This is a basic spool holder specifically designed to fit onto a Printrbot Simple Metal Z Axis guide rail. Its designed so that you don't need to use a ton of plastic to print out a spool holder.

There are two parts:

The Spool Holder The Filament Retainer Bar

The angle of the spool holder keeps the spool on the spool peg. The retainer bar can be used either with the long or short leg in the spool slot so it can be used with "most" filament spools. The retainer bar prevents the filament from wrapping around your z guide rails.

THE FILAMENT RETAINER BAR NEEDS TO BE USED OTHERWISE FILAMENT WILL WRAP AROUND THE Z GUIDE RAILS AND MESS YOUR PRINT UP! Believe me, its happened twice to me: one time wasting almost a whole print, the second time the filament snapped, breaking at the very top of the extruder assembly. It was a pain to get it out. So I redesigned it to have this filament retainer bar!

Assembly:

Just pop the Spool Holder onto the Z Axis Guide Rail. Slip the Filament Retainer bar into the Spool Holder's upper slot. Drop your roll onto the Spool Holder making sure the filament feeds from the top. Make sure the Filament Retainer Bar Covers the whole filament area of the spool so that the filament is "retained" in the area between the spool of filament and the filament retainer bar.

Yer done!