This item is an assembly of cranks and gears with a coin-slot at the top and a slot for an inkwell to be inserted at the bottom.

A user may insert coins into the coin-slot and an inkwell at the bottom and use a handle attached to the gears to grind the items in the coin-slot into a fine powder that will be infused with the ink well at the bottom.  Wizards in ages past have been known to use this to infuse the inks needed to write spells into their spellbooks.

Supposedly it may also be used to grind dry roasted beans into fine bits, but no known application of this practice has been discovered.