Ball-Chain Pulley for Polargraph

This is a ball-chain pulley for 3.5mm ball chain, intended for use as part of a Polargraph:

http://www.polargraph.co.uk/

Regular metal ball-chain was easier to locate versus the type that Sandy had used on his Polargraph.

I use a slightly modified version of Ed's stepper motor mounts as well:

http://softsolder.com/2011/08/23/nema-17-stepper-motor-mount/

The ball-chain I'm using came from here: http://www.kitkraft.biz/product.php?productid=8353&cat=&page=2

Update: The gondola I printed for mine is here: http://www.thingiverse.com/thing:12557 - and it works!