Grand Regulation In Detail - The Drop continued - part 17

34) The Drop (continued)

Regulation of the drop screw was defined in the last post as being the adjustment for regulating the point of escapement for the balancier. Today, we will discuss how to make that adjustment and some problems that may crop up when regulating the drop. 

 

The first priority is to have already regulated the let-off. Second, make sure that the repetititon springs are strong enough to support the hammer. Trying to regulate the drop with weak repetition springs is a lost cause. When watching the amount that the hammer drops after let-off, a weak repetition spring will let the hammer drop too far, since the spring is not strong enough to support the hammer. Adjusting the drop screw up under this condition will not cause the hammer to drop any less, and will be rather frustrating. Third, make sure that there is sufficient dip to enable the action to complete its escapement cycle. 

 

To regulate the drop, remove the action from the piano and place it on level surface. At this time, the drop screws may be either too high, too low, or just about right. Remember that the drop screws must be low enough to see the hammer let-off, so frequently they have been turned down in order to complete step no 33 The Let-off. But if the repetition springs were too weak, many times the drop screws must be turned up in order to see the hammer rise when regulating the repetition springs. So who knows where the drop screws are at this point? 

 

Carefully depress the key of the note that you will be regulating until the hammer lets-off. Watch the amount that the hammer falls below this point of let-off. To make this judgement easier, I frequently depress the neighbouring key first and keep its hammer in a raised position while adjusting the drop. Comparing the height of the hammer being regulated with its neighbour at the point of the let-off and again after it has fallen, I can judge with great accuracy how much the hammer has dropped.

In my earlier years, I was instructed that the drop screw should be turned until the hammer drops ½ the let-off distance. I will advise that it is faster, easier, and more accurate to regulate the drop (as well as other steps) by the way it feels. The ideal is to have the drop screw engage the balancier at exactly the same time that the jack is engaged by the let-off button. This “double escapement” can be felt by a good pianist, and with a little experience, a technician can learn to feel it also. Since I prefer to regulate an action at the piano, regulating the drop to be 1/2 the let-off becomes a problem. The action must be removed from the instrument in order to turn the drop screws. With the action out of the piano, how can a technician know what the let-off distances are (remember that I taper the let-off so it varies with each note)? I don’t have space enough to carry around the complete shop, so I never have a let-off rack with me when I find a piano that needs regulating. The answer to this problem is simple; regulate the drop by feel rather than by a specific distance!

Let me go on record again about the use of let-off racks. I believe that they are a costly item which can easily be eliminated by using the piano strings themselves, which is most accurate. The time spent correctly adjusting a let-off rack to match the string height is in my opinion wasted, as well as being inaccurate.

Once the drop has been regulated, reinstall ... 

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Grand Regulation In Detail - The Drop - part 16

34) The Drop

The modern grand action compared to the old type of action that was used for instance in the square grands show one great difference. Absent in the square grand mechanism is the repetition lever and the auxiliary features which go with it. Namely the drop screw, the repetition lever support spring, and the repetition lever height adjustment screw. The purpose of installing the repetition lever was to gain more positive and faster ability to repeat notes.

The technician who regulates this old style action has an easier job than if he were regulating a modern action, for there are fewer adjustments to make. This is especially true when regulating the escapement. He would only need to regulate the let-off screw. If he were regulating a modern “double escapement” action, he would have to regulate both the let-off and the drop.

Picture how the modern action works in the escapement process. At rest, the hammer is supported at the knuckle mostly by the balancier. As the key is depressed and the whippen rises, the balancier compresses slightly and lets the jack carry the hammer upwards.

Somewhere near the time that the hammer approaches the string, the jack tender engages at the let-off button. Eventually the jack trips out fully from under the knuckle. Likewise, the drop screw must be withholding the upward rise of the balancier as the jack trips or else the balancier would take over the thrust of the hammer and cause it to “block” upon the string. Hence the name “double escapement” action.

Most technicians have experienced “blocking” hammers, especially if it is the let-off that is faulty. Not only will the hammer “block” upon the string, but as long as the key is depressed, the hammer will stay at the string, completely dampening the sound. In the event that the drop screw is too high, the hammer will only momentarily “block” upon the string. Because the balancier is supported by a spring, the hammer will rebound from the string and the knuckle will cause the balancier to compress. In this case, some dampening has occurred, but the string will continue to speak.

