The sound of the piano is produced when hammers strike the strings. The hammers are covered with soft white felt, which is first squeezd into a V shape by a machine. The bass hammers have a thicker layer of felt than the treble hammers; they must be larger in order to make the heavier bass strings vibrate.




The core of the hammer is a piece of wood called the hammer molding. A layer of firm, dark-colored felt is glued around this to form the inner cushion, then the shaped white felt is glued around that. Each hammer is glued to a hammer shank, a piece of wood five inches long. The "handle" of the hammers, one for each key, is mounted on the action frame, which will be installed in the piano case behind the keyboard.


The shape of the hammers determines how they will strike the strings and thus, how the notes will sound. The action man adjusts each hammer so that it will be lined up to hit the proper string at dead center.



The keys, which are made in a different department, are constructed of sugar pine covered with plastic. At one time, white key covers were made of ivory. It is now illegal to kill elephants for their ivory. Unlike the old ivory keys, white plastic keys do not turn yellow with age. When the keys arrive they are placed on a key frame one by one to make the keyboard.


The tone regulator is a specialist who makes the delicate adjustments that affect the overall quality of the piano's sound. Using a piece of wood covered with sandpaper, he carefully files each of the newly installed hammers into an egg shape. How does the action work ?


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