MUSIC QUALITY STABILITY TONE TOUCH TUNE COST BEAUTY DURABILITY SERVICEABILITY

Music is the ultimate goal of the piano, an objective that sometimes gets lost among the tunings, regulations, voicings, etc., etc., etc. At the same time, we must be concerned with the quality and stability of our work and of that of the instruments. Tone, touch and tune are our daily bread, as they are for the musicians, if in somewhat differing manners.

Of great importance to all is cost, beauty and durability, but the final stone in my echelon of priorities is essentially ours and that of the manufacturers or rebuilders: serviceability. In the designing and fabrication of pianos, and during rebuilding, certain practices, procedures and oversights creep in that can have a dramatic effect on one aspect of serviceability - tuneability. The next time you tune a piano that is pleasure to tune, you can be assured that many factors contributed to that quality. Here are listed few of the possible sources of trouble on those pianos that are not as tuneable.

The tuning pins must be round, with a consistent diameter and radius. Poor pins can be too long, too short, out of round, change dimension from pin to pin and from the top to the bottom of the thread. They can be poorly plated, the threads poorly cut, the metal too soft, the holes out of place and too small for the larger gauges, and finally, they may have unsquare tips. The tuning pin may appear to be a very simple piece of metal, but when carefully considered, its complexity emerges to demand our attention.

Tuning pins that are too tight require much effort that could best be used to control the pitch of  the strings. These pins leave one with less than the best feel for the block and what the pin is doing in the block. Tuning pins that are too loose lack ease of control, long term durability and stability of the tuning. Pin block materials and construction need not be discussed here except to define our requirements; rigidity, dimensional stability, resilience and durability. If made and installed with care, all else is fulfilled. What is required at the interface of the tuning pin and the pin block is a slightly different matter. Wood and metal should come together with out any other matter at all; no resins, oils, moisture or carbonized wood. Some tall orders, but the factors of greatest importance are the care in drilling the holes and the cleanliness of the pin and the stringer.

 I have seen beckets (the part of the string that goes through the tuning pin) so long that they have been wound part way around the tuning pin in the opposite direction by an adjacent pin. This is a little long; the proper length is through the pin but not out the other side. The reasons for this are that overly long beckets make repinning that block difficult in the extreme because the becket will not come out of the pin without destroying the coil. The overly long becket represents a painful hazard to the fingers when moving the tuning hammer and, finally, it looks tacky.

Coils that are not tight against each other leave a pin too high, tend to cause tuning instabilities and lack the beauty of neatness. On the finer gauges, a becket can be pulled out of the hole over a period of time. This is why old piano makers put four and five coils in the treble; also, the holes in the pins were bigger than the holes in present pins. Three coils are sufficient; two and a half are not.

Tuning pins that have been left too high present several problems to the tuner, not the least of which is tuning instability. These pins will not twist any less than lowered pins, but the twist can be better perceived and controlled when the majority occurs in the block instead of above it. The principle of an equal force applied to a long and a short object will bend the longer the most applies all too well to tuning hammer and tuning pin. Coils should be 1/16” to 1/8” above the plate. If they have to be left higher than that because they are too tight, then they are just that - too tight.

 High pins will become looser with time because the block/pin interface is smaller per square inch by how much too high it is. If a 3/0 x 2 1/2” pin is 1/8” too high, it loses 0.12in2 of block/pin interface, or 8.3% of all area. This presents substantial loss of pin security. When this pin does become loose in two or ten years, it will then have to be driven. Because the block has become bottlenecked at the bottom, the pins will therefore be held firmly ONLY at the bottom, and a drastic twist problem then occurs. This pin would not become loose beyond control for many more years if it were down where it belongs. Besides, a loose low pin is more tunable longer than a looser high pin. Because of the leverage, a high pin has, the upper laminations of the block or the plate bushings can become deformed into oval holes, which do not hold pins well.

The point is that if they are down where they belong when the instrument is strung, there is far less a future problem for the tuner and for the stability of the tuning, which, after all, is the name of the game.

The strings themselves can help or hinder the tuner. With the new and inexpensive scaling information available, there is no real excuse for current production or for rebuilts to be untunable because of poor scaling. I see a time not too far in the future when all rebuilts will be resealed f o r smoothness of tuning, tone and power. There are some that are doing this now, but soon all will be doing so in order to stay abreast. I personally think it is wonderful that I am in a field that is progressing and is not, as some of my customers comment, a dying industry. It certainly is not, and we will soon be seeing more fine pianos coming into the market.