Almost as critical to the performance of the action would be the maladjustment of the escapement too low. Where the drop is set correctly but the let-off is too far from the string, a loss of power and control would be evident. Removing the jack from its duty too early results in the thrust of the hammer being turned over to the balancier for the remainder of the distance. Just how far from the string the hammer lets-off too early and how strong the repetition spring is would determine how great the power loss.

In the case where the let-off is the correct distance from the string but the drop is too far, a very slight power loss could be evident. More important would be the lack of “surefootedness” as I call it that the pianist would feel. When the drop screw engages the balancier too early, again the balantier compresses, robbing some energy from the hammer’s thrust (however so small the amount, it does exist). The greater the amount that the hammer drops, the more the pianist will feel it as he plays.

 

He won’t be able to explain just what it is, rather the fact that something does not feel correct as he plays. I should probably explain that during normal playing ... 

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Grand Regulation In Detail - The Let-off continued - part 15

33) Let-off (continued)

For those technicians who find it difficult to set the let-off in the piano by watching the space between the top of the hammer compared to the thickness of the corresponding string, there is another method. Find someone in your area who sells magnetic signs such as those found on the sides of cars or trucks. The magnetic backing for these signs comes in 1/8” and 1/16” thicknesses, which are perfect for use as let-off gauges.

Purchase at least two strips of this material, one of each thickness, about one inch wide by around twelve inches long. The one inch width is sufficient to place the strips against the under sides of the strings without having to worry a lot about whether the strips will cover the hammer strike line. The twelve inch length is variable with the piano. The lengths should be no longer than the sections between the plate struts or else the strips will be too long to adhere. The larger the piano, the more sections are created by the struts, and the smaller the widths are of these sections. You may want to carry an assortment of lengths of this magnetic material.

To use, remove the action and set it aside. Take something such as a felt wedge and block up the sustaining pedal to left the dampers away from the strings. Otherwise, if there are bichord or trichord damper wedges in the area where the magnetic strips are to go, they will prevent the strips from adhering. Position the strips against the undersides of the strings, being careful to place them directly at the hammer strike line. Reinstall the action and check to see if the strips are positioned correctly. If not, carefully reposition the strip with a small tool.

Now comes the easy part. Seat yourself at a comfortable height so that you can see and work on the let-off rail. There is no need to see what is happening at the string level. Depress the keys one at a time and adjust the corresponding let-off button until a very slight resistance is felt as the hammer lets-off against the magnetic strip. When regulating in this manner it is important to remember to continuously depress the key and feel how the hammer lets-off

.

Try to get each key regulated so that exactly the same amount of resistance is felt at the point of let-off. Use the 1/8” thickness for the tenor and low treble sections, the 1/16” thickness for the top treble. After all are adjusted, remove the magnetic strips and check the point of let-off visually. This step must not be overlooked! Invariably there are slight corrections which must be made. Despite the fact that the resistance which was felt was uniform, the actual point of let-off will vary a little.

There are both pros and cons to regulating in this manner. The pros are that it is by far easier and faster to set the let-off with a magnetic strip, especially if the regulation was way off from where it should be. However, the cons are important. Obviously, these magnetic strips will not adhere to the bass strings, so approximately 1/4 to 1/3 of the let-off must still be set by eye! As was mentioned above, those which can be set with the strips must be double checked by eye for accuracy. Most importantly, the best let-off is one that is tapered uniformly from note 1 all the way up to note 88. The magnetic strips do not give a tapered let-off. Instead, they give a noticable break where the change was made between the 1/8” thickness strip to the 1/16”.

 

Despite these drawbacks, I still like to use ...

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Grand Regulation In Detail – The Let-off continued - part 14

33) Let-off (continued)

Previously discussed were the regulation steps that affect the point of let-off, namely the jack alignment to the knuckle and the raising or lowering of the whippen either through altering the key height or by turning the capstan. The amount that these changes would affect the point of let-off is marginal. It is far more important to realize that regulating the let-off affects other steps more than the other steps affect it.

The two steps which are affected by regulating the let-off are dip and drop. Remember that in this discussion dip includes aftertouch. Looking first at how let-off affects drop, let us define drop as the amount of downward movement that the hammer has after the point of let-off. Keep in mind that the regulator has to move the key downward very slowly in order to see this drop of the hammer. During normal playing, this drop as such would not be visible, as the hammer would just rebound from the string into check.

