Bluthner 5694 underway

Posted by: Craig Hair

Bluthner 5694 underway - 07/17/13 10:35 PM

Bluthner 5694 has arrived, and work has begun. This piano really is very different from anything we have seen previously. I think we were lucky that the rim was in such bad shape, as the spine almost fell apart. I'm glad we saved all those square grand lids. We will need the rosewood, and, I think, some of the oak cores. The treble agraffs seem to have a brass pin inserted to make a bearing point

[img]https://lh6.googleusercontent.com/eyxgVwqWec6VoHkOLEL_lgCeVoS-qAKhSmiwADXW4nE=w640-h480-no[/img]

[img]https://lh6.googleusercontent.com/rUk2BEB3XKzXUMAtH2bapdomJPF3x31FvT946XFDzdU=w276-h207-p-no[/img]

[img]https://lh3.googleusercontent.com/6gS6Hw0HD5anzRxcOtBsdmNrYzH_-9YkXT_QEk9BClA=w276-h207-p-no[/img]

For the curious, this is the big file of pics:

https://plus.google.com/photos/105412259...CNi8gKKat8Hm3AE
Posted by: OperaTenor

Re: Bluthner 5694 underway - 07/17/13 11:08 PM

It says I need permission to view the album (last link).
Posted by: Craig Hair

Re: Bluthner 5694 underway - 07/17/13 11:19 PM

Does that make it work?
Posted by: OperaTenor

Re: Bluthner 5694 underway - 07/17/13 11:24 PM

Yes, thank you!
Posted by: OperaTenor

Re: Bluthner 5694 underway - 07/18/13 12:02 AM

Wow, that was some major piano porn...

I anxiously await photos of the finished piano.
Posted by: BDB

Re: Bluthner 5694 underway - 07/18/13 12:05 AM

The photo of the serial number says 55694, which is reasonable. That piano was made after the last date on the soundboard decal. 5694 was not.
Posted by: Supply

Re: Bluthner 5694 underway - 07/18/13 01:37 AM

Fascinating piano, no question. I like the way the backscale ends of the tenor go through the bass bridge. I have seen that before on older German pianos. I hope you are being paid by the hour.

I agree with BDB - the piano is not as old as it may appear, it was built in 1899.
Posted by: ando

Re: Bluthner 5694 underway - 07/18/13 01:41 AM

The photos aren't working again...
Posted by: Olek

Re: Bluthner 5694 underway - 07/18/13 04:37 AM

What a huge stripping .. will you un glue the soundboard now ?

Thanks for the pics.
Posted by: Maximillyan

Re: Bluthner 5694 underway - 07/18/13 08:52 AM

Craig Hair,thanks for these photos of a grand. We shall hope to hear its sounds in the future. I wish you patience and intelligent decisions during the restoration work this grand. Good luck!
You are happy man. I like if a tuner had intersting job
Posted by: Craig Hair

Re: Bluthner 5694 underway - 07/18/13 08:56 AM

Are the photos working? I can't tell from my computer.

The date. I can easily be of either mind on the subject. The late number appears once on a paper tag that looks nothing like the paper tags I have seen pictured in other period Bluthners. The early number, I have found four clear examples, and I believe, also evidence of the obliteration of that number on the pinblock face. The four digit number could just be a rotating factory number like Chickering used. Though its presence on the block would compicate that view.

At the moment I am content to leave that question on the shelf. In either case, the piano represents an early phase of Bluthner production, one that earned him his name. This will be informative, even if it is the last Model T to roll off the line, rather than the first.

As a personal aside, my formal training, rather than music or engineering, was in philosophy and archaeology. So this question of the date is a mysterious subplot in an historic adventure. I could not be more entertained.


Yea, next comes the soundboard. Well, first come the plate support strips, then the board. I'm glad you used the term unglue. It is the clearest description of what we try to do.

I have never seen a piano that needed to come so far apart in order to put it back together.
Posted by: ando

Re: Bluthner 5694 underway - 07/18/13 12:28 PM

Holy smokes! That one seriously unhappy piano! May I ask what makes it worth rebuilding? Does it have some sort of historical significance? I can't imagine wanting to pay to have such a rebuild done on a 85 key piano unless there was some great significance attached to it.
Posted by: OperaTenor

Re: Bluthner 5694 underway - 07/18/13 12:47 PM

I was able to open the album again.

I noticed two different four digit numbers on the plate; 2252, and 5694. It is tempting to think of the 5694 as a working number instead of the serial number, but, the 55694 looks like it was typed onto a card and glued in there - not exactly a permanent installation. Has anyone ever seen it done that way before?

Posted by: BDB

Re: Bluthner 5694 underway - 07/18/13 12:55 PM

Yes, that is how Blüthner puts serial numbers on their pianos.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 07/18/13 07:30 PM

What makes it worth it. The piano is a family heirloom. So I guess for the client it is primarily sentiment. It cannot be replaced, and she wants it back the way she remembers. As for myself, I've already learned a lot from this piano. After all, who expects both the soundboard and plate to be recessed into the rim? So, yea, I think it is a worthwhile project.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 07/18/13 07:39 PM

Just a funny piano universe coincidence. I was reading stuff on Bluthner, and it was mentioned that he got his training in the shop of one A Bretschnieder. "I know that name!" I looked in the piano stacks and sure enough I have an old german square by A. Bretscheieder. I haven't had that piano on its feet in twenty years, now its interesting again.
Posted by: Supply

Re: Bluthner 5694 underway - 07/18/13 08:14 PM

For me the date/number question is pretty straight forward. The real number is the one on the paper: 55694, putting the piano at 1899. The 5694 is simply an abbreviation of the longer number, an in-house number. In 1899 there was no question in the factory that they were building pianos in the 50,000 range, making a few thousand per year. So they simply left off the first digit. You see that very so often: a long serial number, but a manufacturing number where they simply truncated the long serial number to the last three or four digits.

A serial # of 5694 would determine that the piano had been built in 1867. This would not only pre-date the soundboard decal dates, but also the Patent Action found in this piano.

