"Giant Wheel Grinds Charcoal! (Yes, it works..!)"
https://youtu.be/4wv19734o3c
Good video.
Instead of adding weight to push the charcoal down, I would make the input box much taller and let the weight of the charcoal push down on the knives.
Jim Altmiller
I think you are right Jim. That would probably work much better.
Phillip