Ron, Would the pitch-change effect then be less, if not negated, by vertical bridge pins. In other words, any guess as to how much of the bridge affecting pitch change is due to the slant of the pins as compared to the offset angles? Has anyone who works with a Wapinized piano observed greater tuning stability after the modification? Alan Eder -----Original Message----- From: Ron Nossaman <rnossaman@cox.net> To: College and University Technicians <caut@ptg.org> Sent: Thu, 7 Jun 2007 9:15 am Subject: Re: [CAUT] pre-stretching new string? <div id=AOLMsgPart_0_3ba5fc00-2a31-4b6a-9770-94fd09a7370f style="FONT-SIZE: 12px; MARGIN: 0px; COLOR: #000; FONT-FAMILY: Tahoma, Verdana, Arial, Sans-Serif; BACKGROUND-COLOR: #fff"> A little trig, a little Pythagoras, and Sanderson's scaling formulas answer a lot of questions. Downbearing deflection angles in pianos are so small, that soundboard rise and fall would have to be enormously more than we observe in actual pianos, to account for observed pitch changes. Dimensional changes in bridge caps, moving strings up and down bridge pins slanted at 15-20° in opposite directions with bearing offset angles around 10°, produce string length changes ten times that of soundboard rise and fall. </div> <div class="AOLPromoFooter"> <hr style="margin-top:10px;" /> AOL now offers free email to everyone. Find out more about what's free from AOL at <a href="http://www.aol.com?ncid=AOLAOF00020000000437" target="_blank">AOL.com</a>. </div>