Summary

Spool holder to fit the large 5kg spools with a 113mm hole
uses 608 bearings.

Instructions

I printed 0.3mm 25% fill.
You may or may not need support, I used supports as it's the inner section that needs it so it doesn't slow it down much.
Need to print one for each side and each can take one or two 608 bearings. Tolerances should be fine for most but it you want to have to force the bearings in you may want to print it a tiny bit smaller.
comes with a blanking disk (608 bearing shape) if you only use one bearing per side (I've been using one per side) and a plastic washer for the nut with a slightly raised inner lip to stop it snagging on the outer edge of the bearing.
Just need some 8mm threaded bar and a few nuts as well as some sort of stand/box to support the spool.
I can print directly from the spool without issue, or you could use it to make spooling off to smaller spools easier.

5kg spool holder