Parts of a Grand Piano

In the introduction to his book ‘Piano Servicing, Tuning & Rebuilding’ Arthur Reblitz writes “The modern piano is a complex musical instrument containing mechanisms which are not found in any other device. Therefore, the piano technician must use specialized knowledge, tools and techniques which are unique to the piano servicing field.” This knowledge and these tools and techniques are necessary for dealing with the more than 10,000 parts that make up the modern grand piano.

Since Bartolomeo Cristofori, in Italy, built the first piano sensitive enough in its mechanism to be played both loudly and softly, the design of piano has evolved over the centuries into an efficient melodic and percussion instrument. Wood remains the material of choice in piano manufacture. Wood is unsurpassed for its resonant qualities through various other materials, both natural and manmade, are important piano materials as well. Frames are nearly always cast iron though very early pianos used heavy wooden oak members, beams and panels to achieve strength. As in most pianos, tuning planks or pin blocks are usually made from maple and in the better quality grand and upright pianos, the pin blocks will be laminated. Ash and walnut wood, ivory, brass, high carbon steel, wool felt and aluminium are other very common materials found in piano manufacture.

The grand piano has its strings in a horizontal orientation, quite different from the upright piano. The hammers in a grand piano strike the strings from their horizontal position beneath the strings and fall back into rest largely through the force of gravity with a little help from string ‘bounce’. Hammers in upright pianos, being more on the vertical plane, must rely on assistance from their mechanisms to return to the rest quickly enough to reset and be ready to strike again.

As in the upright piano, the grand piano has four main systems: The resonating system, the pedal control system, the striking system and the cabinet or case.

  1. The Piano Sound Resonating System: this system is divided into two parts; 1. The strings and their support structure which include the iron frame, the pin block and the wooden back posts. These parts further include the tuning pins, the pressure bars or agraffes and the hitch pins. The strings carry a tension of about 90kg each making a collective tension on the piano iron frame about 20 tonnes. 2. The soundboard lies horizontally underneath the strings, it’s associated structure includes the ribs, and the bridge. These components further include the bridge pins and sounding buttons. The soundboard is most often made of spruce wood which has high sound transference qualities of 5,500 metres per second. Spruce has a low specific gravity – is strong but light. The wood selected for the soundboard will have a close, straight grain with no knots.
  2. The Piano Pedal Control System in the grand piano is suspended from beneath the key bed by the pedal lyre. The lyre holds three pedals, pedal rods, levers, springs, bolts and braces. The left pedal is usually the shifter or una corda pedal; the middle pedal usually is the sostenuto pedal making it possible to sustain one note or a selection of notes played while playing other notes that are not sustained; the right pedal lifts the dampers of all notes at once. The Piano Striking System is composed of two main components - the first being the keyboard; comprised of the keyframe, 88 black and white keys and their associated parts – capstan buttons, key pins, bushing cloth, back rail cloth, cloth and paper punchings. The second main component of the piano striking system is the action. This is comprised of the centre rail, 88 hammers and butt assemblies, 88 wippen assemblies, 65-70 dampers and hammer rail all of which further include the hammer shanks, butts, hammer felt, springs, jacks, backchecks, regulating buttons, damper levers and damper wires. Many of these parts and assemblies contain types of hinging mechanisms with pins and screws, flanges and springs. The Cabinet of a grand piano is made up of the inner and outer rim, back bottom, beam, lid, key bed, front lid, music rack, key slip, fallboard, lyre assembly, leg assemblies, casters, and cheek blocks.