<!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>Alan</FONT></DIV> <DIV><FONT face=Arial size=2>My dad ran a machine shop that catered = to repairs for industrial equipment which included several foundries. I worked = for him for about 11 years.   "Jerry" was the foreman for one of these = foundries.  We watched him unloading used cast to be recycled for = new cast.  He'd set the piano plates aside because they were "pig," = first pour iron  He'd add some nickel to cast to give it a = "little flex."  Brom's Foundry would add chromium to the mix to add = hardness and pour "nyhard" (sp) castings for government contracts.  It was very = hard, and hard on equipment.  Brittle cast was for low stress, low cost castings.  I'm sorry I can't relate any specific formulas.    Some cast machined very well, while other = parts were a head ache.  They had hard spots and cavities.  Until epoxies = came along, we had to bore out and press a steel sleeve in the bearing = journal to make some repairs. We regularly junk old pianos and are amazed how = difficult it is to break up the plates.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Paul Chick</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=mathstar@salemnet.com = href="mailto:mathstar@salemnet.com">Alan R. Barnard</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 = 6:57 PM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Foundry = Castings</DIV> <DIV><BR></DIV> <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></BLOCKQUOTE></BODY></HTM= L>