While playing your piano, you suddenly realize that the tone has changed. It has become very bright and piercing on the ears. What if I told you that your piano doesn’t have to sound this way? That the wonderful mellow tone it had when knew can be restored? Sounds crazy right? Read on to find out how…


Reshaping the felt hammers of a piano can do wonders for the tone. A pianos hammer has a significant effect on the tone. Changing the hammer can affect the brightness of a note, sustain, and harmonic content.

After repeatedly striking a piano string for a long period of time, the felt on a piano’s hammer becomes compressed and grooved. The hard string has worn grooves in to the soft hammer felt causing the slightly pointed ends of the hammers to become less egg shaped and flatter as the grooves become deeper. The deeper the grooves get the brighter and harsher the piano’s tone becomes.

I’m sure you will agree with me when I say: this is not a pleasant tone to listen too. This is because the deeper the grooves, the more surface on the string there is for a hammer to strike. As the surface area of the hammer’s strike point increases, so does the harshness of the tone that is produced. This is because there is a larger surface striking the string which causes excess ringing from the sounding strings.

On newer hammers there is a rounded crown that reduces the striking surface area of the hammer against the strings. Next time you see a new piano, open the lid and see how round the hammers are.

Have you ever played an old upright and heard the extremely bright honky tonk sound? This sound is from the very flat hammers and the piano not being tuned for many years. If you were to open the lid of most old uprights, you would see major grooves and flat spots on the tips of the hammers. Some hammers have flat spots an inch in height.

Reshaping these extremely flat hammers is impossible to do because the reshaping process would remove far too much felt. This would change where the hammer originally struck the string also known as the strike point. This would negatively affect the pianos tone even if the piano were to be adjusted to compensate for the lost felt. In a case like this it is far better to replace with brand new hammers and have the piano fully repaired and regulated.

On many newer pianos in homes the hammers can be reshaped to be as good as new. Reshaping the hammers would take away much of the bright harsh sound and give the piano a more mellow controllable sound. A tuner can tune a piano with reshaped hammers better as it is not so bright and piercing on the ears.

There are other steps that can be taken to improve the tone of the piano, but sometimes a simple hammer shaping is all that is needed. So, what does the hammer reshaping process involve?


The process of reshaping the hammers begins with removing the action from the piano where it is then taken back to the shop.

Any time an action goes to the shop, it always receives some basic maintenance that should always be done before repairs. It is given a cleaning with an air compressor hose to remove years of dust and debris. Next all 240 action screws are tightened to ensure no lose parts. Then the reshaping process can begin.

The hammers are reshaped by using a sand file with varying grits of paper to achieve the desired result. Using an 80-grit piece will take a lot of felt off and is good for starting out with. Finer grits of paper are used to give the hammer a progressively smoother feel.

When reshaping hammers, it is critical that even amounts of felt are removed from the top and bottom shoulders. This is so the striking point of the hammer can remain in the center. This produces the best tone for the piano. Care must also be taken not to reshape them without tilting to the left or right. If tilted the hammer will not strike every string of the 3-string unison at the same time.

The reshaping process takes a few hours to complete. When done, it looks like I shaved an entire sheep on my table because felt shavings are everywhere! The action is cleaned again with the air compressor to remove any bits of felt that may have fallen inside from the reshaping process.


After all hammer shaping is complete the action is returned to the piano. At this point the hammers must be mated to the strings so they will hit all of the unison strings at the same time. This creates a much cleaner sounding unison and makes the piano easier to tune. If the tone of the piano is not satisfactory at this point, further voicing can be done.


If you would like to have us estimate your piano for a hammer reshaping, fill out the contact form and we will get back with you as soon as possible. To get in touch by phone call us at 2563454147. And we would be happy to speak with you.