This is a stand-alone filament spool holder with gearwheel bearings. All parts including the bearing can be 3D printed.

Assembly Steps

Step 1: 3D print the following parts:4 x bearings --> this should be a good quality print with at least 50% infill.2 x body2 x shaft --> You might want to scale this along the long axis if you find the holder too big. The length of the shaft will determine the maximum width of spools that can be used.

Step 2: Loosen the gear wheels using some force and if needed a head screwdriver. Then I used an electric screwdriver to turn each bearing for about 1-2 minutes and afterwards I applied WD40 so they run smoothly.

Step 3: Put everything together like on the pictures. Then you will need some glue to hold everything in place. Don't glue the bearings to the shaft, they need to be able to slide to allow usage of spools with different width. For this step I used cyanoacrylatic glue.

Thanks to Ross Korsky and his Fusion Add-On for helical gears: https://apps.autodesk.com/FUSION/en/Detail/Index?id=9029586664984391977&appLang=en&os=Win64