Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Why and why not adding lead weight to key

Maybe you are right. But, for what I know, lead in keys is used to regulate the weight of the keys to at the desired value, say 52 gr., and then the repetition spring is used to adjust the resetting of the escapement lever.

If you use the lead in the keys to adjust repetition speed, aren't you disturbing the weight of the keys?

Kind of, but not exactly. Lead in the keys has always been used to balance out the weight of the hammers in the system: the heavier the hammers, the more lead in the keys--assuming everything else stays the same.

Yes: absolutely. There are other variables that you would need to change. If you simply add more weight to the back of the keys (i.e., increasing the down weight), the keys will start to feel impossibly heavy. The objective it to get the keys to return faster, without the whole system going beyond its limits.

Are you suggesting that S&S is the only company with a significant action problem? Or are you saying that S&S is the only action that shouldn't, for some random reason, be corrected? Either way, no one has so far been talking about using non-S&S parts. Would you like to start that discussion? Or should we maybe leave that for another thread?

Here you go BDB!

Once again you say partials are not present in the one-tone we hear when a piano string vibrates.

Yes, one single string vibrates with several different frequencies at the same time. They are known as harmonics and in piano strings with iH they are called Partials.

Beats are the proof of the existence of partials.

Tuning forks are made to have a strong fundamental and almost no harmonics or partials at all. So you can make the following experiment to check the existence of partials in a piano note and the absence of those same partials in the tone produced by the tuning fork:

Play the major third F4-A4, you'll hear beats. Those beats come from the 5th partial of F4 and the 4th partial of A4. The rate of these beats is the difference of the frequencies of these two partials. Now play the F4 in the piano and sound an A 440 fork, you will hear no beats. Why? Because the tuning fork produces no 4th partial.

Now play the M10th F3-A4 at the piano, you hear beats again. The 5th partial of F3 is beating with the 2nd partial of F4. But if you play F3 and sound the A 440 fork you'll hear no beats, because the 2nd partial of the fork is way too weak to be heared.

Now play the M17th F2-A4, you hear beats, the 5th partial of F2 is beating with the fundamental, first partial, of A4. Now play F2 and sound the A 440 tuning fork. This time you do hear beats, the 5th partial of F2 is beating with the 1st partial or fundamental of the tuning fork.

This proves the presence of partials 2 and 4 in the piano note A4 and also the presence of the 5th partial in the piano notes F2, F3 and F4.

Ghosting tones will also prove the exitence and presence of several partials in all piano notes.

But I know that this will not convince you. So I will show you the following high speed video of a vibrating piano string.

In this video we can see how the string vibrates simultaneously in all its length, at half the length, and at 1/3rd of its length, etc... all at the same time, and we can appreciate the different frequencies of each vibration.

So you will see, with your eyes, all the partials and their corresponding different frequencies in action. I hope with this you won't deny their existence anymore.

Enjoy it.

"the video is private"

Greetings,
This should be another thread but I would challenge you to make a Steinway with original parts as responsive and sensitive as I, and my clientele, are finding is possible with WNG parts. I cannot find any comparison between the two. If you want to play golf, or ski, or play tennis, or snowboard with wooden equipment, understand that your performance will not compare with those that are using carbon fiber. There are no pros in any of these fields that use the original wooden stuff. If you want to build an action out of unstable material for the sake of tradition, understand that when it comes to immediate or long-time performance, you will be left behind. Regulation is no better than the pinning, and the consistency of factory pinning I have seen is nonexistent.

Maybe if they could get control of their pinning, and machining, and consistency, they could compete with the modern materials, but as it is, I think they are trading on their reputation. It is hard to make the case for quality with 88 hammershanks containing various knuckle placements. It is also hard to make the case for pinning that is either floppy or tight, wood that twists and warps, and flanges that constantly move around in response to humidity.
Regards,

Sorry, I thought private videos were accessible to people with the link.

I've made it public.

Action saturation is simply that point at which the key bottoms out against the front rail punching before the hammer starts to move.

In the real world there is always a delay between the time the key is struck and the time the hammer begins to move. This is due to a number of factors including, but not limited to:
— The compliance of all of the various bits of felt and leather.
— The flexibility of all of the different components of the action (the key being the most significant culprit).
— The mass of the hammer.

