I've been an occasional visitor for a couple of years, and this is my first post. I bought a new 6-10 Heintzman grand (Chinese-made) for my Church. The reputable dealer has a large service department, and I visited with the technician who spent two full days preparing the piano, so I know how thorough he was. Since getting the piano delivered before Christmas. Since then the piano has had repeated action-related problems all related to stiffness. The damper bushings had to be eased with heat, which finally cured those problems. The rest of the felts have been soaked twice with Protec and the felts that touch the capstan surfaces coated with Teflon powder. Although there are no longer any sticking notes, the action is still noticeably uneven and gets significantly stiffer after about 30 minutes of playing. The humidity in the sanctuary is a steady 30%, the temperature varies between 19 and 21 degrees C. Is this normal? Do I have a problem piano? Any thoughts on what to expect when the tech runs out of Protec?

Hello Critic,
I can see that this is your first post, so welcome to the piano tech forum. A couple of comments that you have made in your post I have noted. #1 the humidity in the sanctuary is a steady 30%. Well I am not wanting to be too objective here, but I have had a good deal of experience with church instruments. How can the humidity remain at a steady 30% when every Sunday morning the sanctuary fills up with warm bodies that sweat and sing and, well, do a lot of other things? The moisture content in this room must skyrocket for the one day, due to several services. Then Monday morning, the instrument is all by itself for six days. Then, repeat this next week. What tells me that this is a moisture related problem is two things. One, your techie used heat to chase away the dampness in the damper guide rail? Or the damper levers? Not clear there. Secondly, when you play an instrument that has moisture related problems, too much friction is being created within the flange centre pins. Too much friction will create too much heat, and this will expand the felt bushing rapidly, and crush around the centre pin forcing it to slow, or stop moving completely. This is the resulting "stiffness" you are perceiving. The more you play the "stiffer" it will get. There is no mention of how long this instrument has been in the sanctuary, but I can tell you the first few months with some manufactured instruments can be a little problematic. No, you don't have a "problem piano" you are having problems "with" your piano. Interesting to note that the techie went over this instrument for two days previous to delivery. Problems like this I am certain would have been addressed at the shop. So question for you. Why do you think this instrument is giving problems now? Could it be that the enviroment in the sanctuary is different then the shop this instrument came from? Also, at the risk of sounding glib, when a technician runs out of a product he/she usually purchases more product. Sorry about that one. A discussion of Damp Chaser products might be a good starting point for discussion with the store you have purchased this instrument from.
Cheers...

Although I agree with the fact that all church pianos can really benefit from humidity control, I don't think that is the problem here. Almost every Chinese grand I have worked on has had these issues. Even the one that sits in a second home at 20% humidity and 7500 ft above sea level.

After talking to one of the techs from a Distributor, the best we could come up with was that it was an ISO problem. You see, the ISO certifacations require that specifications be kept within certain limits. For whatever reason, the Chinese are trying to make felt stay in too tight of specs. Combine that with "cost effective" felts and overly dense felts, and small changes in heat can cause binding.

Your piano is not more of a lemon than any other piano in its price range (and probably better prepped than the majority of entry level intruments). However, the bushings, both key and Damper rail, need to be eased more than normal or replaced.
If the feel becomes to sloppy after the easing, and I have found that stability in these instruments requires more free play than I like, you will need to replace felts. It come down to how much you want to put into this instrument. The Chinese pianos can be great deals, but they are still not there yet.

I was un-aware of the issue with cost effective felts installed in Chinese pianos Aaron, thanks for the additional input, and hello to you. I would have to agree with your sentiments on the small changes in heat causing binding. I was dismissing the small change in heat there... Critic, any of this info helpful?

Hi guys. Thanks a lot for the comments. I can appreciate the fluctuations in the sanctuary between weekdays and Sundays -- but if this were a significant factor, then few pianos would be stable, no? (The Heintzman replaced a 120-year-old Hardman grand that only had trouble staying in tune toward the end).
Will repeated applications of Protec shorten the life of the felt in any way?

Well, when you think about it pianos are not really stable.. they rise and fall according to atmospheric conditions. Half a degree in temp. or one point on the humidistat and there is change going on. As far as Protec goes, I will have to defer to Aaron, as this is a product that I do not use, Aaron, any help there for Critic on this one?

I'd probably disagree "just a bit" here

Yes, I too disagree somewhat with the half a degree in temp or one point in degree of humidity.

Disagreement is sometimes a good thing, and hello to you Larry. I am hopeful that you will expand on this statement.

I'll chime in. Humidity fluctuations in the piano are long range. The moisture enters and leaves the parts at a much slower rate than the heat. That means the daily small fluctuations have no or little bearing on the average.

Hello Ron and Larry, I have quickly gone back to a reference book, and yes, I mis-quoted from memory... Here is what I should have stated, and this is a direct quote " Every change of a degree in temperature, or of one-tenth of an inch in barometric pressure has its effect. Dr. William Braid White, Piano tuning and Allied Arts, page 223,last paragraph. My apologies for the misinformation Critic, hope I did not serve to confuse you there,.... Ron and Larry,can either of you two comment on Protec for Critic?

Small changes in temperature can change things quickly. Try measuring pitch on a string with an ETD, then breath on the string, the pitch will change measurably. I have never tried an experiment with humidity like that. However how much do those tiny changes mean to the average client.

In concert work the humidity of a snow melt off day (the highest humidity we normaly have here in Montana) can be enough to change a good regulation. I have found that these Chinese (is Heintzman made by Dongbay?) are very prone to this happening.

As for if Protek will harm the felt.

Anything we do will change it's character. Protek will make tight bushings tight and slick. Therefore it is a quick fix at best. I have found it only has a working life of between appointments, meaning I will be back to fix the same problem in 6 months.

I think the felt will last just as long since your humidity at 30% is not going to react with anything. Protek is designed to be mild on piano parts.

The right fix is still to ease the guide rail bushings, carefully, they are not glued in. Protek is just too temporary and hard to make consistant note to note. I use it for clients who just want to get by. I can lube in seconds.

I would not argue for a moment that small changes to the RH and to some degree temperature will cause changes to regulation and tuning stability.
However a half point of temp or a full degree of RH will not cause noticable difference in my opinion.

Regarding Protek, especially the Protek CLP I cannot give a strong enough recommendation for those who have never tried it. Though rather expensive, it is the best lube for center pins I have ever used. I recently encountered a small Whurlly console whose hammer flanges were virtually frozen. When the soft pedal was depressed, every hammer remained almost touching the strings. I figured as slow as they hammers were, CLP might free it up a little, but would not take care of the problem. I could see a re-pinning job in my future. However a couple of drops of CLP to each flange did the trick, and two weeks later the slowness had not returned. I swear I live and die by this stuff when it comes to flange problems.

Regarding CLP and felt or cloth, I think there are better lubes. Though I dont think it in any way damages or changes the consistency of felt/cloth when it dries. As already mentioned, it works best for flange center pins. In addition to the Wurlitzer mentioned above, my experience is it does indeed have a longer term effect than six months or so. In fact, a Baldwin with very slow hammers comes to mind, that I CLP'ed 4 years ago, and as of this past December there is no slowness. It diminishes and eliminates virtergis. It think that is the miracle behind Protek CLP.

thanks Aaron for the input on Protek. I was suspicious that it was a "bandaid fix". Also we are aware from reading the original post, that one application has resulted in the same problem re-appearing again, and your suggestion of re-felting might end up being the final solution for Critic.
Keith, hello to you, and thanks for chiming in... I would have to disagree somewhat with your statement regarding humidity, especially here where I am residing. This is a northern coastal boreal rainforest, and humidity is a big problem here... Also, where Critic is located, I am not sure if you are aware.. the Toronto area this year has been hit with some of the worst winter storms in its history, a ton of snow they are trampling through, and all those wet overcoats and boots in that sanctuary must be taken into account. Also Toronto is on the edge of the Great Lakes system. My presumption here is that the wood in this instrument is new and will not take much moisture nor give it away, not like the 120yr.old Hardman they disposed of, so where does the water go... perhaps into the feltwork? Maybe we could encourage Critic to get his/her tech to let us all know here what was found to be the culprit.
Cheers

Ron, thanks for the info on Protek.. I feel compelled to order this product and try it out.
Critic, I hope some of this dicussion has helped, or given you some insight as to what could be developing in your instrument.

Hydrostatic pressure does not discriminate between old wood or new.

Temperature differences, well, usually we are dealing with extremes, a church that turns the heat down 15 degrees and back up or the sun that has just come on, or off the piano.

It might be a good study to measure just exactly when and how much specific incremental temp effect the piano. What is the exact rate of change.

The heat used on the damper guide rails was, more than likely used to resize the holes. Felt "irons" very well and this type of an adjustment is one of the more stable.

Thanks Dan. Yes, it is rather pricy stuff, and there are better lubes for cloth, felt, knuckles, etc. But it beats any other center pin lube I have ever used. Go easy though; dont need but just a drop or two. Only in extreme cases do I go a little heavier.

Dampp Chaser might have the answer to that one Larry.

I agree on the Dampp Chaser when the room can't be controlled.

No, Larry, sorry, I wasn't clear enough. I meant that Dampp Chaser might have the stats about what you said about this" "It might be a good study to measure just exactly when and how much specific incremental temp effect the piano. What is the exact rate of change."

A Dampp Chaser isn't going to do much if anything for the action on a grand, unfortunately.

Is it possible that you're experiencing a key/hammer weight problem? Your tech already beat the friction problem to death six times, and that would go right along with the unevenness of the action. I can't say why it would get worse with playing though, unless it's the pianist getting more and more frustrated.

