Weighing off a piano keyboard action

[@AmadeusPiano]

this is so crucial and important - so many hacks taking weights out of keys to "lighten" the keys and there goes the feel forever. Thank you so much for posting this

[@bobsquires4521]

WOW, this is so fine. With this knowledge, one could build the pyramids! Thanks for posting. I was just looking for info (I found) on replacing ivory/plastic key tops and saw this 'Weighing' video related. I'm glad I watched - with your enthusiasm and clarity, I now want to get into 'weighing' my good ole Kawai upright! This makes it interesting and clear. Many thanks!

[@notafanboy250]

Such a cool technical video!

[@ruckus48]

Be cautious about adding too much weight to the keys. It not only changes key weight, it also increases the mass of the key. This affects inertia and slows repetition. There are other techniques for changing touch weight without increasing key mass.

[@jesuslombardia8517]

Congratulations! Very interesting. I would like to know, if possible, how do you calculate the grams of friction of each key of the action?

[@robertgrijalva7158]

The mathematical formula for calculating friction is Down Weight minus Upweight divided by two. (D - U/2 = F). For Balance Weight the formula is Down Weight plus Upweight divided by two (D + U/2 = BW).

[@jorgeandrade20]

I'm mesmerized

[@jamessenior2314]

Hi Robert. Could you say something about how you decide on lead size? For example, why might you use a small weight further from the balance rail instead of a larger one closer closer to the balance rail? Is it possible that achieving the same down weight using small/far or large/close results in different up weights? If so, is that the result of overall weight bearing on the balance felt, or inertia or something? Thanks, James

[@sascho755]

Very nice and precise work. I work in the same field and was wondering isn't 46 grams a bit light?

[@robertgrijalva7158]

Alexander Dimitrov Remember that the object is to make each key conform to the Balance Weight assigned to the section,. Because this key has a friction of only 9 grams, its Downweight would be pretty low, but notice that the Upweight is a really high number, which means that the “under key response” is really quick. Other notes with different frictions would have different Up- and Downweights, but the object is to achieve the same Balance Weight. So, a note with 10 grams of friction in the same section will have a Downweight of 47, and an Upweight of 27, but the exact same Balance weight of 37 as the note with 9 grams friction.

[@usernameihavechosen289]

Now that has been thorough. What is your stance on digital piano keybeds being twice this downweight? Any suggestions to make a Fatar action lighter - leaden weights under keys perhaps? Thanks.

[@robertgrijalva7158]

I am not a digital piano specialist in any sense of the words. I couldn't answer your question in even a general way because I don't know the anatomy of digital piano keyboards.

[@usernameihavechosen289]

@@robertgrijalva7158 Thanks nevertheless.

[@townnet]

I'm curious if insert leads make the key more weight , will it slowdown the fast repetition playing?

[@robertgrijalva7158]

This would be seem logical, wouldn't it? In truth, there is a concern to be voiced about inertia. If one employs too much lead in the keys, there is an unacceptable amount of inertia, and repetition does suffer, and the pianist gets fatigued. This is why this method, which relies on the collection of lots of data, works so well. With information about the Friction in each key, as well as other data that is gathered in analyzing the action's efficiency, most especially calculations of the overall Action Ratio, you can get an accurate and predictable weigh-off profile for the whole keyboard that doesn't load ridiculous amounts of lead into each key. The Balance Weight/Key Friction grid makes that possible, without too much inertia, and enables you to get blazing fast repetition. You just have to look at the numbers.

[@townnet]

@@robertgrijalva7158 Thank you for the explanation. One more question. Why you make 3 section different of weight but not make all 88 key same weight?