 

If a graph were drawn to show the movements of the hammer versus the slow, downward movement of the key by the technician, the amount of drop and how it is affected by the let-off becomes clear. In all of the graphs shown, the key dip is set to a specific measurement which will not be changed. In figure 1 the hammer travels upwards from the point of rest and lets-off (marked “A”) at 1/8” from the string. The hammer then drops away from the string let’s say another 1/8” (marked “B”), and then rises back up yet another 1/8” (marked “C”). This last upward movement of the hammer coincides with a small downward movement of the key which we will define as aftertouch.

Figure 2 illustrates what happens when the hammer lets-off closer to the string, all of the other regulation steps staying unaltered. The point of let-off has changed to 1/16” from the string, the drop increases to about 3/16”, and the aftertouch decreases to about 1/2” of what it was in figure 1. The aftertouch decreases because it took more key dip to raise the hammer to a higher point of let-off, and it took a fraction more dip for the hammer to drop the farther distance compared to figure 1. The pianist will complain that the piano now “plays hard” since there is insufficient aftertouch. The action also feels a bit sloppy because of the excessive drop. He might even notice that when playing very lightly the hammers have a tendency to “bubble”.

Figure 3 tells what changes happen when the let-off is too far from the string. Here the point of let-off is 3/16” from the string. The drop now decreases to about 1/16” and the aftertouch increases to about 1-1/2 times as much as in Figure 1. The aftertouch increases here for the same reasons why it decreased in Figure 2. It took less dip to raise the hammer to the point of let-off, and less dip for the hammer to drop the smaller distance. In this case the pianist will complain that the keys feel spongy, as there is too much aftertouch. I doubt that he would complain of too little drop, as he would not normally be able to feel it. The complaint may be heard of slower repetition.

As can be seen from these graphs, a change in the point of let-off can really affect another regulation step. I will explain now why it is important to know that ... 

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Grand Regulation In Detail – The Hammer Blow continued - part 13

32) The Blow (continued)

To wind up the discussion on blow, I want to describe some different methods that I know of to measure the distance accurately between the tops of the hammers at rest t­o the bottom of the strings. One easy way is to use a small pocket ruler with a sliding clip. The clip is moved to the appropriate mark on the scale, say 17/8“. The ruler is then inserted through the strings until the tip of the ruler touches the top of the hammer to be measured. The clip marking the desired blow distance is then compared to the bottom of the string. The capstan is adjusted until the clip matches this mark.

The good aspects of this method are that the tool used is already in your tool kit and can be used for many other purposes. It is also easily adjustable to provide a blow gauge for whatever blow distance is desired. This can be helpful if the blow distance wanted is measured in millimetres and does not correspond to a normal inch measurement. The drawbacks to this method are that the clip often moves while trying to measure, giving a false reading; and the ruler usually slips out from between your fingers and drops into the action. Both of these problems have forced me to look for a better idea. 

 

A number of years ago while visiting a piano factory I was given a very nice aluminium gauge Figure 1 which can be used to set a blow distance of 17/8“. This tool really caught my eye since it is very easy to use and has a good handle to grab hold of. The technician just inserts the gauge between the hammer and the strings. If the blow distance is too little, the hammer will be pushed downward by the tool. If the blow is too great, the hammer can be seen to rise when the appropriate key is pushed down. Although better than the ruler, the­­ blow gauge also has its faults. Since the measuring portion is fixed it can only be used to set a blow distance of 1 7/8”. It also happens to be too big to fit in the allotted space in my tool kit!

The best solution, as is often the case, is to make a well designed homemade tool. Take a piece of wire and bend it to look like Figure 2. The functional part marked (A) used to measure the blow distance can be made to whatever distance is desired. I made three gauges to carry in my tool kit. One is 44mm (1 3/4“), one is 46mm, the last is 48mm (1 7/8“). They are colour-coded so that I can quickly select the one wanted. Since they are homemade you can vary the length of the tool to fit your tool case or design the handle so it won’t fall from your hand.

An added plus is that by selecting different thicknesses of wire for these gauges ...

