Dual Extruder / Dual Material Makerbot

This is going to be a reaaaal long one, folks. Better buckle up your thingibelts.

I believe this project is complete. There are workable, though probably not ideal, solutions to all major problems. The code and mount are both perfectly usable.

Youtube videos availabe at:
http://www.youtube.com/watch?v=tSp8FKgoY8k
http://www.youtube.com/watch?v=mv3wxvR8w5A
New! http://www.youtube.com/watch?v=XafKYIxlgBk

For people who just want the short version to go with the photos: Of course when I thought about what to print first, I thought the classic 20mm cube, but in a checkerboard pattern.

Setting the head offsets in the software exactly is important, and not difficult, but I couldn't dial it in during the course of this project as every time I'd set it I'd change something to unset it again. That's the only reason many of the prints are overlapping in odd ways.

Any ooze tends to accumulate at the offset position and eventually get rolled into the model, making a mess