Piano Rebuilding: A Primer

Why Do Pianos Need Rebuilding?
Unlike a violin or cello, a piano has around 12,000 parts. The most critical parts in the piano are made from wood, namely the hardrock maple pinblock and the spruce soundboard. It is important to remember that, because the piano was engineered in the 19th century to have greater volume, the soundboard is under rather severe tension from the tight thick strings, which are each scaled to have around 180 lbs. of tension across a cast-iron frame or plate. These strings exert a great force or downbearing on the wooden soundboard. Soft spruce is the preferred wood for soundboards due to its excellent vibrating ability. The board, however, must also function as a rigid tabletop, holding the bridges and strings to the exact correct height. This engineering dilemma was resolved through the use of regularly spaced ribs under the soundboard. These ribs were even notched into the case to improve their holding ability. Also, soundboards were crowned to make them slightly higher in the middle where the board is most flexible. Careful scaling of string tensions can also have a positive effect.

Over time, dryness and neglect in regular tuning (which can equalize the tension on the board) can cause the soundboard to crack and, even worse, slump under the tension of the strings (a sum of 20,000 lbs. across the plate). The board must then be repaired. Age and dryness can similarly affect the pinblock and the torque (tightness) of the tuning pins. Hammers can also age and deteriorate, thus producing an unmusical tone.

What happens first?
Rebuilding begins with removing the old strings and tuning pins, unscrewing and removing the piano's plate or cast-iron frame, finding all the cracks and loose ribs in the board and repairing the cracks by opening them and gluing well fitted spruce shims into them, then doweling and regluing the ribs back into place. Now, the board is sanded and finally refinished with special flexible sealer and instrument lacquer. At this time, the piano plate can be washed, sanded, and refinished in a beautiful piano gold. The new pinblock is rough cut to the correct shape for your piano and must be fine fitted to the plate and drilled to tightly accept the new tuning pins.

The plate is now reattached to the piano case. Critical measurements must be expertly taken and adjustments carefully made to ensure the correct downbearing or bridge height. This step is frequently poorly executed and even overlooked by many factories and shops. Once the scale is obtained and the bass strings manufactured (under Barry's direction), the piano can be restrung. Next, the dampers are refelted, replaced, and regulated.

Now the action work begins.
Old yellowed keytops are replaced with new white ones. Black keys are refinished, if necessary. Hammers are replaced with new ones custom made to Barry's specifications. Felts underneath the keys are replaced and the correct dip (key depth when pressed) must be set. The hammers must be correctly spaced to the strings so they strike all strings evenly. Action regulation also includes many fine adjustments like hammer blow, drop, let-off, and back-check to ensure your piano plays as effortlessly as possible.

Next the strings are tuned.
Tuning starts with at least two chippings (or rough tunings). The new strings must be gradually stretched and brought up to the tension required for A440 pitch. While tunings continue, Barry is able to begin juicing or applying small amounts of lacquer to the shoulders of the hammers to bring up the tone. He uses the finest Steinway techniques he has perfected over decades of work and always relies on his ear for these critical adjustments.

The action has been lubricated with high-tech piano lubricants; any parts that need it have been replaced as required. After more juicing, voicing, and tuning, Barry thoroughly plays and checks over the piano before it is carefully returned to your home, stage, or studio. Your piano is now a prized heirloom possession guaranteed to bring much joy and musical pleasure with some simple maintenance.