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I am in the process of re-stringing my old Schiedmayer upright, dating back to early 1900'.

As I was measuring their diameters with a caliper, I noticed that the diameter was not necessarily constant along the string. I have up to three digit span, up and down, which is altogether 6 digits (in mm, +/- 0.03). As far as I can see, the strings have a circular diameter, so wherever I measure, it should be the same. It may be due to creeping, or not.

QUESTION
How do I know with which string number I have to replace the old string?

Sincere thanks for your guidance.

gauges are often written somewhere, on the bridge for instance
Due to the age and the old scale you need to measure the speaking lenghts it is easier to do that before dismounting the strings

even just with the A's and the C's lengths some techs will compute you a scale , with a little less tension than originally in some regions the tone will be better

inconsistencies in diameter and deformation , corrosion, make the gauges a little approximate today, but may be you can relate them to original gauges, that where in mm, may be yet with 0.025 differences between gauges

caliper are not used to gauge strings but a micrometer (palmer)

Here, for example http://www.heckscher.co.uk/roslau-steel-piano-wire/
Keep in mind that these german old pianos used Poehlmann wire... which can differ for the actual Röslau in diameter for the same number (if indicated in the bridge or tuning pin area).

In general terms, calipers won't be as accurate as a micrometer, particularly if they are inexpensive. There is too much play in them. That said, my high quality micrometer reads to .0001 of an inch, and it will reveal deformities in diameter along the length of wire. And older wire can change its shape over a long period of time as it goes through elastic creep.

Rescale. The scales used by old makers are rarely ideal.

Thanks for the very quick reply. I had not noticed any writings on the bridge, but is it certainly because of the dust accumulated over the last 100 years. I will check it thoroughly.



This is interesting. Is there any link that you can recommend me so that I can learn this particular computation?



Ok. Advice very well noted. I will check for a good micrometer.

I am not sure that I am qualified to do that, although I am very open to learn the fundamentals.
Thanks in any case.

NAIVE QUESTION
Is there any way to get the numbers for the whole scale of a specific piano, without having to measure anything?
Mine is an "F" frame from J. P. Schiedmayer, i think it is 133 cm tall, dating back to 1905 - 1910.

Sincere thanks to all for the previous and future guidance.

As you can understand, I am no expert in pianos, however I have developed/am developing a passion for them. I am pursuing now the practical portion of it, by attempting to execute some restoration (I insist on the some) of a venerable specimen, which was meant to be dumped otherwise. To my ears, it has some good potential, especially compared to many other pianos that I have come across.
Asking a RPT to rebuild it is not an option as I would not learn much, and, as a matter of fact, is out of budget, even though I fully understand the obvious difference in skills, knowledge, quality, and speed.

Could you point me to some good and reasonably priced models?
Thanks in advance.

Basic information here, note that the sollicitation is said here as the first parameter to consider

http://www.stephenpaulello.com/en/optimisation-de-plans-de-cordes

Nevertheless not all builders think that way, tension (high , low or medium, relate to the power of the tone and iH is also an important parameter

You cannot learn scaling without having experimented and being also a tuner and a voicer, but understanding a little an old scale can be interesting

Shiedmeyer where very well build instruments , the scales at that era where not very well balanced; often with too strong mediums and limited treble. too short basses at the break, This is mostly due to the lenghts progression computation method;

AN old board can appreciate being less sollicited, for instance, lowering the tension in low mediums can help the treble to sound more open and clear (when asking too much of the soundboard the tone is short and explosive)

Low constrain of the wire goes together with a rise of iH that make the tone more acid, this is just good up to some point, high iH reinforce the attack as the tone need more time to stabilize, it "catch the ear" more than loz or normal iH, but some fair amount of iH is necessary to compensate for our hearing and to have the treble present enough


WHen you know the lengths and the diameter of the original wire you will know if when you mount new strings they will be sollicited enough, if not mounting the new strings can lend to a hard and noisy tone without singing quality

This is compensated a bit with voicing but having tone quality from the wire is ideal.

The Paulello wire are more expensive, but gives a very clean tone? The duration of tone is also due to a mix that favor the partials vs fundamental hence less energy expense for the fundamental.
mm
Can be very well suited for some instruments, and the soft qualities allow to help the break without wound strings

But if you have enough lenght you can use modern wire, standards are 400 to 410 mm for A440 the lenghts are computed beginning with the highest tone, with C88 52 being an actual standard

Rescaling a piano is a lot easier than it seems.

Tremaine Parsons has an easy program called PTools. He also has an online inharmonicity calculator. With the calculator and the graph paper he has online, you can print out the graph paper, type in the note name, diameter, and speaking length and then plot the inharmonicity coefficient for each string. The graph has a hockey stick shaped band that the iH coefficients should fall into while at the same time falling into the tension band on the same graph paper.

