<HTML style="FONT-SIZE: x-small; FONT-FAMILY: MS Sans Serif"><HEAD> <META charset=US-ASCII http-equiv=Content-Type content="text/html; charset=US-ASCII"> <META content="MSHTML 6.00.2800.1400" name=GENERATOR></HEAD> <BODY style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; BACKGROUND-COLOR: #ffffff"> <DIV><FONT face="MS Sans Serif">Isaac,</FONT></DIV> <DIV><FONT face="MS Sans Serif"></FONT> </DIV> <DIV><FONT face="MS Sans Serif">I'm relying on decades-old memories of college physics for this, so the details may not be exactly right, but I think I have the general principals correct.  Resilience is a measure of how little energy is absorbed, and lost to conversion to heat, by a material when compressed:  the more resilient the hammer, the less energy it absorbs during collision with the string.  As to the other question, how much energy is transferred to the string vs how much is used to propel the hammer into the backcheck, that is influenced by several factors more important than resilience, including the mass and compliance (inverse of stiffness) of both the hammer and the spring.  The example of the ball rebounding from the pavement illustrates an extreme, where the ball is light and compliant, the pavement is massive and stiff.  Heavy hammers transfer more energy to strings than light hammers.</FONT></DIV> <DIV><FONT face="MS Sans Serif"></FONT> </DIV> <DIV><FONT face="MS Sans Serif">hope that helps</FONT></DIV> <DIV><FONT face="MS Sans Serif"></FONT> </DIV> <DIV><FONT face="MS Sans Serif">Mike</FONT></DIV> <DIV> </DIV> <DIV></DIV> <DIV> </DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid"> <DIV style="FONT: 10pt Arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B> <A title=oleg-i@noos.fr href="mailto:oleg-i@noos.fr">Isaac OLEG</A> </DIV> <DIV style="FONT: 10pt arial"><B>To: </B><A title=pianotech@ptg.org href="mailto:pianotech@ptg.org">Pianotech</A></DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> 4/23/2004 2:46:01 AM </DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> RE: Acetone</DIV> <DIV><BR></DIV><FONT size=2> <DIV><SPAN class=074594208-23042004>So the resilience may be adapted in regards of  the hardness, the weight and also the resilience of the object that is contacted , Indeed if the ball rebound, that mean the energy get reflected to the ball. In the hammer we want some to be given to the strings as well is not it ?</SPAN></DIV> <DIV><SPAN class=074594208-23042004></SPAN> </DIV> <DIV><SPAN class=074594208-23042004>Best</SPAN></DIV> <DIV><SPAN class=074594208-23042004></SPAN> </DIV> <DIV><SPAN class=074594208-23042004>Isaac OLEG</SPAN></DIV> <DIV><SPAN class=074594208-23042004></SPAN> </DIV> <DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma>-----Message d'origine-----<BR><B>De :</B> pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]<B>De la part de</B> Erwinspiano@aol.com<BR><B>Envoyé :</B> vendredi 23 avril 2004 00:30<BR><B>À :</B> pianotech@ptg.org<BR><B>Objet :</B> Re: Acetone<BR><BR></FONT></DIV> <DIV> <DIV>In a message dated 4/21/2004 10:58:19 PM Pacific Standard Time, Richard.Brekne@grieg.uib.no writes:</DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT face=Arial>btw... Whats Delwins take on hammers and laquer ?  Seem to remember he <BR>went further then we do over here for the natural  hammer resiliancy <BR>side.  No... this is one of those typical <<opinions vary>> <BR>questions....and so it should be :)<BR><BR>Cheers Dale !<BR><BR>RicB</FONT></BLOCKQUOTE></DIV> <DIV>  Ric</DIV> <DIV>  Right you are.! It all depends on whos defining resieliency Know what I mean. A steel ball is the most reslient when bounced off cement.  It probaly expends the least amount of energy per bounce than the super ball or a felt hammer.</DIV> <DIV>  Cheers back at ya</DIV> <DIV>  Dale</DIV></FONT></BLOCKQUOTE></BODY></HTML>