Tuning

order of regulation

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massimino

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Opening post by massimino

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Hello everyone. Reading an old article on grand piano regulation by Francesco Griffa, some doubts have arisen which I am submitting to you. The article lists, in strict order, the preparatory actions. Excluding the preliminary ones, it says:

1) key dip with a 10 mm gauge etc etc

2) escapement regulation....etc

3) regulation of the let-off screw...etc.

4) bringing the hammers to the necessary distance from the strings using the pilot. The distance is exact when, by depressing the key very slowly, at almost the end of the stroke (9.75 mm) the hammer falls onto the second escapement. If the hammer, when falling onto the second escapement, produces a small notch/click, increase the stroke by tightening the pilot. Conversely, if it fails to perform the first escapement, decrease the stroke by unscrewing the pilot.

5) hammer rail...etc.

The point that is causing me confusion is number 4. I mean, if I first regulate the two escapements and then modify the hammer-string distance, do the escapement distances not change again?

And then, is the hammer-string distance determined by the beginning of the notch (set at 9.75 mm) or is it independent of this factor? Could I also regulate the "beginning" of the notch by making it "higher" or "lower"? But with what benefits, if any.

Perhaps it is a silly question, but considering the author, I asked myself this question which for me is above all an important curiosity.

Thank you all

good day

massimo

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Reply 2 by pianoexpert

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First concept: it is common even among the most "distinguished" Technicians to speak of "double escapement." There is only one escapement!!!! Or rather, the sensation, I say the sensation, of having "two" escapements under the finger is due to the fact that the repetition lever is ready to "escape" even before the key has reached its resting position. This is thanks to the assistance function of the repetition lever. (I discuss this topic in my articles on my website and in my video tutorials)

As for the regulation phases, I absolutely disagree on the sequence and the procedure.

I would also like to specify that regulation must be preceded by a "pre-regulation." This includes alignment as well as the height of the repetition lever relative to the escapement lever.

The hammer-string distance is dictated by the Manufacturer and is in close relationship with the key dip.

Generally, the hammer-string distance is from 45 to 47-48 mm.

Then the escapement from the string is regulated, which varies from about 3mm in the bass, up to 1mm in the treble.

The "hammer drop" is almost always 1mm and the let-off is about 15mm.

Now, to check if the key dip is correct, we observe the behavior of the hammer. We will see it rise slowly and then fall at a certain point... but at this point, the key stroke must not yet be finished. There must be a small "void" when "everything is finished." If this portion of the stroke is too much, we will see the hammer rise again after the fall; if it is too little, the hammer will struggle to "escape and fall." A middle ground is the optimal choice. This small dip distance called aftertouch or "dopotocco" makes it easy for us, for example, to play "jeu perlé" with only finger falls and facilitates the pianissimo.

All the predicted distances are important and interdependent. And they cannot be obtained at the expense of others. I mean that if we were forced to arrive at a hammer-string distance, for example, of 43mm to reach the goal of a 9.5mm dip, we could find ourselves in an unnatural situation, not intended by the design ratio. In fact, it is the "geometry" of the latter that dictates the regulation specifications. Specifications that, yes, can be customized, but with the awareness that some possible performance may be lost. In the aforementioned case, one would have, for instance, an easy dip... but a rather "poor" attack on the string, with difficulty in achieving the excursion between pp and ff.

In a future Tutorial, I could illustrate all the possible customized regulations and the advantages and disadvantages they can cause. In fact, any regulation that is far from and/or different from that recommended by the Manufacturer can favor or disfavor certain performance aspects of the action.

I hope I have been clear and helpful.

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Reply 3 by Sergio

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pianoexpert wrote:

In a future Tutorial, I could illustrate all the possible custom adjustments and the advantages and disadvantages they may cause. In fact, any adjustment that is far from and/or different from the one recommended by the Manufacturer can favor or disfavor certain mechanical performances.

We look forward to it!

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Reply 4 by torrese

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PAOLO FERRARELLI first of all A TRUE FRIEND and A GREAT MASTER, if I were his neighbor I would be in his "workshop" every single day, blessed Simone who lives near Paolo.

