Simple trick for seating nuts in undersized or misshapen holes
As I work to prepare my extruder R4 for installation I am reminded of a simple trick that I'm sure others have stumbled upon, but might help those who haven't. When the recess for a flush mount nut is a bit too small, rather than trying to pull it in place with a screw from the other side -- and in my experience risk breaking the piece in the process -- position the nut over the hole and then gently press it in place with a hot soldering iron element. My soldering iron tip fits neatly inside an M3 with the shoulder pressing on the body. Of course this can be overdone and you can melt your way right through the part, but with a judicious application of pressure and heat this trick works wonders.
Re: Simple trick for seating nuts in undersized or misshapen holes
I moved the topic in the Assembly subforum, it seems to me it suits better this category 😉
Regarding the trick, I would personnaly fear to melt the printed part, but that could help someone 
Re: Simple trick for seating nuts in undersized or misshapen holes
I quite often add M3 brass threaded inserts into printed parts. Gentle application of hot soldering iron melts the plastic and allows the insert to slide in, then removal of the heat allows the plastic to solidify around the knurling of the insert fixing it in place.
It is true you do have to be careful of the amount of heat applied by lifting the hot tip away from the insert to allow some cooling. A little practice is all that is needed though, and the method produces a robust part with an embedded metal thread.
Should work fine for nuts too.
Re: Simple trick for seating nuts in undersized or misshapen holes
I used a needle file set to fix alot of my extruder parts during assembly. I used them so much id go as far to say i wouldn't have got mine assembled without them.