This mounting system was originally designed for a UBNT Loco M9 Nanostation but I have now added quite a few links to expand its uses. Unfortunately I designed it around the hardware I had handy at the time and not standard metric screws. M3 hardware does work although the captive nut holes are to large. The rotator does use M4 hardware as I designed it later on. One day I may redo the design to be all metric but I still have a bunch of the imperial screws left over.
Having use these for awhile I have found using nice thick walls of 2.6mm then 20% infill gives the strength where it needs to be. Everything but the m9 link should be printed on their side, including the wall link to make sure the layer lines are in the strongest direction. The m9 link can be printed standing up.
The first time i used this design I printed with 0.8mm walls and 20% infill. Many parts failed after a few months, so I have found you need to print them with much thicker walls.
Designed in Fusion 360