One of the most common, and, at the same time, most annoying conditions both to the owner of the piano and the tuner, is the “sympathetic rattle.” This trouble is most usual in the square and the grand pianos and is generally due to some loose substance lying on the sound board. The rattle will be apparent only when certain keys are struck, other tones being perfectly free from it. These tones cause the sound board to vibrate in sympathy, so to speak, with the weight of the intruding substance at the point where it lies, and if it be moved the distance of six inches it will sometimes cease to respond to these particular tones, but may respond to others, or cease to cause any trouble.
The article may generally be found near the front of the sound board under the top piece of the case, this being the place where it would most likely fall. No special instrument is made for the purpose of searching for such objects, but one can be easily devised with which the tuner can feel all over the sound board, and remove such articles as well as dust and dirt. Secure a piece of rattan or good pliable hickory, and draw it down to the width of half an inch, thin enough to bend easily, and long enough to reach anywhere under the stringing or metal plate. By putting a cloth over this stick you can remove anything that comes in its way. Some difficulty will be found, however, in getting under the plate in some pianos. In case you cannot procure a suitable piece of wood, a piece of clock spring will be found to answer very well. We have taken from pianos such articles as pencils, pieces of candy, dolls, pointers used by music teachers, tacks, nails, pennies, buttons, pieces of broken lamp chimneys, etc., etc., any one of which is sufficient to render the piano unfit for use. The sound board of the upright being vertical prevents its being subject to the above difficulty.
A split in the sound board, in any style of piano, sometimes causes trouble due to the vibrating edges of the board coming in contact with each other. Insert the point of your screwdriver in the crack, holding it there firmly; if the rattling stops, the difficulty is discovered, and may be remedied by placing a screw or wedge in the crack, or a wedge of wood, cork or rubber between the sound board and iron plate or casing, if the location of the trouble permits. While this method seems a perfunctory one, it is nevertheless the best the tuner is prepared to do, for it is next to impossible to glue a crack in the sound board successfully outside of a regular factory or repair shop, where the instrument may be taken all apart and a new sound board put in or the old one properly repaired.
Sometimes the sound board gets loose or unglued at the edges, or the bridges or ribs come loose. Any part of the piano where there is vibration or loose material may become the source of the sympathetic rattle, as even parts of the case vibrate with the tones struck; so you must examine the panels, lock, hinges, soft pedal bar (in square), in fact all parts of the case and woodwork for the location of the trouble. Once found, the remedy will suggest itself. The greatest difficulty is to locate the cause. Very frequently this will be found entirely outside of the piano; a loose window glass, picture glass, lamp or other article of furniture in the room may respond to a particular tone or its octave. We have never found the sympathetic rattle in the action; it has rattles, but not of this character. Any other defect which may be found under this head will only require the exercise of a little mechanical ingenuity to suggest a remedy.
We will begin with the key and take up each part of the action in the succession in which motion is transmitted.
1. Key.—Keys stick; that is, after being struck, they fail to come up quickly, if at all. First ascertain if the trouble is really in the key, or in the upper part of the action. To do this, lift the extension or wippen until the upper part of the action is entirely free from the key, so that you may test the key inde-pendently. Some keys are leaded so that they will fall in front of the balance rail, others so that they will fall back of it; in either case, lift the low end and let go, to see if it will fall by its own weight. If it seems quite free, you may know the trouble is not in the key; you will also find that when you release the extension or wippen, it will not fall readily, showing that the trouble lies in the upper part.
If the trouble is found in the key, examine the guide pin. See if it is placed in a direct line with the key. If so, and it still binds, enlarge the hole by pressing the wood back slightly with some wedge-shaped instrument, if you have not a pair of the key pliers which are used for this purpose. See that the cloth, with which the hole is bushed, is not loose and wrinkled. Do not oil or grease the guide pin unless such treatment has been previously resorted to, as the polished pin will work more freely in the dry cloth. Do not pinch hard on the pin with rough pliers and spoil the polished surface.
Sometimes you will find one key warped so that it rubs on the next, in which case, plane off a slight shaving to free it. Sometimes changing the position of the guide pin will straighten or level the key and make it work all right.
The balance pin is subject to some of the same difficulties as the guide pin. See that it sets properly and is not bound by the mortise.
Sometimes a splinter will be found on one side of a key where the lead has been put in. A piece of any foreign material between two keys generally causes both to stick.
Where the action is too deep, that is, the keys go down farther than they ought, place cardboard washers under the felt ones around the guide pin, or raise the felt strip under back end of keys.
Where the action is too shallow, place thin washers under those around the balance pin. When this is done, the whole action must be regulated ac-cordingly, as this alteration will make a change in the working of the upper part of the action.
2. The Bottom or Capstan.—This should be so adjusted that when the key falls back to its rest position, the point of the jack will just spring into its place in the nose of the hammer butt. If held too high, the jack fails to catch in the nose, and the key may be struck without producing any effect on the hammer. When the bottom or capstin is too low, the point of the jack will be some distance below the notch, which will cause what is known as lost motion it being necessary to depress the key a portion of its depth before the jack can act upon the hammer. Depress the key slowly, watching the hammer, and the fault will be discovered.
After a piano has been used for some time, the keys that are struck most frequently (those in the middle of the instrument) will be found to have this fault. The felts under the keys and those which are between the working parts of the action become compressed or worn so that the jack will be found to set so low that there will be lost motion in the key. In this case, loosen one of the screws in the bottom and turn the other down so as to move the jack upward until nearly all lost motion is taken up. A little play is generally necessary, but very little. In case the action has a capstan, simply turn it upward.
