Ninjaflex helper for Printerbot simple (alu extruder v1)

** update Dec 5, 2015
Added a model that has a bit more clearance between where the guide ends and direct drive + bearing start. Not sure if this was an issue for anyone, but if you're having difficulty with the original model, try the 'more clearance' stl

This is a guide for the Printrbot simple alum extruder (V1). It should improve the reliability when printing with Ninjaflex. (still have to test it out on a long print)

https://www.youmagine.com/designs/printrbot-alu-extruder

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