Catch hold of the damper rod at the left behind the action and work it.  If it squeaks, you will have to take out the action and oil the swings where they are hinged to the main rail.

QUESTIONS ON LESSON V.

    1.  If you should find a key sticking, how would you determine the
    cause?

    2.  Name all the defects to which the key is subject.

    3.  Describe the proper adjustment of bottom or capstan.

    4.  Give two causes of blocking.

    5.  Give the purpose of the regulating button, and its proper
    adjustment.

LESSON VI.

REGULATING AND REPAIRING.—­(Continued.)

THE SQUARE ACTION.

1. The key in the square piano is subject to the same troubles as that of the upright, and requires the same treatment.  However, the keys being much longer are more liable to cause trouble by warping.

2. Bottom or Key Rocker.—­Unlike in the upright action, the jack is attached directly to the bottom; but, lowering or raising the bottom has the same effect in both cases.  The screws regulating the height of the jack can be gotten at with a proper screwdriver.  If you have to take out the key in order to regulate the bottom, first take particular notice of the conditions in respect to the operation of the jack on the hammer.  Work the key slowly, to discover if there is lost motion.  Decide which way the bottom must go and how far, so that you will not have to remove and replace the key more than once or twice to adjust it.  In taking out the key, remove the board which is set edgewise over the keys immediately back of where the fingers strike, by taking out the screw at each end.  Lift the hammer with the finger until the jack falls out of place; then by lifting the key off the balance pin it can be drawn out.  The back check will sometimes rub so hard against the regulating button that it will be bent somewhat, and must be adjusted after the key is replaced.

The bottom is often found to have shrunken; it rattles at every stroke of the key.  This can generally be stopped by simply turning the back screw down until tight, which can be done without taking the key out.  This will rarely be found to alter the jack enough to cause it to fail to return to the notch in the butt.  After doing this, however, it is well to examine for such a condition.

A sluggish motion of the jack is often found in old square pianos caused by the swelling of the wood, at the point where the jack is hinged to the bottom, or by the center pin’s becoming foul from oxide.  This will cause the jack to fail at times to operate on the hammer, especially in quick repetition.  The key is struck with no response.  Take out the bottom entirely, and with the fingers press the sides of the bottom inward; at the same time, work the jack back and forth.  This will generally free it if the jack-spring is all right.