Speaking personally, no, I'd have no use. I don't need more equipment around, and if it takes longer for the cardboard to break down, that's mostly fine by me.

Sorry, no. My way of worm farming is recycle, reuse, repurpose. I'll buy something only if I absolutely need it and there's no other way to get the job done.

I use corrugated cardboard and same here, no hurry. Besides, the worms like to hide between the layers.

IMHO, once you build the grinder, you need something so the dust won't be flying all over unless you do the grinding outdoors. Still have to be careful not to breath it in. The most compact way to store card board or ccb is in flats.

I use the shredder I have for documents and it does a great job of shredding the cardboard as well. For a while I did it by hand but the amount of time was too much which is why I switched. I eventually gave the shredder to my parents and bought a new one. I do recommend getting one with at least a 12 sheet capacity and this way you can add documents you want destroyed into your worm bin as well!

I know this is an older thread, but I'm hoping @T Walker will see my reply. There didn't seem to be much interest on this site but I'm not sure if you were thinking of providing the ground cardboard or the grinding equipment. In either case, I for one, am interested in learning more about your idea

I use my Fellowes W11C for shredding cardboard had it for years still working great. I have cut up 4' boxes before without a problem. You will have to cut them to size to go thru shredder. It wont do heavy duty cardboard simply because they wont fit thru the slot.