Hi Steffen,
you may want to see what I have done re this..
http://www.iceinspace.com.au/forum/s...ad.php?t=69560
The thread above is not up-to-date, though. now I have 400 s/rev steppers direct with no gears (only timing belt), powered by microstep driver (Pololu) and controlled by SoundStepper.. discussed here:
http://www.iceinspace.com.au/forum/s...=pololu+driver
Belts and pulleys came from
https://sdp-si.com/eStore/Catalog, however the cheaper option is Smallparts (
http://www.smallparts.com.au/.. the parts are the same but postage and handling is much cheaper, especially if you are buying more than one part)
There is also a lot of info on Yahoo groups (EQ6)