Robo 3D R1+ Threaded Rod Spool Holder

Another remix of a great top mount spool holder for the ROBO 3D R1+

This design utilizes a 5/16" threaded rod and spool adaptors ( with skateboard bearings) to make switching spools easy and let them roll with little resistance.

While this does require the use of different adaptors for different brands of filament, and some times different spool styles within a brand, in a pinch I have used a section of 1" pvc to lesson the tension on the spool. (< 4/18/18 - this has become a regular and d