 

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Grand Regulation In Detail - Setting The Hammer Blow - part 12

We left off talking about the two factors that create the striking point for a hammer. Assuming that the hammer glue joint is 90 degrees on the shank, which it must be, these two factors are: 1) The distance from the hammershank centre pin to the centre of the hammer molding, and 2) The position of the hole in the hammer molding, more commonly called the hammer bore distance. In measuring factor number one, the measurement is always taken from the centre of the centre pin, to eliminate any error because of larger centre pins.

Looking at the diagram, this distance for factor number one is labeled (L). In this particular instance, (L) = 5 1/8“, which is a common measurement. (L) determines the type of arc that the hammer will take on its upward movement towards the string. The distance that the hammer travels in this arc is labeled (S). (S) is correctly termed the hammer travel distance. Note that this is different from (6) the hammer blow distance. These two words should not be used interchangeably.

As the hammer is moved in or out on the shank, this distance (S) changes. Minute alterations of (L) by the technician as he glues on a set of new hammers is acceptable in order to achieve the correct striking point. However, keep in mind that the piano was designed with a specific distance for (S). The work that the knuckle does in raising the hammer is in a ratio which is dependent upon (L) and the placement of the knuckle. The closer that these two placements are to what was designed, the better the action will perform.

Of greater importance than factor no1 is factor no2, the hammer bore distance. I regularly find good make grand pianos where the bore distance is wrong from the factory! When manufacturer installs the hammers, he should measure the distance (A) on the diagram. This is the distance between the bottom of the string and the centre of the centre pin on the hammershank. Unfortunately, many pianos are manufactured without regard to this measurement. (A) does fluctuate a little from what the piano was designed to be, mostly because of differences in the thicknesses of the plate castings. Sometimes the string height varies because of improperly installed agraffes, or in the case of a rebuilt piano, the string heights will vary because the plate was lowered in order to achieve proper downbearings.

When rebuilding, always wait until the new strings are installed before sending off for new hammers. Never buy stock hammers. Insist that the hammers be bored to match the piano. Either send to the hammer duplicator the measurements for (A) for each section of the action, or else bore your own. Anyone who has regulated many actions will have noticed that the string heights vary not only between similar pianos of the same make and model, but will also vary between the different sections of one instrument. Ever wonder why the hammer rest rail never fits the bass hammershanks like it does the tenor? One cause can be improper hammer boring. Why? Most grands are made with the hammers bored at a stock distance, to supposedly fit all of the pianos made of that model(s). No interest is paid to what (A) is, or whether (A) is the same for each given section of the action.

Why is this so important? 

 

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Grand Regulation In Detail - part 11

32) The Blow

Step no12 was adjusting the key height and leveling all 88 keys. Last month we discussed step no31, regulating the jack height. These are the only steps that directly affect the blow distance, or hammer line. Indirectly the repetition springs will also affect the hammer line if the springs are weak. However, we had to make sure the springs were strong enough to support the hammers before the jack height was set. Therefore, we should now be ready to set the hammer blow distance.

Once set, there should be no need in doubling back to readjust this distance. Remember that before all of the jack heights were set, a number of sample keys were regulated for jack height, blow, let-off, drop, and then the regulation was proven to be correct with proper after-touch. I always use the end keys in each section as my samples. First, this allows for any irregularities in the string height going from section to section. Second, it gives me a hammer at the end of each section which has been set to the correct blow distance. Doing step no32 The Blow then becomes a simple matter of drawing a line between the tops of these two end hammers and setting the remaining hammers in each section level to this line.

This, of course, is accomplished by raising or lowering the capstans. If the hammers do not return consistently back to the same height when a test blow is given to the keys, check for weak repetition springs, too much lost motion in the jack height, tight hammershank flange centres, or tight key bushings. Any time that the capstan is changed, it is a good rule to give the key a test blow to see where the hammer will settle in its height. During this test, watch the rebound of the hammer as it comes up off the hammer rest rail/felt. All 88 hammers should rebound with the same freedom. If they do not, stop and check for nonuniformity in the centres, as this will make the action play unevenly no matter how well the action was regulated.

When all of the hammers in each section have been made level to the samples, install the action back into the piano and play each note vigorously. At no time should any one hammer be higher or lower than its neighbours in a section. Any unevenness should be corrected. Incidentally, the practice of raising one hammer to give the proper after- touch to that one key is wrong. In order to have perfect evenness of touch, uniformity of tone (i.e. power), and a uniform repetition, all hammers must be the same distance from the strings. More will be said on this subject at a later time.

