The hammers of a piano are similar in function to the tires of a car. Like a car’s tires they wear, reducing your piano’s performance. Worn piano hammers can be resurfaced to restore the original shape and texture of the hammer and its original tone, this process is called reshaping and is usually done as a part of a complete voicing. Loud, harsh hammers can be brought to a more mellow or “classical” tone and soft hammers can be hardened to produce a brighter or “jazzy” sound. Very worn hammers can be replaced with new hammers, usually during a complete rebuilding.