Piano Tuning | Page 7

end. The
center-pin in the wippen is driven through a hole in which it fits tightly
and immovably in the middle part, and it (the center-pin) is
consequently stationary in the wippen. The flange extends down at the
sides of the wippen and the holes in flange are made large enough to

receive bushing cloth in which the center-pin works freely but not
loosely. All flange joints are of this nature; some, however, are
provided with a means for tightening the center-pin in the middle
portion of the joint.
j, is the jack. The purpose of the jack is to communicate the motion of
the wippen to the hammer. The precise adjustment of the jack and the
adjacent parts upon which it depends for its exact movements, play an
important part in regulating the "touch" of the piano, and will be fully
entered into in following lessons.
js, jack spring. Its purpose is to hold the jack inward against the "nose"
or "heel" of the hammer butt. (See Bt, hammer butt.)
Rr, regulating rail. The regulating button is shown attached to the rail
by the regulating screw which is turned by means of its ring on top of
Rr. The purpose of the regulating button is to throw the point of the
jack out of the nose of the hammer butt, and allow the hammer to
rebound from the string. If the button is too high, it does not throw or
trip the jack in time to prevent blocking. When the button is too low, it
disengages too soon, and much of the force of the key is lost before it
reaches the hammer.
BR, is the block rail, felted on the side next to the jack which strikes
against it when thrown from nose. This rail is absent in some actions, in
which case the back of the jack is felted and strikes against the "back
catch," which is also felted on inner side. (The back catch has no mark
in the cut, but is explained below in connection with the "back check.")
BC, is the back check which is simply a piece of wood with a thick
piece of felt glued to the inner face and suspended on a wire.
BCW, back check wire supporting the back check, and screwed to the
wippen. The purpose of the back check is to check the hammer by
coming in contact with the "back catch" (the backward projection of the
butt), at a short distance from the string in its return, and prevent the
hammer from falling entirely back to its rest position, thereby
preventing quick repetition.

Bl, bridle. This is a piece of tape about an eighth of an inch wide with a
piece of leather glued to the end and a hole near the end for the point of
the "stirrup" or bridle wire. The cut shows where the bridle is fastened
in the hammer butt by being put into the hole in the butt, and the back
catch stem covered with glue and driven in by it which precludes all
possibility of its coming loose. The bridle passes through a hole in the
lower part of the back catch. Its purpose is to assist the hammer to
return quickly by hanging to it with the weight of the wippen, extension,
jack, etc., when the key is released. Thus the bridle becomes the main
factor in the matter of quick repetition.
Bl W, bridle wire, screwed into wippen, bent in the shape of a buckle at
top to hold bridle.
Bt, butt; or, more specifically, hammer butt. In some cheap actions the
butt is joined to its flange g, by the means described under the head of
wippen flange; but in this action the center-pin is held firmly in the butt
by a small strip of brass containing a set screw; somewhat obscure in
the cut, but discernible. As explained elsewhere, all center-pins turn in
the flange and not in the middle part.
HS, hammer shank in rest position.
H, hammer showing wood body or head, and covering of two layers of
felt.
H R, hammer rail, resting on felt cushion, c, glued to rail or bracket.
The hammer rail is held in position by the rod, shown under the
hammer shank, which is hinged to the bracket at the lower end, and
which allows it to be moved forward when the soft pedal is used. The
soft pedal communicates with this rail by a rod which moves it forward
and thereby shortens the stroke of the hammers and produces a softer
tone.
sr, spring rail screwed to the brackets. This rail supports the light wire
springs which assist the hammers in returning to rest position.
S, string.

D, is the damper head secured to the damper wire by a set screw.