This is a spool holder that slides on my 8020 1515LITE bar and allows the spool to spin. I will be making a dead version that holds a spool that is only meant for storage, since I only need 1 live spool at a time. The 8020 bar is part of my Replicator table I buiild from scrap 8020 stock. This spool holder has enough clearance to slide on the end of the 8020 bar and be easily positioned for narrow or wide spools. I designed it for spools as small as 160mm diameter, but will work with any size spool you can find. I designed it around parts I had on hand from previous projects. Made with shoulder screws and flanged bearings with extended inner rings. Were I designing from scratch and not recycling parts on hand, I'd use a cheap cam follower. There are a set of holes on the part not being used. I put them there to hold a 1/2" long standoff (F/F #4-40). The fear was the parts would not slide on the 8020 and would need to be stiffened. They are not needed, the shoulder screws work fine. Design is V2, V1 was a single piece design that needed support. This prints quicker and has no overhanges that require support.