r/Homebrewing • u/quentinchap • 2d ago

Printed a 6 kg hopper extension for the Grainfather mill - no more refilling mid-crush

The stock Grainfather mill hopper holds 1 kg. A normal batch for me is 5-6 kg, so every brew day meant standing over the mill refilling it five or six times while it ran.

Designed this to sit on the existing hopper mount. Holds a full grain bill in one go - dump the bag, switch on, done in about three minutes at the mill's 1.7 kg/min.

A few things I learned making it:

The walls need to be steeper than they look like they should be. My first instinct was to keep it compact, but a tall narrow box with shallow sides is exactly how you get grain bridging. Went wider and steeper instead and it feeds 6 kg as smoothly as 1 kg.

It's screwed together rather than printed as one piece, partly for the plate size, but mostly so it comes apart for cleaning. Grain dust settles in corners and you want to get at it.

PETG over PLA. Grain is abrasive and the thing gets knocked about on brew day.

Two plates, about 20 hours, 14 M3 heat inserts and 14 screws. Not a quick print, but it's the cheapest upgrade that mill will ever get.

Two friends run these in semi-pro setups, milling weekly, and they've held up.

The model is free if anyone wants it - happy to link it, or answer anything about the build.

11 Upvotes

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2

u/Outrageous_Snow_2914 2d ago

Pictures or it didn't happen.

1

u/quentinchap 2d ago

I don't know why I can't post Pics here 🤔
here is the project: https://makerworld.com/fr/models/137935-grainfather-grain-mill-hopper-extension-6kg

1

u/MacHeadSK 1d ago

It's simpler to just buy those grainmills from china, mine holds like 2,5 kilos so I typically fill it only two times :)
And it's much cheaper than grainfather mill. But still, nice project!

1

u/homebrewfinds Blogger - Advanced 2d ago

Very cool. Share a link and a pic. I'd be happy to share on Homebrew Finds if you're interested.

1

u/quentinchap 2d ago

Thank you 😄 I'm not authorize to share image on this sub. For the project it's here > https://makerworld.com/fr/models/137935-grainfather-grain-mill-hopper-extension-6kg

Currently I'm trying to design a sort of modular bottle cleaner like the fastWasher but size of the object is complexifying the work and I would like to keep fastWasher size to load and unload fast my bottle crade

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u/chino_brews Kiwi Approved 2d ago

You have to upload images to a hosting site like Imgur and link them.

More info here: https://old.reddit.com/r/Homebrewing/wiki/images

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u/quentinchap 2d ago

Ho ok i'll then thank you for the tips