Quirk Answer: Get some bailing wire and a crescent wrench or square tipped socket wrench and expect to need to follow the advise of the quick answer plus a few hundred dollars to correct your mistake. (I don't believe this is a valid user repair, a technician is the best route on this one)
Long Answer: This, for me, is one of the most frustrating things customers ask for, it is rare, but it happens and often if I am not provided a sample string the customer gets the wrong size wire.
Scenario: Customer calls and wants to repair their own string (not advisable but it happens), or they are calling to have the string ready but do not want to use my services.
How to order piano wire:
With a micrometer measuring in the thousandths of an inch measure the diameter of the wire in any straight section (micrometer prices range from $30 - $250 or more).
What is a micrometer?How piano technicians measure and/or order string:
Micrometer Micrometer 0 reading Micrometer 0.210"
Piano Strings are usually ordered by a "gauge" number and weight. This number is often marked on the bridge of modern pianos (Asian Pianos: Kawai, Yamaha, Young Chang, etc) or in the tuning pin area (Steinway & Sons). If your piano has these numbers, Fantastic!!
Look at the bridge or tuning pin section on key number 88 (your highest note), if there is a number printed in either of these locations on the highest strings this means this is the start of the section of this particular gauge of wire. The piano was likely strung right to left (highest to lowest)
If however you have to look 4-6 notes down (12-18 strings) to find the printed number then key 88 is the last string of that section. This piano was likely strung left to right (lowest plain string to highest)
Where this number is located is extremely important in determining the proper size of wire for replacement.
Right to Left Stringing: Look to the right of your missing string, the first printed string size is the correct wire gaugeThe measurement you will get for modern piano wire will be no less than 0.029"
Left to Right Stringing: Look to the left of the missing string, the first printed string size is the correct wire gauge.
Unknown String Gauge: Using a micrometer measure the diameter of the wire (remember thousandths of an inch) - Count the number of hashes (my micrometer is 0.025" per hash mark as the barrel hashes go to 24 before rolling back to 0). Measure the wire in a few different places to be sure you get the most accurate measurement.
To figure the wire gauge you need to order: Subtract from 29 the number 5. Now divide by 2.
29 - 5 = 24 / 2 = 12
You will need to ask for 12 gauge wire. The largest plain steel piano wire I have seen in a piano is 22 gauge. Calculating in reverse:
22 x 2 = 44 + 5 = 49
micrometer will read 0.049"
If your number falls below the 0.029" mark you either are measuring incorrectly or have something other than piano wire you're needing to replace, guitar strings are significantly thinner than piano strings and might be suitable for your needs. Piano gauges are sizes by halves, so 12, 12.5(or 12 1/2), 13, 13.5, etc.
A technician usually orders plain steel piano wire by the 1 pound or 5 pound roll. I carry in my kit a case with the normal 1 pound rolls of each wire gauge needed in pianos and use these when strings break. In the shop that performs numerous piano restringing jobs a year you will find 5 pound or heavier spools of wire for each size.
A technician usually orders plain steel piano wire by the 1 pound or 5 pound roll. I carry in my kit a case with the normal 1 pound rolls of each wire gauge needed in pianos and use these when strings break. In the shop that performs numerous piano restringing jobs a year you will find 5 pound or heavier spools of wire for each size.
Ordering (gauge + length): When asking to order string for single replacement ask for the gauge and length of wire plus at least 1 foot of extra wire. Measure the total length of the string you need then add 1 foot or if you need to guess, measure from the tuning pin to the hitch pin (this is the point on the plate the the wire is looped around) then double that measurement and add 1 foot.
Why do I need the correct wire? During a routine service call I had customer with a Bosendorfer grand where one string had been broken and replaced... inspect the pictures below and see if you can discern the problem:
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| One of these is not like the other | Look closely at the knots | Look Closer - Which is Different |
In the first picture it is the right string of the 4th group of wires. In the second picture you will notice the "tail" of the knot is pointing the wrong direction. In the third picture you will see a close up of the knot and string.
Other than the mistakes you see with the knot, do you notice anything else that is different? As a practicing technician the mistake caught my eye almost immediately and it is a problem I have seen before and the point of this article...
The technician who replaced the wire did not measure it for diameter! The string diameter is thin enough that without a physical measurement I can visually see the difference, look particularly how the string wraps around itself as compared to the original knots.
How does a competent honest technician approach the customer with a mistake like this? I informed the customer and showed them what was wrong and why and that if they were unhappy with the quality of the sound or the stability of the note they should contact me regarding a replacement string with the proper diameter and tied in the same manner as the original strings.
Why is the diameter important? All piano strings are set to a certain pitch. Strings of different diameters will hold the tension differently based on their diameter. A thin string tuned to the same pitch as a thicker string will resonate differently. I would suggest that the quality of the sound is much like the sound of a "false" string, or a string that has an audible beat-rate when played individually.
This sounds to be a string that will not be in tune when the pitches when listened to individually are correct, but when set in motion with the other regular sized strings has an audible beat-rate as though it is out of tune.
When two strings of nearly identical length but of differing diameters are tuned to the same pitch their tension will be different which will directly affect the harmonic overtones the strings produce and cause the sound to be less than ideal. Aural piano tuners will hear this "inharmonicity" quite quickly. Hopefully my machine tuning colleagues do as well.
Other than the mistakes you see with the knot, do you notice anything else that is different? As a practicing technician the mistake caught my eye almost immediately and it is a problem I have seen before and the point of this article...
The technician who replaced the wire did not measure it for diameter! The string diameter is thin enough that without a physical measurement I can visually see the difference, look particularly how the string wraps around itself as compared to the original knots.
How does a competent honest technician approach the customer with a mistake like this? I informed the customer and showed them what was wrong and why and that if they were unhappy with the quality of the sound or the stability of the note they should contact me regarding a replacement string with the proper diameter and tied in the same manner as the original strings.
Why is the diameter important? All piano strings are set to a certain pitch. Strings of different diameters will hold the tension differently based on their diameter. A thin string tuned to the same pitch as a thicker string will resonate differently. I would suggest that the quality of the sound is much like the sound of a "false" string, or a string that has an audible beat-rate when played individually.
This sounds to be a string that will not be in tune when the pitches when listened to individually are correct, but when set in motion with the other regular sized strings has an audible beat-rate as though it is out of tune.
When two strings of nearly identical length but of differing diameters are tuned to the same pitch their tension will be different which will directly affect the harmonic overtones the strings produce and cause the sound to be less than ideal. Aural piano tuners will hear this "inharmonicity" quite quickly. Hopefully my machine tuning colleagues do as well.
This article pertains only to plain steel strings, it doesn't consider the complexities of bass strings or other strings wound with copper. This will be addressed at another time...
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