Thanks for access to all the great pictures!
Posted by: Craig Hair

Re: Bluthner 5694 underway - 07/18/13 09:40 PM

When was the patent action first introduced?
Posted by: Supply

Re: Bluthner 5694 underway - 07/18/13 11:35 PM

Before anyone else chimes in and declares me wrong, I will do it myself laugh

I just did some research and found that the Blüthner Patent action, which was used into the 1920s alongside of the Erard action, was actually developed early on (Blüthner was founded in 1853) and found its way into the first pianos as early as 1856. That means that this unusual and simple, almost primitive action was used for almost 70 years. Wow.

So I stand corrected in the effort to date this piano by its action. Thanks for letting me throw the first stone (at myself)! thumb
Posted by: Olek

Re: Bluthner 5694 underway - 07/19/13 06:09 AM

Originally Posted By: Craig Hair
Just a funny piano universe coincidence. I was reading stuff on Bluthner, and it was mentioned that he got his training in the shop of one A Bretschnieder. "I know that name!" I looked in the piano stacks and sure enough I have an old german square by A. Bretscheieder. I haven't had that piano on its feet in twenty years, now its interesting again.



Hello, where did you find that mention ? I just had a look back at the Bluethner "150 years of piano making" book, and did not find such name in the early trainings of Julius Bluethner.
A. Brentschnieder was a piano maker in Leipzig, with no direct relation with Bluethner, only that he learned a lot from the lLeipzig instrument makers.
He was first cabinetmaker, worked in a factory called Hölling & Spangenberg as cabinet maker (1842-45) then he went to Ibach and various firms in Leipzich, as Foerster, Kahnt, building square pianos mostly.

I can try to scan you the historic part, was mostly trying to find your model... there is a pic showing "one of the first grands", that looks similar but probably straight strung.
The absence of aliquot should put it before a certain era, I suppose. (1872)
Posted by: Craig Hair

Re: Bluthner 5694 underway - 07/19/13 08:17 AM

Good morning,
I'm just referencing Alfred Dolge. He is a sparce historian at best, and perhapse I am reading more into what he writes than is there.(my particular specialty) He does,however break his early career into "learned", amd "studied", and this in two different cities. Now this is pure conjecture, but I hear a reference to apprenticeship and journeymanship; two unavoidable stages in the guild system.

As I said Dolge is thin soup. But his focus is on who worked for whom and who they learned from. If Dolge makes a special reference, there is most likely a significant relationship.

Here are the pages in question. I think that our scholarly discussion covers "fair use", don't you?

https://plus.google.com/photos/105412259...=COHy7r-ti8e5Rg
Posted by: Olek

Re: Bluthner 5694 underway - 07/19/13 09:38 AM

Seem to me that Julius Bluethner "studied" a lot, also he bought books on "acoustics" , while at the same time he was working as cabinet maker in different factories.
He may have been in contact with different piano makers in Leipzig.

He was very soon determined in understanding anything availeable, he worked to repair an Erard grand with good success, for instance, while at those times was only availeable to him Viennese or "English actions".

That is a long story, the chapter is long, there are not much original illustrations in this book unfortunately. It seem to be focused on the family, the history, more than to technical aspects.

There is a nice color pic of a piano with similar case than yours, however.

Your instrument have the 4th string or no ? It may have been a common feature on most models if not all , seem to me.



Posted by: ando

Re: Bluthner 5694 underway - 07/19/13 09:44 AM

Originally Posted By: Craig Hair
What makes it worth it. The piano is a family heirloom. So I guess for the client it is primarily sentiment. It cannot be replaced, and she wants it back the way she remembers. As for myself, I've already learned a lot from this piano. After all, who expects both the soundboard and plate to be recessed into the rim? So, yea, I think it is a worthwhile project.


Thanks Craig, so it's a family heirloom. I still struggle to understand how a piano gets so dilapidated if it's an heirloom. Even more inexplicable that the owner can recall it being in decent condition. It looks like it sat in a damp barn for 60 years! Still, I'm sure you can resurrect it with your skills. Good luck.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 07/19/13 10:42 AM

No fourth string. And, now that we have some of the plate support strip off, I can say that the board is mounted at right angle to the case. Doesn't the cylindrical soundboard system incorporate an angled mounting?

Wow, this Julius sounds like a real dynamo. How old was he at this time?
Posted by: Olek

Re: Bluthner 5694 underway - 07/20/13 05:21 AM

He was 18 , in fact he said he learned from Bretschneider piano making, when he wanted to build his piano making firm and needed to be made citizen of Leipzig.
SO you are right , he worked for Breitshneider in 1851, and obtained from him a certificate as piano maker, that helpêd him to obtain the citizenship for Leipzig, where he had decided to setup his firm.
Zeit (the original town of Bluethner)was only a few hours from Leipzig, but in Prussia, while Leipzig was in Saxony.
The firm begun from scracth , with 3 workers all diligent cabinet maker.
They produced 8 grands and 2 square pianos the first year. First sale to a reputed university professor, specialize din hearing, made a good advertising to the quality of the instrument.

It is possible that the soundboard was not yet arched, at that time. ribbed, after drying, certainly.

The name of the case wood is may be Jacaranda, a variety of Rio rosewood that was widely used at those times.
The non cast framing makes the instrument prior to 1865 certainly.




Posted by: Strings & Wood

Re: Bluthner 5694 underway - 07/27/13 12:38 PM

Any updates? How is the soundboard restoration going?
Posted by: Craig Hair

Re: Bluthner 5694 underway - 07/30/13 06:54 AM

OK, here is a link to our second photo cashe. This is the extraction of the soundboard and the removal of the ribs and bridges.


https://plus.google.com/photos/105412259...=CMbrvMLtwNmGJQ

It is an interesting board. It has few ribs, particularly in the bass, and these are rather slight, being wider than they are tall. Except in the treble where they are made taller and only a little less wide. It seems Bluthner was trying to graduate the stiffness of the board from highly compliant in the bass to highly resistant in the treble.
Posted by: OperaTenor

Re: Bluthner 5694 underway - 07/30/13 06:55 PM

I think this is a great picture.