With a soft blow—pianissimo—the movement of a light hammer and a heavy hammer relative to the motion of the front of the key is approximately the same. Here there is a fairly direct relationship between the velocity of the front of the key and the velocity of the hammer. In other words, if the overall action ratio is, say, 5.5 : 1 the velocity of the hammer will be ≈ 5.5 times that of the key.

This changes as the speed, or acceleration, at the front of the key increases. At faster key velocities the velocity of the velocity of the hammer will no longer be in a direct relationship to that of the front of the key; it will be somewhat less. Nor will its initial motion be tied directly to that of the key: the hammer will start moving somewhat after the front of the key begins it movement. There is a time lag between the motion of the key and the motion of the hammer. How much of a time lag will be a function of the bending and the compression of the various action parts.

As well, the velocity of the hammer will no longer be a direct multiple of the velocity of the front of the key. It will be somewhat less. How much less will be primarily dependent on the mass of the hammer. As others have pointed out, F = MA. Or, A = F/M. With the added complexity that the force applied to set the hammer in motion is not directly proportional to the force applied to the front of the key.

But—almost none of this has much bearing on the original question about the practice of back-loading the keys of vertical piano actions.

This practice got started because pianists complained that the “touch weight” of vertical actions was so much “lighter” than that of grand pianos. They wanted the vertical action to “feel” more like that of the grand action. The simple solution was to place leads at the back of the keys making the static down weight roughly similar to that of grands. It did little, if anything, to improve—or alter in any way—either the repetition speed or the reliability of the vertical action but this was never the intent of the modification. (Unless, of course, there was something amiss with the geometry or function—friction, etc.—of the action.)

Repetition in a vertical action is a function of many different factors several of which have not been discussed here. Some of these are:
— The angle of the action in relationship with the string plane.
— The strength of the hammer butt spring.
— The strength of the damper lever spring.
— The relationship of the hammer’s center of gravity in relation to the action center of the hammer butt.
— The relationship of the rotating mass of the wippen in relation to that of the key.

We use the terms “light hammers” and “heavy hammers” rather loosely in these discussions; five pound and 100 pound lead balls are freely tossed around. In real terms—in real piano hammers—there is not all that much difference between the two extremes. In modern piano construction practice a “light” A-1 upright hammer might have a mass of somewhere around 8 or 9 grams. A heavy A-1 upright hammer might run up to 11 or 12 grams (though this would, I think, be unusual). At C-88 the range will be somewhere between 3.5 and 5 grams. (There may be some that come in under or above these numbers but I’ve not been able to actually weigh them.)

These differences may not seem to be all that great but they do have a significant impact (no pun intended) on piano tone. Generally—very generally—on a given piano lighter hammers can be somewhat less dense to give satisfactory performance while heavier hammers will need to be somewhat denser. (Note: density and mass are not the same thing. Both might be the same size but one will have more or less mass than the other.) The lighter hammer will rebound away from the string slightly—very slightly—faster. The differences will be subtle but, of course, when creating piano tone subtleties can make a considerable difference.

Again getting back to the original question—it is generally a good practice to have the back of the keys weighted enough such that the back end of each key will rest lightly against the back rail felt without depending on the weight of the wippen to push them down. This is normally done by adding one or more lead weights to the back of the keys. It could also be done by making the front of the key lighter—per Ed’s suggestion—but I’ve never seen this in production. It is also good practice to have the hammer’s center of gravity forward (i.e., toward the front of the keys) of the hammer butt action centers. If anything is to be weighted it should be—but never is—the wippen lever itself.

Since the vertical action is dependent on both a spring return (the hammer butt spring) and gravity (the hammer butt, the wippen and, to a lesser extent, the hammer if the action installation geometry is done well) its repetition speed and reliability will be dependent on how well the individual piano maker blends all of these different elements of the action together in the final product.

ddf

;;; edited

Ed, if I may,

You make use of the argument that all objects are accelerated equally by gravity. While this is true for objects in friction-less free fall, it does not apply to more or less balanced levers. Free fall would be applicable to a keystick only if the keystick consisted of just the distal part (and nothing in front of the balance rail pin). Then, indeed, gravity wouldn't care how light or heavy that keystick is. And yes, your subsequent argumentation would then also hold true: that the repetition spring would accelerate a lighter keystick more strongly, because it has less mass/inertia than a heavier one. Such a rear-half keystick would therefore return faster if one decreased its mass. One might word this as you did: "gravity is fast, but not as fast as a spring."

