I finally (test) built Bumblebee right hand this weekend.
I printed these parts black and white and colored them with markers.
First, let’s see how each joint is made:
- Two thin rings (black ones) at each end of yellow part and one wider (silver) on gray part
- When these rings are firmly attached to their parts, I pass a cylinder through them
- The cylinder is glued to the black rings. The silver ring is kept free so the cylinder is able to roll inside it
You can see some some pics of the completed hand at Bumblebee page