75

(actually the ones at Rapid Online have smaller hole 4.2mm vs 4.6mm for M3)

like I say, the spec for those things suggest my pcb holes are going to be too close to the edge of the board.

[magicniner]

Have you considered M3 RivNuts?
I've set M6 Riv-Nuts in Polycarbonate, Fibreglass and ABS by using a washer on the back and crimping tight enough to hold but not tight enough to damage, the hole in the base material is drilled clearance and it's the tension of the Riv-Nut between head and washer that holds by friction on the surfaces.

I used washers cut from Polyurethane sheet on both sides of the Polycarbonate and Fibreglass to prevent wear with vibration, rain and road dirt but I suspect you won't have those issues ;-)
Regards,
Nick

[mekanik]

thanks but they looks broadly similar to the nuts I referred to in my opening post..

Was just looking for the makings really, it's a simple job to chuck these on a mandrel in the lathe,remove the serations and even skim the flange OD if that's too large.
Regards
Mike

[magicniner]

Was just looking for the makings really, it's a simple job to chuck these on a mandrel in the lathe,remove the serations and even skim the flange OD if that's too large.

You don't need to skim the serrations, you need to adjust the drilled hole size to suit the material you're using to avoid splitting, you'll still have significant resistance to turning from the mechanical fit, add a 2-part adhesive for adequate retention and you're sorted.

thanks but they looks broadly similar to the nuts I referred to in my opening post..

If you use a backing washer, as I stated, the hollow section spreads and partially collapses outside the washer and doesn't spread in the substrate, no stress on the hole, just compression of the board, so no splitting.
I guess that's similar ;-)