I wanted to feed my filament from the top. First tried a long steel pipe with all active spools on it. Worked, but changing a spool wasn't easy. Unload the active filament, remove the steel pipe with 8 to 10 1KG spools, take at least halve the spools of, add new spool, insert pipe again, load filament again.........
So i designed this spool holder. It takes standard 8mm steel rod or 32mm PVC pipe. Front access for easy spool removal. Been using this for about 6 months and it works great. The outside of the holders are flat, so you can put them right next to each other. You can choose the distance between the holders yourself, so any spool, or even 2 or 3 will fit between them.
I designed it to be strong while trying to reduce the amount of plastic = print time
There are four screw holes in each holder base. The load bearing ones are most important, the other 2 are for stability, but i think you don't need them.
It should be strong so use enough infill and shells. I printed it with 2 shells and 40% infill.
And ofcourse, there is a left and right one.