Anycubic Kobra X - Threaded Spool Lock v2 - No-Wobble, Quick Spool Swap

A spool that spins true, and swaps without tools. Stock spool holders, and most bearing upgrades, let the spool rock on the tube. This two-part threaded lock clamps the spool and hub into one rigid unit that spins smoothly on the Kobra X holder. In v2, swapping a spool is just unscrew, slide, screw.

New in v2 (built from your feedback)

• No more removing the end cap: the nut's 35.8 mm bore slides straight over the 34 mm stock end cap.
• The tube stays put: part A lives on the holder. Only the spool and the nut come off.
• Easier to grip: bigger serrated tabs, plus ribs on the nut's inner ring for turning with your fingertips.
• Optional stop collar (3 g): a snap-on clip that keeps A parked while you pull the spool off.

Why the wobble disappears

• Two-point guide: A rides the 24 mm tube on ribs at both ends, about 40 mm apart, so the spool can't tilt.
• Self-centring springs: 4 spiral arms on each part centre themselves in any 50-60 mm spool hole.
• Clamped, not just sitting: the feet clamp both spool walls, so spool and lock turn as one.

Fits

• Holder tube: 24 mm (Kobra X stock holder)
• Stock end cap: 34 mm (the nut passes over it)
• Spool hole: 50-60 mm
• Spool width: 45-70 mm (most 1 kg spools)

Install once

1. Take the stock end cap off the holder tube.
2. Slide A on, feet toward the printer.
3. Put the end cap back. That's the last time you touch it.

Swap a spool in 3 steps

1. Unscrew the nut (B) by its inner ring and slide it off over the end cap.
2. Swap the spool. A stays on the tube.
3. Screw the nut back on until both sets of feet sit firmly against the spool walls.

Print it

• Material: PETG
• Settings: 0.2 mm layers, 4 walls, 100% infill (the spring arms need it)
• Supports / brim: none, both parts print feet-down as placed in the file
• Weight: about 49 g per set (A + B), 3 g per collar

Tested on: Anycubic Kobra X with PETG. v2 spins freely with no wobble, the nut slides over the stock end cap, and A stays on the holder during a swap.

Upgrading from v1

The v2 thread is bigger, so print A and B fresh. v1 and v2 parts don't mix. The v1 files are still in the download as "legacy".

Designed and tested by me: re-engineering legacy designs, one failed prototype at a time.

Storing the spool?

Unscrew the lock and swap in my Universal Spool-Hub Silica Canister - same 50-60 mm hub fit, keeps the spool dry in the bag or tub. You only need as many locks as spool slots on your printer.

Licensed CC BY-NC-ND 4.0 - free to download and print for personal use. Please don't upload remixes or sell prints or files.