Piano strings, pin blocks, and soundboards are considered major components of the piano’s inner workings. In a perfect world, replacing all the strings, the pin block, and the soundboard would be the ideal piano restoration project. Although typically, the majority of piano restoration projects do include a complete set of new bass and treble strings, in reality, existing pin blocks and existing soundboards are often not replaced (provided they are still functioning properly).
Below is information on piano restringing, piano pin block replacement, and piano soundboards.
Piano Restringing (New Piano Strings)
No piano restoration or piano rebuilding would be complete without a new set of bass and treble strings. Piano strings, which are basically steel wire, have a limited useful lifespan. Over the course of time, piano wire (string) tends to experience two significant changes. The first is a loss of elasticity. Most of us do not think of piano strings as being elastic, but they are. A steel wire losing elasticity is best likened to stretching a rubber band between two points for an extended time period. After this extended time period, you remove the rubber band, and the band is simply not as "stretchy" as it once was. The same is true of piano wire (strings).
The other change experienced by piano wire is caused by oxidation. Depending on the environment, the effects of oxidation may be more or less obvious—but they are still there. Oxidation is commonly called "rust", but oxidation can appear in various forms. Most often, we see black "gunk" on the wires. This is the beginnings of oxidation. Other times, the appearance of a typical "rust" is very visible—especially around the tuning pins and wire coils, as well as where the wires turn around or terminate at the hitch pins.
Both loss of elasticity and oxidation will result is less than pleasing experiences for you and your piano. Extreme cases of oxidation (rust) actually make the wires prone to breakage, which can prevent the tuning of the piano to standard pitch—at least without breaking the string. Loss of elasticity—and flexibility— of the wire hinders its ability to vibrate as it should, which in turn, limits the tone and sound capabilities.
Piano Pinblock Replacement
The pin block is a thick slab of hard wood (usually maple) in which the tuning pins are tightly seated. The piano strings (wire) wrap around the tuning pins and are held at the proper tension by the pin block.
So what is the proper tension for piano strings? The short answer is that the tension of the piano strings should be sufficient to maintain the proper pitch across the entire piano—that is it should hold a consistent tune. The long answer would be riddled with half a dozen mathematical equations for tension. The short answer is all that most piano owners need to be concerned with.
If the pin block has crack or the wood has become deteriorated, your piano’s ability to hold a tune will be affected. If the pin block is damaged (cracks and separating layers of wood can be a problem), the only real option is to replace the pin block.
It is possible, in some cases, during restringing to utilize an existing pinblock only if the pinblock is in viable condition.
Just because a pin block is old (or original to the piano) does not mean it will not function. The deciding factor is evident after our evaluation, but you can also determine (to an extent) what the viability of your piano’s pin block is. For example, if your piano will not stay in tune and/or is horribly out of tune no matter what, the pin block is probably suspect. But, that’s just an example. Sometimes other less costly repairs or methods can take care of a piano tuning stability problem—in other words, it’s not always the pin block.
Replacement Piano Tuning Pins
One alternative frequently used during piano restringing is the use of new, larger diameter tuning pins. The tuning pins that are seated in the pin block are replaced with larger pins. The larger pin has a greater diameter and will "seat" better in the hard wood block. This only works if—and only if—the pin block itself is in otherwise good, solid condition, e.g. no cracks, splits, or separations.
There are some caveats to using larger tuning pins during restringing. For instance, if the piano has been restrung one or more times in the past, and if larger tuning pins were used, the additional stress of another set of larger tuning pins on the existing pin block may cause the "larger tuning pin" approach to backfire. Again, it is not always going to backfire, but in these cases, we make it a point to discuss the option of a new pin block in lieu of using the existing block with larger tuning pins.
Usually, a piano’s first restringing can be done using the existing pin block with larger diameter tuning pins.
The bridges play a crucial role in the overall sound of the piano. The bridge and soundboard work in tandem to amplify the sound you hear when a key is pressed and a hammer strikes a string. If the bridge or soundboard is in need of repair, your piano’s tuning could be affected. The strings are held over the bridge at extremely high tension, so bridges are usually crafted from very hard woods such as maple or beech. Metal bridge pins driven into the tops of the bridges serve to evenly space the strings as they pass over the bridges.
Replacement bridges can be fabricated in our shop to be an exact duplicate of your piano’s current bridges (these are not interchangeable from piano to piano, and are not stock items anywhere). If a full replacement is not necessary, the top of the bridge can be recapped (just replaces the top layer), and new bridge pins can be inserted.
The Piano Soundboard
The soundboard acts as a large amplifier. When a string is struck by a hammer, the vibrations are picked-up by the bridge and transferred to the soundboard. If the soundboard lacks "crown" or is damaged to any extent that prevents the amplification of sound, this can be an area to target during restoration. Large cracks (and sometimes even small ones) can cause "buzzing" when notes are played. Cracks and unevenness can usually be repaired, while lack of crown generally requires replacement of the entire soundboard.
The above video clip shows a quick view of a new soundboard and bass bridge, as well as new coat of gold on the cast iron plate.
So What is the Point of New Piano Strings, New Pin Blocks, and New Soundboards
Strings, bridges, and the soundboard work together in tandem within your piano to produce the sound and tone that you hear. Most commonly, with new piano strings you will find a much more pleasing sound and tone, as well as improved tuning stability. Even though not all pin blocks and not all soundboards require replacement, addressing these components will further increase tuning stability as well as provide the proper foundation for the production of your piano’s sound.
So this portion of your piano restoration can involve several different components or a combination of two or more (this list is not inclusive): Pin block Replacement, Replacement Tuning Pins, Bridges, and Soundboard.
Ready to discuss your piano and restoration? Please contact us to begin the process.