Hero me 5 spacer rod for dual 5015 fans (M3)

thingiverse

A simple 51mm spacer with holes for M3 on either side to connect dual 5015 fans. I came up with a simple shape for the holes that works very well for M3 screws and makes them self-tapping. The outer diameter is 3.4mm, the inner diameter is 2.6mm. This gives the M3 screw enough material to grab, but also leaves enough free space for material. It only grabs and deforms the tips of the groove. A straight bus with a 2.8mm hole could burst and a 3.0 mm bus wouldn't grab the screw. The grooves resolve this. Print at 0.16mm layer height for best results. Freecad file included if you need to modify it. Use the AMF file instead of STL, because it supports round shapes and is just better overall.