Sorry Jerry, I am reading too quickly.
They might. I'm a little curious to ask.


There are a range of challenges with Chinese actions. Only a thorough examination will tell that particular story.

As far as beating friction to death. It is well documented that some flange bushings tighten up with use. Every manufacturer of these parts has had to contend with that one.

The Chinese are just the latest.

Renner, Tokiwa and Abel have all been through this. I wish I had paid more attention to what their "solution" was at the manufacturing level.

Might be a good question to email them.

Larry, your comment re: " Hydrostatic pressure does not discriminate between old wood or new" I am wondering now if my mistaken quote earlier in this thread, has got us thinking of two separate things, that being humidity content in the air versus barometric pressure. I beleive there is a difference. Also, I have some interesting case study on this issue, when I worked under contract with six school districts in the local area here. I can research my old files and post, but this may result in some rather long postings and I am mindful of being new here, and do not have a desire to hijack this original thread onto another topic. Should I start another thread on this topic or continue? Hello also to Jerry Groot and Swallowpad, thanks for joining us.

Dan, Well, can you clarify your point?

I've had great success with Pro Tek as well, I found the effect generally to be permanent, the exception being pins with verdigris. My experience is pretty much that it either works or it doesn't. If two applications don't work, then the bushing is just too tight for lubrication to work and it needs to be physically eased. (shrinking, ironing, reaming, etc.)

Where I live, virtually all of the Kimball uprights (70s-80s) had sticky jacks, a single Pro Tek application has been a permanent fix. Prior to this those actions had to go into the shop and get a series of water/alcohol treatments.

It seems to me that flange pins will be sluggish for different reasons. Beside just being too tight, verdigris contamination; also I think either dirt or mold can make even dried out flanges sticky. Ron's story about the Wurlitzer reminds me of this, just a drop of the Pro Tek and they flop back as though it dissolved something in the bushing felt.

I don't think the Pro Tek is that expensive when weighed against the time it takes to water an action, wait for it do dry, retreat it, etc.

Wow. A huge thanks to all of you for providing such thoughtful replies. It will hopefully help me in my discussions with the tech. One more item: On the last visit, the tech noticed what he called a gooey substance on the capstan pins (the brass thingies that screw in to the keys -- I hope I've got the right term). He rubbed each one with Protec (as well as applying the Teflon powder to the felt that came in contact with this spot). Without a magnifying glass, I couldn't see the surface of each capstan clearly enough, but it certainly didn't feel smooth. To my fingertips, it felt pitted. Do you think the factory is trying to cut corners with a cheaper coating to keep the brass from oxidizing? (my father owned a fastener-manufacturing business, and I know that brass parts would get either an oil or light lacquer-type coating to keep the metal clean).
Anyone run across something like this before?

Absolutly. Some of the cheaper pianos they don't bother to clean the capstan before installing.
Quality brass is another issue.

Yes I do agree that the regulation can change far more rapidly than tuning. Felt is hydroscopic.

I have some thoughts on the parts used, but I have to run. Later

John, Dan: Welcome Aboard!

I remember reading a study on treating center pins. It must have been either here or on the Pianotek List. The results were that alcohol/water worked almost as well as Protek in the short term (after the action dried), and out performed Protek and everything else after a few months.

Speaking of Kimball uprights, I fine tuned and adjusted the lost motion on a spinet in a sanctuary yesterday. The more it was played the more sluggish the action became, especially the notes in the high treble that are seldom played. I’m going to call the Pastor today to let him know the options if the pianist doesn’t care for the response. It seemed to work better leaving some lost motion, like giving it some momentum on the return or something. This is in addition to the extra lost motion necessary due to the divot in the hammer butt.

If they want more work done, I plan on removing the action and blowing it out, removing the keys and cleaning the key bed, and using alcohol/water on the wippen flanges and elbows. The keys are very free, but would check them and ease if necessary. A few days later I would return to regulate and as a last resort add jiffy leads.

Any thoughts or advice would be appreciated.

Critic: If you think I’m stealing your thread, please say so. I hope I'm just expanding it.

Originally posted by Critic:
The reputable dealer has a large service department, and I visited with the technician who spent two full days preparing the piano, so I know how thorough he was. ______________________________________________
Do you have any idea what was done to the piano during the two day prep effort?

"Hygroscopic" means it will attract moisture

Larry, I am back to clarify....
"Hydrostatic pressure does not discriminate between old wood or new."

Of course not – but old (dry) wood and new (moister) wood will differ in how they absorb moisture from the air (humidity)

Now I have written it using slightly different wording again if you like this better...

but old (dry) wood and new (moister) wood will differ in how they react to the moisture present in the air (humidity)

hydrostatic pressure:
The pressure exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity. Hydrostatic pressure increases in proportion to depth measured from the surface because of the increasing weight of fluid exerting downward force from above.

atmospheric pressure:
n. Pressure caused by the weight of the atmosphere. At sea level it has a mean value of one atmosphere but reduces with increasing altitude.

Relative humidity:
Measured by percentage… this is the amount of water content in the air, water that the air is holding (suspended)

Larry, with all due respect to your many years of service there, I think we got off track there. I believe we are now referencing two different things. If you will be kind enough to go back to the original posting, I had pin pointed a statement by Critic, 4th to last sentence in the original posting “ the humidity in the sanctuary is a steady 30%.” I am in complete disagreement with this statement. This is why I was expanding on why I felt this new instrument was giving moisture-related problems. More in a moment…

This is coming from old files on Government-controlled, tax-payer funded school districts. In these days of privacy legislation, I have to be careful here. I cannot list schools, districts, cities or people by name, and while IANAL I think we all understand the legal implications here if I do. Legal implications not only for myself but for Mr. F. Baxter too. too.
Humidity experiment 1993-1995 various schools
“You were just here less than a month ago by looking at the invoice I signed off on Mr. Silverwood”, stated the principal on the phone, “and now, in the multi-purpose room, the music teacher says that one of the instruments is badly out of tune again, and the other has keys that don’t work”… This again, I thought to myself, why does this symptom continue to appear, and then disappear….. it had been going on for a while, this intermittent problem, I would attend a school and tune, inspect and/ or repair the instruments only to be called back in a short length of time with this complaint. With six school districts, 398 schools, I was getting this call almost weekly. I had been doing this contract work for approximately 5yrs. And this continual re-occurrence was, well, getting under my skin ok? (Not the language that I want to use here, but this is a family show right?)
Opening the door to this room, I was hit by the dank smell of water… the temp was up as this was a boiler heated building, all rooms virtually the same temperature, controlled by the stationary boiler engineer in the control room.
It felt like stepping off the plane in the Bahamas. Sunny, mid 90’s for temp, and 94% humidity.
I inspected the first instrument. 1963 Sherlock Manning, console style, purchased new, and at that point, in this environment for thirty years. The temperament octave was waaay off high… ten beats over five seconds on the tuning fork, this symptom went from the treble crossover start to the E above high C. the rest of the tuning, bass/ high treble, dead on. But this room was up to temperature I noted. All weekend. Later on, in my theorizing I nicknamed this symptom a “water bubble” Mystified, I inspected the second instrument.
Yamaha, late model P22. Purchased that school year, only a few months old. Tuning. Middle C beatless with the fork. Rest of tuning dead on, well, with a slight variation because of tuning approx. one month or less earlier, but a negligible difference. Played instrument. Sticking hammer flanges. Various sections of the instrument, mostly the lighter hammers on the right side. Played with the dampers released (sustain) hammers sticking, and slow everywhere. The more I played this piece, the slower the hammer set moved, until most stopped within a half inch of the strings.“What has happened since I was here last” I queried the administrator. I received no satisfactory answer that I was willing to accept. I went back to the room. The janitor entered the room. “Oh sorry Dan, did we screw up the tuning by moving it across the room?” “No” I murmured trying to block the frequency of his voice while contemplating. “That would not do this to that extreme” I then stopped my work.
“Why did you have to move the pianos” I asked. Well he said, “a maintenance crew was here Friday night from 3.30 till 10pm. doing some work. That’s why I left the boiler on over the weekend.” “What kind of maintenance I asked.” “Carpet cleaning” he said.
This was Friday night. I went to the school after a holiday weekend (Monday was the holiday) so Tueday the instruments had been sitting in this room with high humidity for 72 hrs. Actually to be more accurate the carpet was drying out over this time too… I could see on the ceiling a collection of moisture similar to dew on the windshield of your car in the early morning. If the carpets were cleaned again, I thought, it may start raining in this room shortly. Temperature for both… Identical. Humidity content in room for both…. Identical. Hydrostatic downward pressure for both…. Identical. Barometric pressure for both…..identical.
How was I to explain this not only to the admin, but to myself?? By this time in the contracts I was beginning to form my own theory, based on my own experience here in the northwest.
Argument:
The old instrument was acting like a dry sponge. When the carpets were cleaned it was like a super-sized Slurpee for this old piece. This old instrument, I theorized, had sucked up a bunch of moisture from the air…just over three days… a very rapid change, I noted for sure. Not the change over time like was stated earlier, in this thread by Mr. Keith Roberts. The new one. Well the wood is new and plump with the remaining moisture left from the kiln processes, probably not going to take up much water there, nor give off much either, until such time as it started to age and the wood quality deteriorates. However, not the same could be said of the new felt in this instrument. This is new felt. Not many emollients from the air have crept into the feltwork yet so I theorized that this felt would be ready to accept any change of those airborne particulates. New felt contains no moisture and is ready and willing to do so I thought.
I could not fix this problem immediately I informed them, and will have to book for later in the week, because I have other schools booked. This was accepted, although begrudgingly.
Returned to the school Friday of that week. Seven days since carpet cleaning.Tuning on the old piece had almost returned to normal… close, but significantly better than the first encounter. The new piece was playing fine in all areas except the high treble (light weight hammers).
I got to know the maintenance crew foremen in all the districts after this revelation. I purposely re-created this symptom time after time with old instrument versus Yamaha, old versus Young Chang, old versus Petrof and on and on. Every time it was the same result with a variation of course on the flange sets sometimes the hammer flange, sometimes the whippen, that kind of variation. But each time the end result was the same. Within seven to ten days this equipment picked up and gave off moisture in two very distinct and different ways. Old wood and new wood reacting differently to the downward pressure of “water in the air” I thought this rapid change to be remarkable.
So let us go back now to the original statement by Critic. The humidity in the sanctuary is a steady 30%.”
How can this be? A couple of hundred people walk into a room with wet coats and boots, sweating and breathing and singing, and children blowing their noses and so on. While they are sitting in the pews are the coats and boot not drying out somewhat? Just like the carpet? Where is all that moisture going? Into the air. This instrument they have purchased in this instance is new. The wood is new. The sponge is full if you will. But the feltwork is new and waiting to suck up anything you present it with. This is why I suggested to Critic that the problem he is having there I have found here to be the sudden addition of “humidity content in the air” measured by percentage.
I now do contract work for a large American church organization. I get a lot of calls on Monday mornings from the church organist/pianists that “the piano is not playing like it did on the weekend.” I usually go to check on a Friday and presto!! plays just fine….. Hope some of this helps….

