a screw or wedge in the
crack, or a wedge of wood, cork or rubber between the sound board and
iron plate or casing, if the location of the trouble permits. While
this method seems a perfunctory one, it is nevertheless the best the
tuner is prepared to do, for it is next to impossible to glue a crack
in the sound board successfully outside of a regular factory or repair
shop, where the instrument may be taken all apart and a new sound
board put in or the old one properly repaired.

Sometimes the sound board gets loose or unglued at the edges, or the
bridges or ribs come loose. Any part of the piano where there is
vibration or loose material may become the source of the sympathetic
rattle, as even parts of the case vibrate with the tones struck; so
you must examine the panels, lock, hinges, soft pedal bar (in square),
in fact all parts of the case and woodwork for the location of the
trouble. Once found, the remedy will suggest itself. The greatest
difficulty is to locate the cause. Very frequently this will be found
entirely outside of the piano; a loose window glass, picture glass,
lamp or other article of furniture in the room may respond to a
particular tone or its octave. We have never found the sympathetic
rattle in the action; it has rattles, but not of this character. Any
other defect which may be found under this head will only require the
exercise of a little mechanical ingenuity to suggest a remedy.

REGULATING AND REPAIRING THE UPRIGHT ACTION.

(Use cut of upright action for reference in following study.)

We will begin with the key and take up each part of the action in the
succession in which motion is transmitted.

1. _Key_.--Keys stick; that is, after being struck, they fail to come
up quickly, if at all. First ascertain if the trouble is really in the
key, or in the upper part of the action. To do this, lift the
extension or wippen until the upper part of the action is entirely
free from the key, so that you may test the key independently. Some
keys are leaded so that they will fall in front of the balance rail,
others so that they will fall back of it; in either case, lift the low
end and let go, to see if it will fall by its own weight. If it seems
quite free, you may know the trouble is not in the key; you will also
find that when you release the extension or wippen, it will not fall
readily, showing that the trouble lies in the upper part.

If the trouble is found in the key, examine the guide