Hammer Down: Why Do Hammers Wear?

One of the many moving parts in any piano is the hammer. The last stop between the player’s fingers and the actual release of a note, the hammers inside the piano strike the strings to create the different chords and melodies, but this same action can lead to wear after years of use.

Modern piano hammers are most commonly a wooden core that is covered with felt. This firm felt lands on the strings in just the right way to produce the desired note. However, this felt can also wear as time goes on, leading to worn grooves and indentations in the hammer head. When this occurs, the hammer no longer strikes the strings in the same manner as it formerly did, which can lead to off-sounding notes and inconsistent tone.

If you have worn hammers, they can often be remedied through voicing or shaping, a process that either changes the firmness of the felt or removes the indentations to restore the hammer – and your piano – back to producing pristine notes. Sometimes, however, this cannot resolve the issue, and the hammer itself must be wholly replaced.

Another common culprit of hammer wear is one that we talked about previously when discussing stuck keys: humidity. Humid conditions can cause wood to swell, contract and harden over time, which can alter the way that it lands on the strings. Plus, that same fluctuation can lead to changes in the condition of the felt, even wearing out the glue that keeps the felt attached to the hammer.

After years of use – the exact number varies significantly, though due to playing conditions, active use and quality of the materials – the whole set of hammers may require replacing. This is typically only necessary if the hammers are unrepairable or if the felt is so worn that it cannot be voiced or shaped back into playing order. This is a fairly involved process that can also require replacements of other components between the hammers and the keys that may have hidden symptoms of wear.

For any of these issues, though, East Coast Piano Rebuilding can help. With more than two decades of experience in the repair, tuning and restoration of pianos, we can bring bright and fresh sounds back to your piano. Contact us today to schedule an appointment or for more information!