Summary

This is a replacement spool holder for a RepRap G3D (Prusa i3 design from Gadgets3D). It utilizes an M8 threaded bolt and a set of four 608ZZ ball bearings. The mount attaches directly to the existing frame bolt pattern. I have found this arrangement to work very well with my printer.
2016-01-24 Update:

• Cleaned up Sketch up file.
• Added universal spindle (is concave and should fit almost all spool cores)
• Inner spindle ridge is now a pentagon and no longer a support that must later be removed
• Slightly enlarged Mount to better match larger universal spindle