Copyright © 2003 CBH
on the spine replacement of the
Michael Thomas French Double Harpsichord in an antique
privately owned in Singapore
NASA VISIBLE EARTH
When tuning the harpsichord at home in Singapore early January 2002, the
owner noticed the spine side of the keywell was very flimsy. Inspection
revealed that the spine was seriously weakened by termites, and the infestation
appeared to be still active.
The instrument was fumigated, crated, airfreighted, and quarantined on
arrival in Sydney prior to delivery to the workshop.
Several specimens of the dead insects and their bolus were sent to Dr Richard
Milner (entomologist late of the CSIRO—and a keen recorder player
and Past President of the Canberra Recorder & Early Music Society)
for identification, and were returned as Cryptotermes sp, either C. domesticus or C.
Singaporean drywood termites are particularly dangerous. At times these
insects are capable of just flying in and establishing a colony in any piece
of wood in your home. They require neither decayed wood, nor wood that is
in contact with moisture.
Removal of the existing spine
The degree of damage to the spine made it necessary to replace it in its
entirety, a most interesting and rarely-undertaken job as the spine is
quite literally the very backbone of the instrument.
Complete replacement of the spine was only practical in this instrument
because of the substantial case structure from Dolmetsch, with slightly thicker
than normal liners, a wrestplank horse arrangement with integral keyend blocks,
as well as a bottom reinforcement probably dating from one of the European
restorations of the 1980s.
The string tension was reduced, and the eaten spine carefully removed
from the structure of the case. The soundboard and its associated spine moulding
remained in place throughout the repair. It was established that the infestation
was largely confined to the wood of the spine and the short beech block spanning
the gap under the bass end of the registers. Damaged areas of the spine liner
were cleaned and filled with epoxy compound to ensure sufficient strength.
Attachment of the new spine
A new spine was prepared in European lime Tilia vulgaris. In the earlier
arrangement, there was no possibility of removing the registers without destringing
the harpsichord, so opportunity was taken to include a spine window for future
convenience. The distortion of the old harpsichord case had to be accounted
for. A clamping method was devized using bench-mounted cams to allow the
replacement spine to be firmly pressed against the bottom of the case while
the glue dried. Traditional cabinetmaker’s screw clamps were able to
be used to clamp the spine against the soundboard moulding and liner, and
a bar clamp was used across the instrument at the wrestplank.
The bare spine was primed, handpainted green using oil-based paints, and
varnished to match the existing decoration on the case exterior. Printed
Flemish papers were prepared and aged to seamlessly match the papers remaining
on the soundboard rim and keywell of the instrument.
Stringing & Action
The action was installed, the existing strings brought up to pitch, and the
The instrument was packed for return by airfreight to Singapore in April 2003.
After reacclimatization, the harpsichord was briefly checked during an Asian
maintenance tour in late May 2003. The repair was judged a success by the owner,
with increased tuning stability.