Below is a picture of a plywood prototype on its way to become version 6.
The three layers of ply are connected in the pivot points by means of paperclip wire through 1mm holes. This is by far not strong and durable enough for the application I have in mind. This leg can easily carry a 2 kg load. But I need to improve the pivots first. As it is, the holes wear out fast and become very loose.
Any inspiration would be welcome.
You can see the black glass head of a pin sticking out in the center. This pivot hinges from the robot's chassis. I call it point €. At the far right is the point that is to be driven by the crank shaft. All the other pivots connect to leg parts only.
The pivot design I am looking for must be:
* tight enough to keep the flat parts snugly together
* without causing too much friction between the plates
* positioned with precision
* allow the rear side to be mounted flush to the flat robot body (so no screw heads sticking out)
I am considering some metal reinforcements of the holes through the plywood. Like hollow rivets or washers and bushes. I am also considering using a different material, like plastic or metal. But I am afraid that those materials will also wear out very rapidly.
I appreciate your inputs.
Update 16 feb 2009: For completeness, I include Chris' video on brass cutting. Thanks dude!