Shpoolie! Modular Dry Box and Standalone Filly Spool Holder

Shpoolie — Modular Cereal Box Spool Roller

Built out of frustration with every other cereal box spool holder on the market — specifically the PRAKI 4L cereal box. Every other design required pulling the spool out just to swap or refill desiccant. Shpoolie lets you dump molecular sieve or silica gel in through the top and empty it the same way, spool still loaded and ready to go.

Made almost entirely from leftover 3D printer parts — F695 or 695 bearings, M3 heat inserts or M3 square nuts depending on what you have on hand.

💡 Why Shpoolie?

Most cereal box spool holders lock your desiccant in place — you have to pull the spool out every time you want to swap or refill it. Shpoolie fixes that.

✅ Spool stays loaded
✅ Pour desiccant in and out through the top
✅ No disassembly required
✅ Modular front attachments
✅ Works inside a PRAKI 4L cereal box or as a standalone spool roller
✅ Up to 69.2mm filament spool width, more if you don't care if it rides up on the lip in the cereal box

📦 Designed for the PRAKI 4L Cereal Box

Shpoolie is designed to fit inside the PRAKI 4L airtight cereal box — a popular and affordable dry storage solution for filament. The box keeps moisture out, and Shpoolie's bearing rollers let your spool spin freely so filament feeds smoothly without ever opening the box.

The PC4-M6 or PC4-M10 bowden mount installs on the top front of the cereal box, or on the lid if you prefer — giving you a clean PTFE tube exit point straight to your printer.

Don't have a PRAKI box? No problem — see Standalone Use below.

🧩 What's Modular?

Front Base — pick one:

Front Attachments — pick one:

Bowden Mount — pick one:

Mount on the top front of the box or on the lid — both include a spacer for proper fitment.

🔩 Bill of Materials

🐻 Bearings

Uses F695 or 695 bearings — same bearing, F695 just has a flanged lip.

• ID: 5mm

• OD: 13mm

• Width: 4mm

Standard 3D printer bearing — easy to find on Amazon, AliExpress, West3D, Fabreeko, or KB3D.

🦶 Standalone Use

No cereal box? No problem. Slots on the bottom let Shpoolie sit on any flat surface as a freestanding spool roller:

• Print the included TPU feet — snap into the bottom slots for grip and vibration dampening

• 1/4" rubber non-slip stickers — stick into the slots if you'd rather skip the TPU print

Sits stable on a desk, shelf, or top of your enclosure.

🔧 Assembly — Step by Step

Step 1 — Remove supports from the bearing roller

The roller has built-in supports. Push them out from the other end using a large stick or screwdriver. They pop out easily.

Step 2 — Install bearings

Press the 4 bearings into the roller seats. They should sit flush and snug.

Step 3 — Install heat inserts or square nuts

Press M3 heat inserts into the front base with a soldering iron, or drop M3 square nuts into the square nut base.

Step 4 — Seat the rollers into the base

Gently flex the Shpoolie base at the thicker sections and snap the bearing rollers into the indents. They click into place.

Step 5 — Attach your chosen front attachment

Screw your chosen front attachment (hygrometer mount, name plate holder, or blank spacer) onto the front base.

Step 6 — Install bowden mount (optional)

Drill or punch a hole in the top front of your PRAKI box or on the lid. Make sure to position the hole at least 1½" (38mm) away from the lid closing flap/hinge so the lid can still open and close freely without obstruction.

• PC4-M10 — drill a 10mm hole

• PC4-M6 — drill a 6mm hole

Thread in your coupler with the included spacer and run your PTFE tube through.

💡 Note: When the spool is not in use, you can use a magnetic PTFE coupler mod to park the end of the PTFE tube — a magnetic receiver screws into the cereal box so the tube snaps neatly into place when not printing. Let me know in the comments if you'd like me to add one to the design!

🖨 Print Settings

Note on PLA: PLA may be too brittle for the flex required during assembly. If you've printed it successfully in PLA let me know in the comments!

Leftover 3D printer parts, a cereal box, and a problem worth solving. Enjoy.