RESTRINGING

I am going to restring my 110b 7'8" Chickering and sons piano.

I am going to calibrate the strings to see if it's the correct string scale.

any help would be appreciated!


thanks in advance

Chris Robinson

http://www.scaleripper.com/
It's free...

Will my piano sound a lot better once restrung it looks to have been restrung in 1936 The piano does not have a lot oF singing voice/ life. I am also going to re crown the board.

any thoughts.


Chris Robinson

If you are doing the work yourself, and cannot answer those questions, there is a good chance the piano will not sound better, because those are the sort of questions that can only be answered with experience, and without experience, you cannot count on the results.

I suggest that you practice on an old upright before committing yourself to a piano that you may want to keep.

Cool . i have replaced strings and been tuning for many years, but not the whole piano.

Thanks for the comments.

??

lol... I think he means he's never restrung the whole piano!

Lol Thnks Phil for correcting that. Yes I have been tuning whole pianos but not restringing the WHOLE pianos. lol

Thanks again

Chris

I expect you'll be surprised by the improvement.

I would suggest to anyone to first build up their skill level and craftsmanship by trying numerous times to perfectly duplicate what the "old guys" created in the first place. This applies to any aspect of piano work - action restoration, soundboard and bridges, stringing etc. The original design and craftsmanship of older, good pianos is often quite difficult to beat, at least for someone with limited experience. Case in point: much of the repair work we see does not live up the the original build quality.

Only when the level of skill, experience, knowledge/understanding and craftsmanship have been tweaked to a higher standard would I recommend branching out and trying to improve things by altering the design or switching materials etc.

Rescaling—even when it is done by someone who knows what they are doing—is not a magical cure-all for every tone problem found in old pianos. It can smooth out peaks and valleys found in the typical old scale but it cannot make wholesale changes in voice.

Neither can rescaling compensate for collapsed soundboards.


No, you’re not. I’m sure you’ll do the best you can but there is no viable method of “re-crowning” a collapsed soundboard; at least not over the long term. Assuming the soundboard in your piano was compression-crowned, there are things that can be done to restore some of the stiffness that has been lost over the decades but that is not quite the same thing. (If it wasn’t compression-crowned then it wouldn’t be necessary to “re-crown” the soundboard.)

From the context of your questions it would seem wise to engage the assistance of an experienced rebuilder to help you though this project. As helpful as members of this forum want to be there are distinct limits to the type and amount of help they can give. There is nothing quite like having been through the process a few times. Even though it might cost you a little it would be money well spent.

ddf

Thanks so much!!

not sure if it was compression crowned or crowned at all . I have seen my same model of piano being re-crowned, i should probably have an expert look at it. I have checked it underneath where the ribs are and going across the board, it is flat and it is still strung.


CHris

Del, you say "if not compression crowned no need to change the crown", but seem to me the ribs flex and take that infamous S shape (flexion spot)

I believe also that the old ribs loose their resiliency, the more you add downbearing the more the ribs flex.

Thinking of the method used by CHuck Behm to glue back ribs and that he said add some "boom" to the panel, I wondered if forcing the ribs in reverse position as he does then gluing them, does not allow the panel to gain some life (not some crown, I tried to recrown with controlled drying (before regluing ribs) and the results where not evident)

I asked on that thread, if the ribs where not having yet some resiliency that can be used when pushed the other way they are supposed to.

Then I would agree to have a less crowned panel assuming it have more inner tension...

May be a method to unglue ribs on a longer part would be useful then...

Any thought ? (if you understand what I mean) Rippen made a soundboard reversely crowned , supposed not to be sensitive to moisture. Only experimental I guess (as the metal soundboard panel from Feurich )

A board can be flat under the strings pressure , and be alive/functional.

The main problem I encounter is the bridge roll, together with a pronounced S shape in front of it.

lack of pressure/firm contact on the front side of the bridge, something that is highly detrimental to tone (and I suggest can be corrected by the use of a new bridge top )

Just tested a grand C3 10 years old played professionally : all strings where missing a firm contact on the bridge (raised on the pins) it produced a very unfocused tone with plenty of defects and noises, only due to that small lack of firmness, so when the soundboard shape push the strings to raise the pins even faster, no way to keep a good tone for long)


correcting that at the moment of the repair may include changing the bridge shape gluing new ribs, all operations that should certainly be almost as expensive as changing for a new soundboard.

