After the independence of the United States, there was a great demand for muskets in the nation, and independence made it possible to produce manufactured goods. Eli Whitney found sponsors to support the concept of interchangeable production parts in the manufacture of muskets. However, their sponsors became very impatient when, after a considerable time had passed and they had spent a lot of money, they learned that they were still making tools to make parts. In the long run, however, their efforts managed to produce interchangeable and economic parts in large quantities. The concept of producing a set of dies to make a million parts, which is already accepted today, was not well understood at that time.
Whitney's invention of the cotton gin typifies many extremely important mechanical advances of the time, but there is little doubt that his concept of creating tools to produce interchangeable parts was the greatest innovation of that period.
Whitney's concepts were later exploited by Henry Ford and others in the industry.
