Printrbot Simple Metal Z-Mounted Spool Holder

Spool holder for Printrbot Simple Metal that sits on the Z-axis assembly so it is always in a good location for dispensing. Held in place by gravity and friction. Requires a 1/4" rod about 6" long for spool shaft. The Simple Metal has a very beefy Z-axis so I think it should carry the extra strain without problem. Possibly with increased wear on the screw thread. The bit on the bottom that holds it in place can be reinforced with a screw by tapping the included hole if desired. I modified mine t