I actually said, “If it wasn’t compression-crowned then it wouldn’t be necessary to ‘re-crown’ the soundboard.” That is not quite the same thing.

Historically, there are two ways of putting crown in a piano soundboard system. Very simplistically, one is by drying the soundboard panel to a very low moisture content, glue on the ribs and have the expanding soundboard panel force crown into the system. This obviously works but it does create—and depends on—more perpendicular-to-grain compression than the wood is able to support over time. As compression-set occurs the crown collapses and the soundboard system goes flat.

With the other method a crown is machined into at least one surface of the ribs and the ribs are treated as structural beams. At least in terms of maintaining crown over the years these systems are more stable. Hence my comment, “… it wouldn’t be necessary to re-crown the soundboard” since the soundboard assembly will probably still have adequate crown.

The infamous S-shape is more common in compression-crowned soundboard systems. But that is a story for another time.




There are a lot of wood technologists who will disagree with this statement. Of course, when more downbearing—string downforce against the bridge(s)—the more the ribs flex, or bend. But their stiffness remains the same. Over time—decades—a wood beam that is under relatively high loading will take on a slight permanent bend due to long-term stress relaxation but the actual stiffness of the beam will remain virtually unchanged.




Rippen soundboard systems were reverse crowned but they also used laminated soundboard-panels. They were relatively insensitive to changes in moisture content because the panels were laminated not because the system was reverse-crowned.

Rippen’s crowning method was really very simple; flat ribs were glued to a laminated soundboard-panel, the bridges were glued on and the assembly was installed in the piano flat. When the piano was strung string downbearing—downforce—pushed the soundboard system into a reverse “crown.”

ddf

Del, could you give a quick description of how to identify the "S-shape" so that when looking at a used piano, I can know what to look for?

Thanks in advance.

Unless you're a rebuilder it is unlikely you'll ever be able to find it on any piano you're likely to be considering.

Basically you stretch a string across the bottom of the soundboard between each pair of ribs and visually observe the contour of the soundboard relative to the taut string.

A faster way to tell if the soundboard has any problems of consequence is to listen very carefully to the balance of sound between attack and sustain. And then just listen to the piano carefully and critically. Most failed soundboards reveal themselves in the tone quality they produce.

ddf

The only reasonable way to assess the condition of a soundboard is by ear. In order to do that, you need to understand the effect of age on strings and on hammers. The only way to get this is by experience, which is why I recommend finding an old upright or two, which you can undoubtedly pick up for free, and work on that first. Get one with no problems with the bridges, and where the soundboard has not separated from the ribs, and restring that, and replace the hammers and do the other necessary work on the action. If you do a good enough job with it, you can sell it for enough to pay for the materials, and the experience will be priceless.

Along with this, you need to listen to a bunch of pianos, so that you have a good idea of what pianos sound like, and the variations you can have even among pianos of the same make and model. The idea that you get from reading descriptions of what pianos should sound like on the internet is no substitute for actually listening to them in person.

THanks for your answer, but Del, most rib crowned soundboards are glued in low humidity, so there is also an amount of comppression crowning involved

I am not a wood specialist, I understand the wood may be resisting up to some point, but its resiliency may be changing with time, most old soundboards have very long basses without a well defined attack , old panels have aparticularly non dynamic tone that reduce the voicing possibilities (sooner saturation)

I also wonder if the intense vibration the assembly is subjected to will not change the wood inner structure.

I also noticed that adding downbearing on some panels, you only have a decent tone for a few years.

Downbearing play a role in tone indeed but crown is just a necessity, apparently just structural.

Boards are also glued in a crowned setup, with flat ribs as with crowned ones. A good part of the resiliency may well be due to the glue joint bewteen the ribs and the panel


About Rippen, I am unsure they used that setup for long, most of the Rippen I have seen have traditional panels, some of then hold nicely in time.

Does anyone make or produce soundboards generically (cheap priced) tha sound and last good???

