Snapmaker U1 Spool Holder with 608 Bearings and Cone Nut (CadQuery)

What it is

A spool holder for the Snapmaker U1 that replaces the original holder in one of the four seats of the side wall. The spool turns on two 608-ZZ ball bearings on a fixed M8 rod. A cone nut screwed onto the hub centres the spool and clamps it against a disc, so spool and hub turn together. One holder per seat.

• Plugs into the original seat: a pin with two snap arms, released by turning it about 90°.

• For 1 kg spools up to 90 mm wide. Snapmaker rates the seat for 1 kg.

• Two nuts: the standard nut fits spool holes up to 62 mm (most 1 kg spools and the Snapmaker spools), the large nut holes up to 78 mm (also Sunlu, Anycubic, Kingroon).

• No electronics in the holder: the U1 reads the spool's RFID tag itself through its side wall.

• The disc has a snap seat for a 25 mm NTAG215 coin tag, for spools without a tag. With the stock firmware the U1 reads only Snapmaker tags; own NTAG tags need a community extended firmware.

• Number plaques "Spule 1" to "Spule 4" (German for "spool") to stick next to the seats, because these holders have no number on the cap like the original ones.

Printed and in use on my own U1; the foot fits very well.

Printing

• Material: PLA / PETG / ...

• The STLs are already in print orientation and need no supports.

  • Foot: lying on its flat side.

  • Hub: lying on one of its flats.

  • Disc: flat, spool side down.

  • Nut and large nut: grip down.

  • Plaques: two colours, white plate and black lettering, top side up. The 3MF holds four objects, each made of plate and lettering, so the slicer keeps the lettering in place.

• Per holder: foot, hub, disc and one of the two nuts. The plaques once.

Hardware per holder

• M8 threaded rod DIN 976, 153 mm long

• 1 × M8 lock nut DIN 985

• 2 × M8 washer ISO 7089

• 2 × 608-ZZ ball bearing

• 2-component epoxy

• optional: NTAG215 coin tag, 25 mm

Assembly

1. Foot: Degrease the threaded rod and screw it into the foot from the front until it stands 1 mm short of the back end of the pin; check with a caliper from the back. The head of the screw that holds the side wall can sit behind the pin. Screw the rod out a little, coat the thread with epoxy, screw it back in and let it cure. Do not use threadlocker: manufacturers such as Loctite advise against it on thermoplastics because it can cause stress cracks.

2. Disc: Slide it over the thread onto the hub until it sits on the collar, and glue it with epoxy.

3. Axle: Washer, hub with both bearings pressed in, washer, lock nut. Tighten the lock nut only until the hub runs without play.

4. Changing a spool: Push the spool against the disc and screw the nut on. While the nut runs freely, the weight of the spool already holds the hub through the disc. To tighten and loosen, hold the spool with the other hand.

5. Coin tag: With the spool removed, slide the tag flat into its seat from the edge of the disc until it snaps in. To take it out, press it towards the edge with your thumb in the window.

CAD: made with CadQuery

The parts are not drawn in a GUI CAD program but written as Python code with CadQuery, an open-source library for parametric 3D models. The scripts are under "Other files":

• u1_spool_holder.py: the holder. All dimensions are named values at the top of the file (spool width, hub length, nut cone, disc, bearing seat, thread clearance), so it is easy to adapt, for example a longer hub for wider spools.

• schilder.py: the number plaques. Change TEXTS for your own text.

• show.py: a small helper that shows the parts as a tree in cq-editor.

To look at the model, install CadQuery (pip install cadquery matplotlib) and cq-editor, the CadQuery GUI, and open u1_spool_holder.py. It shows a tree with the printed parts, the bought parts and the U1 wall with a spool; every group can be switched on and off. Run as a plain Python script, it checks the parts and writes the STLs in print orientation and a picture. Details are in README.md under "Other files".

Credits

The dimensions of the U1's holder seat were taken from the community holders by John S (Snapmaker U1 Easy Spool Holder) and mcpea (Snapmaker U1 Spool holder with bearings) and confirmed by a test fit on my U1. The position of the tag comes from Kit Carlson's Snapmaker U1 RFID tag. The holder itself is my own design, written from scratch in CadQuery. The snap seat of the coin tag follows the principle of a shopping-cart token holder.

License

CC BY-SA 4.0: free to use, change and sell. Credit the author, and changed versions must stay under the same license.

Kurzfassung (Deutsch)

Spulenhalter für den Snapmaker U1, steckt in der Original-Aufnahme der Seitenwand. Die Spule läuft auf zwei Kugellagern 608-ZZ, eine Konusmutter zentriert und klemmt sie. Für 1-kg-Spulen bis 90 mm Breite; die Mutter passt für Spulenlöcher bis 62 mm, die große Mutter bis 78 mm.

Gedruckt in PETG, ohne Stützen, die STL liegen schon in Drucklage. Je Halter: Fuß, Nabe, Scheibe und eine Mutter. Dazu Gewindestange M8 DIN 976 × 153, Stoppmutter M8, 2 Scheiben M8, 2 × 608-ZZ und 2K-Epoxid.

Die Modelle sind mit CadQuery in Python geschrieben. Mit cq-editor lassen sie sich ansehen und über die Werte oben im Skript anpassen; die Skripte liegen unter „Other files“.