In selecting the proper blow distance, look at the tangent relationship between the jack and the knuckle. Ideally, the knuckle should be glued on at 90° to the hammershank, and the jack should be in a straight line with the knuckle core. This would give the ideal of a jack at 90° to the hammershank. The shank should be about a shanks height off the rest felt. If it is a great deal more above the rest felt, make sure that this angle between the jack and shank is checked. An angle of more than 90° will result in a loss of power. What we want is the maximum acceleration of the hammer without destroying this tangent relationship. As has been mentioned before, altering the blow distance or altering the key dip are the only two steps which can be changed to compensate for action wear. Never set the blow distance without also considering the dip. If it is unacceptable to change the dip, and if this tangent relationship of the jack to shank has to be compromised, perhaps you should think in terms of installing a new set of hammers/shanks/flanges.

 

In the past, I have stated that ...

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Grand Regulation In Detail - Jack Adjustment - part 10

I pointed out in the past that we really do not set the jack height, as the jack is not variable in its height. Rather, we set the height of the repetition lever relative to the top of the jack. However, I have always called this regulation setting the jack height, and I intend to continue to do so. The specification in regulating is to have just a fraction of space between the top of the jack and the bottom of the knuckle with the whippen at rest. This can be compared to setting the lost motion in a vertical piano. However, in a grand the amount of space needed is even less than in the vertical.

Before taking the action completely out of the piano to adjust all keys for the jack height, I like to set sample keys for blow, let-off and drop, as well as jack height. Doing this first and proving these sample keys with aftertouch insures that after all of the steps in Section IV are regulated, the piano will play properly.

In order for the jack height regulation to be stable, the repetition springs must be strong enough to support the hammers. We have all seen hammers that do not return to the same height after each time they are played. This can be caused by either too much lost motion between the top of the jack and the knuckle, or by repetition springs that are too weak.

Assuming that the repetition springs are strong enough, the culprit is the jack height. As well as causing an uneven hammer line, too much lost motion also causes a loss of power. On the other hand, too little space will not allow the jack to return under the knuckle as fast as it should (or not at all) and hence cause faulty repetition. Some technicians set this measurement by feeling the top of the jack versus the side of the balancier window where the jack sits. The specs call for a 0.2mm (or a paper’s thickness) space that the jack should be below the window.

This is fine if the piano being regulated is brand new or if the knuckles have just been replaced. Under these conditions, the surface of the knuckle is very even across the face where the jack contacts it. If the knuckle is not new, chances are that the leather has begun to get grooved in the middle from the force of the jack hitting it. To obtain the proper space between the jack and a grooved knuckle will require that less than a 0.2mm measurement be used. In some cases the top of the jack may have to be even with or higher then the balancier window. With a grooved knuckle, there is only one way to regulate. That is by using a process called “winking the jack”.

With the whippen at rest, gently slip your finger in between the top of the jack tender and the bottom of the let off bottom. Slowly depress the jack tender as if it were going through the process of let-off. Be careful not to push down on the whippen while tripping the jack. Depending upon the type of action you are working upon, you may see the hammer “wink” or not! By “wink” I mean that the hammer will fall slightly lower than its neighbours. Sufficent space must be allowed for the hammer to fall, so the hammer rest rail must be set a shanks diameter below the hammershank at rest. If the action has hammershank rest felt instead of a rest rail, either raise the shank or remove some of the rest felt.

For some unknown reason, some makes always give a perfect little “wink” for this test, but others are not as reliable. Therefore, ...

 

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Grand Regulation In Detail – Regulation where the piano is - part 9

Whenever the subject of grand action regulating comes up, the thoughts always turn to benches, key levelers, and let-off racks. As others gloat about how they designed their own bench tops to try to duplicate the piano’s keybed, I usually wander off shaking my head asking myself, why so much bother when they could just use the piano itself? I agree that many of the procedures in the 50-point checklist must be done in the shop. These include such repairs as rebushing keys, refelting the keyframe, replacing keytops, etc.

However, many of the steps that may be done in the shop can also be done at the piano, or at least in the customer’s home. These would include such things as reshaping hammers, repairing action centres, polishing capstans, cleaning knuckles, etc. If the piano is not already in the shop for rebuilding, I much prefer to work right in the customer’s home. I have no need for an elaborate bench top, let-off racks, or Jarvas type key levelers! As a bench, I use the keybed of the piano, or if need be, my lap or the piano’s lid (padded of course with a moving pad). Instead of a let-off rack, I use the strings themselves (far easier and more accurate). In place of a key leveler I use a small straightedge about 15” long which I carry in my case. 

