The (almost) Perfect Master Spool

New Version Released (V13)! Not compatible with old version!

This project is still in development so any feedback is welcome! 😊

Everybody knows there are a lot of master spool designs available for the Bambulab refill filaments (and other brands). But while I was searching for one, all of the designs were missing a feature that others did have and vice versa. None of the designs had ALL of the features you wish to see in a master spool. I was charmed by the MasterSpool that FormFutura has designed, but that one wasn't compatible with BambuLab refills, just their own. So I went out and design my own, of course. (relevant XKCD: https://xkcd.com/927/ ).

My master spool needed to have the following features (V13):

• Bambu/Sunlu/Azurefilm/Panchroma MasterSpool™ refill compatible,

• Works on all AMS systems,

• Lightweight (±100gr total for velcro version, 150gr for cilinder version),

• Easy change of refill spool with velcro or tie wraps,

• Good solution for clamping the end of the filament in the spool,

• Locking cilinder to prevent halves coming loose during printing. Cilinder fits on AMS Lite too!

• Filament left approximation in grams and meters,

• Have an open design for when you want to use a filament dryer to actually be able to dry the filament. Print spool in PETG/ABS!

• RFID support for those who use their own RFID chips (or bambu's)

• Material type indicator in RFID tag

As I think a design like this can always be improved upon I'm open for ideas or suggestions for features you're missing.

You can print the spool in PLA of course, but printing in PETG or better even ASA/ABS is recommended. This is for the temperature resistance when using the spool in a filament dryer or inside a printer.

If you're looking for a nice filament clip to hold your filament when the refill is not on the master spool, use this one: https://www.printables.com/model/554991-grandmas-tags-favorite-filament-clip Works really well and you can have a label of what type the filament is.

If you like this design, consider buying me a beer ❤

Changelog

17-1-2026: V13 - Improved the edges to be stronger where you clip the filament end in.

05-08-2025: V12 - New design with only locking cylinder option but AMS compatible with that. Grams indication.

10-7-2025: V11 - Removable RFID chip slot added and material type in the RFID chip.

6-1-2025: V10 - Added the little nub that goes in the cardboard spool of a Bambu refill.

7-12-2024: V9 - There were some spokes not correctly attached to the outside rim. Fixed that.