Piano Tuning | Page 7

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.
DL, damper lever, working in damper flange g, which is screwed to main rail.
s, spoon; so called from its shape. It is screwed into the wippen. When the key is struck, the motion on the wippen throws the spoon forward, pushing the lower end of damper lever forward, and releasing the damper from its contact with the string. The damper is held against the string by the wire spring which is seen running from the damper flange to the top of the damper lever.
DR, damper rod. This is a rod running from the left or bass end of the action to the right as far as the dampers are continued in the treble. It is acted upon by the "loud" or damper pedal, which raises the outer projection, and by being hinged to