I believe the soundboard in itself is not really expensive, nor it is to build some (once the tools and presses are made)

Then installing new soundboard (and new bridge) is quite some job

The best solution employed seem to be making new bridge tops, then the geometry can be adapted to whatever shape the soundboard took

The S shape is "normal" up to some point, it is a reaction in time

All harpsichords soundboard have that shape

The main problem with bridge roll is that it tend to produce cracks in front and along the bridge, and at the same time the string's pressure still availeable apply more on the back of the bridge than on the front

Tone quality is then lower, and when downbearing is added it apply mostly on the back of the bridge too, that makes the opposite effect of the one expected, often ; the tone begin to be "square" and brutal, probablyy the pressur on the back is accepteable up to some point, then it sort of block the soundboard
So a new bridge top allows to restitute the good geometry

Many bridges are slanted so under the pressure the contact still is firmer on the font side of the bridge than on the back

Unfocused tone and loss of thickness is the effect of lack of contact/pressure on the front part of the bridge

That is whay bridge to string contact have to be corrected regularely, tapping with a brass rod ar a hammer shank on the front of the string, or on the bridge on both sides (less dangerous on the bridge but the idea is not to make huge imprints in the bridge top so light hand and light hammer are necessary)

Then only the piano is tuned

DUring tuning I generally have a big grand bass hammer at hand, it allows to push the strings (massage a bit )

Often correct more than one thing at once, the strings that raised on the pins are not level and hammer mating can be audibly disrupted by a simple lack of mating at briddge level (high whisles in tone)

Then the tone always get thicker (less energy loss) and clearer (partials better defined) simply with a small massaging in front of the pin with a hard wood piece

Eventually it will not even put the note out of tune (a firm pin setting allow even to raise a string with a hook without loosing the unison) but I would do so before the tuner come (in case he does not take the 10 minutes necessary for that operation)

On stabilized pianos, the bends at the bridge can be massaged, providing long lasting tuning and even stronger tone

To meet the loose definition of “compression-crowned” the soundboard panel must be dried to a moisture content of 4% or less. Typically they are dried to 4% during the summer months and around 3.8% during the (drier) winter months.

Soundboards built up with crowned ribs are usually dried to something between 6% and 6.5%. This may not sound like much difference but the long-term effect is significant.

Yes, there is at least the potential for some perpendicular-to-grain compression in soundboard systems that are designed and built with crowned ribs, but it is considerably less than the amount of perpendicular-to-grain compression developed in a compression-crowned soundboard system.

But crown by itself is not the critical factor; it is the combination of system mass and system stiffness in the final construction that is going to determine how energy is transferred from the stings to the soundboard assembly.

In general soundboard systems depending on panel compression for both crown and the added stiffness this compression contributes to the system use relatively flexible ribs. Those depending more on the rib structure for their overall stiffness tend to use stiffer ribs. (Yes, I know there are exceptions on both sides.)

All so-called “solid-spruce” soundboard panels absorb and desorb moisture through the normal cycles of humidity change. The difference is that the compression-crowned soundboard panel is subjected to levels of perpendicular-to-grain compression that causes permanent damage to the cellular structure of the wood. This (usually) does not happen in soundboard systems that are designed as rib-crowned systems.




There are a lot of other factors involved as well. Hammers also change with time (whether the piano is played or not). And, to a lessor extent, so do strings.




I asked a wood technologist at the U.S. Wood Products Lab about this a few years back. His answer was that compared to what wood members endure in a structure like a railroad trestle bridge for decades and, in a few cases, for centuries, the vibrations in a soundboard panel are insignificant. Yes, they vibrate but the range of motion is very small.




I’m not at all convinced crown is necessary. What we are really after is some amount of stiffness. That stiffness can be achieved in many ways. One of them is build up a system that depends on a high amount of perpendicular-to-grain compression within the soundboard panel. Soundboard crown is a natural result of this method. But, as has been discussed at great length on this forum, this compression dissipates over time—years, decades, centuries—and along with it goes the amount of stiffness that was added to the system by that compression. When the perpendicular-to-grain compression has dissipated there may still be enough stiffness in the system for the piano to produce acceptable tone.

Or there may not. And this is the issue that causes so much confusion to so many; the uncertainty and the lack of hard and fast rules. We want rules that are clear and unambiguous: Compression-crowned soundboard systems always act this way and rib-crowned soundboard systems always act that way. The problem is that piano soundboard systems are rarely that clearly defined or constructed. Nor are the results always that predictable. I’ve looked at pianos built with compression-crowned soundboard systems that had failed while still on the showroom floor. I’ve looked and—indeed, I’ve rebuilt—pianos that I know were originally built with compression-crowned soundboard systems a century back in which the original soundboards were in excellent condition; at least based on their sound. Replacing these soundboard panels would not have made the completed piano sound any better. A bit different, perhaps, but not necessarily better.




