Inside A Grand Piano

The inside parts of the piano containing the hammers is called the "action". There is said to be over 10,000 moving parts in a piano. Here is an overview of a grand piano action. For all intents and purposes, there are really only two piano action types, the upright action and the grand action.

The grand piano action is different for many reasons. The obvious difference is that while a hammer shank stands vertically on an upright piano, the grand action is horizontal. The reason concert pianists require a grand piano goes well beyond the sleek and elegant demanding look that a grand piano delivers.

The main difference is the "repetition lever". In the photo above, you see a parallel piece of wood under the hammer shank (the piece of wood connected to the hammer). Once a key has been hit and the hammer rebounds from the string, it is held by the repetition lever against the roller, leaving the jack free to drop into its proper place under the roller. This increases the speed at which the jack can come back into its position under the roller.

Different from an upright action, the grand is immediately ready for another blow of the key, because of the repetition lever. It is this added speed in the grand action that makes the grand piano the #1 choice for the concert pianist.

Front of the piano once the keyslip, key blocks (cheek blocks) and the fallboard (key lid) have been removed.

The grand action removed from the piano, entirely separate from the piano.

Inside the piano when the action has been removed. Notice the piano strings above. The wires directly in front are the damper system that quiets the piano once you let off a key without using a sustain pedal. Using the sustain pedal, raises all the dampers simultaneously.

Inside the keybed area. Notice the holes above. These are the underside of the tuning pin block.