Design Goals

• Compatible with a range of spools without adjustment
  
  For easier spool swaps. The design was inspired by my frustration with fiddling with https://www.thingiverse.com/thing:1332650 every time I swapped spool brands. I have specifically tested Esun, Paramount3d, TronXY, Ninjaflex, HobbyKing, but it should work with just about anything that fits in the dry box.

• Fits in a rubbermaid 21c container
  
  used as a dry box (1776473).

• Prints quickly using a 0.6 nozzle
  
  23g of filament, under an hour

• Minimal part count
• • 4x 608 type skate bearings
• • 2x: roller_608x85mm_VASE_X2.stl (printed)
• • 2x: side_support_100mm_21c_x2.stl (printed)

(the rubbermaid box is too narrow to use 100mm rods and trimming rods is a pain).

There are lots of very nice designs that use far more filament and take 8-36 hours to print. They are great if you want to leave it permanently attached to your printer and nothing I felt like printing a dozen of.

The flare at the top & bottom keeps the spool centered and prevents friction from the spool edge rubbing against the side support.

Printing directions — actually read this — defaults won’t work

The rollers (you need 2) are intended to be printed in spiral vase mode with 0 top/bottom layers in a 0.6 nozzle with the extrusion width set to 1.25mm at a 0.45mm layer height. A larger nozzle should be fine but is untested. The parts are scaled for bearing radius +1.25. If you want a radically different extrusion width you probably need to rescale in your slicer. If you want to print multiple pieces at once you can use non-vase mode with 1 perimeter and 0 top/bottom – this won’t be quite as strong or quite as round. In practice it seems to work for me.

If you can’t get your slicer to do the right thing I included an untested roller_608x85mm_HOLLOW_ALTERNATE.stl that should print with standard settings and a normal 0.4 nozzle. 100% infill recommended and unless your layer adhesion is very good it might be too weak.

The side piece is also fine at 1.25w/0.45lh 1 perimeter but should be printed with 1-2 top/bottom and ~15% infill. You need 2. I print 8x at a time in < an hour.

I have 4 sets running all printed in ABS on the hot side for stronger layer adhesion (and ~5% over-extruded). PETG will probably work fine and is untested.

Since the rollers are one-at-a-time I just pivot them off the still-hot plate and hit print again. They are plenty strong. Test the fit on the first one, if you can’t install without splitting then either decrease extrusion width slightly, flow slightly, (your printer is incorrectly calibrated) or scale the part a couple %. I printed in clear to show the mild discoloring from forcing the bearings in. The roller sides are held together by the rubbermaid box. They work standalone but don’t worry if they seem a bit loose and floppy.

Alternate Parts:

Files with _ALTERNATE in the name are special purpose and not needed for most builds.

The 135mm spacing side is less compatible with smaller spools. It works with ~200mm spools. It also doesn’t fit in a 21c box unless you shrink the rollers slightly (reducing compatibility with wide spools) and is intended for the 16c box.

The _HOLLOW roller is untested and is intended for anyone who can’t get their slicer to hollow out the standard one.

Some comments on dry boxes:

See https://www.thingiverse.com/thing:1332650 and many others for a variety of tube mounting options. Personally I just drill a 3.5mm hole in the lid and friction fit a piece of PTFE tube to act as a guide and to reduce moisture ingress.

I will probably move to a derivative of https://www.thingiverse.com/thing:3737157 for future boxes which uses more compact/cheaper 16 cup containers but I want to make the lid very slightly taller and potentially build the bearing in. It needs a longer bearing spacing to make the spool sit lower which reduces spool compatibility. Use side_support_135mm_16c_ALTERNATE.stl spaces the rollers further apart to make the spool sit lower but is not going to be compatible with low diameter spools. I checked the fit with a Paramount3D spool but am not using it.