But your argumentation seems to overlook that the keystick has a proximal part. This means that the acceleration of the distal lever arm, under gravity, is not determined by free fall, but by the distribution of mass between the proximal and distal lever arms. In fact, if the proximal and distal lever arms are balanced, the distal part won't fall under gravity at all! Once you start adding mass to the distal part, it will fall, and the more mass you add, the faster it will accelerate. The higher the ratio between distal mass and proximal mass becomes, the closer the acceleration of the distal arm will approach g (9.8 m/s²), i.e. "free fall".

Looking at the effect of the rep. spring vs. total keystick mass: if you compare a perfectly balanced heavy keystick (both ends have identical, high mass) to a perfectly balanced light keystick (both ends have identical but low mass), then I do agree that the repetition spring will accelerate the lighter keystick more, because it has less inertia.

But in a real piano, the keystick is out of balance, hence the acceleration of the distal end is related to two factors:
1) the ratio between distal and proximal mass
2) the ratio between the rep. spring force and the inertia of the keystick.

Adding mass to the distal end of the keystick increases ratio (1), aiding repetition, but decreases ratio (2), hindering repetition. Which of the two opposing effects will win out, I cannot say. Your experience seems to point to effect (2), while that of A443 (if I read him correctly) seems to point to effect (1).

I gladly stand corrected, but to my best understanding, this is a more realistic picture of the physics surrounding the keystick.

Dont say anything positive about Steinway it is not in the trend Bob ! (We really can see you are retired there )

Yes it is, certainly, only when a number of "details' are put together.

If not, the hammer are too heavy for the action ratio used, yes..

Managing that touch and feel is my first goal.
The action is supposed to be transparent.

Mass is efficient to a certain level to provide tactile return top the pianist, depending of ratio and global compliance. One paramreter cannot be thrown out simply because it is wrong on the paper.

I have a colleague that cut all hammer shanks to match sticks size (rudely, with a cutter at the base of the shank) then voice the hammers to the max, and pretend he gave the "French tone" (I did not say French touch !) to any piano ! )

more lower frequencies, less power, once the voicing is gone nothing can have it back as all resources have been used yet.

Even with strong assist Springs and almost no lead, the way the action is regulated makes a whole difference. The action compliance is more perceived but the effect of the assist spring is too (plus cause repettion noise and dys synchronization) And of course voicing.

We have not so much points where we can influence the touch and feel unfortunatedly, so a piano that is too "massive" for a given pianist body must be setup specifically with lighter hammers etc, while in the meantime giving more acceleration and less "compression" may help.

Modern pianos where intended for unusually too large concert halls int is no surprise they raised the power to the max.

EUropean concert halls are more human sized, and the European pianos may have avoided a part of that race for power.

Coool ! THe video is nice but not really "laboratory style"

I wonder if this is not a very short wound string installed without enough tension.

Please the one"s" that show a 2 strings, a 3 strings motions at the bridge or agrafe level ....

I only have seen the ones from the Wapin web site.

Ed, you are visibly talking here of the NY production.

Pinning is precise and long lasting on the Hamburg ones, as is knuckle placement. (the hammer center pin is specific to Steinway, with a central recess that probably avoid the pin to move in the wood) friction is in the 3 grams range.

I agree that synthetic parts can have more size accuracy , The ones are played still are damping a little the sensations, as if a condenser was installed.

Eveness of weight, precision, etc balance that certainly, but the pinning is also problematic, be it with cloth bushing or no.

I agree with you that the way the pinning friction behave with the acceleration of parts is what provide the power transmission (and something in the touch of course)

The pinning friction is I am sure also "perceived" by the pianist, as something helping to get the control on the hammer.

Feeling the compliance of the parts is very important to the pianist, I believe, as a security first, as an expression tool second.

Minute modifications of the finger acceleration allow the pianist to have a good control on the hammer.

If too rigid the knuckle will leave the jack immediately in some type of touch, to be joined again only at letoff moment if the pianist is good enough. THat happen in the front punching generally. SO all cloths (WHippen heel) and assemblies (knuckle) must have their elasticity and resilency under control.

Older pianos had even thicker and smoother levers, providing a larger security zone to the pianist.

Now just a too soft whippen heel cloth is absorbing so much energy immediately that it impede the control on touch.

