Pirates of the Caribbean: Dead Man's Chest (2006) revolves around finding the chest which contains Davy Jones' heart. Central to the story is finding the key which unlocks the chest.
Jack seem to have acquired the information as well as a diagram of the key. Based on which he puts together a crew and sets on the journey.
My question is if Jack had the diagram why didn't he got a duplicate made from a key maker?
Is there any supernatural element involved in the original key because it was never explained in the movie?