This universal adapter allows spools with larger inner diameters (55–75 mm) to be used while remaining compatible with smaller spools, such as those for SnapSpeed or BambuLab filament. It attaches securely to the original spool holders and can be left in place or moved between spools as needed.

Uses only 56g of filament and prints in ~1h 50min (using the recommended print settings /.3mf).

Features

• Snug Fit: Designed with friction to stay secure but remain easy to remove.
• Easy Nut Insertion: Screw in the opposite direction until the thread locks.
• Optimized Threading: Two thread starts and 3D-printing-friendly geometry allow for quick screwing and unscrewing.
• One-Handed Operation: Three nubs in the bolt opening to help prevent rotation while screwing.
• Seam Painting: Cuts in the threads with painted seams (in the included .3mf file) ensure consistent dimensions when printed.

How to use

There are two ways to use the adapter: on the spool holders or on the filament spool itself. These instructions assume one-handed use, though two hands will make it easier.

Tip: When using spools that would fit on the original holders (e.g. with an ID of 55mm) screw the nut on with the flat side facing the spool.

Option 1: Adapter on the Filament Spool

Screwing/Unscrewing

1. Place the adapter flat on a surface.
2. Set the spool on top of the adapter.
3. Screw the bolt on securely.

Attaching 

1. Attach the adapter (with spool) to the spool holders by gripping the nubs.

Option 2: Adapter on the Spool Holders

If you often use spools that are incompatible with the original holders, it is useful to leave the adapter installed on them.

However, because you are screwing into a rotating thread, this is slightly more challenging.

Screwing

1. Place the spool onto the bolt.
2. Press the nut firmly onto the bolt to align the threads.
3. Use a finger to rotate the bolt via one of the nubs for the first full turn.
4. Switch to rotating the nut with your thumb while holding the bolt steady with a nub.

Unscrewing

1. To remove the spool, lock the bolt with a nub and unscrew it using your index finger.

Printing

• Print the bolt on its head.
• 0.2mm layer height
• 2 walls
• 10% gyroid infill.
• No supports or brims required.
• PLA

Inspiration

This model is inspired by universal adapters for the AMS Lite but is designed from scratch for the Snapmaker U1. Even though the spool holders of those two look very similar, there are lots of little differences that required different design decisions.

Change Log

• 23.05.26] - uploaded bolt v8, same length as v7, but with threading from the start. Also made the angle on the end steeper, to better support wider 55mm ID spools. (Remember to try using the nut both ways if the standard direction doesn't work!)

  

• [05.05.26] - uploaded bolt v7, making it 1cm longer to fit full-size Sunlu spools