This is the assembly video of the 4B robot:

I'm quite happy with the way the design turned out. 

All parts are 3d-printed with nylon plastic and their finish looks beautiful. Some of the linkages feel a little flexible but that can be easily fixed by making a thicker edge. The servo-motor hubs that are integrated with the linkages fit perfect inside the servo splines and the tiny SMF681X-ZZ bearings snaps firmly in place.

The next step for this project is to start designing the electronics and pcb. Having a custom pcb in place will tidy the wiring mess so that I could test the robot more easily.