Low friction spool holder

Yet another spool holder. :-)

I bought some filament spools that where too small for any spool holders I already had, so designed this low friction holder to sit behind my printer.

2 skateboard bearings are required for the roller on this. It's a bit of a tight squeeze to get them in the first time (brute force and ignorance worked perfectly for that). The bearings I used can be bought from http://amzn.eu/9vQ52eK.