Hammer replacement
This is a widespread procedure, often recommended by piano technicians, but it requires great care. We will explain how it affects the pianist and how we approach it.
Hammer Replacement involves fully replacing the hammer heads, shanks, and flanges.
This procedure is carried out in the following situations:
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Wear and tear
Over the years, the piano has experienced repeated playing, causing the hammers to wear out due to the constant striking of the notes and the repeated contact between the wool felt and the steel strings. The felt gradually becomes compressed, and the sound typically turns increasingly harsh and metallic.
Using brand-new parts allows us to work with much greater ease and longevity when voicing your instrument. This way, you’ll get exactly the sound you’re looking for. We don’t stop the voicing process until the sound fully satisfies you.
Sometimes, if the wear is not too severe, we can adjust the voicing by modifying the elasticity of the existing felts (see the Voicing page).
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At FJV Piano Design, we do not replace hammer felts only, or just the hammer heads, as the quality of the result is significantly inferior.​​
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To improve Sound and Touchweight
Replacing the hammers means we also need to consider factors beyond just the sound. A hammer weighs around 12 grams in the bass section, and every tenth of a gram affects the touch weight (see the page about Touchweight). The feel you have with your original action is therefore of great importance to us.
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If you wish to keep the same touchweight, no problem — we will reproduce the same hammer weights while making them more consistent from one key to another. Below, you'll find a diagram showing the original weights of a set of hammers, followed by the adjusted weights. This results in a much more even touch weight.
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If you would like to modify the touchweight — to make it lighter or heavier, for example — we will adapt accordingly and let you try out the final feel of your action even before the replacement is even done. For more information about this process, please contact us.​​
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To get a better control of the action
The only contact the pianist has with the hammer is called the jack. It is the small wooden part covered with white felt and topped with leather, propelled by the whippen. This part wears out over years of use, and the escapement lever no longer glides properly underneath it. This makes precise control of the hammer nearly impossible. We've often observed this issue in actions that clients had voiced by a previous technician, but without replacing the worn parts (to reduce the price). Unfortunately, the piano was not truly improved from the pianist’s perspective, as they still couldn’t control it—even if the sound seemed better.
The hammer shank also has a rotational axis called the center-pin, usually lined with felt, which can wear out and cause knocking noises, or become stuck, making the action noisy or hard to control. Installing new shanks will solve this problem.
Additionally, replacing the hammers is always an opportunity to carry out a complete regulation of the action (see the Action Regulation page) and to lubricate all contact points.
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How to choose the parts
Most piano manufacturers do not produce their own action parts — they source them from a few independent makers, the main ones being: Renner (Germany), Abel (Germany), Tokiwa (Japan), Yamaha (Japan), Kawai (Japan) or C. Bechstein (hammers only, in Germany). The Steinway & Sons factory recently acquired Renner, giving them control over the production of their action parts.
We naturally select parts that match the geometry of your piano, or original manufacturer parts when they are available.
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How do we proceed
We do everything we can to minimize the time your instrument is out of use. To ensure this, we carefully plan the repair in advance. Once the estimate is approved and signed, we request a deposit to allow us to immediately order the necessary parts.
As soon as the parts arrive, we schedule a first appointment with you to install and glue a few test hammers to find the ideal strike line. After that, we take the action to our workshop to adjust the shanks and glue the hammer heads.
The final stage involves several days of on-site work—typically 3 to 4 days, depending on the instrument, the brand, and other factors. Your piano is only out of service for a short period: usually between one week and 10 days.
If you would like more information, don’t hesitate to contact us.