R1/R2 Cooling Bowl Stirrer (Aillio-Compatible)

This cooling bowl stirrer is an open-hardware accessory designed to be compatible with the Aillio R1 and R2 coffee roaster cooling bowls.

By actively agitating the beans during cooling, it:

• Speeds up heat dissipation

• Improves airflow through the bean bed

• Ejects additional chaff that didn’t escape the drum

• Breaks up clumps for more uniform cooling

• Shortens the total cooling cycle

This is a post-roast cooling accessory only.
It is not for use inside the roasting drum and is not affiliated with Aillio.

The design is fully open-source and released under CC BY-NC 4.0 (non-commercial).

📦 Included Files

STL Files

All components needed for the full assembly:

• Bean Stirrer

• Bottom Wear Plate

• Top Wear Plate

• Axel Hub

• M5 Thumb Screw

• Motor Body Base

• Motor Body Cover

• Motor Body Wire Cover

Documentation

• Full Build Manual (PDF)

• Exploded View with labeled components

• Full Bill of Materials (BOM)

🛠 Recommended Materials

Stir Paddle

• PA6-CF (Nylon Carbon Fiber)

• Recommended: Polymaker Fiberon

• High heat deflection — ideal for hot roasted beans

Wear Plates

• PA6-CF

• Low friction + heat resistant

Housing / Covers / Thumb Screws

• PLA-CF (Bambu Labs or similar)

• Rigid, clean-looking, stable

Special Notes

• Pause paddle print to insert the embedded nut

• Pause thumb screw print to insert M5 screw

• Resin coating + sanding optional for smoother finish

🔩 Hardware Required

• 80 mm stainless square rod (cut to ±0.25 mm)

• PTFE shoulder washers

• M3 and M5 fasteners

• Heat-set inserts

• 12 V DC gear motor (direction reversible)

• 12 V 2 A power supply

🧭 Cutting the Square Rod

1. Mark 80 mm with calipers

2. Cut using hacksaw/bandsaw/cutoff wheel

3. Deburr both ends

4. Confirm smooth sliding fit into hubs

🔧 Assembly Notes

Full step-by-step instructions are included in the PDF manual.

Quick highlights:

• Center the paddle on the cooling bowl’s center pin

• Do not overtighten the paddle screw (free rotation is essential)

• Leave motor screws loose during alignment

• Apply blue Loctite once everything rotates freely

If the paddle spins the wrong direction: swap motor polarity.

🛡 License

This project is released under:

Creative Commons BY-NC 4.0 (Non-Commercial)

You may:

• Print and remix

• Share non-commercially

• Must credit Dustin Betterly

You may NOT:

• Sell prints

• Sell kits

• Sell remixes

• Sell this design in any form

Full text: https://creativecommons.org/licenses/by-nc/4.0/

🙌 Credits

Design & documentation by Dustin Betterly
Open-hardware project hosted on GitHub.