Hello, if possible I would like to ask a question: what are the major problems caused by poor regulation of the screw that determines the hammer repetition, both in the case of excessive repetition (about 5 mm) and limited repetition (0 mm)? Furthermore, I have often happened to see different technicians operating in different ways; for example, some, to perform this regulation, go as far as feeling the escapement point and therefore press it gently, while others do it decisively. The hammer behaves differently. I am convinced that the first hypothesis is the most correct, but after the umpteenth discussion with a technician, I would like to ask your opinion. Thank you very much
One arrives gently at the escapement point and adjusts the appropriate screw so that the hammer "escapes." The hammer, according to the manufacturer's specifications, must move away from the string by 1-2-3 mm. The drop (we are talking about the tail) is 1-2 mm. Excessive drop causes the escapement lever to struggle to reposition itself under the roller and creates confusion with the let-off distance. A small drop, in the presence of correct spring tension, can cause the hammer to jump and nullify the perception of the "escapement" under the finger. Making the hammer escape at a distance of 2.5 and an additional drop, for example, does not favor the pianissimo and invites the pianist to play a "workhorse" keyboard with less sensitivity. The "jeu perlé" that the French teach us is impossible with these distances. In this case: escapement at one millimeter and an equal amount of drop. Naturally, rather weak springs. This way, one can play "sur l'escapement," that is, with the calm fall of the fingers without reaching the "bottom" of the key. In short, customized adjustments can also be obtained. One must be precise and sensitive and notice how the pianist plays. Friction also comes into play. With a high coefficient of friction, the springs must be loaded more heavily and everything becomes more "robust." Conversely, with very loose center pins, we will see the hammer jump and we will not feel a precise drop and let-off under the finger. In short, correct friction and precise adjustment, perhaps done with precision tools and the action removed.
Thanks a million! I fully share your analysis, especially in noting the pianist's difficulties (which are exactly those you describe), particularly regarding the "jeu perlé", and also on the tension of the springs. If possible, I would ask you again: once escapement is reached (starting from this point and not from the full key stroke from the rest position), if the key is pressed down decisively, does the hammer remain gripped to the repetition lever?
The paramartello is specifically used to parry the mezzo and forte stroke. For a piano and pianissimo, the hammer might only fall. It depends precisely on the spring force, which must not cause that small recoil under the finger. This "recoil" also depends on a "pre-regulation" of the escapement upright relative to the level of the repetition lever. The difference in level between the two parts must be neither too much nor too little!!!!!! This is also related, again, to the spring force, but the spring force is related to the friction coefficient etc.....
