<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><BR><DIV><DIV>On Apr 19, 2007, at 1:00 AM, RicB wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">I mean... why would we have any use for super hard abrasives like diamond files or any such thing unless the basic idea that harder vs softer results in softer loosing ?</FONT></P> </BLOCKQUOTE></DIV><BR><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>Hard beats soft if it is an abrasive, meaning it has sharp edges as opposed to being polished. If both are polished surfaces, hard will win, but much more slowly (bridge pins don't wear through, they just get a very slight wear profile). It is also true if you are hammering one object against another, the softer will be dented more, but that doesn't enter into this scenario. </DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>If the hardness is fairly even (as in the case with music wire and, perhaps, a titanium bridge pin - I don't know how different they are, but guess probably not too much), and both are polished, there is likely to be very little wear to either. At any rate, I am quite skeptical that it would be significant, enough to cause increased string breakage. If the pins were rough and impregnated with diamond dust, that would be a different story <G>.</DIV><DIV><BR><DIV><DIV>Regards,</DIV><DIV>Fred Sturm</DIV><DIV>University of New Mexico</DIV><DIV><A href="mailto:fssturm@unm.edu">fssturm@unm.edu</A></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV></DIV></DIV></BODY></HTML>