[@robertgrijalva7158]

The reason for dividing up the keyboard into three sections of different Balance Weight is not actually a necessity. However, there is a psychological reason for doing it. When a pianist sits at a piano, there is an unconscious expectation that the bass note keys should be a bit heavier or more resistant than the treble notes. This is a natural reaction to the fact that the hammers reduce in size as we go from the bass to the treble. Bass hammers are bigger, therefore they should feel more resistance, so the logic goes. It is mechanically possible to make all 88 keys the same Balance Weight, as you suggest. However, I did experiment with this once on a Steinway nine-foot piano action that had adjustable repetition flange assist springs. I adjusted the Balance Weight to make it the same across the entire keyboard. The pianists who tried it were unhappy with it. The overall complaint was that the bass was too easy to play, and they couldn't control it. They had the psychological desire for a heavier bass touch resistance.

[@townnet]

@@robertgrijalva7158 Once again, thank you very much. :)

[@townnet]

@@robertgrijalva7158 Hi Robert, normally what is the standard down weight without press the pedal? I google a lot but can't find anybody talk about this topic.

[@Kref3]

Really fascinating. I own a Bluthner X (230 cm) and its action needs to be adjusted, so I am looking for information what will be done by the technician. I just like to get a general idea, what they have to do. Your method seems to be really interesting and precise. The up-weight is 28 g, the down-weight is 46, the exact center is the balance weight of 37 g. The distance from up to ballance or from down to ballance is 9 g and that is the friction. Here is what I do not fully understand. As far as I (a rather untalented hobby player) know from personal experience, the down-weight must be perfectly even (either exactly the same weight everywhere or - as Steinway does it with a very small decrease from base to trebble). But the up-weight is actually a result of the desired down-weight, let's stick with the 46 g you set up here, and the friction. At a quick glance I saw numbers of 8 to 12 g friction written on your hammers. So looking at the 12 g friction key: with your down-weight of 46 g you would have an up-weight of 22 g, resulting at a ballance weight of 34 g At the 8 g friction key you will have a down-weight of 46 g, an upweight of 30 g and a ballance weight of 38 g. In the end I do not understand, why the ballance weight is so relevant, if it still is different from key to key based on different friction. If of course your method would be to even out friction first (equal friction = equal ballance), I would understand the ballance purpose. My piano technician btw told me, he will replace at my action what needs to be replaced. Then he will adjust it as well as he can. And then he will adjust the down-weight to my liking with leading with the general restriction, that no up-weight must be below 20 or 22 g.

[@MetaView7]

Black Art

[@anthonyoresteen4767]

An obvious question: Does this work for upright pianos? Not everyone has a grand piano.

[@thomaslau9631]

How come the company that manufacture the action or the piano did not do this crucial steps? Some piano ended up with heavy actions.

[@robertgrijalva7158]

You've asked a very good question. I think the answer has to do with the difference between a factory environment and a custom workshop environment. Manufacturers always look for ways to get their pianos out the door with as much ease as possible. This sometimes means that they may settle for a method that the majority of people can accept, even if it isn't really "custom". So, even in the case of high-end pianos like Bösendorfer and Steinway, they base their weigh-off on the simple proposition of getting each key to go down with 50 grams and that's it. They don't really pay attention to balance weight, let alone friction. As the supervisor of the Bösendorfer factory told me in person, they worry about what happens when their pianos reach Japan, and the Japanese piano dealer takes his 50 gram weight and checks the keys. With a balance weigh-off, the down weight is different from key to key in response to the friction parameters. Bösendorfer's view is that they would have to somehow explain this to the Japanese dealer, who will insist that every key go down with 50 grams, and demand some sort of warranty fix. To Bösendorfer, as well as Steinway, it's easier to settle for the 50 gram test, and avoid the headache of explanations. It's a pretty disappointing point of view, in my opinion, because one expects that such an expensive hand-built instrument should be truly a custom machine. For whatever this may be worth, the Bösendorfer factory supervisor did allow me to do an entire weigh-off on a seven-foot piano according to the balance weight method. He played the piano afterward and pronounced it superior in touch to a piano weighed off in the "traditional" way. He even said they should try it on a nine-foot. But that never came to pass.

