These are my knees. They are made of wood with a routed
edge. I purchased the plans for the lower section of the robot from Bermuda
Triangle Engineering. I deviated from the plans and went with the "stepped" look, where the
center rib is the widest and they step smaller as they go up/down. I believe this is
the way the real robot was.
The plans say to coat them by
hand with rubberized auto undercoating.
I found it very difficult to spread the coating on the knees. Even after sanding I
could not get a smooth surface. I decided to spray the coating directly on the knees
and go with the slightly textured natural look. I really like how they turned out as
they have more of a rubbery look and feel.
Here's
the rubber undercoating I used for the knees. I got it at Parts America.
Here
are the different parts of the hinge. The main part of the hinge is
styrene plastic. The center is cut from a 1 inch PVC rod. The two washers
are actually machine shims. In order to get a washer with such a large
opening and thickness, I had to order machine "Arbor Shims" from
McMaster-Carr.
Here
it is mounted to one of my knees. They are only painted with primer at
this point and I only made one so far. Call it a prototype. I wanted
to see how it would turn out before doing the rest. I only hope the rest
come out this good.
7/27/03 - I finally took a
picture of the painted hinge. They came out pretty good. I
made four of them
7/27/03 - I added brackets
like this one to the inside of my knees. They anchor them to the
tread section. I chose wing nuts so that tools are not needed to put
everything together.
7-27-03 - The left knee has
two brackets attached to the outer, inside edge. The wing nuts screw
into threaded inserts that are on the upper rail of the tread section.
7-27-03 - The inner, inside
edge of the knee has a single bracket. I placed it dead center.
Besides provided a solid platform for the legs and everything above, the
brackets align the knees evenly so the legs will set down on the threaded rod at each end of the knee.
