Hi all
Which size nut should I be using for the F-roller?
The measured size in the STL file is 8.2 mm (see attached), and my M4 nut is 6.76 mm which seems to be pretty standard for M4 nuts (see for example here and here) and M3.5 nuts would then be even smaller.
It basically means that the two nuts are too loose and just keeps rotating when I try attach the M4 bolt.
You can put something in there to stop them from rotating while you tighten them. You will only have to do it once. To make these parts work for everybody in the world, I have to go with the largest hardware. Better to have you put a small nail or something in there than have some else try and cut plastic away, or have 7 different sized nut holes for all three machines and a set of mirrored rollers (I don’t want to maintain 42 different rollers).
Sorry for the hassle, don’t over tighten these, snug is more than enough maybe even too much.
Yup, no problem, will do… 
