Horizontal Spool Holder for Filament Dryer #2

thingiverse

This is a horizontal spool holder that was designed to fit in my Rosewill Food Dehydrator, which I use as a filament dryer. The "bottom_mount" part pushes onto the ring on the inside bottom of the dryer. This thing is sort of similar to this thing: https://www.thingiverse.com/thing:3812650, but this one does not require a bearing, uses cones so that it is compatible with any-diameter spool, and has positive retention (spool can't pull up-off the mount). The spool can't be pulled off the holder, which is a common problem with horizontal spool holders. Required hardware: 1/4-20 threaded rod, 1/4-20 locknut (or hex nut with loctite), 1/4-20 washer (under wing nut), 1/4-20 wing nut (or hex nut + customized knob). 6mm hardware might work, too, though I haven't tried it. Instructions: Refer to cross section pictures. I suggest using PETG for temperature resistance and slipperiness. Print 1x bottom_cone, 1x top_cone, 1x bottom_mount, 1x sheath. All can be printed at 0.2mm layer height and 0.5mm line widths. The cones are best printed inverted to prevent the need for supports. The bottom_mount will need supports inside the slot (which is for interfacing with the food dehydrator). The sheath will need supports inside the 6mm hex, which is for a 6mm hex key, which is used to help thread the sheath onto the end of the threaded rod. The sheath is the only part that needs tight diameter tolerances; the uploaded stl's worked perfectly from my printer, but you may need to scale the sheath slightly in XY, sand it, and/or drill it out. You want the sheath-threaded rod interface to be snug, but not tight enough that screwing it on actually cuts threads (though I guess you could tap it if you wanted). You want the sheath-bottom_mount interface to be a slip fit with no radial play: tight enough to prevent wobble, but loose enough to allow the sheath to spin freely in the bottom_mount. Once everything is printed, place the locknut in the hex slot in the bottom_cone, thread the threaded rod through until it is recessed about 5mm from the bottom surface of the bottom_mount, then push/thread the sheath onto the end of the threaded rod. If done right, the flange on the sheath should have about 1mm of clearance so it doesn't rub while the spool spins. This flange provides positive retention: it prevents the cone-spool-cone assembly from being pulled up-off the bottom_mount. At this point, the bottom_cone+threaded rod should rotate freely. If it does not, then the sheath OD needs to be decreased slightly (sand or reprint) or the bottom_mount ID needs to be increased slightly (sand or drill). If there is radial play, i.e. if the bottom_cone can tilt relative to the bottom_mount, then the sheath OD needs to be increased slightly (reprint). Once that is all set, put your spool on, put the top cone on the threaded rod, place a washer in the top cone, then thread the wing nut on until the cones compress the spool slightly. If the cone surfaces are rough, you may need to wiggle them some while tightening the wing nut to make sure the spool centers. Finally, place this assembly in the filament dryer. To change spools, simply undo wing nut, pull top cone off, switch spools, put top cone on, thread wing nut on. The actual spool holder part can be easily adapted for any horizontal spool holding application by modifying the bottom_mount part. An easy way to remix this is to overlap your own mount with bottom_mount in CURA and export the stl.