Summary Notes: Tolerances should be accounted for; the smallest spacing for movable parts is 0.25 mm. Also, I don't know how to orient the stl file in Fusion 360; if you know how, please comment. This is an addition to this frame-mounted spool holder I designed last year: https://www.thingiverse.com/thing:1752018 This prints as 6 pieces: Rod 2 spacer endcaps 1...bushing? I didn't know what to call it. The inner part around the rod. 2 actual holder pieces The rod has a print-in-place truss rod designed. It feels strong, so I think the truss rod helped. The slots in the rod allow it to fit snugly into the old spool holder rod slots. Prints horizontally with no support. Update: I showed my design to a mechanical engineer. They said the truss I designed is not actually a truss and is, in fact, kind of useless. Oh, well; now I know. The spacer endcaps have a tolerance of 0.25 mm which should allow them to slide into place and be held tight by friction. The A8 should be able to print a workable part for this spacing. Prints vertically with no support. The "bushing" was designed this way to save on material and to also positively contribute to the rigidity of the rod. Prints vertically with no support. The holder pieces should allow you to center the spool. They are designed to hold a standard 1 kg spool (or what has been standard across the spools I have purchased) with extra spacing for free spinning of the spool. It should hold a spool with anything above 53.5 mm diameter hole. Prints without support if you stand it on the outer face. Update: Done printing. Everything worked out. The file for the spacer was modified after the fact because I realized that the lengths were different for the two separate spacers in my Fusion 360 file. I just stuck with the ones that printed, but I fixed that issue in the new file. If you have problems with it, let me know. Print Settings Printer: Anet A8 Rafts: No Supports: No Infill: 10% Notes: Doesn't require support material.