One of the first things I downloaded was a "nut trap" in openscad for 3mm nuts. You know, the ones 5mm across. But I couldn't get the nut to go into the hole, so I printed a set 5mm, 5.5mm, 6mm, 6.5mm and 7mm.

Just print the test strip and see how big you need to make a nut trap to fit your 3mm nut. For me, it won't go in a 5.5mm hole, but fits loosely in a 6mm hole.

Somebody made the original module. If I could find it again, I'd give them credit.

Oh. It came from github uploaded by Stemer114 https://gist.github.com/Stemer114/324c382a528d10b43759