 

Also in my case is a good supply of punchings and other repair items so that I can arrive at a home to tune the piano, and end up staying there all day, reshaping hammers, doing action repairs, and a complete action regulation. I don’t work out of a large van either. In fact, many days I work out of a motorcycle! With experience I know what to bring to be prepared for the day’s troubles. In most cases, the customer would rather that I work on the piano in her home. She can watch what I am doing, the piano is not out of commission any longer than need be, and if any unexpected repairs crop up, l can consult with the owner while at the piano. It is certainly easier on me since I often work many miles from home, and it is awfully hard to carry a grand action home on my motorcycle. 

 

These reasons for working at the piano are secondary. Of real importance is the reduced time to complete the work (which means more money) and greater accuracy. Let us make a comparison of two equally fast working technicians, one who regulates at the piano, the other who carts the action back to the shop. Let’s pick a ten-year-old piano which has had normal usage. All that is needed are the usual minor adjustments to the action as a result of a little wear and settling in of the action parts, reshaping and voicing of the hammers, and tuning.

The first technician, who regulates at the piano, immediately proceeds to reshape the hammers. This can be done by turning the action around in the piano with the hammers facing the technician, or else putting the action on top of the piano. He then takes apart the action, removes the keys, reinstalls the action without the keys, and cleans everything prepatory to bedding the keyframe. After bedding he aligns all of the action parts, using thestrings ofthe piano as his guide. Next, he regulates the action mechanism in the piano, and lastly tunes and voices it. Approximate time: one working day.

The second technician, who is going to regulate the action at his shop, takes ...

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Grand Regulation In Detail - Part 8

In part VII of the series on grand regulation we discussed the two methods of regulation for grands, the Dip and Blow Priority. Now that we know the differences between these two methods, two decisions must be made before Section IV ‘The Touch’ can be begun. The first decision is what procedure to use to accomplish the regulation process. The other decision, depending upon which Priority method was chosen, is to determine the correct measurement for the dip or blow. Once these two decisions have been made, the remainder is a piece of cake. Without these two decisions, regulation becomes a long, hard task with lots of wasted time.

Let us look at some of the many grand regulation procedures that are available to choose from. This list is by no means all inclusive, and just because a certain procedure has been omitted from this list does not infer anything about its relative merits and value to us. 

 

The five procedures listed on the left are Dip Priority, the five on the right are Blow Priority. In viewing this chart you will notice that some procedures have more steps than others. But pay more attention to the order in which these steps are listed. For instance, in procedure no10 the whippens are aligned to the knuckles as step number three. But in step number seven the hammers are aligned to the strings, making realignment of the whippens necessary. Other procedures listed have similar mistakes. I would certainly modify the order of some of these procedures to eliminate such needless doubling back. 

 

If you were to regulate an action, which of these procedures would you choose? Should you select the one that is from the factory manual for the brand of piano being worked upon? If so, then each time you regulated a different brand of piano you would use a different procedure! Needless to say, this is awkward. Or should you select a procedure written by your favourite author to use on all brands of pianos? Chances are that your author’s procedure is different from what the manufacturer calls for, and may not be as detailed as the factory manual. As an example, some pianos have an auxiliary whippen spring. If you did not know this, and the procedure you were using doesn’t mention it, you would probably overlook it. Well then, should you select the procedure that is the most detailed? I don’t believe so. Just because it has 125 steps doesn’t mean that it is better than one with 50 steps!

How do you decide upon a procedure? Obviously, you want the one which is easiest and fastest for you. People differ in their abilities and knowledge. What works best for one technician may be awkward for another. I suggest that everyone make up their own procedure to suit their own needs. In creating your own, remember that the order of steps must be logical so that the minimum of doubling back occurs.

As a help here, consult the Grand Regulation Chart which appeared in the 2nd post of this series on grand regulation. Naturally, you will want to include those steps such as reshaping hammers and rebushing keys that are normally done when regulating an action. Every step should be in a convenient order to go along with how you regulate. Do you bench regulate or do you regulate at the piano, or a little of each? In that case, you have to create your own procedure. 

