The bolt of this wooden lock is hollow and the wooden key is inserted into it. Metal pins on the end of the key go through holes in the upper side of the bolt. Once in place, the pins raise the pin-tumblers which project downwards from the fixed staple. When these pin-tumblers are lifted clear of the holes, the bolt can be slid to one side and the door opened. These locks closely resemble locks made in ancient Egypt thousands of years earlier.
© Science Museum / Science & Society Picture Library