oh and a big hello to Upright Tooner and Gene Nelson.... the more the merrier here I say.....

I'm thoroughly enjoying the discussion -- even when it goes off in tangents. I'm not a technician, so every bit of information adds to my education.
Gene -- what I saw the tech do (not necessarily in the right order): pull everything out and vacuum everything, align all the keys, align the hammers and set the blow distance, make sure the hammers were hitting the strings at the right angle and distance, adjusting the dampers and re-seating every string on its hitch pin. He also did some voicing and a full tuning. On my approval visit, at the end of Day Two, two dampers were sticking. The tech had left and I left him a note to that effect.

John,
If the flanges require continued dosing with ProTek this situation will continue until the flange bushings are reamed to get the proper fit to the center pin. There are ways to do this faster than reaming - water alcohol or use of the "zapper" - but not as accurate.
There is probably friction at the balance rail holes and bushings as well.

Yes CLP Helps but on too tight bushings, the original method with a water/alcohol mix is more definitive in the way this is a mecanical action, does the same as getting the center out and punishing the cloth.

All center pins in Renner actions are (where) finally adjusted each other with that method.

Some testing may have to be done on other wood, sometime the result is too good !

Burnishing, not punishing ! but I mean with the use of a conical reamer.

Had also parts that did not like CLP and get froozen after a few weeks (mostly the surface treatment of the centers where not neat, due to corrosion)

I now check the color of the center pin before using a lube.

Dan:

Thank you for the very detailed post about your experience! I read your post carefully and hope that I understand you reasoning.

I am not sure you have taken all the important variables into account in your conclusion about the old versus new soundboard.

I believe that older pianos change more in pitch than newer pianos due to loss of elasticity in the strings and having less downbearing due to loss of crown of the soundboard. I don’t know if the amount of moisture they can absorb is much different than a newer piano or whether that also makes a difference.

I believe if an older piano has say 1 degree downbearing and a newer piano has say 2 degrees, that the same change in soundboard crown due to humidity will affect the pitch of the older piano more. Also if the older piano’s strings are less elastic, the pitch will be affected more than on a newer piano with more elastic strings. The less elastic strings will experience a greater tension (and pitch) change.

Anybody else have thoughts on this?

Kamin: Welcome Aboard!

Forum rules ask that those with "Industry Affiliations" (like being a piano tech) include this in their signature line.

I've been enjoying your posts and see an advantage to your good, but not perfect, English. I find myself really thinking about what you are posting instead of skimming through it.

I get the idea that you are very experienced, much more than me. Could you start a topic telling us about yourself?

Regards,

Upright Tooner,
Hey thanks for the comments and observations. Very good points you have made for further argument. I have to go to work shortly and have no time to post another fascinating story about a small upright that came off a plateau. Then I would like your conclusion on that one. Or should I start a new thread on that one? I don’t want to forget John…. These are all great observations here….. continually soaking a flange in liquid is like Gene stated a “symptom reliever “ and does nothing to address the problem .
Regarding Kamin it is a small error and he is also new too. He appeared yesterday and started sharing his wealth of experience. Yes this guy has some history with European stuff and is knowledgeable regarding design mathematics.
Regarding the English structure he may be doing one of two things. Some translation software really butchers the translation, or he is translating in his mind from French to English or Flemish to English.
I am only presuming here and do not want to offend, most Europeans have the good fortune to have knowledge of more than one language. I like the way he is writing though it does make you slow down and really read for sure
Great stuff here theory, knowledge, argument……

Hello you two !

Indeed I forget to present me , I will do so asap !

My english is pretty basic, I know ! I hardly imagine how it is really easy to understand or if you have to make a great effort to be sure to understand the content.
I know well enough the piano english terminology (and some of the piano gold rules from different continents) so it look easier to me to write than it is for you to read.

Please dont hesitate to correct my grammar if something can lesnd to misundertsanding, and yes I mosly translate my French way of thinking in English words, that may sound like Babelfish !!
I hope the inhalt (is not it a German world ?) is preserved, nowadays.

Upright T, your reasonning for the pitch change is reverse than in real, a recent and more active soundboard will move more with humidity changes, at the same time piano wire settle in 2 to 5 years, then most of the elasticity within the metal is dissipated, the angles of the wire are often enough the to maintain a "playeable" tuning on old instruments even with poor tuning pin stiffeness.

I worked for a 1500 student conservatory in Paris for years, being attentive to make fast tuning tweakings more often than making 2 or 3 "official" tuning the year. Done that for 4 years, the instrument range from 8 to 28 years old.

For some reason the organisation changed and the instrumenst where left untuned at all for 18 months. I was very surprized that the teatchers did not complain, and I finally had some pianos inspected (a compettition to obtain the contract was planned ).
I was expecting 436 Hz pitch and very out of tune instruments. To my big surprize, while the pitch was more 439 than 442 , the pianos I tested where still playeables '"good enough" like many piano teatchers there can state , I hate that !!!)

Settling of the pins and minimum moves from one tuning to another lend to that unbeliveable stability (I also had zero strings breaking in 4 years, most colleagues don't believe me !)

When the wire is less elastic, the regulation is good ane the hammer relatively well voiced, the instrument can be used intensively without damage. Even the wear of the parts was slow, because of the regulation settled, cleaning (dust is abrasive) and lube on the keys pins, whippen's cloth, etc. (attention to the action screw)

But indeed moist of the time it is a continual work. I dont look for music schools actually !

Kamin, I agree with you regarding soundbaord crown and tuning stability.
I will add that there is the occasional new piano that will have a flat soundboard out of the factory. One concert piano in particular at a local university shows amazing tuning stability and does not have humidity control.
I no longer use conical bushing reamers.
In regard to alcohol water I will use it with great results but it eliminates the option to match hammer flange friction to the mass of the hammer.

Kamin:

Thanks for the reply. I am always looking for correction. Please feel free to give it. If I can understand it and it agrees with experience I will accept it.

Now, I think you are right that a new soundboard will change its crown more with a change of humidity than an old one. It doesn’t seem that Dan agrees.

As far as a string’s elasticity, not changing after a few years, I have a different experience in this. Maybe we’re talking about two different things. A new string will stretch after being brought to tension. Some people say for a few years, others say almost immediately. But, I’m not talking about a string continuing to stretch or not. I’m talking about its ability to stretch. I experience older strings requiring much less movement of the tuning pin for the same change of pitch compared to newer strings. I believe the strings’ loss of ability to stretch (elasticity) is one of the reasons that an older piano will go out of tune quicker than newer pianos. The movement of the soundboard due to humidity affects the tension (and pitch) more than a newer piano.

Another experience I’ve had is the loss of soundboard crown (and downbearing) on older pianos. The interiors of buildings in this part of the world go through large humidity swings. I’ve read that this swing in humidity progressively crushes the wood cells in the soundboard, and I believe it. Older pianos, around here, have less downbearing than newer pianos. I believe that a piano with less downbearing will change pitch more due to a change in humidity than one with more downbearing because the relative change of downbearing is more, and affects the tension (and pitch) more.

So, I believe that although an older soundboard will change its crown less due to a humidity change than a newer one, the piano’s pitch will change more due to the strings being less elastic and the dowmbearing experiencing a greater relative change.

So, Kamin and Dan, what are your thoughts?

Gene: appreciate the endorsment on alcohol/water. I don't have as much experience as others and its hard to decide what to do sometimes.

Also, how was the downbearing on the piano with the flat soundboard?

Gene,
indeed I only use them in the field, and prefer long un roughened needles that are sold by Renner.

You can vary the alcohol water mix between 90/10 to 30/70 so if you like to have a little less efect it is always possible . It takes some testing when working with a particular action, and we need to have a few hours to allow the drying of the part. I had good result on some very old Erard that use silk cloth in the bushings (reaming is not an option) But on those it is necessary to reapet the tretment 3 or 4 times since the friction get correct.
I agree to match friction with the hammer weight but a little more firm in the high treble is preferable, to keep a better contatc between jack and roller under the vibrations of the shank.

