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 tar, 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.
3. Jack.—As in the upright, the behavior of the jack depends entirely upon the surrounding mem-bers. A very common occurrence in the square piano is a broken jack-spring. This spring is concealed in a groove on the under side of the bottom, with a linen thread leading around the end of the jack and held fast by a wooden plug. If the spring is found to be long enough, drive out the plug, attach a new thread to the spring, and fasten as before. If a new spring is needed, one may be made by wrapping some small wire round a piece of music wire of the right size.
4. The back check, hammer stem and regulating button are subject to the same faults as their counterparts in the upright, which may be remedied in the same way. Bridles and hammer springs are not needed in the square, as the weight of the hammer, moving in a vertical direction, is sufficient to bring it to its rest position.
5. Hammers, when made of felt, will of course require the same treatment as those in the upright. In many old squares the hammers are built up of buckskin. If this becomes beaten down hard, it is well to cap the hammer with a new soft piece of buckskin, gluing only at the back ends.
6. Butts and Flanges.—A click just as the key comes up, indicates that the felt cushion, against which the jack rests, is worn out and must be replaced.
In all square actions the center pin, in the butt, is held by friction alone, but rarely gets loose; if it should be found loose, put in a larger pin.
The flange, shown in the cut, is what is called a split flange. By the set screw T, the jaws can be regulated so that they neither clamp the center pin so tightly as to make the action sluggish nor so loosely as to let the hammer wabble.
If the bushing cloth is found to be badly worn, it is better to put in new, which must be done neatly, or the result will not be satisfactory.
Hammer flanges, like all other wooden parts, shrink away from the screw heads and allow the hammer to drift to one side or rattle. While the action is in the piano, strike the keys to see if there are any that strike improperly. Mark the keys so as to indicate just what the trouble is, so that you will know how to remedy it when the action is out. If the hammers are set so close that they rub against each other, you may have to cut off a slight shaving of felt, but this is rarely necessary; for if properly placed, there is generally room for all; yet sometimes the expansion of the felt or warping of the shank makes cutting necessary.
7. Dampers.—The dampers in the square action depend entirely upon their weight for their efficiency in damping the strings and returning after being raised by the key. Often, after the key is struck, the damper will not return to its place and the string is undamped. This is generally found to be caused by the wire sticking in the hole through which it passes, the wire being rusty or bent or some foreign substance being in the hole round the wire. The bushing cloth in the hole may be in such condition as to retard the free passage of the damper wire, in which case the wire may be heated with a match and run up and down a few times through the hole, which will free it. The damper may not fall readily on account of a sluggish joint in the flange. Work it back and forth as far as it will go a few times; if necessary, take it off the damper rail and look for the cause of the trouble.
Damper flanges get loose on the damper rail and work to one side, causing defective damping and rattling. See that they are all tight, and in their places.
Damper lifter buttons sometimes hold the damper off the string. See that the top button falls so low that the damper lever does not touch it when the key is released. This is accomplished by altering the lower button. Examine the damper felts to see if they are moth-eaten, or have become hardened or in any way impaired. Notice the adjustment of the shade; that it is not too low or too high. The purpose of the shade is to prevent the damper levers from flying up; but it should be high enough so that the levers do not touch it when the key is depressed gently.
Defective damping is one of the most annoying conditions, and when one is employed to regulate a piano thoroughly and put it in order, he should see that no key is left in which this occurs. Strike each key and immediately let it up to see if it stops the sound quickly, or, in other words, damps perfectly; if it does not, find the cause and regulate until satisfactory.
8. The grand action being, in principle, practically the same as that of the square and the upright, containing the same mechanism as is found in those actions, it is needless to give special instructions concerning it; as the previous work has given the pupil a thorough knowledge of the requirements of all actions, their common faults, and proper methods of regulating to bring about satisfactory results. Let us merely remark: Study thoroughly the behavior of every component part of each action that comes under your observation; understand what each part is for, why it is there, and how it works or should work properly to fill its office. Then regulate and try for results. If you have natural mechanical genius, a little experience will prepare you to do all regulating and repairing with skill and quickness.
A few miscellaneous difficulties, common to all styles of actions, are occasionally met with and need to be rectified.
1. Broken Hammer Shank.—Glue the ends, lay a nicely fitting piece of wood, well coated with glue, on each side and wrap with binding wire. If it is broken off up so close to the hammer as not to permit this, drill a hole through the hammer head in line with the center of the shank, with a small-sized screwdriver such as watchmakers use, and run the wire through this and around the shank, drawing it firm; glue as before; when dry it will be as strong as ever. When the shank is broken off close to the butt, the same treatment will sometimes answer, but the strain here is so much greater that it is sometimes necessary to put in a new shank. In fact, it is always better to do so.
2. Flanges, damper heads, and all small wooden parts are liable to break or come unglued: The watchmaker's screwdriver, the binding wire and the glue must always be at hand for these emer-gencies. These breaks are generally in places where wrapping is not permissible, and you are compelled to drill. Keep the screwdriver well sharpened and the drilling is easy.
3. Ivories.—When unglued, scrape the old glue off, apply glue to both surfaces and clamp with an ivory clamp or rubber band until the glue is firm. Apply the same treatment to ebony sharps.
4. Leads in the keys and the dampers of the square piano get loose and rattle. Hammer them just enough to tighten; too much might split the key.
5. Friction.—Where different materials, such as wood and felt, would rub together they are covered with black lead to lubricate them. The point of the jack where it comes in contact with the butt, the toe of the jack which strikes the regulating but-ton, and the long wooden capstan which takes the place of the extension and works directly on the under side of the wippen, which is covered with felt, are black-leaded. When a key squeaks and goes down reluctantly, the trouble can usually be traced to these places; especially to the wooden capstan, the black lead having worn away. Use powdered black lead on these parts.
There are many things in this kind of work that require only the exercise of “common sense.” These we have omitted to mention, treating only of those things the student does not know intuitively.