Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Correcting Heavy Piano Touchweight in Grand Pianos

https://www.youtube.com/watch?v=cT27R0QRxjE

Looks like this would be a lot of work for all 88
keys.

But since you are moving the knuckle, you
have to push the knuckle farther to get the same
movement of the hammer (less force, longer distance).

So then do you have to adjust the keydip distance
too? or is that not necessary?

Has anyone done this to a Yamaha, to make the action lighter?

What he is doing is lowing the action geometry--making heavier hammers feel lighter, which travel slower over less of a distance. Of course, that will change the down weights, but the important question is: how did everything regulate out before, and what will now be necessary with that change? Furthermore, you can't simply make a knuckle change without adjusting, for example, the whippen/jack location--if you want everything to be in alignment and functioning as intended.

He could have, IMHO, better solved the problem by simply readjusting the two action rails so that everything lined-up properly with those particular parts. Or even better, file the hammers to remove the unnecessary excess weight.

One of the many reasons why Yamaha is an awesome piano, is that they make great parts. If you try to replace Yamaha knuckles like that, the parts will not be as consistent (i.e., getting the knuckle location perfect is not easy).

Pianos are made light/heavy primarily via the hammers and the way in which their weight is scaled. If you want a Yamaha to feel lighter and more responsive/active, slightly reduce the hammer key-lead weight. If you want to go crazier: change the action geometry to meet your specific desires so that you will be .

well, probably the originbal geometry was at 17 mm there

17 g extra DW is not a hammer weight problem in my opinion (17/5.5= 3g) you do not have +-2 more grams on a hammer (the rest comes from the shank) unless the original and shanks where extremly light. That is not the case on the old larger models.

But having that enlarged recess makes the shank more supple.

For smaller models I largedly prefer keeping the original geometry with lighter hammers, 16mm knuckle and small key dip.

Despite that, the knuckle may need top move a little, simply because the screw to center distance was shorter and the jack does not line well in most cases.

And it is better as the old panels do not appreciate heavier hammers.

The problem lies more in the shanks, that are often 1 gram more.

ANd again "restoration" videos from a guy with a large shop, that show a box of replacement dampers felts as if it was original Steinways parts, and glue them without underfelt and may be with pva glue.

WHy all those videos show so incomplete knowledge and/or cheap work. ?

That is really boring at the end. Or more generlaly the one that knows how to do belly work are not that good with actions.

Here is the likely scenario behind his choices: He tells us that the note in the middle has a downweight of 67 grams. It should be somewhere around 50ish. The hammers were replaced as were the shanks and (it looks like) the whippens. The piano is likely an older Steinway which had a low leverage 15.5 mm knuckle. So the restorer reasoned that he should put on a 15.5 mm. knuckle. But the old Steinway hammers were relatively light in comparison to more modern Steinway hammers, or say a Renner Blue hammer which can be a fair bit heavier. That 15.5 mm knuckle was well equipped to lift a light hammer, but not well designed to carry the heavier hammer that he put on the shanks. A 16.5 mm or 17 mm shank would have greater leverage and lift the hammer more easily and measure off at a lower touch weight.

The first restorer could have added lead to the keys to lower the touchweight, but that can carry its penalties to. If he has 5 or 6 leads in the key in order to get the touch weight where he needs it to be (50ish for the sample note), then he has added a lot of inertia.

The choice the second restorer made seems likely to have been a good one, in that the only modification he has to make to the parts themselves is to relocate the knuckles. That's probably 3 to 4 hours labor. The action will have to be completely re-regulated of course, and the touch has likely deepened, so that will need to be addressed.

All of this can be modeled in software these days so that you can predict what the outcomes are going to be. Some techs write their own spreadsheets to do the modeling. An inexpensive program is Nick Gravagne's Action Geometry program.

A443, filing the hammers may lighten the touch somewhat, but it would not do enough to overcome the touchweight issues. The only solution is to replace the hammers and shanks again, or do as he has done and move the knuckles. For what it is worth, I have moved knuckles in this way more or less, and there are many superb action rebuilders who solve touch problems using this method when appropriate.

How did the action play before? It played like a truck, and that is why it ended up in his shop.

About a year ago, I redid an action that was similar to this in terms of hammer issues. That piano was weighing off at 72 to 76 grams in the bass! The pianist was not a happy camper, and she called me to make the action playable for her.

Isaac, this is not a case of a restorer trying to reinvent the wheel. He's rolled up his sleeves and is doing what he needs to do to get the action to play properly.

Will

WIll I know what is it about.

But when keyboar and whippens are intened for that 15.5 ratio, making the action "work" with 17 mm knuckle certainly ^provide less DW, but I notice how bad the touch is then.

