Young Brunette Girl At The Old Piano

The pinblock, which holds the tuning pins in place, is another area of the piano where toughness is important. It is made of hardwood, (typically hard maple or beech), and is laminated for strength, stability and longevity. Piano strings (also called piano wire), which must endure years of extreme tension and hard blows, are made of high carbon steel. They are manufactured to vary as little as possible in diameter, since all deviations from uniformity introduce tonal distortion. The bass strings of a piano are made of a steel core wrapped with copper wire, to increase their mass whilst retaining flexibility. If all strings throughout the piano's compass were individual (monochord), the massive bass strings would overpower the upper ranges. Makers compensate for this with the use of double (bichord) strings in the tenor and triple (trichord) strings throughout the treble.
The plate, or metal frame, of a piano is usually made of cast iron. It is advantageous for the plate to be very massive. Since the strings vibrate from the plate at both ends, vibrations absorbed by the plate will result in energy loss to the desired (efficient) channel of sound transmission, namely the bridge and the soundboard. While some manufacturers now use cast steel in their plates, cast iron remains the preferred metal. Cast iron is easy to cast and machine, has flexibility sufficient for piano use, is tremendously resistant to deformation (unlike steel that can bend), and is especially tolerant of compressive forces. The casting of the plate is a delicate art, since the dimensions are crucial and the iron shrinks by about one percent during cooling.
The inclusion in a piano of an extremely large piece of metal is potentially an aesthetic handicap, which piano makers overcome by polishing, painting and decorating the plate. Plates often include the manufacturer's ornamental medallion and can be strikingly attractive. In an effort to make pianos lighter, Alcoa worked with Winter and Company piano manufacturers to make pianos using an aluminum plate during the 1940s. The use of aluminum for piano plates, however, did not become widely accepted and was discontinued.
The numerous grand parts and upright parts of a piano action are generally hardwood, e.g., maple, beech, or hornbeam. However, since World War II, plastics have become available. Early plastics were incorporated into some pianos in the late 1940s and 1950s, but proved disastrous because they crystallized and lost their strength after only a few decades of use. The Steinway firm once incorporated Teflon, a synthetic material developed by DuPont, for some grand action parts in place of cloth, but ultimately abandoned the experiment due to an inherent "clicking" that invariably developed over time. (Teflon is "humidity stable" whereas the wood adjacent to the Teflon swells and shrinks with humidity changes, causing problems.) More recently, the Kawai firm has built pianos with action parts made of more modern materials such as carbon fiber reinforced plastic; these parts have thus far performed reasonably, but it will take some decades to know if their longevity and performance can match that of wood.