Like any moving parts of a mechanical object, piano hammers are subject to wear and tear with time and will ultimately require replacing. The hammers of a piano are essential for producing sound. As they become worn, the quality of the sound begins to suffer drastically.
How often should piano hammers be replaced? How frequently piano hammers need to be replaced depends on how often the piano is used. Pianos used frequently and vigorously, like concert pianos, need to have their hammers replaced about every five years. A piano used less often may only require hammer replacement every ten years.
There is no specific lifespan to a piano hammer. Still, there are certain signs to watch out for that will tell you when your piano's hammers require replacement. Ensuring your piano is always properly maintained will ensure that the necessary repairs are conducted timeously, thus preventing further damage with time.
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How Often Should Piano Hammers Be Replaced?
A piano's hammers produce sound when the piano's keys are depressed. The hammers consist of a thick stiff felt woven around a timber core in tension. This tension is what causes the hammer to bounce off the string.
When the hammer hits the string, the vibration or tone is created.
Every time a piano hammer hits the string, the felt on the string becomes more compacted, and grooves are worn into the hammer's felt. As a result, the felt becomes harder, and the piano's tone starts to become harsh and metallic.
As a result of the above, a hammer's lifespan is mostly determined by how often the hammer hits the piano's strings. A piano used more frequently will require hammer replacement more often than a piano used on the odd occasion.
Concert pianos will therefore need to have their hammers replaced every five years, on average. A piano used in a school music room, comparatively, may only require hammer replacement every ten years.
On the other end of the spectrum, a piano that lives in a home and is used infrequently will only require hammer replacement once every fifteen to twenty years.
It's important to remember, also, that piano hammers can be reshaped up to three times before full replacement of the hammers becomes necessary. If the hammers are grooved, and there is sufficient felt to be able to reshape the hammers into their characteristic egg shape, they can be restored to the necessary shape and hardness that is required.
This restoration is achieved by using fine sandpaper to carefully sand one layer of the felt at a time before achieving the required shape.
Related article: How Often Should Piano Strings Be Replaced?
Why Is It Necessary To Replace Piano Hammers?
Piano hammers are covered in felts that strike the strings of the piano in order to produce a sound. The continuous striking of these felts on the strings leads to the felts becoming worn. The wearing of the felts can be compared to the tires of a car becoming worn as they accumulate more stress over time.
As a result of this wear and tear, piano hammers eventually require replacement as they become worn out with time. In situations where the piano is used frequently, the hammer felts will naturally become worn out more quickly, so they will need replacement more often.
The treble strings and the copper windings of the bass strings tamp down the felt of the piano hammers, slowly breaking the fibres of the felt. Eventually, the felt starts to become pulpier with each stroke.
As a result of the change in the texture of the hammer's surface, the hammer no longer creates a clean blow on the strings. The strings strike instead with the flat, grooved surface of the hammer's felt.
Naturally, the change in the way the hammer strikes the string causes a change in the sound produced by the piano. The resultant sound of worn-down piano hammers is harsh and unpleasant, with the keys often becoming difficult to control.
If the hammers cannot be sanded down and repaired to their original condition, they will need to be replaced completely. This is the only way by which the original tone of the piano will return.
How Do You Determine If Your Piano Hammers Need Replacing?
There are several ways to know whether the piano hammers need replacing. The first sign to look out for is, in fact, an audible clue. If the hammers are worn, the piano will begin to sound harsh and unpleasant, and the tone will be completely different from what it was previously.
If the piano starts to sound harsh and unpleasant compared to how it has sounded in the past, this may signify that the piano's hammers require replacing, warranting further investigation.
When hiring a professional, they will open up the piano and inspect the hammers to see whether they are in need of reshaping or replacing. If the grooves in the felt are deeper than half the diameter of the wound strings (where the bass hammers are located), then the hammers will need reshaping at a minimum.
When looking at the treble hammers, if the grooves in the hammer felts are the same diameter as the strings themselves, then the hammers will need to be reshaped at the least.
It's important to note that while reshaping the felts is an effective way to prolong the life of the existing felts in your piano, it does not guarantee that they will last forever. A full replacement of the felts will ultimately be required at a later time.
The felts can only be reshaped a maximum of three times. After that, they will need to be replaced. If, after reshaping, the hammers have only a small amount of felt left and the piano's tone begins to darken, this is virtually a guarantee that the felts will need to be reshaped as soon as possible.
Overall, the hammers on your piano will need to be replaced eventually. This all depends on how often the piano is used. The most significant sign to look out for is a substantial change in the piano's sound.
Once a difference in the sound has been noticed, it will be best to bring in professionals to assess the condition of the piano's hammers. This will then determine whether you need to replace the hammers or whether you can get away with simply having them reshaped.