In a compression-crowned soundboard systems the stress-interface between the top of the ribs and the soundboard panel is critical. The glue used must not creep or cold-flow; hence the use of glues that form a absolutely rigid bond. This is less critical in soundboard systems that are rib-crowned; here any modern woodworking adhesive including the so-called PVAs (or polyvinyl acetate emulsions) can be used.




We sold Rippen pianos during the 1970s and this is how all of them were built. I liked the system; for their type and size they could be made to sound quite nice in spite of their erratic stringing scales. And they were very stable in a variety of climates. They would have been even better if their scaling had been any good.

ddf

Thanks again, I seem to notice some parameter of tone in panels mounted only with curved ribs,

Sound like some slowness in the immediatness of attack

The pianos that have the more crisp tone will then have the more fragile soundboard


Seem to me that to have that very fast answer from the soundboard, we have to use a soundboard whose equilibrium condition is easily disturbed

The mental picture I have is the one of panels that are efficient to maintain a long term circulation of tone but seem to ask for more energy to be efficiently producing a nice attack

Then the Viennese setup, with the sound passing thru the case may help to adbsorb some of the hardness of the tone (the plate is supposed to be non participative in the tone for thoses kind of instruments)


And other kind of panels that have a fast reaction time, hence a more large dynamic zone for the attack

I believe (without having so much material to backup that)
That the panel is glued with less moisture than in its future condition, so there is certainly some stress at the glue joint level -

Is it possible that some panel tend to have a static force toward flat, hence a double reaction immediately at the impact (resistance toward the strings pressure dimension, then the other way) ?

I only could obtain information on rib shape and moisture level from a little factories, the ribs seem to be shaped plus moisture level lowered enough to have some effect once the panel is at the normal moisture level later

Then , I recently have seen a NY grand fitted with anew soundboard

While the tone is accepteable, it have nothing of the crispness expected from a S&S panel, it have a "medium" color and a moderate dynamic

I believe that this panel have only the inner compression obtained by the pressure of the strings (so the resiliency is only obtained by the ribs)

I guess I begin to understand and to know well what I prefer


I have read that 5.5 wood moisture level is used on Steingraebers, and possibly on other brands, (I also heard of 4,5 used too but I dont recall which brand) But I have read words of UDO Steingraeber saying that this was because he believe lowering too much the humidity level in the panel would alter the wood cells

I understand that most European makers install some form of compression, not to obtain crown but to make the panel more active .

Yes between 4% and 6% the difference look small on the paper, but I am persuaded it is large in effect, wood dimension change a lot with 1% more or less at those low levels.

I understood the purely compressed crowned method, as a cheap method used on verticals since the 50"s

I indeed may be wrong on that one

Thanks so much for the information, If i left my soundboard as is and just remade or adjusted the bridge do you think this would help alter any OLDness the piano has. I am going to do a mp3 recording with a mic and sound system and put it on this website so that you all can listen to t his piano. I do know that I am going to take off the plate and (clean up the soundboard) and of course make it look all pretty etc.... and RESTRING and eventually Re-do all the action and hammers, one thing at a time as i can afford it. Thanks

Chris

May I suggest that you start with the action, using the original hammers for now? Even better, start with the keyboard, then move on to the action. That way you will get some results that you can try out before you go to the next step, and if it is not coming out well, it should not be too difficult to repair.

I got by for about a dozen years with the action refurbishment on my Mason & Hamlin before I got to the strings and hammers. There were only minor adjustments necessary when the hammers and strings went in.

One difficulty in discussions like this is that we end up talking about only one part of what I call the “design triad”; the character of the string scale, the soundboard system and the character of the hammers.