On entry level instruments I doubt we have to go that far in refinment anyway, having the piano functional and stable is yet a first step.


I no longer use conical bushing reamers.
In regard to alcohol water I will use it with great results but it eliminates the option to match hammer flange friction to the mass of the hammer.

I am very dubious that strings become less elastic with age. The only way that could be true is for the steel's modulus of elasticity to change to some noticeable degree. Although steel's yield point can be changed by tempering and work hardening, I don't think the modulus for any given type of steel is subject to much change at all.

Upright,

what change the pich is the shape of the crown that change with seasons , that is why extreme bass and treble does not vary much.

When the wire is out of elasticity, it is in a plastic state, old strings are really at the edge of this , did you ever noticed that you know when a string is prone to break, because you turn the pin, and nothing happens in the wire.
I believe tat too old wire will loose its tune mostly because it is played and then it deforms.

Change in down bearing is not related to pitch really, but to tone strenght and purity, downbearing is a necessary evil that allow for a good contact of the wire on the bridge. It is also then used to stiffen the soundboard in some regions, depending of the kind of construction. One big tendancy actually is to say that we need flat soundboards, absolutely free to vibrate up and down, and a better way than bridge pins to secure the strings on the bridge, string's agrafes, for instance, like uses Stuart, Stephen Paulello, Richard Dain.

I have not enough understanding of the different methods and intentions in soundboard making, but , I have a feel that slowing the reaction of the soundboard, is possibly some advantage in the tone stabilisation and act like filtering unwanted noises (a little the same idea apply on action, that need inertia and friction for tactile feedback and security reasons).

Older (grands) instruments can stay in tune very long sometime, assuming they are played gently, the loss of friction around the tuning pin is mostly a problem while tuning, but once the tuning pin is in an accepteable setting (the force from the string help the tuning pin not to turn) the friction under the wire can keep the pitch very stable for a long time.

I suspect that the vibrations when the piano is played strong can un wind the pin settling and then the tension disspate,on vertical pianos there is not much friction and the wire is a very short lenght , what I said about stability of old instruments apply only for grand pianos indeed ( sorry if it was not clear from the start)

Also, if the wire is hard and without enough elasticity, you hardly can use it to help the pin setting, I've find that it is easier to set the pin when a string have been changed, despite the lack of holding of the pins.

The extra elasticity of a plain wire can be as high as a major third for the first note on the long bridge, ranging to a half tone in the high treble.


eform while tuning,

Thanks for the Erard tip - I have not had the chance to work on one to date.
One other trick that I was taught in regard to university pianos was the use of an electronic tuning device. If every tuning was exactly the same the tunings would be more stable over time.
UT - I did not do accurate bubble gauge measurements on this piano - however, using the string test under the soundboard there was zero crown with exception of slight crown of maybe .5mm in the bass. Unabel to access the high treble area. The rocker gauge on the bridge was inconclusive.
I have been taught that it would not be a good thing to have measurable downbearing combined with zero measurable crown.

Gene: Thanks for the additonal info.

Kamin: Thanks for the response.

I've got some food for thought. I think I'll digest for a while.

Gene ,

ETD You bet I used one !(see my english get netter ! ) indeed this was of big help for stability, BUT as sounboard shape differs from season to season, tuning the same does not absolutely mean using the same exact picth and stretch at each seasonal tuning. I had a VT100 , and used it for years (even in concert venues as I worked for that as well).
Once my VT100 was robbed (by someone who did not knew what was in the box. I decided not to buy another, and I finally tune way faster without it , and have let's say more pleasure to tune.

I use now a tunelb for pitch raises and pitch check, besides I am one of those pure ear guys, and using the boxes for so many years recorded in my ears a lot of things, like may be the overpull to be used for pitch raises.

I decided I can do a less "perfect" tuning that is sometime more pleasing, the lot of copromizing of the VT 100 tend to be a little too much sometime.
I rely on my ear to regulate the tone energy availeable, it helps for the octave stretch and good adaptation to room.

Indeed if I where to make music schools tunings, I'd buy another box, only to fight tiredness it is yet nice... but I've find those too long to regulate so they propose exactly what you like to hear, then you are loosing some time.

Gene ,

ETD You bet I used one !(see my english get better ! ) indeed this was of big help for stability, BUT as sounboard shape differs from season to season, tuning the same does not absolutely mean using the same exact picth and stretch at each seasonal tuning. I had a VT100 , and used it for years (even in concert venues as I worked for that as well).
Once my VT100 was robbed (by someone who did not knew what was in the box. I decided not to buy another, and I finally tune way faster without it , and have let's say more pleasure to tune.

I use now a tunelb for pitch raises and pitch check, besides I am one of those pure ear guys, and using the boxes for so many years recorded in my ears a lot of things, like may be the overpull to be used for pitch raises.

I decided I can do a less "perfect" tuning that is sometime more pleasing, the lot of copromizing of the VT 100 tend to be a little too much sometime.
I rely on my ear to regulate the tone energy availeable, it helps for the octave stretch and good adaptation to room.

Indeed if I where to make music schools tunings, I'd buy another box, only to fight tiredness it is yet nice... but I've find those too long to regulate so they propose exactly what you like to hear, then you are loosing some time.

Talking about pitch in our region, the 442 pitch goes down to 440 during winter and raised up to 444 when the school begin in september. So the pitch is somewhat corrected during winter but not completly, and if it goes down before summer I don't correct it, as I will always have to lower the medium first 2 octaves +- in september.

Acceptable strech can vary, so we have room there, hopefully.

Nowadays school tuning means mostly a good appreciation of the moving of the ocatves, and a correction "on the fly" with the use of an EDT, that is the best method to have some money and a stable instrument. Concert tuning gives some good (or bad ?) habits to do so, because of the focus on unisons.

Upright Tooner,
I ran this test between 6 and 10 times.
I made sure when a carpet was being cleaned, there were two pianos in the room. Every atmospheric condition was identical. One piano more than 30 yrs. One piano less than 5yrs.
Here it is in one short paragraph: The tuning on the old instrument always went sharp significantly. No sticky flanges or keys, ever.
The tuning on the new instrument never moved much at all, but lots of sticky flanges. And even sometimes those new Teflon pedal bushings or whatever they are.
After seven to ten days the instruments mostly returned to normal, this being a relative word. Yes, I had to repair some of the tuning structure( musical scale) and yes, there were a few flanges I had to alcohol, but the adjustment after a week or so was significantly less (moisture leaving the room)
I theorized , that the new felt would pick up moisture readily, and jam up the new instrument mechanically, the felt in the old instrument was full of dirt and crap and would not accept water.
I theorized the wood in the old instrument was dry and took on water, the wood in the new instrument was already full of its proper water content.
I am sure some here might think this a fairy tale however remember, it may not be real for you there, but it really happened here. Over and over I made sure……..
Comments and opinions please………

Well I believe you Dan, no problem, as you say may be the old instrument laquer did not protect the soundboard as well as the recent one, hence a bigger change in pitch.
That does not say about the crown of the instruments, a 25 or even 50 years old instrument can retain a lot of crown (it depends of the ribbing I have seen 1885 Erard or pleyel with lot of crown and eventually not a crack).
What I state and what colleagues also say is that flat soundboard instrument have less seosonal pitch changes than well crowned ones, and I noticed also that on more lively toning pianos vs low downbearing ones.

Seosonal change mean longer exposure to moisture, day after day, laquer is doing its best but finally the moisture pass thru.


You may be right with the felts an cloth questions.
Cheers !

This would bring up the question of weather or not action centers change friction with changes in relative humidity when installed on parts that are manufactured from composites like the Wessel Nickel and Gross or Kawai Mellenium action parts.
Part of the appeal of these parts is to avoid humidity related issues. The flanges are bushed with typical bushing cloth.

Good question, Gene.

I don't think that the flange material (wood vs composites) is as important as the bushing itself. In decent, high quality wooden parts, I don't see too much variation in center pin friction when the piano is in an environment that is reasonable for pianos. I see many more problems with lesser quality parts. Perhaps it is the quality and the characteristics of the bushing cloth and pin material, or maybe the processing and manufacturing.

What I am saying is that a good quality wooden flange will out-perform a lesser quality flange of any other material, inert or not. Incidently, I recently saw some of the new black plastic (composite?) flanges - friction was all over the map - I rest my case.

Regarding the original post of this thread - if there are new flanges which are too tight and a single treatment doesn't free them up properly, there is only one solution: repinning. They are too tight from the factory, or the cloth strip was too wide, or the sizing was incorrect, or the cloth was inferior, or.... ???

It doesn't really matter, you need to repin. And this is fairly common in Chinese pianos, end of story. While the tech is at it, repin them all - the ones that aren't fixed this week will be the ones that act up next week...

Jurgen: Thanks for joining in. I was hoping you would. I think we have been missing some pieces to the puzzle and you just provided a few.

All: We all know that wood and wool felt expand when they absorb moisture. It just occurred to me that this is an argument against composite flanges! When a (edit -wood- ) flange absorbs moisture it gets larger, including the hole for the bushing cloth. The bushing felt also expands, but probably more, and quicker than the flange. I would expect a composite flange, since it does not expand much (if any) with moisture, would develop more friction with an increase of RH than a wooden flange.

Dan: Thanks for more details on your experiments. I believe you reported exactly what happened. Now, why those pianos behaved like they did is a separate thing.

I would expect the tuning to change differently between the pianos for the reasons I mentioned in other posts. The strings are less elastic and there is less downbearing in the older piano. The change in crown affected the pitch more, because it affected the tension of the strings more.