Just for geometry reasons (jack is far on the back, unless the hammers are bored for that posture and eentually the stack repositionned the touch will be slow and with too much friction.

Hammers could be lightenedd but 2 grams, I dont think so it is attaineable.
Simply unless all the geometry is rewieved just mounting the modern hammers and 17 mm knuckle oblige to many other operations until the touch is pleasing.
My experience anyway, including rebuilding the stack. The keyboard is not setup for that.

Hopefully mod B, C and D accept more the heavier hammers, forget the Steinway touch then, or make new keys.


An sorry, but with his damper gluing, wrong felts, no underfelt glued, the guy is totally out of standards, to make a small gain on furnitures and time, I never would have show such damper work and present it as original way of gluing dampers on a Stainway this is abusive.

WilliamTruitt, I really appreciate your post; I think I understand and agree 100% with what you are writing about re: what happen in this hypothetical re-rebuild scenario.

From my perspective:
Rebuilder No.1 rebuilds with the correct-sized-replacement parts, but doesn't understand that the heavier modern day parts overburden the system to such an extent that the piano doesn't even come close to functioning musically as intended. The customer, unhappy with the complete lack of musical response, searches out for help.

Rebuilder No.2's response was to change something that was already known to be "right/correct." We know the hammers/shanks are MUCH heavier now than in the past, we also know that lighter hammers will lighten the action and reduce the downweight (which is the known problem), why not just lighten the hammers? Lighten them as much as it takes to reach the weight the action setup was originally designed? Or, if you don't know what that was, just go slowly, and set the scaling by your own touch/hand at the keyboard and even things out with a scale on the back.

My opinion: the voicer is responsible for the shape AND weight of the hammer--when done thoroughly "needle work" becomes less-and-less significant as the hammers approach their intended weight.

That was a shock for me to realise: I was taught to voice my problems away; I had a specific way of yielding my needles for every situation imaginable. When the hammers are the correct weight, the hammers need less specialised attention. I know it sounds crazy, , but it's true.

Sorry for my ignorant newbiness on this subject,
but when you say "hammer key-lead weight," what do you
mean? The lead weights they put into the keys?

Do they ever actually put lead into the hammers themselves?

The hammer strike weight (the weight of the hammer assembly) is primarily how the pianist "feels" their sense of key weight and response. The strike weight scale (i.e., the weight of the hammer assembly) needs to first match the desired performance characteristics of the pianist(s). Assuming that the parts are properly aligned--which they rarely are--the hammer weight is the main thing that needs to be reduced, until the desired action response is attained in each section of the piano.

There is typically lead in the front of the piano keys, but this is only there in modern actions to coverup the fact that the hammers are way too heavy! Lead and other "heavy/light" adjustments can be made, but they only influence the situation--they are never a substitute for adjusting the real "feel" of the hammers, IMHO.

Yes, they do, and it is a horrible approach! I tried it: the hammers are evenly even heavier. That is the wrong direction: down with hammer weight!

Hi Isaac:

The best decision would have been for the first restorer to have made the right choices the first time. I agree that the best decision, if he were going to use 15.5 mm knuckles, would have been to match the hammer to the rest of that particular action in terms of touchweight, and then do lead removal or addition to achieve the desired specs. Were that done properly, the action would likely never have ended up in the shop of the second restorer.

You are correct that the jack will need to be positioned further back in the window of the rep lever to line up with the knuckle. And if it is moved far enough, the jack and knuckle core may not form that straight line we desire to see for best performance. Sometimes you can shim the whippen flange to tilt the whippen back to achieve a better jack alignment.

There are lots of ifs and compromises involved. He may still have to be satisfied with the action working well but not optimally.

The other issues you bring up should be part of any modeling leading to decision making for the best strategy. And he should have done a couple of test notes in the piano taking it through the knuckle relocation and any other work that may become part of the process. He may have done all of these, he has not shared the whole picture with us, so we should not draw too many conclusions on what he may have or may not have done.

I do lighten hammers where that may bring us closer to our goals, usually with full side tapering if it was lacking before.

I also explore the value of moving capstans if that will help.

We should also remember that he may be working under budgetary constraints that might preclude the opportunity to start over again with new hammers and parts.



A443, a lighter hammer is what should have gone onto that piano originally. And another path he might have taken would have been to retain the 15.5 mm. shanks but replace the hammers with a lighter hammer better suited for this action. As far as lightening up the hammers that are on the piano, the hammer diet just isn't going to give you all you need, so other avenues must be explored.

I agree that the voicer is responsible for the shape and weight of the hammer. But, unless he is replacing the hammers again, he still must play the hand he is dealt. Doing good work is always about making good compromises.

