<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; = charset=iso-8859-1"> <META content="MSHTML 6.00.2716.2200" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2>Cast iron IS brittle but it will not = deform nor compress under stress and tension the way steel, aluminum, and other = metals do. Nor does it expand and contract with changing temperatures as much as = other metals. The key point is that it holds its shape and, most important, = the critical string length dimensions. </FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>I understand that cast aluminum was = tried back in the 40's or so. It would sure be nice to find a different, lighter, less = brittle material--then you wouldn't need such a heavy wood frame either. Every = time I move a piano, my thoughts stray in this direction ...</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>I'm guessing that a lot of the metal in = the casting is just to make the plate "beefier" so it doesn't break so easily. = </FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Alan R. Barnard</FONT></DIV> <DIV><FONT face=Arial size=2>Salem, MO</FONT></DIV> <BLOCKQUOTE dir=ltr style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: = black"><B>From:</B> <A title=pianobuilders@olynet.com href="mailto:pianobuilders@olynet.com">Delwin D Fandrich</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A = title=pianotech@ptg.org href="mailto:pianotech@ptg.org">pianotech@ptg.org</A> </DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, August 27, 2002 = 1:16 PM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Foundry = Castings</DIV> <DIV><BR></DIV> <DIV><FONT color=#000080>And If I haven't created enough confusion = yet, I'll toss out another one:</FONT></DIV> <DIV><FONT color=#000080></FONT> </DIV> <DIV><FONT color=#000080>Just why do we think gray iron is the best = of all possible materials to use for piano plates anyway? What is it about = gray iron that is so special? </FONT></DIV> <DIV><FONT color=#000080></FONT> </DIV> <DIV><FONT color=#000080>We say it is extremely rigid -- but it is = not. It's brittle. Is this an advantage?</FONT></DIV> <DIV><FONT color=#000080></FONT> </DIV> <DIV><FONT color=#000080>We say it has excellent internal damping characteristics -- but is this an advantage? Why?</FONT></DIV> <DIV><FONT color=#000080></FONT> </DIV> <DIV><FONT color=#000080>Right off hand I can think of only two characteristics that make it a particularly good choice for piano = plates: [1] It is easy to machine and [2] it is cheap. Neither of these has = anything to do with its performance in the piano.</FONT></DIV> <DIV> </DIV> <DIV><FONT color=#000080>Del</FONT> </DIV> <DIV><FONT color=#000080></FONT> </DIV> <DIV><FONT color=#000080></FONT> </DIV> <DIV><FONT = color=#000080></FONT> </DIV></BLOCKQUOTE></BODY></HTML>