Some pianos were very well scaled but have been repaired or restrung with the wrong size of wire. This is not as uncommon as one might think. Never assume that because the stringing appears to be from the factory that the factory stringer used the right wire sizes. Or that several replacement strings are of the right size. Either learn to use the math and calculators and rescale it yourself, or have it done by someone who can - just to be on the safe side.

The worst thing that is happening to piano tone, scales, and inharmonicity is strings wound with too little copper. According to the most recent information on scaling, the copper should come to within 3/8’’ to 1/2” of the terminus of the string at BOTH ends. Inharmonicity increases by the CUBE of the distance left unwound. Changing the specification of the windings from 1/2” to 1” at both termini increases the inharmonicity by eight times. What this does to the tone is unconscionable, and what it does to the tunability of that string can well be imagined.

Strings that are not properly seated on the bridge can cause the pitch to shift while the note is sounding. The unanswered question is which pitch is the proper one, the first or the second? I have chosen the second, since it is the tone with duration. Unseated strings also cause voicing problems.

One problem that also has the bridge as source is one that has been notched so that the vertical plane and the horizontal plane of the string vibration are of different lengths. The string has an almost circular motion so the horizontal bridge notch and the vertical bridge pin must have the same terminus plane perpendicular to the string’s length. Otherwise, the string has severe partial mismatches and/or false beats to the extent that unisons are difficult or impossible to tune.

When there are severe angles at agraffes or cape bars or at the pressure bars, then the tuning pins must be turned a large amount before the pitch changes. This can also happen with very old strings that have conformed to the angles and those that have a severe corrosion problem. Pressure bars can be raised (with the tension lowered to prevent shearing a screw), the piano may need restringing, and some thought can be given to modifying the plate slightly to reduce the angles, again cautiously.

Duplex scales can be so out of tune that they create a lot of noise that is difficult to tune against. I am not one who thinks that the piano will sound better without the duplex. I take some masking tape and mute the strings between the bridge and the aliquots, which makes tuning much easier; I then remove the tape for final checking. If one or two notes are causing severe problems, a little plain Vaseline, judiciously applied near the aliquot, will mute the nonspeaking length. The Vaseline can be removed easily if need be.

Hammers that are too hard, too soft or poorly shaped cause their own problems, as do hammers that have too little felt.

This does not pretend to be a complete listing of all the trouble I have seen, but I wished to show where attention to details can make or break a good piano. Trifles make for perfection, but perfection is no trifle.

TUNING INSTABILITY

In speaking to our customers about what causes a piano to go out of tune, the most common subject is the weather. A change in temperature will have little or no effect on the tune of the instrument except that most temperature changes are directly coupled to a change in humidity. Humidity change is the major factor when pianos are tuned two or more times a year.

The next most common factor is string stretch. It takes very little stretch, as we all well know from what a new string does, to make a piano sound horrid. Several years of tunings are needed to get all the stretch out of new strings. The newer pianos seem to go out because of settling of the structure as well as the stretch of the strings, but I have no proof of that.

Time itself, with the changes of weather, string stretch and structure, all cause the tuning to slide downward.

Hard playing and especially hard hammers will knock out the tuning of even the best tuner and the best piano.

One factor that seems to be rather neglected is the degree of sensitivity of the client. Some pianists are on the phone the instant the piano thinks about going out of tune, others can let the instrument go for ten years and not know the difference.

After the piano is settled in and the weather, stretch, age, time and customer demands are compensated for any real problems of the instrument itself can be considered.

One common cause of tuning instability is pinblock-back separation, where the pinblock is being pulled away from the back posts of uprights by the tension of the strings. This is most easily spotted by looking at the top of the assembly or from the bottom of the block. When the sides begin to separate from the back a weak piano plate and back can flex more than planned by the designers; tapping with the knuckles along the side will produce a hollow sound where the glue has failed.

A good number of pianos were produced with aluminium / magnesium plates that over extended periods do not have the rigidity and stamina of cast iron. This is a chronic problem without any real solution for that instrument.

