This is my 3rd attempt of making a bionic claw. I declare this design as a FAIL, because i did not consider the weakness of the nylon material, so i can�´t transmit big forces over the small lever! Anyways its a nice model and fun to play around with :) demovid: https://www.youtube.com/watch?v=vIAQCaxmLYAto make this thing you need to print: 3 claws (z or z2) 3 rings 3 gears (zr) 1 gear rack (Stange) also you will need something to hold the gears onto the ring. A 10mm bearing and a 5mm axis, that schould do the job ;-)