Low Friction Filament Stand/Holder for M3D

Once I saw the great 3d printed bearing at http://www.thingiverse.com/thing:53451 I realized that finally I can design a low friction spool holder for M3D, which is important for direct extrusion printing system.

This design is based on central symmetry and simplicity, which can be easily printed by M3D itself. None printed part needed:
M3x40 screw x3
M3 nut x12