To hold the rods on which the filament spools are mounted I created 2 types of holders, the first version is for sliding the washer with the nut, the second type is for heat inserted nut. A plastic water pipe with a diameter of approx. 25 mm is used as a rod for fixing the spools.
I used this clip to attach the box lid: https://www.printables.com/model/367033-never-lost-ikea-samla-clip-remix-11l-22l-45l-65l
The author marked this model as their own original creation.