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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