universalmasterspool

in my opinion the biggest problem about the Masterspool is different manufacturers creating their own norms for it and even if two use the same norm being a mm or two off could result in to much slack and therefore filament tangling. Therefore you either buy only one brand of filament or you have multiple masterspools printed for every brand you buy.
by using 3 M6 machine screws as the hub you get a masterspool that works with every size of refill out there. Also you save a lot of filament and print time,
i have also cut one out of cardboard and it worked saving even more plastic.

The outer diameter makes max use of my i3 megas printbed while the inner diameter just fits the default spool holder. I have included the .scad file so feel free to remix it for your printer setup, also you can change the screw thickness or whatever you want.

for assembly you need
both halves ( except for the nametag their identical ),
3 M6 machine screws 80 mm long,
6 hex nuts,
3 wing nuts.

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