Breville / Sage Barrista Express Grinder Gear (BES875)

Breville / Sage Barrista Express (model BES785) main grinder drive assembly gear (the off-white one in the image). These are not available as a separate spare part from Breville (Sage), but are the first to fail if the grinder gets jammed for whatever reason, despite the other gear having a built-in clutch, which should prevent this.

Tested in an actual device, and works just as good as the original, with slightly more snug fit.

PLA seems to provide best results in terms of durability. I had one of these fail, due to a stone jamming the burrs, and after disassembly there was no visible wear on the undamaged teeth after 6kg+ of coffee going through the machine.

Print Settings

Printer Brand:

Prusa

Printer:

I3 MK3S

Rafts:

No

Supports:

Yes

Resolution:

0.2mm

Infill:

30% gyroid

Filament: Prusament PLA

Notes:

These are OK printed from PLA, PC, possibly even PETG.
Best results with 4+ perimeters, 30%+ gyroid infill, 1mm minimum shell thickness.

How I Designed This

I've used Fusion 360 to design this.

The smaller top gear was designed using the built-in SpurGear add-in, and the main gear was designed using the free "Helical Gear Generator" add-in by Ross Korsky, available on Autodesk App Store.

Then it was just a matter of combining the two main bodies and ensuring proper tolerances.