As your piano tuner Wilmington DE, I wanted to continue the explanation of some of the more common piano repairs that a piano technician performs. In the last article, we discussed replacement of bridle straps, and piano hammers. In this article will discuss loose tuning pins.
Each piano string is wound tightly around a tuning pin, so that each string may be tuned frequently. Each piano string has about 150 pounds of tension, so the tuning pins must be very tight to maintain a tuning. The tuning pins are held at the bottom in a piece of wood called the “wrest plank” or “pin block.” The pin block is typically made of several laminations of hardwood with the grain running in different directions, so that the tuning pins are held tightly. Prior to construction of the piano, the wood of the pin block is aged, so that it will shrink very little over time. All wood does lose some moisture over time, so that the wood will shrink away from the tuning pins. The pins, then, gradually get loose over time.
When a piano is strung in the factory, the coils of the strings are purposely left about one-quarter inch above the cast iron plate. This is done, so that when the pins get loose, they can be pounded farther into the wood of the pin block. When they are pounded farther down, the tuning pins usually get tight enough that the piano can be tuned for a few years before the tuning pins need to be replaced with the next larger diameter tuning pins.
For an upright piano, the pins are simply pounded in and they self-thread in the wood. In a grand piano, the preferred technique is to remove the piano action and jack up the pin block, so that the pounding does not crack the pin block. The pounding of the pins disrupts the tuning of each instrument enough that two tunings are usually needed to restore a stable tuning to the piano. The next time the pins get loose, the tuning pins must be replaced with larger diameter tuning pins. At that time, it must be discussed whether to replace the strings at the same time.
If you have any questions about pianos, please let us know. Kenneth Keith Piano Services is your Wilmington DE piano tuning experts. We also provide professional piano services Philadelphia PA, Eastern Shore MD, Southern NJ and the surrounding areas.