[@thomaslau9631]

@@robertgrijalva7158 。Thank you for your detail explanation. Both of my Bosendorfer 170 & 130 respectively were bought before Yamaha took over. The 170 has good standard 50g action set-up but the 130 has been on the higher side that I have tried to lower the actions to some extent. With your demo, I shall approach my piano technician again to see whether adding weight balance is an issue to be considered, assumed fricton is not the cause of the heavy feel at the keys. Many thsnks.

[@channelthechannel]

Seems like you're making it light as hell.

[@robertgrijalva7158]

Actually, it isn't overly light; just about a gram lighter than what I do for concert pianos.

[@avantpianist6636]

Is your way of weighing similar to Stanwood Precision Touch?

[@robertgrijalva7158]

Yes. It is Dave Stanwood’s preferred method of weigh-off after employing his Front Weight method. But it can be used whether or not you employ his Front Weight method. In order to implement the entire Stanwood System, you need repetitions (wippens) with adjustable helper springs. Only Tokiwa makes adjustable helper springs as a feature of a factory-produced part. You can order the Tokiwa parts from Pianotek Supply in Clawson, Michigan.

[@staalewikdahl]

what do you use to measure the friction of the hammer ??

[@juanmoa719]

How did you get the friction number? Is this the friction of the hammer shank flange or are there other parts involved?

[@robertgrijalva7158]

There is a simple algebraic equation that is useful. To calculate Friction Weight: D-U/2; Downweight of the key minus upweight of the key, divided by 2 equals the total friction of the key, including the hammershank, repetition, and keystick. An example: Downweight 50, Upweight 20. 50-20/2 = Friction Weight of 15 grams. The Friction Weight is then used as one factor in setting up the weigh-off grid one eventually wants to have for each individual key. The grid is a snapshot of the larger chart that shows the downweight and upweight figures for a given key. Friction Weight is correlated with Balance Weight to determine what the Down- and Upweight of a key should be.

[@robertgrijalva7158]

This method is NOT about achieving even Down Weight. The point of this method is to achieve even Balance Weight! Also, I think you are basing your comment about the number of leads from your observation of those leads sitting atop the keys only. These are leads that I added to existing leads in the keys, so you don't get a picture of the even distribution of the leads at the conclusion of the effort. Additionally, lead plugs have different sizes and weights, so the total amount of lead is actually pretty consistent from key to key. The resulting inertia is pretty consistent from key to key. The bottom line is that if you achieve an even Balance Weight, the other physical considerations fall into line: a discernable key leading pattern and inertia naturally follow. Lastly, I should point out that this is a RE-leading job. I had to make certain compromises, such as the different sized leads, in order to not have to remove and plug an excessive number of original leads. This keyboard started out with 5 and 6 leads in the bass, four in the middle, three in capo #1, and and two leads in capo #2 all the way up to note 88! In the end, I balanced it such that the result was three leads in the bass, two leads in the middle of the piano, one lead throughout most of the capo section of the keyboard, and I only had to back-lead two keys! I did not have the option to replace the original keyframe and keys with a new keyframe and keys. Were that the case, I could have stuck with one size of lead and achieved a cleaner leading pattern from the start. I hope this helps you to better understand what I undertook to do with this particular set of keys.

[@zvelekva]

I thought the point in weighing the keys is to achieve even down weight, i.e. even touch within set parameter (50 grams +/- 2)? With your method you will achieve completely (and possibly wildly) different down weight between most keys, making the resistance to touch from key to key feel different (which is the exact opposite of the point of the exercise).

[@Goodi8]

Interesting

[@rogershaffer1]

Hocus pocus All your DW measurements are based on wacking the stack with your hand Tolerances no more refined than + or- 5 grams

[@ChernobieffPiano]

But it's NOT balanced. You can tell just by looking at the leads. For example one key has one lead and a neighbor has two leads. That means the inertia is all over the place too. So you might get the downweight even, but its at the expense of every other parameter.

[@dylanmcqueen4656]

And then how would it be balanced? I wonder the same thing, although in reality what is sought is the uniformity of the action, mathematically inertia would not be affected if the order of the factors does not alter the product? What method could you recommend so that it is balanced without altering the inertia? I would appreciate.