 

Now that the procedure has been decided upon, next is to decide what measurement to use for the ...

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Grand Regulation In Detail - Part 7

Last discussed in the 50-point guide to grand regulation were the two main methods to regulate. One is called the Blow Priority method, the other is the Dip Priority. To determine whether a given procedure is Dip or Blow Priority, just look to see which of the two is regulated first in the order of steps listed. Once the dip or blow has been adjusted, all of the other action regulations are then set based upon this first measurement.

To explain this further, there are seven main steps in section IV, The Touch portion of the 50-point checklist These seven are: 1) Blow, 2) Dip, 3) Let-off, 4) Drop, 5) Backcheck distance, 6) Repetition strength, and 9) Jack Height to the balancier. Again, as in the past, the dip includes the correct aftertouch measurement. Let us take the example of a Blow Priority system first. If the repetition spring is strong enough to support the hammer first adjust the jack height in order to insure that as the blow is set that the hammers will always return to the same setting. Step two then would be to set the predetermined blow distance.

Depending upon how worn the whippen felt is, how flattened the knuckle has become, and how much the hammer has been filed the capstan will need to be raised further to compensate for greater wear in order to achieve the desired blow distance.

Raising or lowering the capstan affects directly or indirectly all of the remaining steps. Raising the capstan raises the whippen assembly, which causes the jack tender to become closer to the let-off button, and the balancier to become closer to the bottom of the drop screw. Once the let-off and drop are correctly set, changing the capstan will necessitate readjusting the let-off and drop. If the correct after-touch is to be achieved, the dip measurement is predetermined by the blow and let-off distances selected. The amount of dip will affect the backcheck angle. And, as we all should know, we set the repetition spring strength based upon the hammer’s release from the backcheck. So out of the seven main steps in section IV TheTouch, changing the capstan will affect one way or another all seven steps: To eliminate any unnecessary doubling back to reregulate a step already performed, set the blow distance right in the first place, and all of the other six steps will come out correct the first time through.

Remember the “circle of five steps” as explained in the first article of our series on grand regulation? If not, please look again at our first post. This illustration helps to show how each step affects the others.

 

Adding the let-off and drop in between the blow and the dip completes the circle with all seven steps. Of these seven, only two can be places of compromise to compensate for action wear. The let-off, drop, backcheck distance, repetition spring strength, and jack height can only be regulated to specific tolerances or distances, with very little room for variation. Only the dip and blow can compensate for action wear. The Dip and Blow Priority methods are the means of setting one of these variables in the beginning, making any compromises needed with the other variable latter.

One school of thought amongst piano technicians is that the dip is not a variable. In other words, there is a specific measurement that the key is supposed to go down, that measurement being standard throughout the world, and no variation from that measurement (usually 3/8”) is acceptable. This of course leaves only the blow distance as a means of compromise as the action wears. I believe this school of thought to be a little narrow minded. There are times when the dip should be altered a little. When I say a little, I mean within + or - .036” at the maximum. Next week, we will discuss just how “‘standard” this measurement is.

We have already discussed what the main areas of wear are: 1) ...

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Grand Regulation In Detail - Part 6

Section III. Alignments

29) Align jack to knuckle core

In order for the power to be transmitted from the whippen to the hammershank efficiently, the jack must be properly aligned under the knuckle. 

Looking at the action sideways, the rear of the jack (the surface towards the hammer) should line up perfectly with the rear of the knuckle core. Normally, this alignment is easy to see. The knuckle should be glued on perpendicular to the shank, and if the hammer is new and was bored correctly, the shank should be perpendicular to the jack. Sighting along the rear of the jack, it should be easy to tell when the jack is in line with the knuckle core.

However, if the shank is not perpendicular to the jack this alignment is hard to see. Two things can cause this:

A. The hammer has worn resulting in the capstan being turned up to keep the blow distance close enough. The shank then becomes more than 90 degrees from the rear of the jack. In such cases, imagine a line drawn from the rear of the knuckle core down to the point on the knuckle leather where the jack would touch it. Then line up the rear of the jack to this point.

B. The other reason, which is fairly common, is that the hammer hole was not placed correctly in the molding. This results in the top of the hammer, either, being too high, or too low in relation to a line drawn down the middle of the hammershank.

