In 1794, Jefferson set up a nailmaking operation to generate additional income for the plantation. For 10 to 14 hours a day, up to a dozen enslaved boys, aged ten to twenty-one, each pounded out approximately 1,000 nails in the smoky shop on Mulberry Row. It was a tedious, repetitive job, and Jefferson carefully monitored their work. The most productive went on to learn skilled trades. The rest became field hands.
On a typical day in 1796, the fires of the Mulberry Row nailery produced about 5,000 to 10,000 nails in seven different sizes, including fourpenny brads cut from hoop iron by a nail-cutting machine.
The nails were sold in the neighborhood and in stores in the towns of Charlottesville and Staunton. In its first years the nailery was quite profitable, grossing over $2,000 in 1796, but Jefferson soon encountered competition from cheaper imported nails as well as difficulties in management. By the time the War of 1812 cut off the shipment of nailrod, the nailery had ceased to be a profitmaking operation.