I would also expect the action to change differently. The older piano has bushings that have seen more wear. They also have gone through more humidity cycles (which is what an alcohol / water treatment does). The older piano has looser action centers and the increased friction did not cause problems. It might have even made the action work better!

Does any one else have an opinion on this?

Edited Post

I don't know the effect of the hardening of the strings with age on pitch, one may want to analyse the pitch formula and see if the elasticity of the wire is a large parameter for the pitch.

It may play a role, but I thought not so much, less than tension, lenght/diameter.

Kamin:

What I mean is, if two wires are compared that have the same length and pitch but different elasticity, if each is stretched the same amount, the one with less elasticity will be at a higher pitch than the one with more elasticity.

"When a (edit -wood- ) flange absorbs moisture it gets larger, including the hole for the bushing cloth. The bushing felt also expands"
_________________________________________________
Would a logical analogy of this idea mean that tuning pins get looser as humidity and moisture content of the pin block increase?
Not in my experience.
Waiting for my WNG parts to install on 1913 Knabe. Bruce did a wonderful job designing the whips. They are innovative, not just composite - I believe carbon and glass fibers, not plastic.

The debate get philosophical there !
but the pinblock is a very differnt part than the flange, with have small thickness till the edge and react differntly (expanding , more along the grain than vertically I believe the whole tend to get oval)

The quality of the bushing cloth is a complicated setup when it have to be used in ABS or synthetic flange. I am sure that many tests have to be done before using the flanges in reality. I for instance find the Kawai flange cloth to be soft at first sight, but the softness is may be only a larger elasticity used to allow more compression of the cloth and return with moisture changes)
I have been told this cloth is a mix of differnt fabrics.
For the wooden flanges Renner still uses pure wool cashmere (and some thin graphite coat within, that is said to have also some hygroscopic function, while this seem and old method may be not really backed by careful research)

Gene:

I agree with you on tuning pin tightness, but not everybody does. There was a discussion on this during this topic:

http://www.pianoworld.com/ubb/ubb/ultimatebb.php?/topic/3/3384.html#000018

I do notice that keys need easing more often in dry weather. I think the difference may be either in the pinblock being laminated or being screwed to the plate.

How about another analogy - when soundboards are dried to 5% moisture content then the ribs are glued on - then the assembly is exposed to higher moisture content in the atmosphere - the result is compression of the wood fibers and some crown on the board. Does wood expand in both directions along three planes with moisture increase?
Taken to an extreme this compression will damage wood fibers.
here is a interesting tool and the download is free:
http://justwoodworking.com/software/wood_move.php

Jürgen,
Just watched a new Kawai upright #FL01**** being un-packed and installed at one of my churches. (dropped shipped) Black composite jack and tower, black composite whippen, did not view the whippen flange.
One full tone flat( delivered from a cold warehouse and “friction all over the map”) Ho hum just another day with a “entry level instrument”

Gene
I went back to my notes, and interesting that yes this did not happen with two new kawai instruments, remember this happened 15yrs. ago. Interestingly though I have all Kawai in my churches and this does not happen there, this symptom, but with some of the Young Changs, it still does. Quality difference in production maybe? Or quality of part assembly perhaps?

Gene,
Sorry I mis-spoke there. what I meant was the Kawai instruments demonstrated much "less change" and this problem was not as dramtic as the old versus yammy, or old versus young chang, or old versus petrof...

Hi Larry,
Point taken, and no offence meant in my post. I have edited it to remove any identifyers. Perhaps you can do that to your response as well?

My point was that the flange body material is secondary to the quality of the entire flange (cloth quality, pinning workmanship etc.) in terms of the flange performance.

regards,

Dan: The reason the problem was not observed in Kawaii's might be their bushing cloth doesn't expand in humid environments as much.

Gene This is only one of the four methods employed to rib a soundboard - beside, none of the european piano maker dry the sounboard panel to less than 7 % , (not even Steinway) it is actually considered as mediocre workmanship to do so. Some brand even verify after the ribbing that the wood cell have not suffered from crusching, as this will lend to problems in the long run. Ill have alook to your link , thanks

European makers routinely dry well past 7%.

Steingraeber is one.
Hardly mediocre.

Sorry Larry, absolutely not,

I'll provide you (when I'll put my hand on it) a private mail from Udo Steingraeber himself in fact he stated that drying under 7% was "old method for mediocre builders at best" .

The example you choose was not the good one.

Bosendorefer as well range 7%

Steingraeber doesn't care about the crown along the ribs. Udo Steingreaber has NEVER checked for crown along the ribs. He is only concerned about the crown along the long rib (bridge). That would be a quote, but Dale did a very poor european accent when repeating what Udo said.

Gene, the pins are driven in holes that are smaller than the pins. This crushes wood. The humdidity swells up the crushed wood more than the hole expands. This would make the pins tighten up. Also a laminate piece of wood will not absorb moisture in the same manner. The old pin blocks that are weak and the crushed wood that has given up expanding, they let loose in winter here.

One guy on the piano tech list was tired of all the, yes it does and no it doesn't. He drilled several 3/4 inch holes in various pieces of wood then threw them in a bucket of water. They were measurably larger than 3/4 after swelling up. Then they shrunk back when dried. If you draw grid lines on the block of wood you can see how the holes axpand too.

"...........Personellement je trouve que l'on perd des qualités sonore a
faire cuire
les bois a 5%..........."

"Oui, tout á fait !! Vous avez raison".

Mais les temps ou un facteur "cuit" le bois sont passée pour nous depuis 30 ans - c'est la manière des mediocres et la bas gamme.

- nous limitons la température à secher à 45 degree Celisius ! Et:
vérification si les cells sont propres et correct par microscopage de l'université d'Erlangen.

" I believe that the wood loose some tonal quality when dried at 5% "
answer : "you are right, but times when the piano builder "cooked" his panels is finished for us since 30 years, this is the way for entry level pianos"
Temperature run no more than 45 celcius, and we look at the wood afterhat with the Erlingen university to see if cells are clean and not crushed "

Origin of information is important, on Internet.

Crown along the ribs is probably necessary, even if we believe actually than the lesser crowned it is the better the soundbord is.

But I dont have first hand information there.

Kamin, Post Udo's letter here.

Everyone should have a chance to read it.

In the meantime, steingraeber@steingraeber.de

For anyone who is interested.

I was referring to Dale Erwin's conversation with Udo at the grand opening of the west coast Steingraeber dealer, David Anderson. Dale asked him how he checked for crown on the boards. With a string? He had never done this, he said.

Keith, I do not have any evidence one way or the other. The wood in the water bucket sounds a bit crude.
Have a new board - unfinished - at about 9.4%mc -will measure nose bolt holes now and after I get it down to 7% when I set bearing this weekend.
As it is easy to imagine wood movement in all directions (not equally) due to humidity changes I think that possibly the grain orientation in relation to the hole may be important? Possibly the size and shape of the sample as well?
If you could measure accurately possibly a round hole now could be slightly egg shape then?
Probably the larger the sample the more the movement.
There is a wood technology class scheduled at the National in June. See ya there maybe?

A quick google search says Heintzmans are made in China with the finest available materials, renner hammers, bolduc soundboard, Mapes bass strings, Roslau wire, etc. I would definitely stop easing right away, because when you get the felt broken in you will have really wobbly keys that are _no_fun_ to play. I would *start* by rebushing the both rails on the keyboard, using the Spurlock method, and polishing the key pins.
IMHO easing keys is for installation _only_. If it needs further easing, rebush instead.
Easing at other times would be an emergency resort, right before a concert.

Be nice to your keysticks.
They are worth it.

It not crude at all. It the best way to see the extremes and what really happens to the hole. The hole gets larger too. This is by actual measurement and you can try it. Measure the outside dimensions of the wood too. What do you think the range of expansion and contraction is in a pinblock?

Wood in old houses shrinks around old galvanized pipes so tight you have to drive them out with a hammer. Look at how shrunk up some of those flages on 100 year old uprights are and people wonder why the bushings are so tight. My mentor conceded I might be right on this one.

Guys, thanks again for the fascinating comments, insights and digressions. I'm going to refer the owner of the piano business to this thread as I request another visit from a tech. Hopefully your considerable combined wisdom will help.
I'll let you know how it turns out.
John

100% agreed but easing may be necessary for correct adapation to different climate. afterthat, none is necessary.

see above ...

they have no real reason to check for sb crown, only bridge height.

Kamin,

It may be that mis-information is floating around.

I think your posting of Udo's letter would clear it up.

Crown IS important in their formula.

Is there a reason for not posting the letter?

I was recanting what Dale Erwin said Udo told him at the grand opening of the west coast Steingraeber dealer, David Anderson. I didn't say crown wasn't important. I said which crown was important to him.

Dale asked him how he measured crown along the ribs, with a string?

He said He half never measured crown in this way. The crown along the long bridge is what he considered important.

If there is more of an explanation I would like to see it.

Larry, it is not a letter, and by evidence Udao will not explain step by step what they do or do not. Simply I had so much heard of sb panels dryed to death, and it seems so strange to me that I asked by mail at differnt factories I had contact with and friends/colleagues as well.

Steinway Hamburg : 7%
Bôsendorfer : not less than 7% (fax from Ferdinand Brau)
Steingraeber : a short answer in 3 phrases I translated above in that thread.

I will ask Petrof if you wish

I can ask Grotrian Steinweg too

Sauter ...


There are 4 ways to obtain crown for a piano soundboard, and crown tend to be considered as a pre stressing of the panel which have to be counter acted by the string's pressure so the soundboard is then free to vibrate at his best.

But those are theories - we will see what the future will provide us.

