The lock, on the Calder and Hebble Navigation, was drained so that both sets of gates could be lifted out and replaced. Visitors were able to go into the bottom of the lock chamber and walk along the drained lock bed.
The £100,000 project was carried out by the Canal and River Trust.
Jon Horsfall, waterway manager for the trust said: “We care for a remarkable and historic network of canals and rivers which are still working just as they were designed to 200 years ago. Keeping them in top working order requires a huge amount of planning, investment and craftsmanship and it’s great that we’ve been able to showcase this to members of the public.”