A big hello to all the friends of the forum.

saverio

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Reply 5 by massimino

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Dear M° Ferrarelli, first of all, thank you for the clarity and professionalism of your interventions.

In effect, I share with you the doubts regarding the article that I cited at the beginning of this discussion, but a small doubt remains for me also concerning the regulation of the hammer-string distance and the "aftertouch" space. Is this extra space managed through the approaching or receding of the hammer from the string (via the pilot) or by inserting or removing shims at the bottom of the key? However, in this latter case, I believe the depth of the key itself would change.

Thank you all

good day

massimo

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Reply 6 by pianoexpert

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So: obviously the two distances (hammer-string and key dip) are interdependent. However, they must remain within certain limits and must not deviate too much from the Manufacturer's specifications. Now we have to choose: what is more important. I believe that if we leave the hammer-string distance fixed, we can only act on the thicknesses under the key. The hammer-string distance causes the intensity of the hammer attack to vary. A distance that is too large would make the keyboard difficult; if it is too short (43-44), the impact of the hammer would be felt less. In any case, everything can vary slightly from instrument to instrument. For example, the "sacred" Steinway specifies 47mm and a dip of 9.5. Sometimes 9.5 might not be enough. I say 9.7 if not 10mm. The "aftertouch," as the Americans say, should have the thickness of a penny!! In my opinion, that is too much. We can check if it is correct on our instrument and we can also vary it to our liking (without exaggerating... otherwise the hammer, after the fall, rises back up).

Attention: How deep must the black key be? As much as corresponds to the same "aftertouch" of the white key!!!!!! Therefore, a very useful measurement.

I leave it to you to discover, but the quiz is also open to other readers: how to determine the same measurement for both the white key and the black key!!!!!

...I'll set you on the right track: you can use the actual front shims of the key lever........

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Reply 7 by Thesimon

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saverio wrote:

PAOLO FERRARELLI first of all A TRUE FRIEND and A GREAT MASTER, if I were his next-door neighbor I would be in his "workshop" every single day, blessed Simone who lives near Paolo.

A big hello to all the friends of the forum.

saverio

Ahahahah and who's going to see it?

If we manage to catch up once every two weeks, that's already a lot!! He has his commitments and I have mine, we both return home at dinner time and we are both quite exhausted to retire to "our respective apartments" and not go out again until the next day. But those two times a month, one never gives up Happy Hour in Grottaferrata!!! Ahahahah is that you, Pà???

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Reply 8 by massimino

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Dear Maestro Ferralli, your quiz is quite complex (at least for me) ...I fear you are overestimating me...

I will try to rely on my intuition (with all the associated risks): it seems to me that I have understood that the hammer-string distance is not to be touched and consequently one should act on the key bushings (but I continue to think that this alters the key dip). For example, on my piano (Kawai KG 2D), the manufacturer specifies white key dip 10.5 - distance from the string 46 - hammer escapement 17 - the black key dip is not specified (unfortunately for me). In my opinion, it should dip at 10.1

Thanks a million! see you soon

massimo

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Reply 9 by pianoexpert

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Aside from the fact that Simone is right! We are so busy that we see each other too rarely. But better times will come!!..In the meantime, we will see each other next Sunday at the house of mutual friends... they don't mess around.....we're going to eat heartily!!!!

For Massimo: The measurements are fine. White key: get yourself a shim/spacer of about 0.50. That is your template for the after-touch!!!. Place it under a white key. If the hammer still "clicks" near the string, add shims until the hammer, with great finger pressure, no longer clicks (or follow the reverse procedure, should the hammer not click at all)!!!! You have thus determined the correct let-off/dip with an after-touch of 0.50. Do the same on the black key. You will see that the respective dips are different.....but the after-touch is the same!!!! Good luck

P.S. "it seems father-father...but I know the tricks!!" (Antonio Albanese - Cetto La Qualunque)

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Reply 10 by massimino

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Thank you M° Ferrarelli for your availability, I wouldn't have guessed the quiz.

regarding the relationship between white and black keys, I have some doubts about the technical specifications dictated by the manufacturer. In my case (Kawai KG 2D) the parameters indicate a key dip of 10.5 mm for the white key; they do not specify the dip of the black key but indicate its height at 12.5 mm, which seems a bit too much to me. Currently my black keys are at 11 mm in height.....

thanks a million!

good day

massimo

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Reply 12 by Fra

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One can also check that the two adjacent keys (white and black) bring their respective wippens or levers to the same height once fully depressed, and the background looks good between blacks and whites... after leveling and checking the regulators... this is to go faster.

