IT Jan 2008 - Industrial Technology Magazine

DESIGN NEWS
Linear motion hits the right note
in guitar string manufacture
The sound quality of British manufacturer
Rotosound’s guitar strings has made them the
choice of successive music generations. Jimi
Hendrix, ELO’s Jeff Lynne, 10CC’s Eric Stewart
and Iron Maiden’s Steve Harris count amongst its
high-profile customers.
This enviable reputation derives from
Rotosound’s careful choice of raw
materials and the bespoke
winding process that
gives its strings their
distinctive sound.
The process itself
is fundamentally
the same today as
it was when the
current Chairman’s father started
the business in the 1960s. Also unchanged is
Rotosound’s use of HepcoMotion linear slides to
guide the cradle that carries the wire spool set. Indeed
the Generation 1 Hepco slides that were specified for
the first winding machines are still working today, more
than 30 years later.
Rotosound came into being as a result of zither
collecting. Having learned to play the instrument in the
Army, James How started to
buy old zithers most of which had
missing strings. As a typical instrument
can require up to 150 strings the need to
mechanise the winding process became
apparent to make restoration viable. As he was
working at the Royal Ordnance Factory in Woolwich
at the time James had the means to design and make
the machine which was ultimately to form the basis of his
guitar string manufacturing business.
“The late ’60s was a good time to start,” explains
Jason How, the founder’s son and Chairman of
Rotosound since the mid ’90s. “Floyd, The Who
and The Beatles were at their peak and there
were virtually no imported US strings into the
UK so the potential was considerable.” The
reputation of Rotosound’s products travelled
with those bands and a global market soon
opened up for this Sevenoaks-based company.
The first generation of the Rotosound winding machines were
highly labour intensive. They required the wire to be fed manually
and their throughput was just 20 to 30 strings per hour. The
process involves wrapping various types of cover wire over a
choice of base core wires and then, in many cases, gluing on
a final layer of silk. As demand for the product has grown so
Cool Acoustics’
polymer guitar
collaboration
Cool Acoustics, the Loughborough University
venture developing foamed polymer technology
for acoustic guitars, has unveiled its Secret
Valentine project. This yearlong
collaboration with renowned UK guitarist
Gordon Giltrap and master guitar-maker
Rob Armstrong has resulted in a specially
commissioned studio album recorded on a
stunning new polymer acoustic guitar.
The new Rob Armstrong Secret
Valentine guitar is a handmade hybrid
acoustic guitar, featuring a wooden body
and neck but with a Cool Acoustics
soundboard. The soundboard is the flat
front panel that shapes the majority of a
guitar’s sound and is traditionally made of
spruce or cedar. But these materials are
vulnerable to tonal and structural changes
caused by fluctuations in temperature and
humidity, and there can be a variation in the
tonal quality of guitars that are massproduced
to a standard construction. Cool
Acoustics soundboards are manufactured
from foamed polycarbonate, a manmade
10
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INDUSTRIAL TECHNOLOGY • January 2008