Posted by: Craig Hair

Re: Bluthner 5694 underway - 07/30/13 09:01 PM

Yea, I think I really caught him in that one.
Posted by: Olek

Re: Bluthner 5694 underway - 07/31/13 06:08 AM

Thank you Craig , wonderful job (you did that with an help ?)

I am amazed you keep the roomm clean !

The construction is certainly very well setup.

What are those green boxes ? weights or some water drop system ?


Best Regards


















Posted by: Craig Hair

Re: Bluthner 5694 underway - 07/31/13 09:54 AM

Hi, Isaac,

The green things are just tins full of old keyleads. They hold down the orange silicon rubber gaskets that direct the steam through a channel on the underside.

Help? No, that's my business partner.
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 07/31/13 12:07 PM

Wow, I had no idea, when reading about your soundboard restoration. Your photos tell a very intriguing story. Looking forward to the next chapter. Hopefully, this it will end with a sound clip.
Carl
Posted by: Olek

Re: Bluthner 5694 underway - 08/01/13 08:53 AM

Originally Posted By: Strings & Wood
Wow, I had no idea, when reading about your soundboard restoration. Your photos tell a very intriguing story. Looking forward to the next chapter. Hopefully, this it will end with a sound clip.
Carl


That is the usual way to restore historical instruments , soundboard wise. (well, not so usual today wink
Posted by: Olek

Re: Bluthner 5694 underway - 08/01/13 08:56 AM

Originally Posted By: Craig Hair
Hi, Isaac,

The green things are just tins full of old keyleads. They hold down the orange silicon rubber gaskets that direct the steam through a channel on the underside.

Help? No, that's my business partner.


Thank you , I thought it was not a steam machine but a system that provide water drops (as for gardening).

You can regulate the speam pressure ? is it a machine for wall paper, or some "cleaning steam machine" ?

Dry cleaning use some "dry moisture" systems, they are expensive, I dont know if they would be adapted to that use or even if they can work for long periods of time.

What shape are the ribs after all those years ?

Regards
Posted by: Craig Hair

Re: Bluthner 5694 underway - 08/01/13 02:19 PM

We do not regulate the pressure directly. we have over time come to use a less powerful steam souurce. We have also experimented with captive steam passing through copper tubing in order to heat the water. this proves to be much slower than expected, so there comes a trade off between heat levels and the total time spent wet. Each application has its advantages.

Here are some pictures of the ribs all cleaned up.

https://plus.google.com/photos/105412259...=CKaC_PHCwoTaYQ

Note how tight the grain gets in the two shortest ribs.
Posted by: Minnesota Marty

Re: Bluthner 5694 underway - 08/01/13 02:51 PM

Craig - This is a fascinating thread.

Thank you!
Posted by: Olek

Re: Bluthner 5694 underway - 08/02/13 09:01 AM

Originally Posted By: Craig Hair
We do not regulate the pressure directly. we have over time come to use a less powerful steam souurce. We have also experimented with captive steam passing through copper tubing in order to heat the water. this proves to be much slower than expected, so there comes a trade off between heat levels and the total time spent wet. Each application has its advantages.

Here are some pictures of the ribs all cleaned up.

https://plus.google.com/photos/105412259...=CKaC_PHCwoTaYQ

Note how tight the grain gets in the two shortest ribs.


Thanks for the pics.
Do you try to evaluate the resistance of those ribs ? due to the difference in grain it may not be easy.

I wonder how do you deal with the drying and stabilization of the wood after all that humidity. It may take some time.

What amount of drying will you use before ribbing ? do you only look at the dimension change or do you work with somewhat precise wood moisture level ,it may be possible just with temperature and room humidity observation I suppose, but for instance to attain 5.5% one need to dry the air, temperature enough would cause the use of very high temperature, I believe that an industrial air drier is better (allow to work at moderate temperature)

Just curious

Best regards
Posted by: Craig Hair

Re: Bluthner 5694 underway - 08/09/13 09:49 PM

Isaac,
Sorry to have let a week go by before responding. Your questions got me thinking, and, unfortunately, that is a slow process.

In the past, we have never paid too much attention to the actual stiffnesses of any given ribs. As we have always reused the original ribs, and,since we are in no position alter their strength, measuring the stiffness seemed secondary.

On the other hand, we have always used the inherant stiffness of the wood as our guide in the calulation of pressing cauls. using a couple of blocks clamped to the side of a blank caul, just about where the gaining starts on the ribs, we flex the rib to form an arch. Rather than being scientific about this stressing of the rib, we use our sense of wood to tell us what arc is proper for that rib. The rib should be stressed, but also feel like it could go a bit farther. this arc is traced as a basic pattern for all the ribs. We have tended to dish in the treble ribs a bit more, both because they can take it, and the treble is the zone of the board that simply must have crown to function. So we tend to err on the side of caution.

The drying and stabilization of the wood only takes a day or two. Its odd, but old wood seems to both take on and give off moisture at a very rapid pace. By the end of steaming day, the wood no longer looks wet, but if you handle it, it feels both heavy and cold to the touch. The next day the wood feels lighter, but still cool. the day after that the wood is light in weight and warm to the touch because evaporation has finished.

We have always used the dimensional change in the panel as our guide to when to press on the ribs. We find that 24 hours under the heat is enough time to shrink the board. This is the time of year that we avoided any bellywork because the temp needed to shift the wood is very high.

I would love to have a climate control system. It would allow us to regularize the enviroment we press in and we could ignore the weather. Even with climate controll, we would still run the space at around 100F. We use cow-hide glue, and that is best applied to well warmed pieces of wood, and the heated environment will help dry the board after we clean up the excess glue with water. This is where the woods ability to give off excess water so rapidly comes into play.

Thanks for the interest, I do appreciate it

By the way, I came across an old "Piano Atlas" by Sievers, 1868. Is this an available book, and should I digitize it?

