CTC Replicator Overhead Spool Holder

When mounting spools on the back of the printer I often had trouble with the loop of filament going to the print head getting trapped underneath another loop. Since changing to this design I haven't experienced that problem. For each spool you will need a holder, a mirror image of the holder, two tubes, two spool bushes and two threaded bushes. The spool bushes are intentionally a loose fit on the metal tube, this puts the centre of gravity of the spool below the axis of the tube. The result of