i've designed this spool holder for the my ender3, to replace the original one that is not very flowing. you do not have to make any changes but take apart the old one and put this in place. there are two versions of 45mm and 20mm rollers that allow the installation of reels of different thickness, the system can be disassembled for inserting and unloading reels with a smaller hole, using 3 x 6mm cylindrical magnets to make it easily mountable and dismountable.

bill of materials:

pieces to use of the printer:
-ender3 spool holder bracket

3d printed parts:
2x base for bearing
2x roller, the combinations that I recommend 45 + 20 45 + 45

15cm M8
1x bearing 22 x 8 x 7 mm type 608ZZ
4x M3 20mm screws
4x nut m3
4x nut m8
6x 6x3 cylindrical magnet

disassembling the old reel holder, insert the cooker in one of the two bases, they are identical, they only need to rotate 180 ° to allow it to be mounted in the hole of the bracket.
Assemble everything with the 4 M3 screws.

insert the threaded rod into the bearing and fix with two M8 nuts the bar at the base on the sides of the bearing, put a further nut as thickness, insert the first roller after having inserted the magnets in the upper part, paying attention to the polarity. in the hexagonal seat insert a nut and tighten everything.
prepare the second roller only with the magnets with the inverted polarity and thread until it comes to pack and the magnets are not attracted.

you have finished the assembly, mounts where you prefer the bracket, for convenience I preferred to fix it on the side exploiting the hole in the upper bar

assembly completed

Creality

Ender 3

No

No

0.24

15