As your piano tuner Wilmington DE, I have been writing about some of the more common piano repairs that a piano technician performs. So far, we have discussed replacement of bridle straps, piano hammers, and piano tuning pins. Additionally, in the last article, we discussed repairs due to water damage. This article will cover the replacement of piano key bushings. There are two symptoms which can indicate that your key bushings need replacing. The first is a small high-pitched squeak each time a note is depressed. The second indication is that the piano keys seem slightly loose and wobbly.
It will help to first describe the structure of keys and the role key bushings play in a piano action. The keys of a piano are kept aligned by two pins, one at the front of the key and one in the middle of the key. You cannot see the front key pin, because it comes up from underneath the key. Each key has a mortise or small hole in the bottom of the piano key, so that the key surrounds the pin. On each side of the mortise is glued a thin piece of wool cloth. This is the “key bushing.” It’s purpose is two-fold. First, it protects the wood of the key from wear, so that the metal pin does not damage the wood. Second, it eliminates the squeaking sound that would result if the metal slid on the wood repeatedly.
When the key bushing wears out, it can be relatively easily replaced. Without the key bushing, a piano technician would need to replace the key when it would get worn. With the bushings, only the bushing is replaced, and a piano can keep the original keys for its entire life.
The pin that is located half-way back on the key is called the “balance rail pin.” It also comes up from underneath the key, but in this location, the mortise in the key goes all the way through the key. If you are able to look at the top of the middle of the keys, you will see this pin surrounded by a cloth bushing at the center of each key. The bushings serve the same purpose as the key bushings at the front pin.
When either of these bushings wear out, the keys can start to wobble and squeak when played. As part of your tuning and piano maintenance appointment, we always examine the wear on the key bushings, and we will advise you when they need replacement.
If you have any other questions about pianos, or if you wish to schedule an appointment, please let us know. Kenneth Keith Piano Services is your piano tuning Wilmington DE, Philadelphia, Eastern Shore MD and Southern NJ piano services professional.