While Cyrus was working out a controversy involving his patent of the reaper they lived in Washington, DC. She had a keen business sense and became a great asset to her husband. Nettie became his financial counselor and oversaw many of the business affairs. She toured expositions in McCormick's interest making contacts for the company. In 1871, the Great Chicago Fire destroyed McCormick Harvesting Machine Company. But, despite Cyrus' thoughts of retirement afterward, Nettie insisted on rebuilding even larger than before.