How to Select a Piano String (Wire) for Replacement
If you have a broken piano string, you can’t simply select a random piano wire for replacement. Each note has a specific wire that is required.
The most important thing to remember is that the string number and key number do not go together!
Higher notes have more strings than lower notes, so it’s important to identify the exact wire you need for your instrument.
Opening Your Piano
First, open your piano as much as possible. For a grand piano, raise the lid to access the strings. For an upright or spinet, remove the music desk and knee panel to expose the strings and make this process easier.
Identifying Piano Strings
Strings usually break at the tuning pin, so check the pinblock to find the string in question.
“Wrapped” strings (generally called bass strings) travel from the tuning pin to a hitch pin. You can find the hitch pin at the opposite end of the piano in a grand, or near the bottom or near the pedal mechanism on the upright or spinet. Notice that some strings travel over other strings and some travel under.
Steel strings (generally called treble strings) usually travel from one tuning pin, around a hitch pin, and finally attach to the next tuning pin on the piano. Again, notice that some strings travel over other strings and some travel under.
A rare few treble strings are set up like a bass string, traveling from the tuning pin to the hitch pin.
Removing the Broken String
Treble strings usually break on one end, and you will have to cut the other end near the tuning pin. Check carefully that you are cutting the correct string, or you will have a much bigger job on your hands.
Carefully detach the string from the hitch pin and remove the string. Avoid scratching any part of your piano and be sure to avoid damaging the piano hammers and dampers.
Do not discard the string yet — you will need to measure it before you select a replacement.
Measuring the String
If the bass string has a double layer of copper wrapping, it is best to contact a piano technician since the string will have to be professionally duplicated. Save the broken string for the technician.
Single-wrapped bass strings and steel treble strings must be measured, then purchased for replacement. Pay close attention to the string diameter when measuring.
To get the most accurate measurement, use a micrometer to measure your broken string. You will need to measure to the 1,000th of an inch. I recommend using a digital micrometer since they’re easier to read accurately. Strings can stretch before they break, so check multiple spots along the string to confirm its diameter.
Remember: the string number, gauge, and size have no relationship to the key number on the piano.
Order a New Piano String
Order your new string based on your measurements. There may be a variance of a thousandth of an inch or so, but this is generally acceptable. Strings are made longer than the actual finished length so they can accommodate most pianos of any size.
If you’re unsure what size to order or are struggling to remove the broken string, contact me at everettpianoservices@gmail.com