I have constructed a portafilter funnel for my DeLonghi EC 685 Espresso machine and my Graeff CM800 coffee mill. The funnel is attached to the portafilter with a bayonet lock. Optional magnets (d: 5x 1.5m) can be used for a better user experience. My funnel consists of two parts that can be plugged and glued together. Optionally, 3 pins (d: 2 x 10mm) can also be used to give the component more stability. The inner diameter of 52mm is large enough for the tamper of the EC 685.
STEP files are provided for remixing or easy editing.

Note:
If the pins cannot be pressed into the holes, the holes can be widened with an M2 drill.