<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: [CAUT] String scaling help svp?</title></head><body> <div>Hi Mark,</div> <div><br></div> <blockquote type="cite" cite><font face="Arial" size="-1">from the comments below (kawai kg-2A string breakage, november 22/06) I'm not sure if we resolved whether string gauge was a factor in excess breakage on these high-tension scales?</font></blockquote> <blockquote type="cite" cite> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">Anyone with scaling software mind running some numbers for me?</font></blockquote> <blockquote type="cite" cite> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1" >note            string diameter     speaking length</font></blockquote> <blockquote type="cite" cite> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1"># 75 (B6)     .033" (#14)          <span ></span>  105mm</font></blockquote> <div><br></div> <div>That's about 61%</div> <div><br></div> <blockquote type="cite" cite> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">#80 (E7)     .033" (#14)          <span ></span>    80mm    </font></blockquote > <div><br></div> <div>That's about 63%.</div> <div><br></div> <div>In both cases, I don't think the tension is high enough to be the root cause.</div> <div><br></div> <blockquote type="cite" cite> <font face="Arial" size="-1">I'm curious about the % of break point, and what consequence there would be in replacing these with .032" wire. </font></blockquote> <div><br></div> <div>Changing the wire gauge will make very little difference to the break %. It mostly changes the inharmonicity. I'd look for problems with either the counter-bearing or Capo bar and/or the string approach angle.</div> <div><br></div> <blockquote type="cite" cite> <font face="Arial" size="-1">Within the last two years, I've had Jeremy re-string trebles in a half-dozen KG-2 incarnations as "prevention." However, string breakage seems as rampant now as it did with the original strings.</font></blockquote> <div><br></div> <div>The half round brass counter-bearing bars in the KG pianos can grab the wire a bit, and the KG capo bars are very soft, which also allows the wire to dig in. Apart from the poor tonal result, it also causes the bar to 'grab' the wire when rendering. The string approach angle on some of the KG Kawais can be a bit excessive, which can also encourage string breakage.</div> <div><br></div> <div>Sometimes when re-stringing I grind the plate thinner where the counter-bearing bar sits, or file the counter-bearing bar base to lower the profile, or both. I don't like a  string approach angle of over 15 degrees as a general rule.</div> <div><br></div> <div>If you've got a case of 'bashers' using the practice room pianos and fatiguing the wire early, bringing the strike a little closer and reducing the dip can be a good way of extending wire life.</div> <div><br></div> <div>I used to tune for a known 'basher' concert pianist here for many years. I would invariably bring the strike up to around 40-42 mm for his performances just to reduce the problems created by his 'meat cleaver' hands and his approach to performance. I always used to think the guy should have been a race car driver instead of a pianist.</div> <div><br></div> <div>How did the Wapin conversion on the SD10 turn out?</div> <div><br></div> <div>Best regards,</div> <div>Ron O.</div> <x-sigsep><pre>-- </pre></x-sigsep> <div><font face="Times New Roman" size="+1" color="#0000FF"><b>OVERS PIANOS - SYDNEY</b></font></div> <div><font color="#000000"><i>   </i></font><font color="#0000FF"><i>Grand Piano Manufacturers</i></font><font color="#000000"><br> _______________________</font></div> <div><font size="-2" color="#000000"><br> </font><font color="#000000">Web http://overspianos.com.au</font></div> <div><font color="#000000">mailto:ron@overspianos.com.au<br> _______________________</font></div> </body> </html>