universal smal and lightweight spool holder vor typical filament spools.
use 608z bearings with 8mm inner diameter.
needs only 0.65m of 3mm filament. cost ~0.14 €
print time 20min on my k8200
work fine with 6 and 8mm threaded bolts.
now including adapter vor 6mm threaded bolts.
filament spools testet: vellemann, innofil, 3dmarkt.at, reprapworld.com
heat the slot vor the 608z bearing with a hot air gun, than it easily fits into it.