Motor Mount for Tricopter by Lucas Weakley. This replaces plywood disks used to mount motors. Note, print both to align wiring in symmetrical fashion. http://lucasweakley.com/product/maker-hangar-tricopter-kit/

Note, this design contains a thin layer below top portion of mount. This is to ensure that shaft hole is able to print with FFF printer. After printing, drill out holes for shaft and mounting screws.

I've included the SCAD files if you would like to modify design to fit your "arm"

Instructions

Printed in PLA using 0.2 mm layer height and 50% in-fill. Less in-fill can be used to reduce weight.