Micro-CT scan reveals the secret of a centuries-old combination lock

Experts used micro-CT scanning to examine the interior of an old combination lock found on a Welsh beach and work out its code. Metal-detector enthusiast Peter Hughes had been unable to solve the puzzle for years.

A team from National Museum Wales and Cardiff University examined the mechanism without breaking it apart. Researcher David Williams said different scanning approaches revealed letters inside the lock.

Four rotating rings, each carrying six letters, allow 1,296 combinations. Fixed letters at either end may have added confusion for anyone trying to open it. The lock may have secured a small box containing documents or cloth, but what the box held remains unknown. Curators said the mechanism remained in good working condition.