"A rusty, old gear. It looks like it belongs to some machine or another."
The Large Gear is a key item in the Resident Evil 2 remake.
This large gear is first used to lower the stairs, by placing on the machinery on the right upon entry to the Clock Tower. It can be removed afterwards, and placed on the machinery upstairs, thus ringing the bell, releasing the Power Panel Part.
This item can be found inside the East Storage Room, at the center of the room.