Parametric(ish) OpenSCAD ball chain pulley wheels for a v-plotter/polargraph machine.
I've included a few stls. 2 different size pulleys for 4 & 5mm shaft steppers.
Hopefully the scad is easy to understand. As mentioned in the scad file, the pully size you ask the script for, might not be the size you get because the script works out the nearest size pulley that can accomodate x number of evenly spaced balls. The script will tell you in the scad console what the final circumference is. You can then use that value in your software.
The script ball chain settings are for the metal chain commonly available from hardware chains in the UK (see http://bit.ly/20xqx43) but can be configured to suit whatever chain you get (I hope).