The Refurbishing Process
Refurbishing: Hammers & Tone
Hammer spacing
The above photo isn't bad. We see much worse. Due to loose screws and warpage of hammer shanks from time and usage, hammer spacing can become wildly uneven. Hammers even twist away from parallel. The result is poor hammer-to-string contact.
While tightening screws and again in a later pass, we return hammers to their appropriate spacing and alignment. Twisted hammer shanks are corrected through a process involving heat.
Hammer shaping
before
after
Hammers get deeply grooved over time. Improved hammer-to-string contact is achieved by filing the hammers down while retaining their original shape. This results in improved tone and reduces problems that could arise from other changes like hammer spacing.
Voicing
Density differences among hammers (plus other factors) often result in uneven tone across the keyboard. One note may sound bright and "live" while its neighbor sounds muted and dull. This is especially common when the strings change from copper-wound to steel in the tenor section. A special tool with very hard, sharp needles is used to "voice" the hammers by altering the density of felt at various points on the hammer. Remarkable changes in tone can be achieved.
In addition to smoothing out uneven tone, we often voice pianos to sound "mellower." A major issue with older, inexpensive pianos is that they sound too bright or "tinny." Voicing hammers that have been compacted by years of use can produce a significant improvement in overall tone.
>>>Next: Refurbishing the Strung Back
Hammer spacing
The above photo isn't bad. We see much worse. Due to loose screws and warpage of hammer shanks from time and usage, hammer spacing can become wildly uneven. Hammers even twist away from parallel. The result is poor hammer-to-string contact.
While tightening screws and again in a later pass, we return hammers to their appropriate spacing and alignment. Twisted hammer shanks are corrected through a process involving heat.
Hammer shaping
before afterHammers get deeply grooved over time. Improved hammer-to-string contact is achieved by filing the hammers down while retaining their original shape. This results in improved tone and reduces problems that could arise from other changes like hammer spacing.
Voicing
Density differences among hammers (plus other factors) often result in uneven tone across the keyboard. One note may sound bright and "live" while its neighbor sounds muted and dull. This is especially common when the strings change from copper-wound to steel in the tenor section. A special tool with very hard, sharp needles is used to "voice" the hammers by altering the density of felt at various points on the hammer. Remarkable changes in tone can be achieved.
In addition to smoothing out uneven tone, we often voice pianos to sound "mellower." A major issue with older, inexpensive pianos is that they sound too bright or "tinny." Voicing hammers that have been compacted by years of use can produce a significant improvement in overall tone.
>>>Next: Refurbishing the Strung Back