Kossel mini Spool fixer

This thing is made with the purpose to complement this spool holder:

http://www.thingiverse.com/thing:380636

In fact the spool_fixer locks the holder upon the HDD motor (used just to spin).
Finally the the screw fixes the filament spool in order to avoid it to fall (as I use to move my kossel mini a lot it was a problem).

I placed some pictures to ilustrate the usage.