About this 3D model

This is a belt tightener for reprap printers. This mechanism can regulate the tighten of the belt. I had problems with high speed movements of the Y axis that moves in the wrong way the object i was printing. This is caused by the motor that make to jump the belt on the pulley, that make an Y position error. You should use a 608Z ball bearing i hope this thing can help if you have the same problem. sorry for my english i'm trying to learn it :)