I wanted a secure & smooth quick change direct feed spool setup for my Aluminatus TrinityOne. I also wanted as few parts and fasteners as possible. This is what I came up with. This system can hold multiple spools and allows for quick change by just loosening one 4mm socket head screw. I sized it to accept any size spools with any size holes. You can also put non-spooled filament on it very quickly by just lifting the rod and sliding it on. I plan to make a spool for loose filament at some point. You will be setup for dual extruders as soon as someone does it on this printer. Just print more cones and stoppers. The smooth rod used is 5/16" (about 8mm) and can be whatever length you want. I happened to have this one laying around or I would recommend buying one the full length of the top of the Aluminatus. The 5/16" rod lets the 608 bearings slide on easily. 8mm rod should work also. The stoppers use M4 socket head bolts and M4 Nuts. These only press against the inner race of the bearing in the cone, so these retain things without adding friction. The spool spins super easy and smooth. The bearings used are 608's that are easy to find and cheap. I picked up an 8 pack at the skate shop for $12. The brackets are held to the top extrusion with M5 x 10mm .08 pitch socket head bolts and T-slot nuts. I printed all parts with 3mm ABS filament with these settings: Spool Cone: .3 Layer Height 20% Infill Stopper: .3 Layer Height 75% Infill Bracket: .3 Layer Height 33% infill Please ignore the looks of my brackets. The orange one was the first prototype and the final version printed in silver did not print well for me (still learning the tricks of big ABS parts). I used acetone to correct my novice printing skills for now :). I also ran out of orange after the prototype bracket and I am waiting for more. The system is working great though. I will post new pictures when I get the brackets reprinted and mounted. I will probably make a filament guide for this setup. to reprint the brackets when I get more orange.