Harpsichord Wire

[Stephen Birkett]

Fred wrote:
>Actually, I think the reason the smaller diameter works (is "stronger" and
>less likely to break) is because it takes a lower tension to produce the same
>pitch. Has more to do with the mass of the wire, "slowing the vibrations"
>through the operation of inertia. At the same tension, with the same length, a
>thicker wire will sound lower. ...etc

Fred, you're confusing tension with stress = tension per cross sectional 
area. The latter is the factor that has to be considered when it comes to 
breaking wires. Breaking stress should be given in MPa (or nasty psi) for 
each gauge. Very often, though, wrie "strength" is expressed for each gauge 
by wire manufacturers in terms of maximum breaking tension. In a 
pythagorean scale every note will have the same stress level regardless of 
the diameters used. If there were no tensile pickup a single value only 
would have to be given for breaking stress for all the gauges, i.e. it 
would be a characteristic only of the wire material. In reality, there is 
tensile pickup. Thinner wires can withstand greater stress, so you have to 
give breaking stress as a function of diameter. Historical builders were 
very familiar with tensile pickup, but once high carbon steel started to be 
common the knowledge receded into the depths and was generally forgotten.

Stephen

Stephen Birkett Fortepianos
Authentic Reproductions of 18th and 19th Century Pianos
464 Winchester Drive
Waterloo, Ontario
Canada N2T 1K5
tel: 519-885-2228
mailto: sbirkett[at]real.uwaterloo.ca
http://real.uwaterloo.ca/~sbirkett