According to a technician who attended the Hamburg Steinway acadamy just a few weeks ago, the boards there are dried down to as low as 5%.
Hamburg S&S ribbing description

Jurgen you're A1 in my book! (Hope that doesn't hurt your reputation. )

Kamin, I would like to know how many manufacturers glue the bridge on in the crowned position. Steinway New York does.

What was funny was only thing my mentor had heard from Udao up till the grand opening was at a convention. Udao heard Dales S&S D and said, "That sounds like my piano."

Dale then heard a 9' Steingraeber and thought it sounded like his piano.

By Kamin
I have spoken personally to many manufacturers about their sound board process. I am not inclined to name drop here.

Manufacturers routinely dry their boards to 4.5-5.5 EMC for ribbing.

I encourage you to post any email or letter you have in support of your claim.

Crown is measured along the bridge by most. This is NOT to say that the bridge is the support for the crown. most manufacturers and myself included crown the bridge as well as glue it to the board in the crowned position for several reasons, one of them being that it does play a part in the support. As do the ribs and as does the crowned belly rail and inner rim.

I know this is off topic from the original question.

There have been some great answers to the original question and I have enjoyed reading them.

What was the original question anyway???

When you say crowned belly rail and rim, you mean the reverse bevel??

The belly rail is not crowned left to right, right?

Do you think Udao is in the habit of giving conflicting information? Maybe he thought you meant 7% when you glue the ribs on but 5% when you put it in the piano to get the compression crown. I don't think you would want the board at a different EMC than the ribs when gluing.

Ulrich Sauter will be in California at the end of April. He will do a special presentation to our and other chpaters while here.
Title of lecture is "Soundboard Design 2"
PM me privately for details if you are interested.

Wood moves in three dimensions in response to humidity changes. Still think the sample in the bucket is too crude to draw any real conclusions and probably the hole was elongated.
Action centers will change friction because of both the wool and wood moving.
Wool also moves in three dimensions - made of cells as well.
This gets back to the original question.
Normally, an action that has been pinned correctly will survive normal humidity fluctuations.
If it is not then it is probably poor quality parts and or workmanship.

While wood does expand and contract in three dimensions, I think that the expansion/contraction in grain direction is so minimal as to be insignificant for our applications in piano actions.

Jurgen: Good point. I will remember that next time I ream key balance holes. I will only ream crosswise, not longwise.

Well - maybe. - sorry to belabor the issue, but it is too interesting at this point and everyone seems to be guessing.
If part makers cut the action parts with consistent grain orientation from part to part so the hole is drilled perpendicular to the grain and paralell to the growth rings you could expect that if the hole were drilled at say .05" diameter with mc of 14% then dried to 7% the hole would get shallower by about 1% of it's depth, wider by about 4% of it's width in one direction and wider in the other direction by about 8% - as an example.
This would mean less chance for rubbing of flange against the birds eye and a widened hole that grows 50% more in one direction than the other - being .004" and .002" respectively - this is a conservative number for maple.
My guess is that the felt will move some amount but equally in all directions unlike wood.
Correct me if I am wrong.
Reference "Understanding Wood" - estimating shrinkage and swelling.

The other part would change in size too.

Correct - to tell how much and in what direction, you would need to know the grain orientation.
My guess is that action parts are not consistent in this regard and little effort is put into the process.

I think so too. I don't think its necessary either, but still interesting.

The original topic is about flange friction. I can see how a sudden increase in RH would make the bushing cloth swell quicker than the flange and cause more friction. What I don't think has been answered yet is how just playing will increase friction. I have experienced this.

So, if the pin and bushing are being heated by the friction, I would expect the bushing to dry out and shrink, and the pin to expand a tiny bit, but have less friction, not more. But if there were some kind of substance on the pin that gets tacky when heated, then I would expect the friction to increase while playing.

Anybody have comments on this?

Upright Tooner,
most likely the metal center pin is expanding more rapidly than the bushing is drying out. Steel expands very quickly because it is a solid and conducts heat quicker than a porous material like felt work. Only a guess…
Gene,
"Ulrich Sauter will be in California at the end of April. He will do a special presentation to our and other chapters while here.
Title of lecture is "Soundboard Design 2" "
I just had a hour long conversation with a well known fellow in Toronto. His comment was “well the industry is on the move again, with carbon fiber sounding board coming.” Do you have any info on this yet?

The only person that I have heard about that has talked about experimenting with carbon fiber sounding boards is Del Fandrich - it is just a rumor.
Alternates to spruce are inevitable - if not now then certainly later when old growth sitka supplies are gone.
If Ulrich is dabbling I suppose that we may hear about it soon enough.

From Silverwood pianos,

There was a grand presented at the Musikmess Frankfurt 2008, not from Sauter but from Steingraeber: the Steingraeber Phoenix:

http://www.piano-klavier.eu/content/view/231/467/lang,de/

Sorry this information is in German.

schwammerl.

No question that wood does inevitably expand and contract as it takes up or releases moisture, but do you know of any action maker who uses wood at 14% mc?

Schwammerl...thanks for that I will translate.....
Gene.., thanks for the comments yes I am sure you are correct, we will all hear soon enough....

Jurgen, I have no idea what moisture content is in the wood of parts makers.
14% appears high but if the parts are being machined in a climate that is 90 deg f and 75% rh - 14% would be in equalibrium with the climate - this would be air dried.
What is the climate like in southern China?

Slightly green wood mills much better. Less spliting. Carpenters don't use the old wood that has been sitting around. It gets hard and is a smaller width by up to 1/4 inch on a 2x6.

I would think that if a manufacteror wanted no problem, they would have to pay strict attention to the seasoning of the wood. The raw boards can be smaller on the ends than in the middle.

What part of southern China, Gene?

I haven't read all the comments! Baldwin in the 50's labeled some of their pianos "specially treated for humid climates" If I remember right this meant that the centers were treated with a wood alcohol and water mixture. They start with a 25% water mix. And increase the water if it did not work up to 50%. The water is the part that does the work. The Idea is to expand the wood with a higher moisture content than the atmosphere. When dry nature won't expand it to that degree. Food for thought

tuneit@swbell.net

All Renner pinning uses the mix Water alcohool as a pinning lubricating agent first, then to adapt the pin vs the bushing to required tolerance.

Bushing are reamed as well but with needles, not with a rough reamer.

It may explain wahy the pinning is so time resistant (and why sometime it is too tight)

The alcohol/water treatment is for sizing the bushings. Felt is wool and the little interlocking fibers tighten up when worked. With the alcohol as a surfactant and carrier for the water, the bushings swell up, then shrink. Of course you must have the right amount of felt in the holes, etc. The process then does not require any reaming, just a minor burnishing.

Check Bill Spurlocks site.

Saying the mix range from 95% alcohol 5 % water for tight bushings (vertical dampers), to 30% alcohol 70% water for very free centers -like the jack center ).

Depending of the wood and the cloth quality, the mix may differ, one have to try it and wait .

a piece of soap in the mix helps as a wetting agent.

An other "important" point that is rarely understood is that the original insertion orientation is to be respected, the inside fibers run parallel in one way only.
Running a rough reamer may be done any method as one want, but afterthat a clean reamer is used to strighten the fiber orientation.
A good method is to use rough reamers (to clean the metal deposit and dirt inside the bushing) done with a long "fil de centre", that at the same time reorient the fiber and prepare the bushing to the new center. I heard a Swiss technician use the same long center to ream, burnish and repin. Using those long 50 cm centers is less expensive, and the result is more consistent, more than that one can find special sizes like 1300 "strong" or "thin" because of tolerance of fabrication.
One need a jig to hold the part square from the center which is hold with pliers pulled very straight (Renner state that in that case the pinning is finally more straight and square in the center of the bushing than with small centers). It is less easy because one need force to go thru the birdseye, but it is worth it.

Old processe have generally some advantage, but indeed one may use a gallon of CA in the pinning it it is too much free

I did my test of the diameter changes of the nose bolt holes in a new board measured while at 9.6%mc and then again at 7%mc.
Not conclusive. The inside measure using a digital caliper is just not accurate enough and I could not detect any meaningful change.
Probably something more dramatic like the sample in the bucket is more appropriate. And probably a change like this is not significant in normal everyday piano life.- - thank you Keith and Jurgen.
But I will test again, the next time I oven try a sample I will dirll a couple of holes first and try again to measure changes. 10%mc to 0%mc should reveal some mesaurable change.

Kamin, can you post a picture of the jig you mention?

You know, earlier, one tech mentioned that:
Humidity fluctuations in the piano are long range. The moisture enters and leaves the parts at a much slower rate than the heat. That means the daily small fluctuations have no or little bearing on the average[/b]

I agree but, I also disagree. While yes, humidity fluctuations are of course, long range too, they are also short range.

Tune a piano at 50 degree's and listen to it change as the heat is turned up. It changes rather quickly as it warms up in the room to 55, 58 and eventually up to 72. In a few days, that longer range theory is now beginning to also take effect as the piano flattens in pitch a little bit at a time. Provided of course, the heat is left up. As winter passes, the piano eventually falls 1/4 tone or more, flat.

If you're doing a concert tuning and they turn on the stage lights when you're almost finished, the tuning will almost immediately begin to change a little bit as the heat from above shines onto the piano. So will the pitch. While it really isn't all that hot and certainly, not unbearable by any means, it is heat and "hotter" now, that it was 15 minutes earlier nonetheless and as time passes, that heat will increase.

Here in Michigan, many people turn the heat down in their homes during the day to 58 or 60 while they are at work and turn it down again at night while they are sleeping. So, the heat is not up for all that long during each day.

