Legs                                                                     

After much consternation, I settled on 34 inch legs with the knee half way. 

The lamp from A Christmas Story.

Robot legs.

Top of "thigh bone".

The “thigh bone” is made of three bolted together one inch square aluminum tubes snugly filled with pieces of hardwood. Four skate bearings are recessed into the top and bottom of the piece, such that 5/32” all-threaded turns effortlessly at the hip and knee joints. 

Knee joint.

The “shin bone” is also made from 1” square tubing and is reinforced laterally with light weight aluminum bar. At the moment, “the feet” consist of rubber crutch tips. There is a steel hanger at the top-back of the leg to hold the big piston and another bracket at the bottom of the leg to receive the end of the piston rod. Just below the knee there is a smaller bracket that attaches the heavy piston return springs to the lower leg. There is a short piece of 1” U-channel attached to the lower leg at the “knee-cap” which stops the leg from over extending. 

Altogether, there is very little play in any of the leg joints and the extended legs move less than a quarter inch in the sideways direction when wiggled.