In any case, theory is theory but what matters is always the result: when the technician then finds themselves at a customer's house, perhaps in front of an old piano, they have their work cut out for them to obtain a satisfactory result in half a day!

For example:

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Reply 13 by massimino

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Hello everyone.

In my piano, it often happens that the hammer rebound, after the first escapement release, occurs differently even when applying the same force and pressing from the same point. Sometimes a few millimeters, other times more than a centimeter. I would like to ask you if such inconsistent behavior is due to a very specific and clear reason or to something else.

Thanks a million

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Reply 14 by Fra

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When the strike is not strong enough, the repetition lever supports the hammer thanks to the charge of the repetition spring so that the pusher is ready to return under the let-off (the effect of what many call the second escapement); if, instead, the strike is stronger, the hammer is parried by the hammer check....

Double escapement double position

Ciao

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Reply 15 by massimino

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Thanks Fra, but even with the same force, the hammer changes position for me. That is, I proceed like this: I depress the key very, very slowly until the hammer escapes and falls back a few millimeters lower; but if I repeat the operation several times (always with the same minimum pressure), the hammer descends differently every time. Instead, as you point out, if I proceed decisively and very quickly, the hammer engages with the capstan. I think I understand that for a good regulation one must depress the key very slowly, but every time I get a different result even with the same pressure. Or are other factors at play?

Thanks a million!

bye

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Reply 16 by Fra

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In these cases, if the spring is charged, the fault lies with the height of the repetition lever; I mean the height relative to the surface of the pusher (which must be well aligned with the roller's wooden piece).

The repetition lever must be higher than the pusher! By how much? My tuner says "about the thickness of a tram ticket," referring to the tissue paper tram tickets used in the sixties.

Ok, but how can I see it? It's not like I have a microscope to appreciate a tenth of a millimeter....

So he pulled a rectangular object (perfectly flat) about 1 cm wide out of his bag and slid it transversely along the repetition lever, which must first be lowered and then raised gradually until the rectangular object (it could also be a perfectly straight piece of cardboard) stops dragging the pusher... there is no need to rush....

The position between dragging and not dragging is the correct one...

If fixing this parameter does not solve the problem, you have to look elsewhere...

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Reply 17 by Fra

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To ensure that the pressure is the same, use a weight sufficient to trigger the escapement; I suggest a stack of 5-cent coins, 20 should be enough (and then some)

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Reply 18 by massimino

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Good morning everyone.

On my Kawai kg 2 Ds, the distance called "after touch" is not uniform and varies in certain areas of the keyboard compared to others. I should preface that the depth of all keys is absolutely the same (10.5) throughout the entire keyboard. In your opinion, are there other causes that determine this factor? Perhaps I could remedy it with shims under the keys, but in this way, the equality of the depth would no longer be guaranteed....what would you prefer?

thanks to all

good day

m

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Reply 19 by Fra

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You would have to do a complete mechanical regulation. The position of the pusher, escapement, hammer drop, and spring tension are all things that influence the after-blow for the same let-off.

In this file you will find all the measurements; remember that the hammer drop after the let-off must be equal to the escapement: if the escapement is fixed at 2 mm from the string, the drop will be at 4 mm from the string (also called second escapement).

http://www.kawaius-tsd.com/PDF/Regulation%20GP-English%201.6.pdf

http://www.kawaius-tsd.com/PDF/Regulation%20GP-English%201.6.pdf

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Reply 20 by pianoexpert

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Given the same escapement depth.... either the hammers "escape" at different and non-uniform distances from the strings and/or the hammer-to-string distance is not uniform. Anyway, I also agree on a complete precision regulation, preceded by a pre-regulation check of the part of the repetitions (cavalletti).

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