Summary

This is crazy quad Creality 3D Digital Spool Holder project.
You can put 3kg(and more) heavy weight filament spool onto your 2020 extrusion to save the space and nice looking and easy maintenance.

Your feedback and comments are every time very helpful to improve my design.

BOM

• M4 x 50mm screw 3pcs
• M4 nut 3pcs
• Creality 3D Digital Spool Holder 4set
• (Optional : M4 x 30mm screw 1pcs + M4 nut 1pcs for Core connection)
• (Optional : M4 x 18mm screw 2pcs + M4 T nut x 2pcs for 2020 extrusion mount, Holder Core has 13.5mm height compatible with Elegoo stock spool Holder)

Cost me > $60++ but very meaningful for stable use of 3kg filament spool smoothly work with filament sensor. OR you can put multiple 1kg filament spools.
You can measure the 3kg or 5kg spool weight with Creality 3D Digital Spool. If you want to try all quad or just try with single it totally depends but the kind of workable to deal with your 3D model filament use vs. act remainining for quick check.

Tested w/ Polymaker and eSun 3kg spools but I assume 5kg or other vende's 3kg spool also work well you can refer spool diameter from those 2 venders

• in singale spool use case, min Inside width is about 82mm so almost all the 3kg filament spool work
• in dual or hanging use case, whichever 1kg spool works, works well with elegoo stock spool holder at least Neptune3/4 series.

I highly recommend to print with tough PLA or such solid/hard material not just avoid break but avoid vibration when you put heavy weight on it. 3 parts require snug simple support, you can just refer the picture attached.

You can use Elegoo neptune 3 or 4 series stock spool holder if you want to save the printing time, just use with multiple 1kg spools NOT 3kg or 5kg spool.
But my spool holder "core" attached is much stronger and capable for weight handling.

Build Step

1. Put Joint parts to Holder Core
2. Screw RollerBody parts both Right and Left
3. Use M4 50mm screw and hex nut and fix the parts 3 points.
4. Mount it on 2020 extrusion
   Optional - You can use M4 30mm screw and M4 nut for Holder Core connection. I just use it when I super glue Core parts in my case.

As first release I just remove the pop-guard because every open spool holder in the market doesnt have it also I expect to use with filament sensor just control the force not to direct to side but more center as you can see the picture as usual bed-slinger 3D printer, this actually helps to avoid the off course drop :)