This tells us that the pianos wood is expanding and shrinking fairly quickly. Our ears can tell us that much. Otherwise, the tuning and pitch would not change at all. That affect, isn't much different on a 15 year old piano than on a 40 year old piano.

That same thing is happening to every single part of the piano to some degree or another (pardon the pun.)

In churches, heat is cranked up and turned down, up and down again. During the week, at 48 or 50 degree's, moisture can build up easier on center pins and in the wood maybe swelling it slightly. While on the weekends, when the heat is only up to 72 for maybe one or two days. This isn't allowing enough time to pass to let the wood shrink enough for the moisture that was let in during the week, to go out again during the weekend.

All of these little factors will certainly affect stickiness.

I don't know. Maybe I'm all "wet."

Jerry, are you saying that the wood swells and shrinks as a result of the temperature changing 10 degrees inside a home? I would think there are other factors at play here... It is the steel wire than responds immediately to changes in heat. This is very easily observable.

There are humidity swings in the felt that happen faster than the swings in the wood. This goes back to the original topic. Sorry about misleading the topic.

Well, the tuning changes from humidity swings right? From the wood expanding and contracting. At 50 degree's here, the RH is probably around 35-40%. Now, raise that temperature up to 72 and the RH drops like a rocket and is now at probably around 22 %. So yes, with a temp change, there is also a humidity change. Therefore, the wood is shrinking and expanding accordingly. That's what I'm getting at.

Hmmm interesting. Jurgen I think Jerry is talking about church situations with wide swings in temp which result in changes to humidity. I have several where I have noticed these slight changes in the tuning because the piano may sit at 50 degrees with say 30 percent humidity and then on Sunday they crank the thermstat up to 75 degree for the old folks and the RH changes enough to send the tuning out. Maybe I'm all wrong, but I dont think even these changes would be enough to change the density of the strings.
Am I wrong in this thinking?

Yes, that's pretty much it Ron. I'm referring to concert work as well though and temp and RH. Look at it this way guys and tell me your opinions.

How many times haven't you seen a piano that is setting directly where the sun can shine on it? All of a sudden the sun comes out. The tuning changes drastically because NOW the sun IS shining on it? It changes very quickly. I do not believe that is the wires. I do not believe either that you can actually observe the wires expanding or contracting just with your eyes. At least not with mine. :-) I believe it is the wood shrinking and the wires following it. It almost always changes the most, in the middle of the tenor or center of the piano.

I have a church that blows air right on the piano. Every time that thing comes on, the tuning changes almost immediately. That can't be the strings expanding and contracting so quickly, can it? It has got to be the wood, right?

No, the air blowing on the strings causes them to expand and contract immediately with the temepature changes. Metal reacts to temperature changes quickly. That's why the self tuning thing works and they make cookware out of metal. Check out how fast your tuning fork changes with temperature. There is more metal in the fork than a wire so it will change temperature slower.

It takes a week before you see much noticeable change in the EMC of the wood. You can base this on how many days after the weather changes till the phone starts ringing.

It is exactly the strings, as Keith points out. The sun (or stage lights) shining on the strings does very little or nothing to change the hunidity of air surrounding the piano. And even if so, it would take a lot time for the woodenparts of the piano to find the new equilibrium with the air, several hours at least.

It sure makes tuning in west facing amphitheaters interesting.

"PHOENIX" is the name of the experiments made by Richard Dain, a rich retired engineer and industrial, that run a piano bizness, customizing pianos like Steingraeber, Bluthner, Bosendorfer (the main job is done by a subcontractor in Poland)

bridges agrafes, thin high treble, lately they thinned the soundboards to the max.

If so they are interested to try that seriously, as Petrof is probably.

But I know at last a pofessional pianist that did not like the changes made - job provided by the polish subcontractor of R. Dain.

Very controversed, (like Ron Overs) I heard the music samples on the web site, and the¨Bôsendorfer is nice, then I heard that concert pianist that told me that when he was there, he disliked a lot the modified instruments, uneven voicing, misergulated, he was depited, expecting probably way better .
When he was there he played side by side Staingraeber Phoenix and normal he preferred the original version of the piano (for whatever reason).

Tone and action behavior is certainly a standard, it may be difficult to introduce something new (way less difficulat actually as the listening of people is changing, as musical taste)

Talking again of moisture and pinning, I have tuned a Kaway, with all black whippen/jack and hamer butt.

This is a silent piano and the pianist plays it a lot, as he prepare to enter the Paris National Music school.

6 month's old, I noticed that the pinning is now uneven like it can be on an used piano. In the medium range, the violent stopping of the hammer shank by the silent system conduced to fast wear of the pinning (the key mortise as well have too much and uneven play)

As usual you rarely can't win both ways. This is a traditional instrument, with good reasons to use parts done that way or another.

I believe that if I use the Renner bushing cloth in a Kawai flange I take the risk of sluggish pârts in humid days. the cloth seem twice stiffer to me.

Well, that is very interesting indeed. I did not know this. I still find it hard to believe though..

Let me give one more thought. A grand, setting in the living room of a home. A heat vent directly on the floor blowing up at the sounding board. The heat turns on. The tuning changes rather quickly. The heat turns off, it reverses.

From what you two are saying, the heat is actually being pretty much ignored by the wood at this point but, is instead being transfered to the strings for them to expand and contract, right? If so, how is that not affecting the sounding board first?

I was taught, that a pianos wood breathes constantly. It's expanding and contracting according to the amount of moisture content in the air that affects the amount of moisture content in the wood. That if the sun shines on IT, the moisture content immediately began to change.

Maybe this doesn't matter but, I've carried a Hygrometer with me that I set on the harp for over 10 years now. The very second the heat changes in either direction, the RH also goes up or down accordingly.

Your thoughts once again please?

Jerry,

Heat and moisture content are intimely related, that is why giving air moisture content mean not much if the air temperature is not given as well.

As I had high tech EDt some years ago, I could check the drift of a string only afer warming id with my thumb on it for a minute, the drift was around 1 cts , and very immediate.

Wood react way less than metal to temperature change, and moisture goes in an out but slowly.
A point you may want to consider also is that the iron frame expand with the warming, it takes a few hours but it will bring that pitch alost as high as it was befor the heat was turned on.

Hello,
I did not understood how to post pictures.

This is a very simple setup : a vertical small metal plank that can be secured on the bench, have a saw line in it , a wooden plank can do the job as well but it may be thin enough, because the end of the long center is thinned no more than 0.75 ', and you have to catch that thinned end with the flat pliers, a too thick plank will not allow for it.
mine have a wooden plank as main support, and a smaller metal sheet with the saw line on the top of it.
Pinning a vertical flange set with that method is less than 1.5 hours, and the result is more consistent than with little centers.

BTW in the factory , the centers have an annealed portion that allow it to be cut without cutting pliers. that is how one can understand the initial insertion direction one side (the sharp side) have that annealed part still showing, the other ide is shiny.

Is it possible to post pictures from my own hard disk without uploading them on a web site first ?

Kamin,
Quote,” Wood react way less than metal to temperature change, and moisture goes in an out but slowly.”

Agreed. However in boiler heated buildings(churches and schools) here in the northwest my experience has been the older the instrument (longer it has been in this environment) the more rapid the moisture loss or gain. Jerry this might be what you are experiencing there as you are in the north somewhat and referring to instruments in churches, or large rooms where a lot of people suddenly gather.

Keith,
Quote,” It takes a week before you see much noticeable change in the EMC of the wood.”
Agreed. For “new equipment” in these boiler heated buildings ……..recall the first posting by John. This would be a boiler heated building with a new instrument, here in the north. For older equipment I don’t believe this applies or better, applies in a different way.

Jurgen, Quote “It is exactly the strings, as Keith points out. The sun (or stage lights) shining on the strings does very little or nothing to change the humidity of air surrounding the piano. And even if so, it would take a lot of time for the wooden parts of the piano to find the new equilibrium with the air, several hours at least.”

Agreed on the strings. Jerry from my experience with being a former welder and fitter, this is correct, metal does expand really fast. Copper especially. Copper expands faster than the steel core actually.

Jurgen I would have to disagree somewhat on the stage lights comments. Again on the parts changing shape and taking time to find the new equilibrium, I am of the opinion it is the new felt that will readily accept contaminants more rapidly then the new wooden parts. I am going back to the original posting of sticky keys/action parts.

Dan what contaminants, and what would they do to the felt and or pin?

I'm guessing that the bushings are a little tight from being unworn and the flange wood shrinking. The sudden humidity change on Sunday morning could also swell the bushings. I believe that the friction from playing is causing the center pin to expand by being heated, and/or some contaminant from the factory turning tacky.

Hey Tooner,
There are a lot of airborne particles that I believe we cannot see. Moisture is one for sure. I have had experience where cooking oils are another. Dusty conditions could be a third, generally dirt particles. Remember Tooner, I am going back to the original posting here and trying to address the friction problems .
Yes I totally agree that new flanges could be too tight to begin with, or shrink, but remember, yes, the sudden humidity changes, especially in the sanctuary, or chapel if you like. These particular instruments stand alone all week, like I stated previous, suddenly 200 people crowd in the room with damp coats and wet boots and sit for over an hour. I am of the firm belief that we would be foolish to presume that the humidity in these types of rooms would not change. I am going back to the statement from John’s original posting. “the humidity in this room is steady at 30%.” Well, maybe six days a week ok? Remember this, I believe is also important, it is a “localized problem” particular to church rooms and school classrooms.
Tooner I am only theorizing here based on my own experience. I believe that new wood, yes, will pick up some moisture, but the change is not a great as an instrument that “has been in this environment “for some time.
I am theorizing that new felt is not dirty or full of anything, but will fill up quickly with whatever is presented to it, water, oils, airborne particles. Say it again? New wood will attract airborne contaminants less rapidly than new cloth. This could be why John is having sticking and the sticking is getting worse as the instrument is played. The instrument is new, the wood is new. The felt is new.
I am just saying in this particular situation moisture might be the culprit. Reasoning? 200 people walk into this room once a week. It will be interesting to see if this particular problem is noted in the heat of a Toronto summer. This is where John and the instrument reside.