You can change the diameters if the iH coefficient doesn't fit. (That's rescaling)

This will also iron out the measuring problem since even if you measured incorrectly, but the iH coefficient falls in the band, your erroneous measurement is the better diameter.

This hand method only works for the bare wires.

The program rescales automatically without you needing to take any diameter measurements, and it will rescale the wound bass strings as well.

+1 for rescaling old pianos.

Respectfully disagree that reshaping only is about iH.
iH can be wrong due to thickness or tension, but there are low tension and high tension scales, each with different iH.

Tension come first as this induce power of tone (more tension more power and dynamics) and stiffness applied to the soundboard.
Even if downbearing is stiffening the soundboard the tension is also.

It is "easy" to play with numbers but having an overview of what is happening is not.

There are mechanical parameters, iH is just a tone quality parameter.
Some iH is also due to the panel stiffness.

And some small pianos need stiffer strings in the basses only because too light ones will not move the soundboard enough (a problem due to bridge location)

Many thanks for your extensive replies.

Debate is absolutely delightful, but somehow confusing for the learner.
I will first check the speaking length of my strings. That will certainly give some more data to support/correct my diameter measurements.

And I will get an accurate micrometer too.

Regards,

A micrometer sufficient for your needs should not be too expensive, and you can find used ones also.

While checking the bridges and frame for string numbers, I found out that both bridges - bass and treble - were cracked. I did not realise it until I vacuum cleaned the layer of dust covering them. Indeed, it was difficult to clean the bridge unless removing the strings first, which I only recently did.

photos 1-7


QUESTIONS

1. I thoroughly checked the frame, but I could not see any number, or letter, or anything that may refer to string numbers. On the bridges, I do not see anything either. I understood that the string numbers are usually written there, or did I misunderstood?

2. As I do not have the necessarily skills and knowledge to manufacture the bridges, cracks are a terrible finding for me. I had not noticed them, nor did I notice anything particular while testing the piano. I doubt that these cracks can be repaired with glue. I am now very reluctant to restring it, knowing that the bridges are cracked. Do you think that these cracks are such that re-stringing would not be worth it? Or is there a way to stabilise them in such a way to preserve the sound?

Sincere thanks for your advices and guidance.

How should I insert a picture?

Me, I would not entertain the thought of restringing a piano more than one hundred years old with already-visibly-cracked bridges. I think the piano is trying to tell you that it is not strong enough to withstand the additional stresses and re-established tensions that the restringing would require.

And I have rarely seen string gauges or sizes written on piano bridges. Even if I were to see numbers which looked likely, there would be questions of the accuracy of the writer and the conventions of his time period which would mean that using those numbers would not be a simple matter. Mark's suggestion of a scaling program makes more sense to me -- and then, right away, we get into questions of whether your piano is in good enough condition to respond to the amount of effort of all sorts which which this project would require.

Would it not be possible for you to give this piano an honorable retirement/burial and buy an inexpensive, substantially newer instrument for you to learn on? I think I'm asking you to look frankly and honestly at your purposes, resources, and goals here. Best wishes as you move forward in your learning experience.

Thank your for your honest advice.
I hoped that there would be an easy solution. Are 110 years too many for a world-class piano, made in Germany? I guess it is for mine.

Fabricating a bridge is a tedious and precise work that surpasses my skills. Too bad...
I liked this Schiedmayer.


Finding another piano, I noticed, is not a difficult task. Many are even given for free in my region. But finding one that speaks to one's soul is rarer, I think.

Yes, I agree -- but if your heart and mind are open, your piano will arrive, maybe with another family's story connected to it at first, but it will become yours. It will be interesting to see what skills this next piano asks of you. Keep in touch.

I would not worry about those small cracks in the bridges. They may have been there since the piano was only a couple of years old. These are not the sort of cracks that will grow unchecked. You could pull out the loose pins, put epoxy in and use it like that, or just restring and not worry about it.

There are too many people around here who think that everything has to be ideal, visually and aurally. Nothing is perfect, including the concept of "ideal."

bridges are recapped usually on that sort of piano; the fact it cracked does not mean the rest is shot, but indeed that is a bad sign.

Dorrie, string gauges are generally written somewhere sometime stamped on the bridge, sometime simplyu with a paper pencil.

There are not so much standards that the gauges are useless

WHat happens sometime is that there was too high tension on the piano in basses and in mediums, and if it was in adverse conditions of course the bridge crack

ALso those instruments where build with very good wood generally but not dried as much as today (the % number escapes me but it can be as high as 2% difference of "dry condition" which is a lot for raw wood?
Then if stored in modern very dry places the wood retract and get fragile.

The air moisture percentage considered for old pianos where 50-65% , not the 45% admitted today