Will

Well, out of the fact that enlarging the jack recess is not excellent for shank resiliency, I mostly say that lighter hammers and lighter shanks work better , also because the action is setup that way but mostly because fast an light is extracting more juice of an old piano.

AGreed you cannot gain 3 g by shaping hammers and shanks, but even if the new parts are very heavy they cannot be the only responsible for heavyness.

I mean with 67 g a piano can be playeable if the geometry is good, Kaway often have 60g DW 30 UW without reclamations

51g DW does not prove anything, may be UW is then too low.

Just looking on the 2 papers on the rail it is seen that the precedent tech did not know how to work on Steinways.

I think the whippens also are possibly not good (they are not originals S&S nor Renner a too tall jack here will make the letoff horribly heavy)



But I was not about to judge that job without knowing all, what chocked me is the dampers job on another video. That shows cheap way of working, it does not go along with quality.

Also, when I do a proposal I do the price, if too low corners need to be severly cut later..

WHen I need to deal with that sort of things, I will unglue the hammers and relocate everything, or if it works fine use 17 mm knuckle (new shanks)

I of course worked on many pianos in that sort of situation, it happens all the time. We develop a feeling for the action behavior, that allow to modify the geometry with minimal measurements in the end.

New hammers could have been not more expensive or not much, in the end. those light hammers are not sold by Steinway anyway (in europe)

I would say the hammers are UNevenly heavier, which is noticed on dynamic mode (may be if you ad the same weight at the same location on all hammers it does not, but the sensation is strange anyway .

For those of you brave enough to have your mind blown, and your entire voicing reality expanded (i.e., like dark matter vs. gravity, just instead: in the realm of the piano worlds): dare to experiment with an old set of hammers, right before you intend to replace them anyway.

Forget everything you know about hammer shape and how hammers are 'supposed to' look and function. Just let its touch and sound guide your hand...that is all you need to know.


Harden the hammers--with your choice of hardener. Leave the impact zone alone: start slowing removing felt anywhere on the hammer, except the strike point, to remove weight. Forget about beauty: the hammers are destined for the trash anyway, right?!?

As the hammers get lighter, you should notice a proportional need to flatten the strike point--to maintain the tonal body and attack (i.e., make sure you leave enough room to go flatter than you ever would with heavy hammers: that is a proportional relationship). You should also notice a proportional need to soften the top of the hammer--more than you ever would with a heavy hammer: that is a proportional relationship.

As long as there is at least a bit of cushion on the top of the hammers to work with, you can use that approach to turn any tired old worn-out hammers into a gorgeous sound with a luscious/responsive keyboard--simply by setting the proper strike weight, with the corresponding strike point surface area and softness.

In institutional settings, where pianos get a lot use, one naturally learns to look for ways to maximize resources. That is one of the reasons I stumbled upon this approach.

Just try it sometime: go as light, flat, and soft as you possibly can. See if you can find the acoustic limits of where the sound begins to get objectionable.


HINT: razor blade sculpting!

I have been reducing the mass of hammers in an organized way during tone regulation since 1983. I do much of the work by tapering the sides and narrowing the width. I can make an action with a set of hammers made from the lightest wood and felt of modest density that requires almost no front key leads to have an agreeably fluid, easily controllable, really fast, touch. The static touch weights can be 70 grams in the low bass-and pianists "feel" the action as light. I call the procedure LightHammer Tone Regulation.

Unless there is nothing left to shape or work with...that being the general rationale for new hammers anyhow.

Not so OT :
It is about " the action of grand piano, by Nikolaus Schimmel - 1992)
Nikolaus Schimmel always tried to get numbers for any element in the instruments an particularity the action.
With the tendency of the times to obtain somewhat massive touch those may be very important .

UW was not 'officially' considered, but those details where hidden (due to factory secrets and researches) , and it is well said that 2 static weights are necessary to control an action behavior and balancing.

They used electronics equipment to deal with the action balancing in the factory, and for researches in other fields as well).

Anyway he provided a book where many dimensions and "gives" are proposed, for all of the mobile parts. That is always good to hae those sort of references as some calibrated metal blades can be used to compare the "feel" with measures, for instance, when regulating.



if someone is interested, the minimal dynamic weight propose by N; Schimmel in 1992 was :

for basses 100-125 grs
Med 85-105 g
treble 70- 85 g

Schimmel grands being not known to be particularly "light at those times, with a large key dip 10.4 0.8 mm and massive hammers, assist springs and a little slow key return.

However their larger (concert) grand models are impressive (rare)
and the construction is very well thought.

Those weights are laid on the key, and supposed to produce a minimum pianissimo tone (right pedal untouched)

+- 20% variations allowed forom mediums to basses and depending of moisture conditions.

Schimmel state that very high moisture may change the static and dynamic downweights (in the piano, including dampers ) up to 40% more in extreme cases .