We can speak of the variations in soundboard types and construction but the ultimate sound of the piano will be based on how those three elements work together in synergy. A soundboard type that may work perfectly with one type of scale may work very poorly with another. A string scale and soundboard type that are very well matched can still perform poorly with the wrong hammer type




Yes. All wood construction, whether it be a piano soundboard or a dining room table, is done at a moisture content that is just below the average moisture content that is anticipated in its “normal” environment. Most furniture factories—at least the good ones—try to maintain a working environment with a moisture content of around 7% to 8%. Because of their unique construction—a thin spruce panel stressed in the perpendicular-to-grain direction—piano makers generally keep the moisture content of the panel a little below this; typically between 5.5% and 6.5%. As you say, the difference doesn’t look like much on paper but it is significant in the real world.




In a stressed system such as a piano soundboard that is loaded with some amount of string bearing both the soundboard assembly and the strings want to return to equilibrium. But it is the string bearing working against a stressed soundboard system having some amount of stiffness that is important, not the soundboard crown as such. Soundboard systems can be light or massive, flexible or stiff quite independently of crown.




The exact method of soundboard construction is often considered a trade secret by piano makers. Sometimes this is because they genuinely believe their historically significant and precisely controlled process gives their pianos a competitive edge over their competitor’s pianos. Other times I think is because they are not too sure exactly what they are doing!




There are many reasons why the sound may be as it is. The design of the ribs is important in these systems. With careful selection of the crown radii and the rib cross-sections—height vs. width—it is possible to build a rib-crowned system with performance that is virtually indistinguishable from that of a good compression-crowned system.





Most, if not all, cheap pianos have used poorly designed rib-crowned soundboard systems. These soundboard systems may not sound very good but they are cheap to build, the quality of wood used doesn’t matter much and they don’t often crack.

ddf

Personally, I'd start with the action and keyset. In terms of musicality this will give you the most noticeable improvement with the lowest monetary investment.

If the piano is untenable because of loose tuning pins they can tightened up at least temporarily with the CA treatments described elsewhere on this forum.

ddf

Is it possible that my board is flat under pressure and that if I put a thicker Bridge on it the piano will have the loud volume and bounce that it is missing? or should I RE CROWN too?


Thanks


Chris

There is no meaningful recrowning of an old board. You can chase after bearing by either lowering the plate or raising the height of the bridge, but you can't really change the liveliness of the board of which original crown was but an indicator.

There is benefit to establishing appropriate bearing (which will be less on an old board) but that is a separate benefit from having a lively board.

Original piano soundboards can be recrowned. It is not a simple process, but it can be done. We do it regularly, and the results are predictable and long lasting. I hope I am not crossing the line of self-promotion, but pronouncements of "it cannot be done" have to be answered.

The 110B that Chrisman has been following is in our shop, and we just removed the board from the press a few days ago. The board has been blooming sinse then. Now that it is crowned, I thought it would be informative to post a couple of pictures:





The long rib is about 120cm long and has 9mm of crown.
The short rib is 28cm long and has 4mm of crown.

This method of recrowning, because the board is removed from the case, allows a complete reset of the stress interface between the ribs and the board. This, in turn, allows true compression to reform in the entire board, so there is crown in the whole system, particularly in the treble.

hello, that is impressive, you need special cauls to rib with the bridge on ?

sound as a good process, but dismounting the ribs and the board without damage ?

Did you use hide glue for the ribs ? I did once on a little grand where almost all the ribs where unglued.
I used a very strong hide glue.
The results where very positive and surprising, I heard a 1920 grand with some dynamics , more than the usual old panel.

I thought that 8 mm was yet a good crowning, (with highers spot at the treble break).

I agree that the resiliency between ribs and panel is where most of the soundboard capacity to react fast to the disequilibrium lies.
That is what I think anyway.

Now I wonder how to evaluate the original ribbing process used.

Olek,
Good morning.

In the early days we used notched caulding in the press, but then we figured out how to remove the bridges. So that is no longer a complication

We use steam, deviously applied, to unglue the board from the rim, and then the component parts, in turn. Done patiently, any damage to the material is minimal.

Hide glue! Yes, its wonderful stuff. Its all we use.

We have done a number of pianos like your 20s grand, here in piano parching New England. A lot of pop can be returned to a board if you can relieve the accumulated shrinkage, and then add a little compression during glue up. This helps a piano a great deal, but we were never able to do much in the treble due to space constraints.

