JPS website

Glossary...some terms you may hear during a
service call...

Action - The mechanism comprised of the keys and hammers and all the parts in
between through which a pianist transmits energy to produce music in a piano.

Action regulation - The process of adjusting all the moving parts of the action
so that they work within required tolerances.

Back action - Found in grand pianos, but not uprights, this is the damper
mechanism, also called the "underlevers".

Back check - Action part that determines how far the hammer rebounds off the
strings.

Balance rail - Part of the action frame that provides the pivot point for the keys.

Bass string - Found in the lower registers of the piano, bass strings are
comprised of a steel core wire and have copper wire wound around the core.

Bridge - Wood rail attached to the sound board that transmits vibrations from
the strings to the sound board.

Bridge pin - Pin embedded in the bridge which guides the path of a string over
the bridge.

Bridle strap - Cloth strap that holds the wippen in place so that the action can be
removed and replaced without the jack dropping out of place and getting jammed.
Found only in uprights.

Capstan - Screw that is mounted on the back of a key that regulates the amount
of lost motion (play) in the action.

Center pin - Metal pin, usually made of brass, around which moving parts pivot.

Damper - Part of the action that stops the vibrations of the strings.

Damper head - Comprised of the damper felt and the wood molding on which it
is glued.

Damper lever - Found in uprights, this lifts the damper felt off the string.

Drop action - Type of action found in spinets where most of the mechanism is
recessed below the keys. Also called an indirect blow action.

Elbow - Part of the spinet action that, along with a long rod, connects the key to
the rest of the action.

Flange - Action part that connects a moving part to another, usually fixed, part.

Front rail - Part of the action frame that hold the guide pins for the front of the
key.

Hammer - Component that strikes the strings. Consists of firm felt glued to a
wood molding.

Hammer butt - Part in upright action in which the hammer shank is embedded.

Hammer rail - Bar on which the hammer shanks (grands) or the hammer butts
(uprights) are mounted.

Hammer shank � Dowel-like part on which the hammer is glued.

Hitch pin - Pin embedded in the plate which holds one end of a string.

Indirect blow action - See "drop action".

Jack - "L" shaped part of the wippen (in both grands and uprights) that lifts the
hammer and hammer shank toward the string and then allows it to be released
just before the hammer strikes.

Key � Wooden lever that allows a pianist to activate the action. Front end of
naturals (white keys) are usually covered with either plastic or ivory. Sharps
(black keys) are covered with either plastic or wood.

Key bed � The basic foundation on which the action is mounted.

Key bushing � The dense felt cloth which lines mortises through which pins
guide the movement of the key.

Key frame � The wooden frame on which the keys are placed.

Key pin � Metal guide pins which are embedded in the key frame. Balance rail
pins guide the key at its pivot point. Front rail pins guide the front of the key.

Let-off button - The point of adjustment for determining when the hammer is
released by the jack before it strikes the strings.

Let-off rail - Bar that holds the adjustable buttons that determine the point
where the hammer is released by the jack before it strikes the strings.

Lost motion - The amount of "play" in an action. Adjusted by a capstan on the
back of each key.

Grand piano � Piano with construction where the sound board and strings are
horizontal.

Music wire � Wire of varying gages of diameter which is used for the tenor and
treble sections of the piano. Made from high grade spring steel.

Pedal lyre � Usually found only in grand pianos, this is an encasement in which
the pedals are mounted and ultimately attached to the piano.

Pin block � Also called a �wrest plank� this is a wooden block into which the
tuning pins are installed. Traditionally, in quality pianos, it consists of five layers
of quarter sawn hard maple. Other designs, such as blocks consisting of dozens of
thin veneer, are common today. During construction of the piano, holes for the
tuning pins are drilled in the pin block and the pins are then hammered to the
appropriate depth.

Pitch adjustment � A rough tuning during which the overall tension of the
piano is either raised or lowered. Usually this is done to bring the piano close to
standard pitch so that a fine tuning can be accomplished.

Plate � Metal frame , traditionally made of cast iron, that supports much of the
tension from the strings. Usually painted bronze and sometimes called the �harp�.

Punching � Any one of a number of cloth or paper parts which are used in
setting the tolerances for action regulation. May be made of paper, cardboard,
felt or leather depending upon the purpose for which it is used.

Rail - A bar made of wood or metal on which action parts are mounted.

Rebuilding � The process of disassembling a piano and reassembling it with new
parts.

Repetition - 1. The part of the action mechanism which allows a note to be
repeated. 2. The rate at which a given note can be repeated.

Repetition lever � Found only in grands, this allows a note to be repeated
without requiring a key to return to the full height of its resting position, thus
allowing for quicker response.

Restoration � A process of careful repair using original parts as much as
possible to restore a piano to its original state.

Soft pedal � The far left pedal. In most grands, the soft pedal shifts the action
sideways, thereby causing the hammers to strike one fewer string on each note
(except the low bass where there is only one string to begin with), thus producing
less volume. In a few grands and most uprights, the pedal lifts the hammers closer
to the strings, thus reducing the momentum with which they strike the strings.

Sound board � Traditionally made from quarter-sawn spruce, the sound board
amplifies the vibrations from the strings as they are transmitted through the
bridge.

Sostenuto pedal � Found in all better quality grands and only rarely in
uprights, this is the middle pedal that sustains only notes for which keys are
already depressed at the time the pedal is depressed. This is done by lifting the
dampers for those notes off the strings while the rest remain dampened. This is
different from the right pedal, called the �sustain pedal�, which lifts all the
dampers at the same time.

Sustain pedal � Always the right most pedal, this lifts all the dampers off the
strings at the same time.

Trapwork � Levers that connect the pedals to the dampers, sostenuto and soft
pedal mechanisms.

Tuning � Process of adjusting the tension on the strings to change their pitches.
This is accomplished by turning the tuning pins.

Tuning pin � The point of adjustment for each string. This is a metal pin with
fine threads which is hammered into the pin block. On the exposed end, the string
is attached and wrapped around the pin three or four times.

Underlevers - See "back action"

Upright piano � Piano that has strings and sound board oriented vertically.
Note the four main types:

Full size - over 48"
Studio - 44-48"
Console - 40-43", has same parts as studio uprights, but parts may be
proportionately smaller.
Spinet 0 under 40", has "drop action" which is recessed below the keys.

Vertical piano - See "upright".

Voicing

Hammer - Process of manipulating the density of hammer felt to
change the tone quality of the piano.
String - Process of adjusting the string level so that the strings of a
given note are in the same plane. This is done to ensure that the
hammer strikes the strings evenly and at the same time. The strings
are also "seated" to ensure solid contact with the bridge.

Wippen - Also called the "repetition", this is the part of the action
that allows a note to be played more than once.