He also state that the static weight or DownWeight can correspond +- to the dynamic weight at ppp level , then be 40 times that at the faster levels of acceleration an force.

N.Schimmel have the elegance to write that the static weight relations are not decisive in assessing the touch of an instrument.
Regulation (geometry then) are more important to him.

Modifying the dynamic behavior can be one by adding lead back leading) but that is not recommended. for good reasons due to the small role of the key, out of its resiliency, in dynamic mode)
I think small leading on the whippen may give interesting results eventually, but my gut feeling tells me the whippen must be "transparent" at the most .

May be leading on the shank, to modify the GC of the assembly, can give some interesting results too. not very practical but I like to test that.

The experience could be interesting to see if balancing the mass acceleration of a too heavy hammer with a heavier whippen gives a more pleasing touch or no .

Slowing the key by adding inertia (lead) seem to help because of better coherence between the masses (less disequilibrium when accelerated) , but as the key is not really the most accelerated part this benefit is of course all relative.
It makes you play as sending a ball with a moderate to slow rebound on a wall, with more effort the ball will bounce more, but of course I do not take in account the limits of resiliency (action saturation) there.
(nor the acclerate where of frictional points)

Anyway I suggest, even with very light hammers (it should even easier then to notice results) to check with different screwed leads what is the tonal advantage if any an how playable a slowed keyboard can be.

THe leading on vertical whippens as done by Ed shoudl be an interesting way. on verticals the force direction of the jack is very well oriented, not as on grands, so leading at the base of the backcheck wire for instance, may gibe perceptible results. (again, in dynamic mode..;)

Hi Will,

I like this hypothesis; you are probably right.

But I wonder - wouldn't it be more elegant, easier, and faster (assuming the piano is already regulated correctly, especially blow distance, jack position, rep lever height, letoff, and drop) to pop the hammers off from the shanks and taper them on a table saw to the desired weight, then reglue? Of course you'd leave end section hammers in place as guides, then taper those last. Wouldn't that be less work and less time reregulating, while solving the real issue and probably improving the tone?

I have also been wondering about 15.5, 16.5 and 17 knuckles and Steinway repetitions. What exactly are the dimensions of the NYI (NY improved) shanks? (Part #6617) Are they 16.5 or 17? I keep meaning to measure these every time I tune a newer Steinway and then I forget. I also wonder why Steinway doesn't give the dimension in the parts catalog. I do know that Pianotek sells 15.5, 16.5 and 17 knuckles with a Steinway flange made by either Tokiwa or Abel, but from what I can tell Steinway only offers two knuckle/shank types.

I would also like to know if there are any differences between older Steinway reps and current production, other than the placement of the jack center closer to the flange in the current production reps. Steinway says the jack center is 1mm closer to the flange, but I have heard from other techs that the only difference is in the length of the jack. Anyone know?

A few months back I replaced a broken shank on a late 60s M with all-original parts; I only had a 17mm knuckle/shank on hand and it was impossible to regulate, no matter what I did. Then again, this particular M has the gigantic white knuckles made of felt (what years did those things appear on Steinway?) and of course the new leather knuckle was much smaller. I had to return with a 15.5 knuckle a couple of days later.

So my question to the experienced rebuilders like Will, Ed F, Ed M, Jim I: How often can you successfully regulate NYI shanks/flanges to older reps without problems? It would seem to me that this is a highly variable situation that is dependent on the initial factory placement of the stack on the keyframe.

And, one final question. Can 15.5 knuckles be successfully regulated with new Steinway production repetitions? (I realize this would be an unusual scenario, but I'm curious from a geometry perspective.) Wondering if that was also part of the problem with the above situation and the high DW. It seems to me that the biggest mistake made here was the selection of a 15.5 knuckle to be used with new repetitions. And even with weight-prepped hammers, can that combination work well? If not, then Will's idea to move the knuckles is indeed probably best, due to the presence of the new reps.

The action spread (i.e., the spacing of the hammer and whip pen rails), dictates where the knuckle must be in relation to the whippen/jack. Knuckle size, will also have an effect, but this has more to do with the starting angle of the hammer shank at rest--and how the knuckle+jack crosses the centre line at mid-blow.

You can read this information from your action rail alignment. It may not have been done properly to begin with--which is usually the case! So, if technicians are trying to compensate elsewhere with other knuckle locations, which is possible, they are not solving the real problem: they are causing others!

Solution: align the action rails properly for the parts you have. Then adjust the hammer weights so that it allows that particular setup to function properly. This is the traditional/standard approach to piano-building and action setup that makes high-end pianos actually function musically as intended. Its all about how the parts are intended to come together, and making sure that they get that way.