That left us with primarily the hammer shank the key and the stacks as the main "springs" in the action. ((sorry I forget the hammer felt)

That colleague that made the shanks too supple, gave the pianist a high sensation of control on the hammer, because that springiness is perceived and one can play with it (changing hammer orientation at strike, probably)
That gave him a high reputation, while primarily he destroy the action !

High velocity technique is mostly playing with inertia .

Seem to me that most pianists appreciate that the front of key is not too light for that reason.

Using BW (balance weight) rather than just DW (downweight) or UW (upweight) numbers will result in a much more accurate evaluation/analysis/troubleshooting/redesigning of the piano action.

Why? Because in quality pianos with quality parts, the BW numbers will be quite consistent from part to part, and friction (F) can also be measured as an average between DW and UW. The equation for friction is DW - UW /2.

Balance weights (DW + UW / 2) are more accurate to use than downweights or upweights alone, because if two adjacent keys have different friction levels somewhere in the system (which they very often do in real world pianos), the DW and UW numbers could be radically different from one note to the next. Additionally, friction levels can be expected to vary - sometimes quite wildly - in the future. So, let's say one note is at 53g DW. The adjacent note is at 48g DW. Their upweights will also be different, but the balance weight will likely be the same. This BW is crucial information to know, because if you then measure for friction - and come up with different friction readings on both keys - you will have a much greater understanding of why any discrepancy exists, and what to do to make the DW and UW on those adjacent keys more uniform. (Solve the friction issue in this case.)

If you didn't know these BW and F readings (and what they mean) you could easily make the wrong decisions, like adding lead to a key instead of reducing friction somewhere in the system. And these "wrong" decisions are often made at the piano factory or the rebuilder's shop, if measurements are not taken and analyzed to account for friction when installing lead in keys, or if new hammers are not measured and their weights adjusted prior to installation.

<good points ! but modern quality hammers have not much weight unevenesses, and also the weighting of hammers does not take in account the shaping so some pinch of salt can be added.


BW is anyway a good number to show discrepancies.

It does show also a knuckle that is not lining with neighbors, this can be a cause of ratio change. by raising UW for instance. Not anything goes with the hammer mass and friction.
Rake angle variations, as often necessary, may change the apparent action ratio somehow, too.

When weighting often , the technician is used to look at the motion of the hammer and detect is something is wrong just then, along with a "minimal upweight" used always at the same location.

DW is never used alone, while most small "mistakes" are pushed under the carpet of UW, I agree.

This is obviously faster than measuring all weights and that is why factory may focus on the weight of parts without measuring them on a one by one basis.

A progressive placement of leads in the keys also is a good thing, I would take example there on Yamaha or Steinway, Yamaha with a simple progressive placement (so the keys have their own inertia balancing done)
Following simple rules to choose and place the leads is neat (without giving them more attention than neeeded)

Eventually I do that, then see if I have any hops and look for the cause.
Factory bypass small geometric or hammer weight mismatches , for sure. Evening impact mass is a luxury, but I do not find that an absolute necessity to provide an even touch.

Overpassing friction defects is a huge mistake indeed, an that I avoid at any price.

I focus on vertical masses lining, consistency in shanks stiffness (progression +-) and consistency in lead placement.
If that last is not possible the cause have to be find.

BW is a good tool for that. (while I agree it can have no significance if used alone)


Regards

Greetings,
Above is snipped:

The problem of pinning is not unique to any brand, I have had to stop using Renner parts because of the common tightening of the pinning as the parts are in service. It only takes one or two stiffening jack pinnings to require a concert piano to be disassembled and repinned.

The center pins I have seen that have a groove cut in the middle are all on Renner parts.

Inre compliance: The hard bushings remove a lot of compliance, while maintaining solid control with very little friction in the hammer flanges. If you were to pin a cloth bushing firmly enough to match the control of the hard bushings, it would be so tight you couldn't play it. I have had 4 of these actions in school practice rooms, played 8-12 hours a day by students at FFF levels. There is not a single shank that needs to be repinned. This does happen with cloth bushings. I do go through the set with the WNG swing jig before I install, and I do end up repining 5 or 8 each time because of irregularity. Once properly pinned, they do not change with use.

