You will, of course, know that the front top panel of the case has to
be removed to give access to the tuning pins, and that you should have
a regular tuning hammer and set of mutes to begin with. The panel is
held in place in various ways: sometimes with buttons, sometimes with
pins set in slots, and sometimes with patent fastenings; but a little
examination will reveal how it may be removed.

To produce a tone of a certain pitch, the string must be of the right
thickness and length. These items are decided by the scale draughtsman
in the factory; if incorrect, the tuner can do nothing to improve
them.

To produce the correct pitch, the string must be of the right tension,
which is brought about by winding one end of the string around the
tuning pin until the proper degree of tension is reached. This must be
decided by the ear of the tuner. Two strings of equal thickness and
equal length produce the same tone when brought to the same tension;
the result being known as "unison." A defect in the unison being the
easiest way in which to detect the beats, we advise that the student
practice on it first.

After taking out the panel, the first thing to do is to place your
rubber mute between two trios of strings (if the piano is an upright
which usually has three strings to a note) so that only two strings
sound when the key is struck. Select some key near the middle of the
keyboard. Strike the key strongly and hold it down. If the two
sounding strings give forth a smooth, unwavering tone--a tone that
sounds as if it came from one string, the unison is perfect. If you
find it so, remove the mute and place it on the other side of the trio