Be well,
Craig
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 08/23/13 08:43 AM

Hello Craig,
It has been a few weeks, any updates on the 5694 Bluthner, you care to share?
Carl
Posted by: Craig Hair

Re: Bluthner 5694 underway - 08/24/13 12:15 PM

Sure,
So far work has concentrated on the board. The latest Photo barrage shows the reconstitution of the panel into a single unit and its preparation for pressing.

https://plus.google.com/photos/105412259...CLyok5PL08i19AE

As far as the date of the piano goes, we have been in touch with an expert in Ashburnham, and he assures us that according to recent research our serial number actually does come from 1870.
Posted by: OperaTenor

Re: Bluthner 5694 underway - 08/24/13 12:31 PM

Craig, you are amazing.

But, you need to smile for this one:


wink
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 08/24/13 09:08 PM

Mesmerizing skills at work here! I am just dumbfounded.
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 09/04/13 06:33 PM

"Bump"
To keep this daunting project relevant.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 09/10/13 07:38 AM

More soundboard progress:

fitting, shrinkage compensation, pressing, crown development, and finaly a little french polishing to bring out the wonderful color of the aged spruce.

Caul curvatures are 2mm on short ribs to 5mm on longest.

Thank heaven for hide glue!

https://plus.google.com/photos/105412259...=CNziyM-MoqbMTQ
Posted by: OperaTenor

Re: Bluthner 5694 underway - 09/10/13 11:12 AM

50% of why I come to PW these days is to see what you post next on this fascinating project, Craig. Thank you!
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 09/10/13 09:52 PM

Craig,
Were the ribs glued onto the sound board before, after or during the re-crown of the board?
Posted by: Craig Hair

Re: Bluthner 5694 underway - 09/11/13 07:52 AM

Good Morning,
In this piano, I would have to say that the ribs are glued on both during and before the crowning takes place. We used gently dished cauls to do the gluing, so the board came out of the press with a little crown displayed. We also dried the board our beforehand,120F, such that the panel shrank about 6mm across its width. After the gluing, when the moisture returns to the panel, the crown in the long ribs develops. This happens over several days. This morning, the crown on the underside, between the longest ribs, is about 16mm. Between the two top treble ribs we have about 4mm. A good deal of this displayed crown will be lost when the rib ends are glued down to a 90 deg. shelf.
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 09/11/13 09:45 PM

Thanks for the info Craig. And thanks for taking the time to post the photos.

Carl
Posted by: phacke

Re: Bluthner 5694 underway - 09/12/13 01:27 AM

Thank you indeed for posting these pictures, Mr. Hair. Having an interest in the mechanical properties of the soundboard, but not being in the business, I was very interested in seeing the cross section of the grain.

The following appears truly quarter-sawn:

https://plus.google.com/photos/105412259...259108667869462

The following does not appear to be, should there be no illusions created by the cut or camera angles (is there?):

https://plus.google.com/photos/105412259...259108667869462

I wonder if such mix is par for the course in soundboards.

Not being able to assume true quarter-sawn boards makes valid computation of the properties more difficult considering the anisotropic nature of wood.

Anyway, it is just fantastic and admirable restoration work, I too thank you for your postings and your information above in this thread.

Best regards-
Posted by: Craig Hair

Re: Bluthner 5694 underway - 09/12/13 08:23 PM

Good evening,
Its only part illusion. the grain is far from vertical. Actually much of the wood in this board seems less than ideal. There is a lot of grain runout in the planks. One board has a curve of about 2 inches in the grain from one end to the other.

Perhapse we are just spoiled when it comes to wood selection in America. The German city-states of the 19th century were royal holdings as were the forests. Quality lumber was a closely controled commodity. You got the best that you could, used all that you could, and were probably happy just to get it.

That being said, The wood is now 140+ years old. The wood's tonal capacity more than makes up for any percieved shortcomings. And I say percieved shortcomings because the crowning capacity of the wood is still more than sufficient, as demonstrated in the photos.

It may be that our fetish for perfectly quartersawn lumber is just that: a fetish. a preferrence that is not really demanded of the enterprise.

A lot of old boards have less than quartersawn wood in them, and a lot of it seems to be used in the rear section of the board. In the back, under the plate, and so out of sight. Saving the clean stuff for where it can be seen? That would be human nature. Or it could be placed there so that the bass bridge would sit on a more compliant zone of the board.

The only board I ever saw with perfectly quartersawn wood throughout the board was from a Chickering square from the 1870s. We still have it, just for looking at.

Thanks for the kind words.
Posted by: Olek

Re: Bluthner 5694 underway - 09/13/13 05:29 AM

Thanks Craig, very nice looking. it is nice to take all those pics.

The wood lost by shrinkage is impressing

I do not understand whay you glue the ribs one by one, and not all at once as is it usual to ? You may need to keep the moisture very low all the time.

The relation with future cracking is clearly stated in all the litterature.

The equuilibrium between panel retractation and the force of the ribs may not be so easy to find however.

All the best
Posted by: Craig Hair

Re: Bluthner 5694 underway - 09/13/13 12:07 PM

Good morning,Isaac,

Why one by one? Half the reason has to do with our use of hide glue. In the pictures you can see how the hide glue squeezes out onto the surface of the board. You can see how wet the surface gets from the clean up. We've never felt comfortable attatching another rib until the board has given that moisture up. We also like to keep the board at the working temperature. In the time it takes to glue the rib, the whole board cools, we wrap it up til everything is back to warm and dry. The other reason is that we just have'nt gotten around to it. Shameful, I know.

Future cracking. You are referring to the mortal fear of compression ridges? First, I think I must point out that all the literature is written about new wood. Old wood is qualitatively different. Rather than being weaker than new wood, it is actually a good bit stronger, particularly across the grain. Its hygroscopic movement may or may not be equal to that of new wood,( don't know, never used any), but its ability to absorb this pressure without damaging itself is greater. We just have'nt had any occurances of compression ridges. which is probably why we have had a tendancy to put maybe little too healthy a crown in the board. Too much crown has always seemed a better bet than too little, as the excess arch can be pressed out when mounting. This increases the compression in the panel and raises the impedance of the board as a whole. It also means that there will be more time before the natural shrinkage puts the panel into tension, and starts it into pulling on the ribs. In new wood, this might be a recipe for disaster. The old wood seems to take it without a problem.

