Piano Wire

[John Delacour]

At 9:06 pm -0700 9/5/02, Joseph Garrett wrote:

|  My next trial wire will be the
| "Pure Tone" stuff. I am curious and would like to try it. The problem there
| is I need to find out what the math/density coeficient is for the scaling
| program. Any one have a thought on that?

The specifications are at the web site <http://www.puresound-wire.com/>
The specific gravity is higher (7.9+ v. 7.85 for common wire) and the tensile strength is significantly lower, though he now makes a few of the thinner gauges with a higher breaking strain, so you need more tension to bring the string to pitch while the wire will break at a lower tension -- not what I'd call an ideal state of affairs!

Note C64 with length 18.1 cm. will come to pitch (A=440) at 170.2 lbf. using standard wire of density 7.85 g/cc.  Using the higher density wire, a tension of 171.3 lbf will be required.  I append a perl script detailing the calculation.  So you see that the increase in tension is insignificant, whereas the much lower breaking strain is important and must be taken into account.

JD

#perl -w
( $note, $length, $diameter ) = qw~
    64     18.1    0.0925   ~ ;

( $rho,   $a49,   $g45   ) = qw~
  7.85     440   980616  ~ ;

$K = $g45 / 3.14159265358979 / $rho / 2.205 ;
$frequency = $a49 * (2 ** (1/12)) ** ($note - 49) ;
$tension = sprintf "%.1f",
   ($length * $diameter * $frequency)**2 / $K ;
print "Tension: $tension lbf.\n" ;

   #### -> Tension: 170.2 lbf.
   #### _____________________