[vivek16]

ok i attached a sketch to my original post. the mast part is going to be two 3' long peices of aluminum tubing (1.5x1.5x1/16). the next part is going to be two peices of 1x1x1/16 peices of aluminum tubing. the next part is going to be a pneumatic piston and four peices of aluminum tubing that can slide within each other. and the claw is going to have four fingers and be a pincher like thing.

i approximate the overall weight of the arm to be around 15-20 pounds.

thanks.

and i was planning on having some sort of supports underneath the sprocket like plastic blocks or something low friction. (i like the ball transfer but i dont want to steal anyones ideas and i thing i could much better support it with some sort of roller system)

and only the 3/8 bearing retainers work for this size sprocket.