Some thoughts on seasoning of wood. The whole purpose of seasoning wood is to make it stable, and its behavior predictable within a window of acceptable limits, so that it might be used as a reliable engineering material. Spruce is a conifer, and like all conifers it is a very wet wood. Both in terms of water and organic volitals. Excess water weight is easily lost to the air, this is drying, and that is all it is. Seasoning is what takes place after the water is lost. Seasoning is the stabilization of the resins in the wood, and that takes a while (seasons). In its first years, when the wood still has a lot of soft resins in it, the wood moves a great deal with the natural movement of water in and out of the cells. At the same time, the softness of the resins keep the wood's compression failure limit rather low. Consequently the wood has a strong capacity to expasnd and a weaker capacity to resist. With the seasons, the expansive tendancy lessens while the resistive potential increases. Like two lines on a graph, they converge. When the two lines meet, the wood is finally strong enough to resist its own strength. This would be the point where the wood could be safely used for predictable results. This is just traditional seasoning.

Where am I goiung with this? Well that process does not stop. It slows and slows, becomming glacial, but over a century has a cumulative effect. Accumulated shrinkage pulls the board flat or even concave. If that shrinkage is relieved, however, the panel once again has the capacity to expand and bend the ribs. And being stronger, it can do that without approaching the compressive fiber limit. I think that is why we have not had problems with compression ridges.

I agree, though, that we could probably dial back on the crown a bit. We have done some experiments with some boards from dead pianos, and it looks like we may be able to dispense with dished cauls altoghether and just press on a flat deck, go pure compression.

Be well,
Posted by: phacke

Re: Bluthner 5694 underway - 09/14/13 01:44 AM

Thank you very much for your answers and the interesting background, Mr. Hair.

Best regards-

Originally Posted By: Craig Hair
Good evening,
Its only part illusion. the grain is far from vertical. Actually much of the wood in this board seems less than ideal. There is a lot of grain runout in the planks. One board has a curve of about 2 inches in the grain from one end to the other.

Perhapse we are just spoiled when it comes to wood selection in America. The German city-states of the 19th century were royal holdings as were the forests. Quality lumber was a closely controled commodity. You got the best that you could, used all that you could, and were probably happy just to get it.

That being said, The wood is now 140+ years old. The wood's tonal capacity more than makes up for any percieved shortcomings. And I say percieved shortcomings because the crowning capacity of the wood is still more than sufficient, as demonstrated in the photos.

It may be that our fetish for perfectly quartersawn lumber is just that: a fetish. a preferrence that is not really demanded of the enterprise.

A lot of old boards have less than quartersawn wood in them, and a lot of it seems to be used in the rear section of the board. In the back, under the plate, and so out of sight. Saving the clean stuff for where it can be seen? That would be human nature. Or it could be placed there so that the bass bridge would sit on a more compliant zone of the board.

The only board I ever saw with perfectly quartersawn wood throughout the board was from a Chickering square from the 1870s. We still have it, just for looking at.

Thanks for the kind words.
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 10/01/13 07:19 PM

Hello Craig,
A while back, you stated that you were going to try and revive the original strings. I was wondering if you have done so, and if so, did they they respond? Could you expound on the process?
Thanks,
Carl
Posted by: Kyle_G

Re: Bluthner 5694 underway - 10/01/13 10:44 PM

Hi Craig,

This is one of the best restorations I've seen in a while. Thank you for taking the time to take pictures.

Your work on the original soundboard is very interesting. I'm excited to hear what this piano will sound like when its all done.

-Thanks
Kyle G.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 10/05/13 12:28 PM

Kyle,
thanks, we appreciate the compliment. This certainly is an interesting piano. The piano is very modern for its day, but the bass bridge is still unlike anything else I've seen. Its like three bridges in one. One thing I can say is that this is the lowest mass bass bridge Ive ever seen. The closest is the bridge-on-the-bridge construction in the Knabes from the 1890s. (In passing, those knabes also used a rib-crowned suspension with a contoured rim. Earliest I know of.)

Here are a few pictures of the bass bridge being worked on.

https://plus.google.com/u/0/photos/105412259108667869462/albums/5931301887475980705
Posted by: OperaTenor

Re: Bluthner 5694 underway - 10/05/13 01:29 PM

This is hard-core piano porn. Love it.

Craig, I take it you didn't replace any of the pieces of the bass bridge, and it looks like the string grooves in the cap were sanded out. Dumb question: Does that have any effect on down bearing?

Also, what are you refinishing it with?
Posted by: Craig Hair

Re: Bluthner 5694 underway - 10/05/13 06:34 PM

Jim,
Nice to hear from you.
Yes, its all the original parts.

We do sand the caps some to make a smoother surface, but I don't think there is as much material removed as it appears. Perhaps half a mm, if that.

If the board were still mounted to the rim then a mm lost in bridge height could mean a mm lost in bearing. But this board is out and already has more than sufficient crown. So I don't think there will be any problem accomodating a small dimensional change; considering also that the tennor bridge will be similarly treated.

For now the bridge just has some shellac on it to keep it clean. they will later be alcohol cleaned and french polished. The cap face is finished with a 220 one direction sanding, colored with Higgins's Black Magic(high quality india ink), then burnished with graphite with a leather covered wooden block.

Be well,
Posted by: OperaTenor

Re: Bluthner 5694 underway - 10/05/13 06:42 PM

That all makes perfect sense, thanks!
Posted by: Gary Fowler

Re: Bluthner 5694 underway - 10/06/13 12:29 AM

Bluthner is one of the few pianos I have never had a chance to rebuild. I have not even seen one in my career!
Posted by: Kyle_G

Re: Bluthner 5694 underway - 10/06/13 01:10 PM

I have this feeling when the piano is complete the bass will be heart stopping.
Posted by: OperaTenor

Re: Bluthner 5694 underway - 10/06/13 04:15 PM

Originally Posted By: Kyle_G
I have this feeling when the piano is complete the bass will be heart stopping.


