Simple spool holder with a lot of inspiration from https://www.thingiverse.com/thing:767317
But I had problems with the dimensions of this one, since the hole through is 8mm which is the same as my threaded rod - this made the bearing useless. I have changed this to 10mm. The two opposites will self center and thereby use the bearings.
You need two of these to make a set, one 608ZZ bearing for each and a 8mm rod to hang them on and two 8mm bolts to keep them in place.
Print the thing having the bearing hole pointing upwards this eliminates any printing issues.