When the smaller pianos were in their developmental stages, many of their unique problems were yet to be solved. One of which was determining the minimum weight and the structural rigidity for long-term integrity. Some of these early instruments tend to be unstable because of weakness and, of course, because of advanced age.

Closely related to the above is poor or improper scaling. Today there seem to be several instruments available that can yet be improved in this area, but many of the older spinets were and are unstable because of poor scaling.

As mentioned earlier, overly hard hammers can cause a piano to go out of tune because of the severe shocks to the strings, the excessive energy imposed on the friction systern of the strings which helps the strings to ride up on the bridge pins.

If the plate screws and bolts are just a little loose the piano will not be nearly as stable as when they are tight. I know one tuner who tightens the plate screws on every new client’s piano, and every year in the dry season as well. I do it often (once every two years or so) on all my large or critical instruments.

One seemingly insignificant point is one overturned screw in the plate. Any lack of mechanical integrity introduces that much instability. That overturned screw must be replaced or the hole plugged and redrilled.

Along the same lines, if there is a gap, as thin as a piece of typing paper more than three or four inches long between the plate flange and the pinblock of a grand, the stresses placed on the block by the pins will try to force that space to be filled by the block. This should be checked just before the dry season is over. The gaps can be filled with very thin, long maple shims that have been dried out thoroughly so that any moisture in the air will cause the shim to swell after it is installed. Using epoxy will not swell the wood for a tighter fit.

Sometimes the plate is warped or the pinblock is warped so that there is poor contact between the two. This is especially bad in the tuning pin area. If this is the case then a new block is in order or a long fitting process is required.

A pressure bar that has been screwed down too far can make tuning difficult and contribute to string breakage. A close examination of the area should indicate if this is the case. Generally speaking, the pressure bar should be set so that the strings will remain in position no matter how hard they are struck and so that it introduces some friction so that the tuning pin is not doing all the work. On average, fourteen degrees is sufficient.

With time, the strings will conform to the bearing points; the V-bar, pressure bar, bridges, aliquots, agraffes, bearing pins, etc. When you remove an old broken string you can see the bends in it. These bends have to be straightened out, and to some degree, made again when the pitch of a string is changed. In newer pianos the strings make nice curves around these points, but in the older ones they conform and contribute to string breakage, difficult pin setting and to tuning instability.

Excessive friction caused by corroded strings, cape bars, pressure bars, V-bars and bearing bars and occasionally with contaminated bearing felts generally tend to contribute little to the ease of tuning.

Poor hammer technique and poor pin setting are a major source of customer complaints about the tuning instability of their pianos. You should always inform the customers that if there is a problem with the piano to call you immediately. This gives you the chance to go and check the instrument to determine if it is at fault or if you need to retune the piano and concentrate more fully on your approach to the job.

Tight tuning pins and tuning pins that are very high from the plate are difficult to tune, but are not impossible. They just take more time. Coils that are more than 1/8” inch from the plate are in no manner justifiable. These pins should be driven down and properly leveled with tight coils.

The final note on my list is loose tuning pins. How loose is too loose. If you can raise the string to pitch and the tension of the string pulls the hammer around, that is too loose. Also too loose is if you return to a piano after only a few months and find several notes playing major or minor triads.

Too loose is when, even if the pins are tight by measurement (above 75 inch pounds), but they are still a major third low a few months later. These pins may be contaminated with something like oil or silicone which will not allow the wood to grasp the pin for long periods. A new block may be in order.

Even if the block is generally loose, it does not mean that the piano is untunable. I have tuned pianos where every string would turn the pin around, but I could get the block to lock into the pin by raising it to the exact point I wanted, holding steady for just a second, then gently releasing the pressure and gently lifting the hammer off the pin. When the weather changed, it was when I earned my fee.

I prefer pins that are not too tight; I don’t have to work so hard and have some energy left for writing articles.

If it can be made to stay, it is not too loose. European pianos generally do not have pins that are tight, yet they stay and stay and stay and . . .

The degree of looseness is not as important as its staying ability, which is determined by the bearing point angles, the friction across all bearing points, the angle of the tuning pins to the block, the angle of the string to the pins, the texture of the block and the patience of the tuner.

Unless the cause is obvious and until the piano has been tuned at least once by yourself, go cautiously and carefully, as you would like someone to go with your car or TV or with whatever you have a major emotional investment.