+1
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 10/28/13 09:38 PM

Craig,
Did you complete the restoration of the Bluthner? If so, any thoughts/information you would like to share.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 10/31/13 07:30 PM

Carl,

Finished? heavens no. But we did just get the board remounted.

https://plus.google.com/photos/105412259108667869462/albums/5941003537049872049

I was never really worried about the board, beyond figuring out how to get it out. The real adventure in this piano is going to be the pinblock. The block did not fail bacause the wood around the pins cracked or anything like that, the block failed because every screw that went through the plate nad into the block failed, and the middle of the block twisted down. When we removed the tension, the body of the pinblock returned to straight(straight enough). The majority of the distortion is in the bottom board, so I am thinking of replacing only the bottom board, along with splicing in some new maple pinfield cap where it was smooshed against the plate. this should clear up any clearance problems with the action. Beyond that I am contemplating replacing all of the failed screws with machine screws and t-nuts set flush in the bottom. Its not original, but it is the least intrusive means to add stability to the system. Any thoughts? Anyone?

https://plus.google.com/photos/105412259108667869462/albums/5941064749641705585

Be well
Posted by: Ed McMorrow, RPT

Re: Bluthner 5694 underway - 10/31/13 11:33 PM

I don't envy your task Craig. Is it possible to get a casting of some sort to replace the board under the pinblock with, and bolt through both the strut and pin-block into machine screw threads? Sort of a cast plate for under the pin-block to stiffen the whole structure against the rotational vectors.
Posted by: Mark R.

Re: Bluthner 5694 underway - 11/01/13 04:31 AM

Craig,

Not that I'd ever try to give any advice... But I am fascinated by the whole thread, and I'd like to understand the original design better, in terms of how much of that torsional down-force was meant to be borne by the plate or by the bottom board (and rim). My apologies if these questions appear trivial:
1) Did the old screws go through the block and into to bottom board?
2) Was the pinblock glued to the bottom board?
Posted by: ando

Re: Bluthner 5694 underway - 11/01/13 07:12 AM

Hi Craig,

With a rebuild like this, how much are you trying to stick to the original design, and how much are you willing to deviate from it? For example, the original pinblock seems to be on using 2 or 3 plys. Would you build a pinblock of the same construction, or would you install a modern pinblock with many plys? In terms of the torsional stress which destroyed the original pinblock, could you take any design cues from later Bluthners which probably solved that problem?

Regards,
Andy
Posted by: Craig Hair

Re: Bluthner 5694 underway - 11/01/13 11:36 AM

Ed,
We have had discussions about a steel plate a la Hardman keybed. The t-nut idea is a minimalist aproach, their strength only radiates a small distance. Their positive quality is that they have a great deal of thread to hold with. I don't think it would be good to replace the entire bottom board . I think that the block body needs to actually be glued to something. I'm thinking that the apron should be as thin as will reliably hold the threads under full tension, but I would hate to under estimate those rotational vectors.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 11/01/13 03:04 PM

Mark,
The short screws in the webbing go into the bottom board. But they only penetrate about a half an inch. They don't seem to have held much for long. The long screws go through the struts and go into the block body.

Yes the block body is glued to the bottom board.

It is an interesting system. There is an iron bar running through the stretcher, that I think he felt would restrain some of thosr rotational forces. Unfortunately, I think that, rather than restraining those forces, the bar leverages those forces to the front of the block. It seems that the bottom board was meant to controll forward bowing of the block and act as support for the leading edge of the block. It did well against bowing, but the screws in the webbing were just inadequate. A curious detail is how little of the block face actually touches the plate. only the top 3/4 of an inch touches. even with that, the majority of compression in the blockface seems to have come from the rotational failure.

trivial? Nah, this is the juicy stuff.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 11/01/13 03:47 PM

Ando,
Generally, I try to keep my ego in my back pocket and stick with the designers choice. That being said, I do have a responsibility to make as stable and durable an instrument as I can. Consequently I feel I have to do something to keep the block from failing in the same way. I just want that something to be as effective and inobtrusive as possible.

I haven't reached the point where I feel that the entire block needs replacing. If I had to, I would want to go with the original design. That would require that I find a suitable piece of maple. That might not be so easy these days.
Should that prove elusive, a block made of multiply would be acceptable. Not Delignit, I hate that stuff. Even then I would put the maple ply on the face to hide the ugly.

I would love to see some newer Bluthners, there are just none around here.
Posted by: OperaTenor

Re: Bluthner 5694 underway - 11/01/13 04:08 PM

Thank you again, grain, for sharing this process with us.

I took a look at the Steinertone photos while I was looking at the Bluthner. Do you specialize in 'problem children'? That action...
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 11/02/13 01:21 PM

Wish you were closer, so I could see some of this up close.
Posted by: Ed McMorrow, RPT

Re: Bluthner 5694 underway - 11/02/13 10:57 PM

The problems this Bluthner shows, is the reason that design was abandoned. The rotational vectors are too large for the support structure to hold. That is why I was suggesting adding some sort of non-deformable bracing tied to the plate struts.

The new Bluthners are very interesting pianos. They have done the fourth string aliquot in a very stable way. But I wish they would not do any of that. The added weight of a fourth string and bridge pin to the bridge makes the tone thinner. The precision of the bridge pin placement is amazing though.
Posted by: Dale Fox

Re: Bluthner 5694 underway - 11/02/13 11:23 PM

Hi Craig,

I've seen a couple more recent Bechsteins with the same rotating pinblock problem. Added to this Bluthner was the fairly obvious moisture issues and general glue joint failure. If I were you Craig, I'd let my ego take over. Replacing this with a similar structure is problematic at best!

The Bechstein I saw most recently could have benefited with far more screws (and some longer) in the available casting area. There was room for more screw density in the plate. I don't recall what type pinblock material it had. It was only about 25 years old though.

Having said all that, I haven't read the thread from the beginning which I will now endeavor to do. I'm sure that will explain why you chose to go through more trouble to salvage the original board than to just yank it out and make a new one. Not to mention not making new bridge roots instead repairing the pulpy stuff you are working with. I must now go forth and read. Good luck. Nice craftsmanship in any case. Great pictorial, too.
Posted by: OperaTenor

Re: Bluthner 5694 underway - 11/02/13 11:50 PM

Originally Posted By: OperaTenor
Thank you again, grain, for sharing this process with us.

