About this 3D model

http://www.youtube.com/watch?v=1659NiCCgh8&feature=c4-overview&list=UUnyyenl1R2XbUurYMoan9Ww My new version single Z motor system for Prusa i3. In new version Z thread rod fixed with 2 nut on bearing. Old design with locking bolts on the pulleys was bad idea. Need 7 pcs - 624 bearing 2 pcs - 625 bearing Loop MXL belt about 1000 mm