Boring the hammer wrong of course results in the shank not being perpendicular to the jack as in cause A. If this angle of the shank to the jack becomes too great, then either the hammer has worn excessively so that it should be replaced, or if the hammers are new, then the hole in the molding should be plugged and rebored.

Why was the hammer bored incorrectly? Have you ever noticed when regulating the hammer-blow distance, that when the tops of the hammers are adjusted so they all are, say, 1 3/4” from the strings at rest, that the hammers in each section vary as to their heights measured from the keybed to the top of the hammers?

We should expect the bass hammers to be higher since the bass strings are higher so they can cross over the tenor strings. But notice that if the agraffes are not the same height as the capo d’astro, the hammers will also vary in their heights between these sections.

If the original or duplicate hammers were not bored taking into account these different string heights, then the hammershanks will not be perpendicular to the jacks with the hammers at rest.

We will discuss this problem further in a later post on hammers, but let me add here that some pianos have a different string height for each section!

An easy way to align all of the jacks is to align the end hammers in each section, and then by using a straightedge or a thread, align the jacks in the respective sections to the end samples.

Note that some manufacturers mark a line on top of the balanciers. This line serves as a guide only when  ...

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Grand Regulation In Detail - Part 5

Section III. Alignments

27) Align hammers to strings

 

To facilitate this alignment procedure, install the action into the piano andmake a rough check of the let-off measurement. If the let-off is very far from the strings, the hammer-to-string alignment will be very hard to make. So try adjusting the let-off by say one-half or one complete turn of the adjusting screw and see what number of turns it takes to get the hammer to let-off right next to the string.

 

At this point in the regulation procedure, if the hammer blocks on the string, it will be all the easier to make the alignment. Then remove the action and turn all of the let-off screws the number of turns that you found necessary to get the hammer closer to the strings.

 

Before starting to centre the hammer to the strings, make sure that the hammers have been filed, removing all traces of former string grooves. If the piano has agraffes, then your job will only be to align the hammers to the strings. If the piano does not have string aligning mechanisms throughout, then you must make sure that the strings are properly spaced and centred before attempting to align any hammers.

 

Normally, unless the plate has been repositioned or a bridge reglued onto the soundboard, there should be a straight line running from the hitch pin through the bridge pins and on to the tuning pin hole in the plate. The middle string of a trichord should run along this line, with the right and left strings having the same inward pointing angle, since the bridge pins are wider spaced than the spacing at the V bar.

 

Begin aligning the hammers to the strings by taking a wire hook and coming down from the strings, lifting the shank so that the hammer blocks on the string. Or, take a finger and lift the bottom of the whippen taking the hammer past let-off and pushing up until the hammer again blocks on the string. I prefer the latter method since the wire hook is slower and can cause the hammer to be pulled to one side if you are not careful.

 

Looking directly above the hammer, check to see, if it is properly centred to the strings. For a trichord, equal amounts of hammer should be seen on both sides of the unison. On single or double unisons, the hammer can either be likewise centred, or they can favour the bass side a little, depending upon how you want the hammer to strike when using the una corda pedal.

Any hammers which are properly centred on the strings, I mark with an “O” on the key with a piece of chalk. Those which are off to one side, l mark with a straight line on the key to the side which they need to go, varying the thickness of the chalk mark as the amount the hammer needs to be moved. Do one section at a time.

Pull the action out after chalking all of the keys, and compare the marks with the way the hammers look. All of the chalk marks must coincide with either a perfectly centred hammer or else a hammer that needs to be traveled, angled, spaced, or a combination of these three.

Place a long screwdriver blade or other object such as a spare pedal rod under all of the shanks in this section and check the hammers first for traveling. Even though a key was marked “O” the hammer may be traveling or have the incorrect angle. After correcting the traveling, heat the shanks of those traveled along with any others whose angle needs to be changed until all of the hammer angles look uniform. Lastly, space the hammer by slightly moving the flange sideways.

If the flanges are of the type where a screwdriver or flange spacer can be used, install the action into the piano and space the flanges directly by lifting up the hammer until it blocks on the string. If the flanges are not of this type, then they must be spaced outside of the piano. Use the width of the chalk marks as a guide to how far to move the flange, and try to use any keys marked with the “O” as a point of departure.

I get two keys about five or six keys apart marked with the “O” and work from these, putting t action back into the piano and making any needed refinements.

Remember that some manufacturers ...

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