LUCAS extruder version 2

EDIT 23/09/2014
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I have just uploaded a new 2.01 version with minor updates and I'm unchecking the "work-in-progress" checkbox, since I have been receiving lots of positive feedback about this project, from which I understood that it is working as expected. YAY!
From my personal experience, I can say that replacing and removing hotends for maintenance is a piece of cake, and I have been swearing a lot less lately.
I still need, though, to write a step-by-step guide and a complete hardware list as well. But time is short, and I apologize if I can't dedicate enough time to this thing or answer your private messages as quickly as I'd like to.
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This is the new version of my "universal" extruder (version 1 is here http://www.thingiverse.com/thing:378330)
After the initial success of that project I decided to upgrade it and tried to address some problems:
• the extruder is attached directly to X carriage, so a table is no longer needed; it is far easier no