RepRap Belt Tightener for Y axis

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 :)