Dan: I think we are mostly in agreement. I just wondered about the contaminants.

All: Speaking of temperature changing piano tunings, here's an experience I had once, for what its worth. An old upright in a small church. There was friction between the Pastor and congregation about whether the damp-chaser heating bar (low wattage, no tank) should be plugged in or not. The pastor didn't want to spent the money on the electric. I asked that it be plugged in for a week before I came and tuned it. I think it was early spring. There was no heat in the Church except on Sundays. So I tune the piano. Started with the fork and set a fresh temperment. The tenor section was pretty much on pitch. So I touch it up and move up the scale. By the time I got to the treble break, there was no real tuning left to do, only to touch up a unison here and there. Same with the bass. Same with taking out the temperment strip, just a little touch up. This piano hadn't been tuned in years. I had other work in the area, so I explained the situation and only charged half price. If they had listened to it after the DC had been plugged in a while, they probably would have cancelled the appointment. The reason this always has stayed in my mind is because the previous tuner and I must have set the exact same temperment at the same temperature and humidity.

Tooner
Quote,
The reason this always has stayed in my mind is because the previous tuner and I must have set the exact same temperament at the same temperature and humidity.
You got it. Hey I am not the “piano swami” or anything here, but sometimes these instruments have done things that I just could not believe was right…. But it was happening!! I didn’t have the time to figure it out totally, so I just took a lot of notes thinking that one day it will be of use.
Some of the stuff that went on regarding changes in particular situations I just had learned that this was not so. I don’t believe this anymore. What I do believe is that we all collectively have not had every situation documented in how wood and cloth and metal changes. I don’t believe there is “only one way” took look at the documentation from previous experience.

"I don’t believe there is “only one way” took look at the documentation from previous experience."

Can't agree more, Dan.

I notice that some old uprights will stay in tune very well. It could be that the sound board doesn't change much with humidity. But I think it is because the strings, not being very elastic, render easily and the tuning pins, not being very tight, settle easily. It would be hard not to tune a piano like this with stability, as long as you go over the treble break one last time (the downbearing is usually lacking there). Its hard to know what to think sometimes.

Hey Tooner,
Couple more things. I always try to tune the instrument in the same period of seasonal change each time.
Example: I tune at Whistler B.C. in the mountains, in January. All the heat is on and the instruments are flat. Mountain conditions. The rest of the year they will float up sharp, and by the next January are flat.
Example: Down at sea level September or May is best here. Do not know why and don’t care. It is just the way it is in some areas here. My own local study. Tooner take notes on every instrument you work on. This is a reference for your own “localized work”.
Cheers...gotta go.... I will post the one from the plateau..... found it...... interesting study that one.....

When this thread took a turn in this direction, I must admit I was leary of the temp changes having any real affect on the strings. I sat here reading, and really resisting this idea. However after reading Dan's comments and then suddenly remembering how my tuning forks react to room temperature, I must admit you guys have thrown some new light on this "subjeck."

I must agree now. Churches I tune in really come to mind now, I can see where it's the strings more than the wood. But tell me this.
Over a period of time, with the wood increasing in moisture in warmer weather, and then decreasing in colder weather, and the overall affect of the piano falling or rising in pitch, depending on the season....what happens with the strings gaining and then losing density. Do the strings by themselves, lend cause to this overall effect on pitch, not taking into account the wood?

Hope my comments make some degree of sense!

Ron: "....what happens with the strings gaining and then losing density." Uhm, if you mean the strings weigh more per cubic inch of material, I don't see how they could. Or do you mean something else?

Tooner, I suppose what I'm trying to convey is as Dan says metals either expand or contract when heated and cooled. We all know that to be true. What I was having a hard time with is the changes in a few degrees of temperature seem to me to be so neglegible, it would have no noticable effect on piano wire.

But then I began thinking about how tuning forks can change even with just a few degree of temp change, and I saw the light!!!!

Not sure how the wire is affected with regard to cubic weight other otherwise. Maybe we need someone with a better knowledge of physics to fully explain it.

First, I have to apologize for not having enough time at this very moment to read all of what was written above, as I have been surfing the internet in support of all of our claims and have just enough time to post this now and then I must leave for work. I will read more when I return. I have found nothing so far, that states strings or harps as the major cause of pitch or tuning changes. Ya, I feel like disagreeing a little bit today. :-)

This is one of the most interesting topics I have encountered in a while here.

From the PTG web site:

Why does a piano's pitch change?

Piano strings change pitch for two primary reasons: the initial stretching and settling of strings when the piano is new, and soundboard movement due to humidity variation. In the case of new pianos, the pitch drops quickly for the first couple of years as the new strings stretch and wood parts settle. It's very important to maintain any new piano at the proper pitch during this period, so the string tension and piano structure can reach a stable equilibrium. (Most piano manufacturers recommend three to four tunings the first year, and at least two per year after that.)

Aside from this initial settling, climate change is the main cause of pitch change. That's because the piano's main acoustical structure -- the soundboard -- is made of wood. While wooden soundboards produce a wonderful sound, they also react constantly to climate changes. As the relative humidity goes up, the soundboard swells, increasing its crowned shape and stretching the piano's strings to a higher pitch. Then during dry times the soundboard flattens out, lowering tension on the strings and causing the pitch to drop. The drop in the dry season tends to exceed the rise during humid times, so the net result is a drop in pitch each year that the piano isn't serviced.

Here's one from Braid Whites web site:
http://www.kenfoster.com/PianoTuning/Why.html

Quote: Why has my piano become out of tune?
Changes take place because your piano’s overall pitch is dependent upon changes in the relative humidity. In some temperate regions of the country, the relative humidity increases in the summer resulting in a higher moisture content in the soundboard and a higher string tension (pitch). In the winter, when heating systems dry the air, the soundboard loses moisture and contracts, causing the pitch to drop. The drop in the winter tends to exceed the rise in the summer, so the net result is a drop in pitch each year that the piano isn’t serviced. In some parts of the country where the cold season is exceptionally long, the annual drop can be considerable. In other parts, mild winters combined with dry summers cause the cycle to be reversed. You can, however, greatly increase the stability of your piano’s pitch by maintaining a relatively consistent humidity level in the room.

Here's another web site that basically says the same things as above...
http://www.serve.com/marbeth/tune_piano.html

--------------------

I have been unable to locate anywhere so far on the web that satisfies your claims.

Jerry G wrote:
Let me give one more thought. A grand, setting in the living room of a home. A heat vent directly on the floor blowing up at the sounding board. The heat turns on. The tuning changes rather quickly. The heat turns off, it reverses.

From what you two are saying, the heat is actually being pretty much ignored by the wood at this point but, is instead being transfered to the strings for them to expand and contract, right? If so, how is that not affecting the sounding board first?

I'll get into vapor pressure and why the process is slow to change the emc. Do you think it's the old wood that changes moisture fast or the fact that the coating (shellac or varnish)has gotten old and exposes the wood to the moisture?

Also, there is the expansion of the wood due to temperature. The wood can change temperature almost as fast as steel. Wood has a different expansion/contraction rate per degree of temp change than steel. Wood will tend to warp very easily when exposed to heat from one side because the surface differential will cause the side exposed to expand faster than the other side. Plastic really expands the most. Run hot water across the plastic cutting boards and watch it change shape.

So, what I was trying to say was;
That is a very good point Jerry.

The wood does react to the heat as well as the steel. This is different than humidity changes in the wood, which still happens slowly.

Thanks, Jerry.

Ron: Ok, I got it now. Not sure what I was thinking. Of course as a metal expands, its density goes down. Thats what expansion is. And as a string expands (gets longer) the tension drops and the pitch falls.

Kamin posted "A point you may want to consider also is that the iron frame expand with the warming, it takes a few hours but it will bring that pitch alost as high as it was befor the heat was turned on."

I suppose it would, but it would take an excellent design to compensate completely.

So I guess it would depend on how well the iron frame compensates, or over compensates, for the change in the strings. It would only make a difference if the environment's temperature changes as the humidity changes.

Makes me think of the inventor of the clock pendulum that had a grid of brass and iron. It compensated itself and did not get shorter when it got colder.

"I found it on the internet, so I know it is true..." :p
Just kidding, Jerry.

What they are talking about is longer range going out of tune, not the immediate effect of a temperature change.

When temperature changes suddenly, it takes a long time for wood to adjust its temperature, compared to metal. Wood is a pretty good temperature insulator, and steel is a good heat conductor.

On top of that, wood has an extremely low coefficient of heat expansion, and steel has a very high one.

So: steel strings will adjust to the change in temperature very quickly and will expand and contract a lot (relatively speaking) right away, detuning the instrument.

If you don't beleive that string expansion/contraction is significant, consider that to change the pitch of a string by one cent in tuning, the tuning pin only needs to be turned in the magnitude of one ten-thousandths of an inch.


This thread is moving off into several directions at one time. Perhaps it would it be sensible to split it up into different segments such as pinning procedures, tuning stability factors, physical characteristics of materials used in piano manufacturing, air contaminents, pinning problems with entry-level chinese pianos etc etc etc...