Credit - I've tested a few dosing funnels on Printables before designing this (E61 Dosing Funnel, Gaggia Dosing Funnel with Magnets), so I'm sure my design is somewhat influenced by those. That being said, this is a ground-up new design with features focused on my use case.

Description

This is a dosing funnel for Gaggia portafilters, though it may work with others. Compatible portafilter bodies should have an outer diameter of 69-70.8 mm and ears no more than 6.6 mm thick. I've also designed a mount for attaching to a magnetic surface. This pairs well with my portafilter stand, especially if you have a Timemore grinder.

My specific use case is grinding from a Timemore Sculptor into ridgeless baskets in a Gaggia Classic portafilter, so this resulted in a slightly steeper, taller funnel with latching arms to hold on instead of magnets.

Print settings

PETG for hot portafilter compatibility, 0.4 mm nozzle/line width, 0.2 mm layers, 3 wall lines, print per model orientation. Zig-zag supports with 0 horizontal expansion recommended for the ear latches. Material use is minimal despite the larger than typical funnel. Make sure you have good bed adhesion, though!