3. Back Check.—Blocking is most usually caused by the back check being too near the back catch, so that when the key is struck, the back check holds the hammer against the string. This should be seen after raising the bottom or capstan as above referred to. It will be observed that when this is done on account of the wear of the felts, the back check will stand much nearer the back catch than it did before. and will need bending back so as to give the hammer plenty of “rebound.” A steel instrument with properly shaped notches at the point, called a regu lator, is used for bending wires in regulating the action. See that the wires stand as nearly in line as is possible. In old actions that are considerably worn, however, you will be obliged to alter some more than others.
4. Bridle and Bridle Wire..—In putting in a new bridle, it should be doubled over at the end and secured to the hammer butt by a small tack. Be sure you get it exactly the same length as the others; otherwise it will be necessary to bend the bridle wire out of line. Some tuners glue the bridle around the Dack catch stem, but the above method is preferable.
The purpose of the bridle is to jerk the hammer back quickly and the wire must be set, neither so far back as to check the stroke of the hammer, nor so far forward that the bridle is too slack to draw upon the hammer.
5. Jack.—The jack itself seldom gets out of order. So long as its flange does not come unglued in the wippen, or its spring get out of place or broken, or get tight in its joint, it will need nothing. Its adjustment and action is controlled by the bottom or capstan, and the regulating button.
6. Regulating Button.—This button determines the point in the stroke of the hammer where the jack flies off from the nose of the butt. If the button is too high, the jack does not fly off soon enough, and the result is, that the hammer either llocks against the string or bounces from the jack after the stroke has been made, striking the string a second or third time from one stroke of the key. The felt punching on the lower side of the button often wears until this trouble prevails. Lower the button by turning down the screw on top of the regulator rail; if lowered too far, however, the action is weakened by causing the jack to fly off too soon, without giving the hammer a sufficient impulse. A regulating screwdriver is used for this, but in its absence, a wire hook, similar to a shoe buttoner, will turn the screw.
The block rail is properly adjusted at the factory and requires no attention.
7. Hammer Butt.—The felts and leather on the heel of the hammer butt wear out and must be re-placed. The felt cushion, that is lowest and farthest to the left (see illustration), is the one that wears out first. The jack, in returning to the notch, strikes this cushion, and in time wears it away so that the jack in returning strikes the wood of the hammer butt, producing a sharp click, which is very annoy-ing, to say the least. This click is heard at the instant the key rises to its rest position. Sometimes, however, a similar click is produced by the top of the key striking the board which is set over the keys, due to the cloth being eaten off by moths, or a pencil or some other article lying on the keys back of this board.
The center pin in the butt of some cheap actions is not held in the butt by metal clip and screw, and if it gets loose so that it works out, must be replaced by a larger pin. The size of center pins generally used in the factory, is .050 of an inch in diameter; the size for repairing should be .053. All of the best actions have the set screw with which to make the pin fast in the butt.
Hammers stick when the center pin is too tight in the flange. The bushing in the flange often ex-pands. Some tuners oil at the ends of the pin with kerosene or wet it with alcohol, which is very good; but a better plan is to shrink the bushing with a drop of water on each side so that it will penetrate the bushing. After this is done, the piano cannot be used for a day or two, as the water first swells the bushing, making all the hammers stick; but when they are dry again, they will be found free. This may seem a curious method, but you need not be afraid of it; it is the most effective.
Before leaving the hammer butt, see that the hammer spring is in its place.
8. Hammer Stem.—These sometimes warp, split, crack, or come unglued at the butt or hammer. If twisted so far that it does not strike properly on the strings, or that it binds against the next hammer, the best thing is to put in a new stem. If merely split or unglued, it may be repaired. Sometimes a click is heard and it will seem impossible to find the cause, the hammer and stem apparently perfect, but a close examination will reveal a looseness in the stem somewhere.
In putting in a new shank, drill or chip out the old one, scrape the holes out clean, take your measure carefully, and do not make the new shank too tight, but large enough to fill the hole snugly. Apply glue to the ends of the shank and also in the holes. Cedar is used in some makes, but good maple is stronger, and is more generally used.
9. Hammers.—When too hard, soften with a felt pick. Do not raise the felt up, but stick the pick in the felt just back of the point and this will loosen it up and make it softer and more elastic. Where the strings have worn deep grooves, sandpaper them down nearly even and soften the felt as above.
In regluing the felt to the head, glue only the back ends of the felt, and clamp with strong rubber band till the glue sets. Use tailor's chalk (fuller's earth) to clean hammer felts. To harden or draw felts back in shape, place a damp cloth over them, and then pass a hot iron over it.
10. Dampers.—Damper felt often gets hardened so that when it comes against the vibrating string, it causes a sort of buzzing sound. Loosen it up with the pick. Imperfect damping can sometimes be corrected in the same way.
The damper head sometimes turns round on its wire, leaving one or two strings undamped. Tighten the set screw. See that the dampers are in line; and that they will stop the tone properly when the key is released.
Damper springs sometimes break. It is necessary to take out the damper lever to put in a new one.
See that the spoons are in line and work properly. Press the sustaining pedal down, and see if all the dampers are in line; if not, bend the damper wires with the regulator until they line up perfectly.
11. Damper Rod.—When the sustaining pedal squeaks, look first to the pedal, then to the wooden rods leading up to the damper rod. If the trouble is found in any of these, or the springs, use sperm oil or vaseline. 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.