I took a look at the Steinertone photos while I was looking at the Bluthner. Do you specialize in 'problem children'? That action...



I swear I wrote "Craig" instead of "grain."

:-/
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 12/24/13 09:07 PM

Hello Craig,
Have you made a decision on the hammers for this piano?
Thxs,
Carl
Posted by: Craig Hair

Re: Bluthner 5694 underway - 12/30/13 04:46 PM

Carl,
I have only just now started to clean up the action and look at the parts. The hammers look to be original to the action parts, and they are Bluthner slant sliced. They seem to be very light hammers. #2 bass may weigh 8 grams, at most. So weight is a major concern.

My first thought would be the hammers that Jurgen sells, though I have yet to quiz him about them. Abel makes a patent grand hammer, too. Though I suspect that is what pianofortesupply.com sells. They seem to make everything these days. I just hung a set of Encore Naturals on a BB, and they made them, too.

Odd thing about this Bluthner, while they sliced the hammers from the bar at an angle, they then hung the hammers straight to the shank.

If the available hammers are all too heavy, I may have to see what Ronson can do for a light weight.

As for the rest of the piano, all concentration has been on the pin block. We have decided to go with a sheet steel apron fit to the full bottom of the block, as Ed suggested, but also let into the bottom of the plate below the agraffes. This will provide stable support for the front edge of the block for its full length, and provide something meaty for the new machine screws, passing through the webbing, to bite into. All this is supposed to happen inside the original contoures. And that will be the limit of my minimal and inobtrusive. The rest has proven to be majorly obtrusive, invasive even. But it has also proven to be necesary. We disassembled the pinblock, and we found, at its heart, that the main plank had split along the rear line of tuning pins in the two center sections. It could never have been salvaged.

So the plan now is to reproduce the block, as closely as we can, with the retrofit included, and to reuse what original parts we can manage.

Here is a link to the latest photo cashe. There is a lot going on inside one of these blocks.

https://plus.google.com/u/0/photos/105412259108667869462/albums/5963186350603739985
Posted by: OperaTenor

Re: Bluthner 5694 underway - 12/30/13 06:28 PM

I'm overwhelmed...
Posted by: Craig Hair

Re: Bluthner 5694 underway - 12/30/13 07:43 PM

Yeah, it sure makes you appreciate the modern full fit pinblocks for their genius of simplification.
Posted by: OperaTenor

Re: Bluthner 5694 underway - 12/30/13 11:06 PM

Originally Posted By: Craig Hair
Yeah, it sure makes you appreciate the modern full fit pinblocks for their genius of simplification.


Oh my goodness, yes.

You are a master craftsman, Craig. Thank you again for sharing what you do with us.

That is by far the most complex pin block configuration I have ever seen. I wonder how Julius contrived it.
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 12/31/13 01:52 PM

Wow, those hammers were played out. I wonder what they must have sounded like before the piano was taken out of action. Obviously, this piano was a players instrument.
Posted by: SMHaley

Re: Bluthner 5694 underway - 12/31/13 02:56 PM

Some fine work here. I hope we get a taste of it after completion.
Posted by: David-G

Re: Bluthner 5694 underway - 12/31/13 05:06 PM

This may be a silly question, but ... any idea why some of the hammer shanks have bits carved out of them? It doesn't look like wear.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 12/31/13 06:12 PM

The pinblock was rotating downward and interfering with the shank travel. I guess the shanks were easier to cut away at than the bottom of the block. One is almost cut through.
Posted by: OperaTenor

Re: Bluthner 5694 underway - 02/20/14 04:58 PM

Bumping to see if there's any more of this solid gold piano porn for Craig to post...
Posted by: Craig Hair

Re: Bluthner 5694 underway - 02/24/14 10:16 AM

OperaTennor,
Good morninng, and thanks for the nudge. Everything is rather mid-stream at the moment, and if I waited till some aspect was actually finished, it could be a while. So here are a lot of process pictures. work on the block, work on the case parts and work on the action, particularly the shanks. I guess I can't show any work on the playing surface, not that I have any of the banned stuff myself, don't ya know. the action is proving quite interesting. there does't seem to be two parallel lines in the whole geometry, just varying, but complimentary, action ratios i.e. long bass keys with shorter hammershanks and short treble keys with long hammershanks. It all seems to work out pretty evenly between the key tip and the hammershank tip. I've never seen anything like this from the US; the keys may change, but the shanks are the same length

https://plus.google.com/photos/105412259...=CNaH6PHdvtT-Pw

All the best,
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 02/25/14 09:31 AM

Hi Craig,
Thanks for posting the picture link. I have been checking back from time to time to see if there was an update. I have already pestered you a couple of times for that.

Your shop seems to have an inexhaustible abundance of tools, but I am curious, have you had to acquire any special ones for this project?
Also, at this juncture of the project, is it starting to feel a bit like, "labor of love", "still curious george" or "bane of my existence"?

Again, Thanks for keeping us up to date.
Carl
Posted by: OperaTenor

Re: Bluthner 5694 underway - 02/25/14 10:20 AM

Craig, thank you for the update. What you're doing is fascinating in every respect. I'm amazed at what you did with the hammer shanks, for instance.

Out of curiosity, why are you using hot glue for things like the lyre mount repair, or the hammer shank repairs?
Posted by: Craig Hair

Re: Bluthner 5694 underway - 02/25/14 11:24 AM

OT,
Thanks for coming back.

Hot hide glue is basicly the only glue we use for wood. It takes more preparation, like warming everything up, and dry clamping everything fist to get ready, but it makes for a strong, rigid bond. It is also easy to clean up. A missed squeezed out will not ruin the surface of a veneer, and can be dealt with using a steamed rag and some patience. Add to that the fact that the joint can be undone should we misalign something makes it a very friendly material to work with. Traditional, too.

We have, however, come to see the value of the super glue. In the case of crazing veneer, where a dozen small cracks are all lifting at the edges, the wicking properies pull the glue in deep. A layer of mylar keeps anything from sticking to the veneer, and we are left with a smooth face. dry clamping is a good idea here, too. Hide glue, no matter how thin or how hot, never solved that problem so nicely.

