GRAND REGULATION - A CHECKLIST - PART 2

Last week we talked about a 50-point checklist and knowing what changes are taking place during action regulation. A three-question quiz was also given which will be repeated here:

1)    Does regulating the jack height to the balancier affect the strength of the repetition spring?

2)    Does regulating the let-off affect the backcheck distance?

3)    Which of the following affect the amount of aftertouch: key height, blow, jack alignment, jack height, let-off, drop, backcheck, repetition spring?

Now that a month has passed to think about the answers, wouldn’t it be great if there were some place to turn to look up the correct answers? How many of us have taken the time to thoroughly investigate and think out what happens in grand action regulating? Everyone should own or have access to a grand action model. These are a great help in trying to figure out a problem or to understand the hows and whys of the working parts.

Here is a grand regulation chart which lists the nine action regulation steps and how they directly affect each other. (You can find the chart at the bottom of my last post. It’s the 2^nd graphic.) X’s mark steps which are affected, O’s mark those which are not.

It should now be quite easy to find the answers to the quiz. The answer to question no 1 is yes. Think of the butterfly type repetition spring as now used in Bosendorfer, Steinway, and Yamaha grands. As the balancier is raised or lowered to the correct height above the top of the jack, the tension on the repetition spring is changed. Think of the balancier and whippen as opening and closing like a jaw. The tension on the spring increases as the balancier is lowered. However, the effect this style of spring has is the opposite one would expect. Even though the tension increases, the hook of the spring moves forward (toward the keyboard) in the spring slot on the bottom of the balancier. This necessitates the spring tension to be increased in order to achieve the same effect, since the point of contact is now further from the balancier’s flange.

In answer to question no 2, the grand regulation chart is marked no. Now it is possible to argue that if the key is depressed slow enough, as when we regulate the let-off, and if the let-off is changed considerably, that the hammer will check at a different height. True, but the main factor here is not the let-off distance. Rather, the speed at which the key is depressed. In actual playing, the hammer must continue to move upwards after let-off in order to strike the string, then it falls back, going into check Changing the let-off only changes the amount of power that the key gives the hammer. The backcheck distance does change, of course, on whether the player gives the key a hard or soft blow. On a hard blow, the hammer rebounds more forcefully into the check position and ends up a little lower. On a very light blow, the hammer may not even go into check. Anyway, we can be pretty safe if the backchecks are regulated before the let-off, since as can be seen on the grand regulation chart, the backchecks only affect the repetition spring strength.

For the third question, the factors which affect aftertouch are:

1)    Key height. Changing the key at the balance rail affects the key at the front rail by a factor of about 1:2. Adding a 0.010 balance rail punching will increase the dip, and hence the aftertouch, by about 0.020.

2)    Blow. Piano actions are designed so that the dip to blow ratio is about 1:5. Changing the blow changes the amount of key dip needed for total escapement. When we raise the capstan to lessen the blow distance, the effect of raising the whippen puts the jack tender closer to the letoff button and the end of the balancier closer to the drop screw. This causes escapement to happen sooner in the stroke of the key, giving more aftertouch.

3)    Jack alignment to the knuckle. Since the jack has a double function of raising the hammer and also causing let-off, regulating the jack to the knuckle changes when the jack tender engages the button. Therefore, if the jack is moved inward, toward the keys, the tender moves down and away from the let-off button, creating escapement later in the dip, meaning less aftertouch.

4)    Let-off. From what has already been said, it is obvious that let-off directly influences aftertouch. Making the let-off closer to the string creates less aftertouch.

5)    Drop. If drop is defined as the amount that the hammer drops after let-off, and that aftertouch is defined as the downward movement of the key after drop, then the amount of drop is proportionate to the amount of aftertouch. Decreasing the amount of drop increases the amount of aftertouch.

Notice that on the grand regulation chart the first left to right column is marked dip. This is the column which is read for aftertouch, since aftertouch is a part of dip. The factors which do not affect aftertouch are the jack height, backcheck distance, and the repetition spring strength. Of course, the jack height and repetition spring indirectly affect the aftertouch by affecting the hammer blow distance. But this chart only shows direct relationships.

Having answers to questions like these is a great help in figuring how to approach the specific action at hand. Remember last week’s post that the order of section IV “The Touch” of the 50-point checklist may be changed to suit the needs?

IV. Touch

31) Jack height to the balancier

32) Blow

33) Let-off

34) Drop

35) Aftertouch

36) Backcheck distance

37) Repetition spring

38) Check gram weight resistance all 88 keys

39) Adjust key stop rail 

This order would be fine for dealer preparation on a new piano. But what about an old action where the repetition springs are weak? (Remember “the circle of five steps”? See the 1^st graphic in my last week’s post.) Then the jack height will vary each time the key is played, making it impossible to set the hammer line straight. In this case we could not begin with setting the jack height and blow distance. Rather, we should start with the backcheck distance and go immediately to strengthening the repetition springs. A quick glance at the grand regulating charts shows that only two steps affect the backcheck distance. One is the key height which was set in step #12 on the checklist. The other is the dip. So after setting the dip be sure to go back and readjust the backchecks! See how easy it is with the proper information at hand? Now you can start with setting the jack height and blow and go on as is listed in IVTouch.

Remember in selecting the proper sequence in this IVTouch section that those steps which affect the others the most should be completed as soon as is possible. In reading the far right-hand total column we see that the key height and blow affect four other steps versus only one or two for the other procedures. Therefore, try to adjust the key height and blow first. Similarly, make sure that the dip is one of the last steps to be completed, since as seen in the bottom column, five other steps affect it.

Now that we have a grand regulation chart which shows how each step affects and is affected by another, we can use it as a check while going through the 50-point checklist. A checkup and a check! If we go one step further and put them both together along with a “how to”, an excellent guide will be created which will help anyone through regulating a grand action. Coming up in the next post, an enormous 50 - point guide to grand regulation.

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.