February 24, 2026
Description
This adapter enables you to use your old Prusament spools as a Multispool for filament refills of the “Recycling Fabrik” https://www.recyclingfabrik.com
It is a sturdy and long lasting alternative to fully printed spools and the refill is held much tighter by the spool than by the original Multispool. To improve the reliability in systems like the BambuLab AMS, the end of the filament is secured on the spool center. This prevents the filament refill from rotating on the spool, which is a common issue with refills in the AMS.
For printers with filament runout detection, it's best not to attach the end of the filament. The extruder will probably not be able to pull the filament out of the hole.
This applies to the version with the short screws and inserted nuts. The pictures show the assembly process in the right order.
Remove the cardboard center of the Prusa Spool. The cardboard can be tight, but you should get it out by wiggling the spool halves. Don't use excessive force, otherwise you might break the spool halves.
Prepare the Prusa Spool halves: The outer ring that holds the cardboard spool center has to be cut off in order to make space for the refill. You can use a hacksaw, dremel, lathe, …
Prepare the Center Piece: Press in the M4 nuts.
Not all nuts are made equal, some are a bit smaller than 3mm height and some a bit taller. Therefore the installation can be challenging.
Attention: Please check if you have regular sized nuts (3mm tall) or flat nuts (2mm) tall and select the appropriate model.
Screw on the bottom piece of the spool halves. You can use either one of the halves, just make sure to use the side of the center piece that does not have the filament throughhole.
Rotate the zip ties of the Refill to the outside before putting it onto the center piece.
Find the beginning of the filament on the inside of the Refill. This side has to face up. Pull out the end of the filament one third (towards the next zip tie).
Put the refill onto the center piece. The center piece is intentionally tight to avoid rotation of the filament on the spool. Make sure to align the end of end of the filament towards the filament throughhole.
Insert the filament end into the throughhole. Depending on the type color of the filament, it can be a bit brittle so be careful not to break it. If you do, just pull/push the broken piece through the hole.
Once the filament comes out at the end, pull it tight and make sure the filament lies in the groove. You can use pliers to help you.
(Optionally) Cut the end of the filament that is sticking out into the center.
Align the top half of the spool and tighten the screws lightly (not all the way yet!). Try to make sure the filament did not jump out of it's groove.
Attach the outer end of the filament string to the filament spool, so it won't unwind itself.
Cut the zip ties and pull the first one out, then tighten the adjacent screw(s). Proceed the same way with the rest of the zip ties.
Make sure all screws are tight.
Apply the sticker to the spool.
DONE! 🥳
8x M4x16mm (or longer, up to ~25mm should be fine) Screws, DIN 9784 or DIN 84 for flush outer spool surface, otherwise DIN 912 works too
8x M4 DIN 934 Nuts (Model Regular Nuts) or DIN 439/ISO 4035 nuts (Model Flat Nuts)
It is possible to use four very long screws instead of the eight short screws and inserted nuts and make use of the fact that the hexagons of the Prusa spool are 7mm wide, leaving the perfect room for an M4 nut. This is not recommended though as it is more finnicky to assemble the spool.
4x M4x65mm Screws, preferrably DIN 9784 Cylinder Screws (if you can find them that long) or DIN 84 Slotted Screw. DIN 912 works as well, but the head will protrude the spool. If that does not bother you, these are the easiest to find
4x M4 DIN 934 or DIN 439/ISO 4035 nuts
Use a temperature resistant filament like ABS, ASA, PC(CF), … if you want to put the spool into a filament dryer.
It is recommended not to use a hydrophilic material such as PLA, PETG, PA, … if you want to dry your filament, because you'll have to dry filament AND spool center.
With three outer perimeters, the important parts of the perimeter is completely filled. The actual infill in the center part is not incredibly relevant for the strength.
No supports are required.
Optimized for 0.25mm layer height.
Please consider liking and posting a make if you find this useful 🙂
Update 22.12.2024: Version v9 introduces holes on the opposite side of the nuts, so you're able to push them out again in case you want to recycle the spool center.
License:
Creative Commons — Attribution — Share Alike
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