Keyboard leveling

I would say that in this case the ends of the keyboard can be used as a reference.

You need to have a line as long as the entire keyboard to proceed with leveling by adding the necessary thickness paper: the rule to follow (or at least what I follow by personal choice, but no one forbids doing otherwise) is to put under the cashmere or felt rosettes (respectively for the center and the back) the fewest number of papers possible; that is, when it is necessary to raise the key by 2 tenths of a mm, I prefer to put one 2-tenths of a mm paper instead of 4 papers of 0.5 tenths, to avoid the quicksand or accordion effect that occurs between the papers because there is always air, except for the many years of use and the famous discussions about settling/maturation...

if two or three papers are used, the thinnest one should be placed on top of all others.

Upstream of the papers, however, rosettes of the correct thickness and proper density should be chosen to avoid the aforementioned effect due to the compression and decompression of the felt and to avoid creating deleterious towers of paper.

Sometimes in old pianos, the soundboard may have warped and consequently the keyboard frame, which follows it in a solid manner. In this case, the level of the keys must be restored not with individual papers but by lifting the frame in the center with cardboard spacers at the fixing screws of the frame to the soundboard (I call it 'tavolaccio' [soundboard], but it can also be called keyboard holder and sometimes it can be made with a sub-frame of aluminum profiles, depending on the quality of the piano, but the concept does not change).

Rules exist mainly to determine the inclination of the key in relation to the placement of the action, therefore the thickness of the felt behind the key, but these are long discussions that go beyond DIY and I hope they can be ignored in this case (provided that no one has worked on it in the past).

The leveling can be perfectly horizontal or slightly convex towards the center (up to 2 mm of difference between the center and the ends). Since this is a used piano, with rosettes already settled and compressed, I would say to proceed with horizontal leveling, without taking into account the phenomena of greater compression or flexion in the center due to use, which for obvious reasons have already occurred.

Good luck with your work.

There is a balance between the center level, rear level and front depth of the key. All this results in the correct functioning of the action. I do the calculation with three keys: one left, one central, and one right. This way I can see the average of the system well. Especially old pianos are not completely straight and equal everywhere. I place a felt pad (red) of 1 mm under the key at the center bar. The strip of felt (green) under the key at the rear side must have such a thickness that the height of the key at the front part must measure 2 cm. The depth of the key when playing it must be 1 cm. Then put the action back and try playing the three keys. When the hammer makes its complete movement, touch the strings and then go back; if all measurements are correct.

Then you can treat the rest of the keyboard in the same way. It might be necessary to put a piece of paper under the felt of some keys. All keys must have the same level. Also the depth of the keys when played must be equal everywhere.

As I said, everything is a balance. It is not an easy thing at all. But try it this way to see how it turns out.

And excuse my Italian, I hope I have written in a way that you can understand.

I agree with all the clarifications. I would like to add that, to simulate the weight of the action, there are special lead weights to be attached to the hammer rails (if it is a grand piano) or, as in this case, resting on the back of the key. One can level the keyboard of an upright even without such weights, by removing key by key and adjusting the bushings. It is a long job. I would recommend letting the keyboard rest once the work is finished, to then perfect any keys that have undergone settling.

Thank you all for your precious advice. I will get to work immediately.

Good morning everyone. A curiosity that occurred to me while reading your posts and the advice from M Ferrarelli: in the case of a grand piano, not having the special weights to attach to the hammer rails, how could I approach leveling? Would any other system be possible?

Thank you

Kind regards to all

The best and most effective procedure is, with patience, to check the leveling with a straightedge and place a shim on top of the key where it appears to be missing, and so on for each key.

Afterward, unscrew the action, remove it, and insert the shims under the keys. Reassemble the action and repeat the operation with thinner shims where needed.

It takes a bit more time; consider that plumb bobs for fine leveling do not work well. They act by applying weight in the wrong position (normally weighing on the pilot) and therefore compress the key spring differently (which is not of extremely high density and hardness in all pianos).

For minor touch-ups of a few keys, 0.5mm shims can even be inserted with long tweezers under the key without removing the action, but the shim must be cut.

Bye

Thanks Giovanning, I confirm your impressions. I am following your advice with a great deal of patience (and effort), but the work turning out is more than satisfactory. Then, obviously, there will be all the other adjustments to make.....

A warm greeting to everyone

m

Good evening everyone. I wanted to reopen the discussion by proposing a matter that, in my opinion, is quite thorny. Regarding the keyboard leveling of an upright piano, I have no problems whatsoever since it is possible to modify the level with the weight of the action that rests directly on the key, by removing the key as needed. For the grand piano, the issue becomes more complicated. I am trying to level the keyboard of my Yamaha C3 at 64mm, but I am encountering the problem that I will now explain. I proceeded in the following way: first, I measured the distance from the keybed of some sample keys... some were 64, some were slightly out of alignment. The interesting thing is that when I removed the key action, placed it on the workbench, and measured the distance from the wippen to the surface of the bench, almost all the measurements were off by about 1mm (further away). I assume this is due to the irregularities of that specific keybed, which are difficult to reproduce on another support. At this point, I disassembled the action and removed most of the keys, leaving only 3 or 4 reference keys for the various sections. I then applied specific weights to the hammer regulating levers to simulate the weight of the action, but even this time the resulting distance was imprecise: I applied 90g weights to the bass keys and found that the distance became even greater compared to what was measured with the action assembled on the workbench. To get the same measurement (anyway 1mm more than the key-to-keybed distance), I had to go down to 40g per key (in the bass). In essence, I have no reference points to perform a precision adjustment because the distance I detect on the workbench does not exactly correspond to what I measure once the action is placed in the piano. Besides this, the use of weights was unsuccessful since I am detecting a third measurement, which doesn't even correspond to what I find with the action assembled on the workbench.

How do you proceed in these cases to perform an adjustment that is not coarse, but precise? Should I perform the measurement on the workbench considering the 1mm discrepancy? Is it better to level the grand piano directly on the instrument? But if so, how? Help

...Is anyone there?