Replacement for belts on x-axis
I was sick of this unprecise belt stuff. So I replaced them by rack and pinion.
Using 1/16 microstepping I now have 19.2 steps/mm.
I had to turn up the potentiometer of the x-pololu a little bit. A little fan cools it down now.
Below the rack a 608 ball bearing presses it against the pinion.
Here you can see it working: http://www.youtube.com/watch?feature=player_embedded&v=RgG2ghtuO-c