[timmmoore]

The arm consists of 3 types of wood, the struts are straight grain spruce, it was 1 piece of rough lumber cut up on a table saw.
There are 2 types of plywood - aircraft grade okoume and marine grade. This was cut with a table or scroll saw and sometimes scissors (the okoume for the truss re-enforcing is very thin)
Mostly wood glue is used to glue everything together (titebond III), some 2 part expoxy used when gluing alum to wood (e.g. ends of the gripper), plastic to wood and a few wood to wood bonds when we couldnt be sure of a close mating of the wood surfaces.
The corners of the struts are re-enforced using small pieces of okoume. There are pieces of plywood at each end of the truss for the joint to the gripper and to the boom. The boom is a box structure of plywood and spruce also glued. The back of the box is screwed to allow the back to be removed to get into the box (it contains gas struts for preload, window motors, timing belts, etc). No nails anywhere, lots a clamps when glueing.
The gripper is controlled with a banebot motor into a drill gearbox, mounted at the top of the truss with wire running down inside the truss to the gripper. The truss and boom are controlled using window motors and timing belts.