Modular Spool Holder

Because there aren't enough spool holder models already, right?

Version 2

Modular Spool Holder includes the following stand options:

• Desktop - includes ability to clip multiple together for MMU, etc.
• Wall Mount 
• Lack Lid Mount - brackets are at a slight angle so that you don't dump the spool out when you lift the lid.  Includes alignment guide to install 5 stands while avoiding the lack frame.
• Center top mount for direct drive Ender/CR10/other 2020.  Remix of mounts originally designed for Auto-Rewind spool holder.  Bonus version with loops to mount an LED light bar using this closed channel holder included.
• Center top mounts for MK3 and MK4

Includes the following mechanisms:

• 75mm roller for use with 608 bearings for a super smooth and quiet roll.
• 75mm roller with dummy bearings.  The dummy bearings replace the 608 bearings for a bit more friction which avoid over spinning but makes noise.
• Support for 75mm Integrated Auto-Rewind spool.

The key to this spool holder is that, once assembled, it's 2 pieces that drop in place easily. No screwing down clamps to the spool or fiddling with aligning a small axle end with slots.  Just slide the mechanism through the center of the spool and drop it in place.  Done!

Why use this instead of the plethora of stands for the Auto-Rewind spool? Basically, it works the same but it a lot simpler to drop the spool in place because it slides right into the brackets and auto-aligns itself.

Some notable features:

• Slim design.  I've made these about as narrow as you can get away with and still accommodate a standard 70-ish mm spool.
• Super quiet (when using the 608 bearing option)
• Easy drop in spool swaps
• Brackets are keyed so that when using the Auto-Rewind, you don't have to worry about putting it in backwards - the rewind mechanism is always winding the right way.
• All stands and mechanisms are interchangeable.
• No supports needed for any prints.  Where there are counterbores for the M3 screws, I have built in sacrificial bridges.  Just poke an M3 screw, screwdriver, or w/e through the hold to break the bridge.
• Most parts print well with 0.6mm nozzle for reduced printing time.
• Lack Lid stand has a 4mm hole in the front brace to hold PTFE for an over-the spool feed.  May need bored out a bit depending on your PTFE's real OD and your printer's tuning.

Assembly is fairly simple and the only hardware required are M3 screws and M3 heat inserts.  I chose heat inserts over captive nuts because they're actually easier to work with and a lot more reliable.  If you have been avoiding them because they seem complicated, they really aren't.  You just need just about any soldering iron that can reach 250-300C.  You can choose to get special heat insert tips that will help you heat the inserts more evenly and keep them aligned but a standard soldering tip can do the job fine.

Print Instructions:

• Stands
  • 0.6mm nozzle
  • 0.3mm layer height
  • 15% gyroid infill
  • 2 perimeters
• Roller
  • 0.6mm nozzle
  • 0.3mm layer height
  • 0.5 variable layer height (optional)
  • 10% gyroid infill
  • 30% gyroid infill for top and bottom 12mm - See included 3mf for easy mode
  • 2 perimeters
  • Seams: Random
• Other Fiddly Bits
  • Whatever you normally print with, eg:
  • 0.4mm nozzle
  • 0.2mm layer height
  • 20% gyroid infill
  • 2 perimeters

Assembly is pretty simple. I've included an exploded view for each of the 3 mechanisms.  For Auto-Rewind option, make sure you get the keyed cap on the correct end so you're rewinding in the correct direction.  For the Lack Lid stand, use 60mm M5 screws washers and nuts

This is designed completely in Tinkercad so, unfortunately, no step file.  However, if you want a custom version, let me know what specs you would like to change and I can probably accommodate most requests.

I ended up designing most of this from scratch but credit where it's due.. I drew inspiration from other spool holders I've used in the past:
https://www.printables.com/model/174620-filler-filament-holder
https://www.printables.com/model/168-universal-auto-rewind-spool-holder-mm
https://www.thingiverse.com/thing:3627169 

** Note:  If, when using the auto-rewind option, you find that it's trying to jump out of the stand it may be that the stand has bowed outward at the top so the keyed ends aren't seating well.  Adding an additional clip to the axle on one end to make up for the extra width of the stand is a workaround.  I suspect printing in a more rigid material like PC-CF might mitigate this in the long run.

UPDATE 2023-04-22: Added a snap in filament guide for the Single spool Ender and MK3/MK4 brackets.  Includes a print-in-place swivel mechanism.  If you have trouble with the swivel being seized to the arm, you've got some calibration to do (elephant foot is a likely culprit).  Insert a short piece of PTFE through the swivel part to protect it from wear as the filament passes through. I used 3mm ID but the normal 2mm ID would be fine as well. Updated 2023-04-23 to add a small parking slot for filament that's not fed into the printer to prevent unspooling/tangle.

UPDATE 2023-04-20: Added brackets to mount a single spool on top of MK3 and MK4 frame.  Note that the Nextruder has very narrow clearance at the top so the one specifically for the MK4 has a bit of the front clip sliced off.  This may impact it's durability so definitely print in something stronger than basic PLA and with 4 perimeters to avoid infill in that area.

UPDATE 2023-01-23:  Version 2 released.  Entire description rewritten to reflect the updated design.

(Obsolete) UPDATE 2023-01-14:  I've added an axel and end caps to adapt the Integrated Auto-Rewinder as a drop-in replacement for the roller.  Print 2 ends, and 1 rod plus the base stand only.  Install an M3x5.7mm into each end of the rod and use M3x8mm screws to assemble.  Files have been shuffled around to clarify what's optional but none of the base files have been modified.

(Obsolete) UPDATE 2022-12-27:  I've added a “Dummy Bearing” as an option to use in place of the pins, washers and 608 bearings.  I've found that the 608s actually make it spin too smoothly and often the spool will overspin when filament is fed resulting in a bit of loose filament. Not a big deal, but it's evidence the bearings are overkill.  I printed these dummy bearings and swapped those in and it still rolls perfectly smoothly.  The dummy bearings are counter bored so you can use ~14mm regular M3s instead of countersunk.  Remember to use random seam placement to avoid the “thunk” as it turns over an aligned seam.  Even with a good sanding, they won't be as quiet as using the bearings, of course.