Just seen this, I can't watch the videos at work though:angel:
http://hackaday.com/2013/09/17/automatic-tool-changing-on-a-3d-printer/#more-103182
https://www.youtube.com/watch?&v=CW-z6XN-1II
http://hackaday.com/2013/09/17/automatic-tool-changing-on-a-3d-printer/#more-103182
https://www.youtube.com/watch?&v=CW-z6XN-1II