Filament Spool Adapter/Spool Holder Upgrade for Creality Ender 3 Printers

If you're like me, you don't like the way the stock filament holder works on Creality's Ender and other printers.  I wanted something that would hold my filament spools more in the center and allowed for the spool to spin smoothly.  I looked online at a lot of other spool holders and spool adapters, but wasn't able to find what I was wanting.  Most of them other people have created replace the stock spool holder entirely, but I wanted something that would fit onto most any brand of filament and be able to slip over the stock Creality spool holder.  I found a design made by a guy on YouTube I really liked for the most part (his channel name is Design Prototype Test, here's a link to his video if you'd like to check it out https://www.youtube.com/watch?v=8zT_F1Q-Sxg), but his design replaced the entire spool holder which I didn't want and he also only distributes his design to his Patreon supporters.  Since his design wasn't exactly what I was wanting anyway I decided to use his design as inspiration for my own and this is what I came up with.

I haven't use a wide variety of different brands of filament spools, but the few I have used all have different inner diameter holes meaning any adapter I made needed to be able to be usuable with spools with different inner diameter holes, so I made it able to accomodate spools with an inner diameter of 50mm up to around 84mm (1.97 to 3.3 inches).  It's super simple to install onto any spool of filament, fits perfectly onto the stock spool holder Creality uses on many of their FDM printers and allows the spool to smoothly unwind.  I prefer this over the full spool holder replacements because my printer sits on a shelf with the back to the wall.  The full spool holder replacements similar to this design require you to screw on a nut of somekind where you can't really see it as your view is blocked by the filament spool.  This design allows you to install the adapter onto your filament spool and then place it onto the printer, so no feeling around blindly trying to find where the nut needs to thread on to.

Since this part isn't exposed to heat and doesn't need to be crazy strong, you can print it in any material you like.  I used Creality CR-PETG, but I'm sure PLA would work just fine.

While this adapter is for my Creality Ender 3 V2 printer I actually printed it on my Bambu Lab P1S using the Bambu Studio Slicer.  As for my slicer settings they are as follows…

Layer Height - you can print at 0.2, but I would recommend 0.12 or 0.08 for the threaded parts. The finer your layers are the easier it is to break the threads in. At 0.2 it can be pretty tough getting it to thread together the first time and requires a lot of effort. At 0.12 or 0.08 this becomes much easier.

Ironing Type - Topmost surface (ironing is optional, I just like the way the parts look when ironed)

Only one wall on top of surfaces - Top Surfaces

Only one wall on first layer - Enabled

Wall loops - 4

Top shell layers - 4

Bottom shell layers - 4

Sparse infill density - 15%

Sparse infill pattern - Gyroid

All other settings I leave at default

No support is needed

The locking nut and the main part of the adapter were a bit tight as I tried to screw them together for the first time, but I just kept working it by tightening it and then loosening it until it threaded smoothly.  You really only need the nut to thread on about 25mm at most (about 1 inch) so there's no need to worry about threading the nut all the way.