At the age of 22 in 1753, he invented a wooden clock. It was modeled to scale from a borrowed pocket watch. The clock continued to work until Banneker’s death in 1806.
He became friends with the Ellicotts, a family of Quakers who helped him with his career. The Ellicotts were abolitionists and shared similar views as Banneker. He learned astronomy from the family’s patriarch, George Ellicott. His connection with the Ellicotts landed him a chance to survey land for Washington D.C., in 1791 and 1792.