M3 nut tool
thingiverse
I used MoonCactus' nut calumet design (http://www.thingiverse.com/thing:44118), but the holes for the nuts were too tight, so I made my own tool with two sticks - one for 6.4mm and another for 6.8mm nut diameter. The smaller keeps M3 nuts secure while the larger fits easily on them. The design includes two holes for M3 nuts, one on each side. I printed this from PLA using settings of 20% infill, 0.1 mm layer height (0.2 mm is also possible), 210 C, standard 50 mm/s print speed, and no support needed. I used Cura 12.12 for slicing and printing.
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