InMoov has most of the body movements that a human has from the waste up. In this video I show a close up of the gearing that makes InMoov twist to the left or to the right.
These are jumbo hobby grade servos that were modified to allow continuous rotation in either direction. In short the internal Potentiometer was removed and the physical hard stop was cut out of the servo. I will take the potentiometers and wire them externally to create the needed positioning.
These were 100% 3D printed on a Makerbot Replicator + in PLA. They were lightly sanded down to smooth the surface some and then some petroleum jelly was used as a grease as it will not hurt the PLA.