I maintain that compliance is required in an action for the pianist's comfort, but there are good places for it,(key-flex and hammershank), and bad places, (hammershank pinning). The idea of wooden shanks providing resources to the pianist via their flex is misinformed. If all the wooden shanks flexed the same, it would be acceptable, but that doesn't happen. And even if did, when the humidity changes, the wood will change, and it is not even plausible that all 88 would change the same. Composite shanks avoid all of that. I have also yet to find a pianist that can tell anything about the WNG actions I have put into service other that it is more even than they are accustomed to. Questions of tonal changes are moot until the same set of hammers is taken off the WNG action and reinstalled on the same action with wooden ones. Otherwise, differences in sets of hammers are far greater than the differences of tone that can be ascribed to the material in the shank.

I would offer that what pianists need in the action is not compliance, which is uncontrollable with wood, but, rather, damping, which can be controlled by pinning. And that damping is more important in the repetition pinning than anywhere else. This is because it allows stronger pressure on the jack and more consistent spring tension across the action. With strong springs and 7 gram pinning on the repetition, the repetition speed goes up, consistency is easier to maintain, and jacks will reliably reset with slightly more contact pressure on the knuckle.

I will say it once again, a regulation will be no better than the pinning, and I haven't found anything that is as consistent as the WNG parts.
Regards,

For new China pianos, some keys not sit on the felt. Some models' black key have lead in in front of balance pin hole. There also a German upright with short key stick without any lead. I am not sure if these are design purpose, or just randomly assembled parts.

Having followed this thread and another in teachres' forum, key weight is related to action geometry and play style. Not simple decision and not easy to explain to customer. Better left this part untouched.

Let me suggest modestly it is because you "don't know " how to deal with stiffened Renner centers.
They do not need to be dismounted, the cloth have been burnished and compressed, they will need a little more compression eventually.
I accept that the friction change with moisture however.

The wooden shanks are selected prior installation (something I have seen dismissed by some techs here) t-hen once the hammer is glued they are also adjusted by scraping.
This I suppose take care of the amount of resiliency of the shanks, and indeed once the "tone" of the assembly is evened there is a sudden more homogenous impact tone.

I know regulation is easy with the WNG parts, Now as generally with aluminium rails stacks there is some material signature in the tone.
I have no idea of the linearity of the answer of composite shanks vs wooden ones, but I think that is where the difference is.

Certainly if the action is stable that is a good solution for studio and students pianos. Good for you if you have such good results.

Regards

Ah Ed, Like you I have found studying pianos by examining the "dampening" characteristics very productive to producing service protocols that predictably produce a great musical instrument. A fine piano is a study in damping.

I have never found shank flex to be a helpful behavior regarding tone, touch and durability.

Even regarding key weights you can look at their effect on damping the rate with which an action can stop, start and change directions of movement.

The angular momentum issues are "pivotal", (pun intended), to how a pianist perceives the action response.

My work has shown there is no doubt that static touch weight measurements do not indicate how an action will play or sound. These measurements are only good for assessing some level of evenness across the compass, but even that characteristic is limited in resolution.

As you lower the sum total inertia in an action by removing mass-it is at the hammer that this is very, very critical.

Now on the question of static touch weight levels. I have found that as you reduce the hammer mass you can increase the static touch weight. In my rebuilding work I often have pianists audition some of my pianos to give me feedback on which range of touch resistance they prefer.

Then when I tone regulate the action I set the static touch weight at the high end of what I think they like. Then I am prepared to reduce the touch weight further if they so require after playing the piano for a few days or weeks. I inform them that all pianos get lighter and brighter with use and that it is easier to make an action lighter than heavier once it has been assembled.

The result is such that many of my actions have DW of 70 grams at note 1 and taper to 55 grams at note 88, and most of the keys from 68-88 have one back weight. Keys from 50-68 have no front weights, and keys from 1 to 30 never have more than two front weights.

I have done some actions with no front weights for some pianists. static touch weights there are 75 grams at note 1 with these actions.

I have also had technicians play these actions and ask them to slowly move some of the lowest and middle range keys and just make a guess at the static touch weight. They invariable underestimate the weight by 10 to 15 grams! These have been technicians who do much tone regulation and are experienced at touch weight measurement.

My LightHammer Tone Regulation procedure is a way to develop tone and touch together. There have been many detailed and careful analysis's done of touch characteristics but they invariably leave out tone. TONE, just another" four letter word"!