Rebuilding a piano is designed to restore an instrument to its original condition, or better. It involves the complete disassembly of the piano into its smallest constituent parts; these are then individually cleaned, repaired, or entirely replaced with new, so that when the piano is reassembled it can be regulated and tuned to the closest tolerances.
With over 10,000 parts such comprehensive work is very expensive, and is usually only deemed appropriate for high-quality and valued instrument.
Any rebuild starts with an assessment by a technician to evaluate the instrument’s design and build quality. This ensures that the piano’s potential performance when rebuilt will both meet the owner’s expectations and justify the cost involved. The assessment should also make it clear immediately whether it would be more cost-effective to replace the piano rather than rebuild it.
Since the cost of a rebuild may equal or exceed the purchase price of a high quality piano in showroom condition, the evaluating technician must satisfy himself that the instrument once rebuilt will compare favorably with a new piano.
The technician then evaluates the current condition of the instrument to determine whether it has deteriorated so far that it is beyond repair. Pianos damaged by fire or flood are not generally repairable as they tend to suffer severe structural damage, some of which may develop years after the initial accident.
Much the same is true of pianos that have been damaged during handling. The iron frame, although strong enough to resist the tension of the strings, is brittle and will easily crack if the piano is dropped. Although a repair is possible, it is both costly and risky as the repaired frame cannot be entirely guaranteed to withstand the returning string load.
Once a full assessment of a piano’s condition of potential rebuilder has been made, it is moved to a workshop and work can begin. Here are some idea how rebuilding works:
- Detailed measurements are taken from the strung back before the strings are removed and the frame lifted out.
- The soundboard, bridges, and pin block or wrest plank can then be clearly reinspected, and repaired or replaced as deemed appropriate. The increased access also allows further inspection and any necessary repair of the strung back’s supporting structure.
- The frame is regilded and then secured back in place, particular attention being paid to its height in relation to the bridges. The strings and wrest pins are replaced with new and the tension is returned as quickly as possible to the strung back in order not to distort the soundboard or its structure.
- The action, keyboard, and damper mechanisms are completely disassembled and thoroughly rebuilt, with all the felt parts recovered, the springs replaced, and every center pin checked for the correct tolerance.
- New hammer heads are always fitted in the rebuilding of a piano, careful calculations being made to ensure that their dimensions will allow them to strike the string accurately and produce their best tone.
- The trapwork is cleaned and lubricated and the case is refinished. All the hardware, such as the pedals and hinges, is polished or replated, felt trims, and rubber buttons are returned.
- The instrument is then regulated and its keyboard reweighted to compensate for any changes in the hammer weight.
- Finally the piano is tuned several times to stabilize the new strings, and voice so that it produces its most pleasing and appropriate sound.