Nowadays, nails are generally made of steel; traditionally, they were wrought iron and made by hand, with a characteristic, square-section shank. From the eighteenth century onwards, they were ‘“cut”—i.e. punched or cut from a flat sheet of iron—which produced a four-sided cross-section tapering in on two sides. However, from the end of the nineteenth century “wire nails” were produced. Made from coils of thick wire with a characteristic parallel, round, wire-shaped shank, these are weaker than earlier nails but suited to the increasingly thinnersection lumber construction that has become the norm.