I created a slightly modified version from my previous Yaw mechanism which inverts the Servo and generally lowers the height of the assembly. I also switched from screwholes to square holes for zip-ties. ( See original design here: http://www.thingiverse.com/thing:341801 )Print with at least 20% infill, I went for 30% for stability. You need a 4mm Axel and two 9x4x4 Ball bearings. I use a clip to secure the axel. Servo is a BMS A206, the motor mounting holes are 25mm apart. I used standard PLA this time.