The original ribbing process. We may never know some particulars of original bellying techniques. Were these boards pressed on flat or contoured decking? We can't know. The only thing I can prove about Steinways, for example, is that they were pressed on a go-bar deck. It can be seen in the background of a photo. As for rib-crowned systems, I know for a fact that they were used in Knabes as far back as the 1890s. So they are a legitimate configuration in their own right. We just do our best to re-realize the designers intent, using the original piano as a guide. These Chickerings, for example, were built with a 1 to 1 ratio of unstrung bearing to as mounted crown.

WoW! That crown looks like a new board. I never would have thought a process like yours possible. If your post is considered advertising-then I don't know how anyone could share real information on the web.

It still seems like more work than it is worth. I would rather have new wood if I am going through a belly process. However for those who want to restore as closely as possible to original-and have a fine piano to play-your system is a godsend. Have you been asked to present this material at a PTG convention?

Hello , good evening !

I do not believe in any flat glueing unless cheap quality pianos. Looking at the ribs may show their shape enough I believe.

Heat and moisture ... I did not thought that it could be done as clean as pictured.

The hide glue by evidence add constrain, the one I have chip the glass when it harden, if you come by I will give you some (historical glue in sheets, stamped "extra strong ")

Nevertheless I wondered if some skin glue must be added for plasticity of the joint, but I dont think so.

I am sure some old panels are really worth keeping.

What I noticed is that the raise obtained with the humidity back was not as much as expected, I can dry air to 14% HR, may be less, but it took too long to glue all ribs while keeping the piano in this hard environment ( I used moistened rags and plastic sheets around the pinblock)

The factory had special warming equipment to glue the ribs, with heat, the glue really go deep in the wood. Not much needed but still a little.

I will try to provide you a few readings on that part of tge building, may be it will give you some ideas..

Regards


Ps traditionally alcohol is used to soften the glue , may allow the water to attain the glue within the wood.

We could not do that with the more modern glue used, as urea formalehyde

Ed,
Thank you for responding. "like a new board",huh? Fine praise and we will accept it.

There are many qualities to ultra seasoned tonewood that make it worth the effort. You seem to be a sober material scientist, so I will select something fundamental and crucial: Stability.

Wood expands and contracts with the seasons and shrinks over time. More in the early years and less as time passes. The wood in the original board has done just about all the shrinking its going to. That said, the wood is still strongly hygroscopic. We use curved caulding to press our boards. Even with the curve in the press, the boards come out with only a minimal crown. Scares the stuff out of me every time. The bow in the picture developes over the course of a week or so.

If you can accept the combination of a good renewed crown matched with a glacial annual shrink, then perhapse you can see how these boards have the potential to show considerable longetivity. This is stability in the long term. In the short term, my tuner friends say that these pianos only move about one quarter as much seasonaly as other solid wood boards, and so are more stable in the short term.

Anyway, in too many words, that is one reason why I find the old wood rewarding to work with. I wont even go into the lighter, stiffer, stronger triad and their multiplying influences on tone, promptness and projection.

We gave some talks in Boston and Connecticut many years ago. I think it is time to revamp the roadshow.

"godsend" Can I quote you out of context with that one?

Craig, Well I guess since I put it in print here on line I can't stop you from quoting me. Don't think it will help much with your marketing as I am only at most what some call "boutique famous". I would reserve any endorsement of your process until I heard and played a couple of your pianos.

Your description of the picture being taken a week after belly puts your system in more focus. I would have that much crown with a new board three to four hours after ribbing. I also wondered if the soundboard would be shrunken slightly from its original size.

The greater stability of the original wood is due to it being somewhat fatigued compared to new wood.

Anyway, good luck to you!

About shinkeage, old wood continue to shrink, as it was demonstrated to me recently.

Due to a heating fail (during a few weeks I guess) an old furniture (300 years) veener on oak, shrinked enough so all the veener fall on the floor. almost 2 mm reduction in size on 10 cm large panels ...

Certainly not shrinking as much as when new.

Probably the peliculars of old panels are good for some part and less for others.

New wood is more springy, usually, violin makers know that an old Stradivarius does not provide as much tone as a new violin, for instance.

But I am sure that the color of the original tone will be retained with the original panel, while changing totally with a new one. That should be a sufficient reason, to me, and you can talk of "restoration" then.

BTW that is the exact process used by Fortepiana restorers.


Regards