All the best,
Posted by: OperaTenor

Re: Bluthner 5694 underway - 02/25/14 06:24 PM

Thanks, Craig.

All that being said, what are your thoughts about PVC glue (e.g., Tite-Bond, etc.)?
Posted by: Craig Hair

Re: Bluthner 5694 underway - 02/25/14 07:20 PM

For spot repairs on the road, yellow glue is great stuff. Every road kit should have a little bottle. It tacks up fairly quickly, and can be cleaned up with warm water before it sets. so its good for putting back a chip of veneer

I don't do much on the road anymore, and in the shop, I haven't found any use where it beats hide glue. I'm told that the yellow glue bond is slightly flexible, and I get the impression that this is so. For this reason I woud never use it to belly or mount a board. Another drawback is that the stuff has a shelf life and does get old. Hide glue is mixed fresh for every job.
Posted by: Mark R.

Re: Bluthner 5694 underway - 02/26/14 02:29 AM

Craig,

Many thanks for the fascinating pictures. Again I have a few questions, I hope you don't mind.

1) In pic 88-95 [Edit: of album 8], you show the details of the pinblock apron made of sheet steel. You milled a recess (rebate/rabbet) into the plate, so that the sheet steel pinblock apron has a smooth bearing surface, and lies flush with the plate. You then drilled and tapped holes into this milled surface (pic 91), to accept the countersunk machine screws that affix the apron. All of that looks like a very neat solution to me. I'm just wondering about the dimensions: that milled recess looks to be about 1/2" to 5/8" wide, and those holes seem to be quite close (1/8" ?) to the edge of the plate. Is there enough "meat" left between the pinblock and the screw threads? Was there a reason not to mill a wider recess, and place the holes further away from the plate edge? I'm thinking that once the string tension is added, there might me a shear force on the screws, towards the plate edge. (Just an amateur asking, though!)
2) What is your experience (or prognosis) regarding the repaired hammer shanks: will the V-joints and scarf joints be directionally stable under humidity fluctuations? And will the hide glue seam stand up to shank burning (if it is required)?

Thanks again for sharing all the wonderful pictures and explanations.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 02/26/14 08:27 PM

Carl,
sorry, I must have missed your post.

One thing I love about New England is the ready availability of old seriously high quality tools, You never know what will be at a family yard sale. I've even found a couple of tuning kits with old rosewood hale tuning hammers and a conn strobotuner. but,no, we haven't had to get anything special. The shank steamer was new because I wanted to steam the entire shank. In general, to straighten a shank I wrap it in a damp bit of cloth and gently squeeze it with a pair of those old electric shank bending pliers. I find that the steam is more effective than dry heat.

At this point in the process, we are still in a labor of love with a good dose of curiosoty still in effect. We scheduled this project for an extended period so that it wouldnt be a case of creativity on a deadline. there is so much about this piano that is different from anything I've worked on before, that the anticipation only grows as progress is made.

You asked me once about the wires from this piano an whether we would re install them. I extracted all the wires from this piano such that I could reinstall them. I haven't ruled out their re use, but they have just enough actuall corrosion to make me really worry. If they were in very good shape, I would not hesitate to reinstall them. We have a system to chemically clean copper wound bass strings,(secret ingredient: Parson's lemon scent ammonia) and have had great success. We have a big old Baldwin upright that we are going to spruce up and donate to the house that holds all the musician's parties around here. I plan on making a youtube video of the string cleaning from that.
Posted by: Craig Hair

Re: Bluthner 5694 underway - 02/26/14 09:13 PM

Mark,
thanks for looking and thanks for the questions.

About the plate flange, no, there was no reason that we did not go deeper.
we just thought that that was a good enough bite. To be sure, these rotational forces have both a downward and a pulling aspect. But in examining the piano it was evident that there was also a strong forward thrusting force. The pinblck didn't just twist in the middle, it also smooshed forward. It was our feeling that if we could arrest the downward force at the front edge of the block, keep that from moving, that the pulling (shear) stress would be neutalized by the block pushing forward. The end result would be that the stresses on the flange and screws would be primarily downward. The flange lip is not the only place where the apron will be secured. Screws that went through the plate and into the bottom plank of the block will be replaced with machine screws that will thread into the apron, along with wood screws up into the bottom of the block along the other edge. Perhaps all this attatchement will rigidify the system, perhaps it will give the block better grip to exert the shear force you describe. you do have me pondering, though. but this is what we have been thinking.

The shanks:

The material I used to repair the shanks was 100 year old quartersawn maple from an old pinblock, gorgeous stuff. I cut it to match the quartersawn grain in the shanks I notched, and tried to stay aligned to the grain in the shanks I tipped. So I am hoping that any movement will be minor. I would think they would be fine with heat straightening. It has not been my experience that hide glue softens with heat.

Thanks again for your interest and your questions.
Posted by: Mark R.

Re: Bluthner 5694 underway - 02/27/14 02:31 AM

Originally Posted By: Craig Hair
Perhaps all this attatchement will rigidify the system, perhaps it will give the block better grip to exert the shear force you describe. you do have me pondering, though. but this is what we have been thinking.


I certainly wouldn't want to interfere with your expertise...

But I was indeed wondering about this issue: rigidify vs. grip-and-shear. I was thinking that if the front part of the pinblock (i.e. plate flange side) was free to "slide" (minimally) on the the apron, then it would exert only a downward pull on the machine screws, but if it was solidly affixed to the apron, close to the plate flange, it might exert a shear force on those screws as well. This is conjecture, I'll gladly be corrected (or told to shut up and watch the pro's work wink ).

I'll be very interested to see your final arrangement.
Posted by: Strings & Wood

Re: Bluthner 5694 underway - 02/27/14 09:34 PM

Quote:
We have a big old Baldwin upright that we are going to spruce up and donate to the house that holds all the musician's parties around here. I plan on making a youtube video of the string cleaning from that.


Looking forward to seeing that when you are done.

My 1908 Bluthner has the original strings. They are in pretty good shape, but wondered if they could be cleaned up. After following this thread, I'm thinking I should just have Walter Piano Transport deliver the piano to you for restoration.