Ultimate Expandable Adjustable Filament Spool

prusaprinters

This my latest (and final?) design for an adjustable, expandable filament holder for loose coils or samples. It supports filament coil diameters of 60-200mm and up to 3 coils (although I don't know why you would want to do that).Print InstructionsAll parts are printable with no support.Simple default settings are OK: 20% infill, 0.20mm, 2 perimeters, PLA.My print times:2 hub sides and 3 hub connectors 1:556 spokes 3:146 arms and 6 spoke connectors 2:35How To UseThere are many ways you can use this (here are some):A single coil hanging on the side arms. (my preferred)A single coil between the spokes.2 coils - one between the spokes and the other on the arms.2 coils - one on each side on arms.2 coils - one on a side with 3 spokes and the other on 3 staggered spokes3 coils - one in between and the others on arms.All parts easily snap together and pull apart for easy configuration. The arms rotate so you can drop a coil on then rotate them out.How I Designed ThisI have studied a lot of spool designs. I didn't like most of them - too big, too long to print, required winding, etc.I have designed several of my own. They work OK to a point. But I have always been on a quest for one that is flexible, easy and (reasonably) fast to print. I decided to go back to the drawing board and designed this one.These are some of the designs that this is loosely based on.https://www.thingiverse.com/thing:7980https://www.thingiverse.com/thing:62710https://www.thingiverse.com/thing:13395https://www.thingiverse.com/thing:1852953https://www.printables.com/model/5627-print-in-place-adjustable-filament-sample-spoolThese were the most promising:https://www.thingiverse.com/thing:298768https://www.printables.com/model/18581-loose-filament-spool-for-makerboxI especially liked the Snap-Fit in this one:https://www.thingiverse.com/thing:1986210/remixesBut the link to how to create the Snap-Fit is broken, so I did a little research and a couple of small tests and designed something that seems to work OK. Although I found engineering formulas for this, they were too complicated for me. So, I've included a little detail of my design.I use Fusion 360 for most of my design work (sometimes OpenSCAD and TinkerCAD). I'm not claiming to be an expert with Fusion 360, but I have designed dozens of projects and learned a lot along the way.I am including the .F3D source file as that is usually my biggest complaint - downloading a promising design that needs a little customization and no source file to modify.My design is 99% parametric. I have a Prusa MK3S which drives the hub diameter (to fit the Prusa "T" holder; and the overall radius (to swing from the "T" and clear the top frame rail. I used hex for the holes and connectors because it is one of the few shapes that prints laying down without support.