For centuries, strings for instruments such as harps were crafted from animal tendons, with thinner tendons used for higher pitches and thicker ones for lower notes. Over time, techniques were developed to increase the mass of these strings, including coating and early forms of intertwining rather than wrapping. By the 14th century, metal strings emerged, made from brass or iron. Initially, these strings were limited in gauge options and produced using cold-drawing techniques. The innovation of winding a metal wire around a core material did not appear until the late 18th century, and early windings were loosely coiled compared to modern tightly-packed designs. The advent of hot-drawing techniques later expanded the range of available gauges, marking a significant advancement in string production. Modern high-quality strings are crafted using high-grade steel, as detailed in materials science studies. The late 18th century also saw the introduction of three-string unison choirs in keyboard instruments. When restoring historical instruments, it is crucial to avoid using modern wires; specialized materials and gauges from qualified suppliers are necessary to maintain authenticity.

Manufacturing Process
The production of piano wire begins with cast bars drawn into a 5.5 mm thick wire. This wire undergoes heat treatment, being heated to 900°C and rapidly cooled to 500°C in molten lead or salt. During the process, impurities are chemically removed, and the wire is lubricated to preserve its integrity during the stretching phase. Drawing machines progressively reduce the wire's thickness while elongating it. Synchronization of the machine's gears with the increasing wire passage speed is essential to maintain consistency in the final product.