<!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 6.00.2800.1126" name=GENERATOR></HEAD> <BODY> <DIV>Hello, Dale,</DIV> <DIV> </DIV> <DIV>Yes I = agree it is not easy to write about these, without sketches.</DIV> <DIV>Sure that = I measure how much the board move after un stringing with the same method as you. That = mean I can have things back in place at last.</DIV> <DIV> </DIV> <DIV>But I did not thought of using the pre stressing method = yet. I just think about the error made by most while "reading" with a string, = and having for instance 10 mm apparent height below the bridge, when the = bridge is slanted a lot in fact as on Bösendorfers. The first time I've seen = that I believed there was something wrong, and I worked to have the rests higher.</DIV> <DIV> </DIV> <DIV>In fact (I believe) the slant on the bridge mean that = the thread method is useless (unless we apply some fixed parameters as on new = pianos) because the back of the bridge is lower, the amount of defluxion should = be computed in regard of the apex of the 2 angles, and it is not possible = with a thread, if you see what I mean.</DIV> <DIV> </DIV> <DIV>Talking about Nick articles, I understand = that the 0.29 method is useless as things move under the pressure, but he explain an = approach based on the evaluated crown in regard with rib length , that can with = some computation give the maximum amount of defluxion of a thread without oil = canning the board.</DIV> <DIV>I was just talking about numbers there, a 1/4 " on a thread, when pushed flat, = will lower the bridge a little less, say if the ratio between speaking length = and rear length is 4 for 1, when lowering the string 5 units, only 4 = are produced on the bridge, that was the only idea I wanted to express.</DIV> <DIV> </DIV> <DIV>I totally agree with the remaining you wrote and I am very interested in = the john Hartmann articles. I will check if by chance I have these issues, but I = doubt of having them all.</DIV> <DIV> </DIV> <DIV> </DIV> <DIV>Best Regards.</DIV> <DIV> </DIV> <DIV> </DIV> <DIV> </DIV> <DIV>PianoTech 17 rue de Choisy 94400 VITRY sur SEINE FRANCE tel : 033 01 47 18 06 = 98 fax : 033 01 47 18 06 90 cell: 06 60 42 58 77 </DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px = solid"> <DIV class=OutlookMessageHeader dir=ltr align=left>-----Message d'origine----- De : = Erwinspiano@aol.com [mailto:Erwinspiano@aol.com] Envoyé : lundi 3 = février 2003 05:49 À : oleg-i@wanadoo.fr Objet : = Re: Bearing difference on different soundboards </DIV>In a message dated 2/2/2003 3:36:25 PM Pacific Standard Time, = oleg-i@wanadoo.fr writes: <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px = solid; MARGIN-RIGHT: 0px" TYPE="CITE">Subj: RE: Bearing difference on different soundboards = Date: 2/2/2003 3:36:25 PM Pacific Standard Time From: <A href="mailto:oleg-i@wanadoo.fr">oleg-i@wanadoo.fr</A> To: <A = href="mailto:Erwinspiano@aol.com">Erwinspiano@aol.com</A> Sent = from the Internet Dale, I remember I've seen one issue of the = journal, with this article on pre stressing the board but I am not sure that I = have the whole numbers. Can you please tell me what months if you = recall ?</BLOCKQUOTE>   = August 1995 <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px = solid; MARGIN-RIGHT: 0px" TYPE="CITE"> Don't = look too far, I have an index on an Excel file, and should find it there, but = remember me the title of the article if you please.</BLOCKQUOTE> >>>The effects of Downbearing on = tone  by John Hartman <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px = solid; MARGIN-RIGHT: 0px" TYPE="CITE"> Do you = use dial gauge with magnetic base to see how much distance the board goes down ? I = just bought one of these bases and the simple ones are cheap, very useful = to follow moves against the iron plate for instance. But I = guess 4 or 5 of them may be necessary (I've heard of a tech that pre stresses while = looking at such a large amount of gauges)</BLOCKQUOTE>    No dial gauge. A simply way to = measure is lay a straight edge across the top of the rim Use tape to mark it's = location and use a measuring device to measure down to a spot on the bridge before = and after stringing. My new boards usually deflect/go down about 3 to 3.5 = mm in the central Part of the board , about 2 in the first capo and about = 1mm in the top. They deflect about 2mm in the bottom tenor and about 1 in the = bass. This is a hard subject to write about on the computer don't you agree?     These are concepts so complex and = involved  that it took  me some years  to actually  absorb them = to the point that I really understood them. But NOw I know how to make the = practical application in reality.    Good night--Dale <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px = solid; MARGIN-RIGHT: 0px" TYPE="CITE"> Good = night , time to go for me ....   = Friendly wishes and for sure I should like to = come some day and make you a visit, thanks for your offer.   Isaac   Isaac OLEG Entretien et réparation de pianos. PianoTech 17 rue de Choisy 94400 VITRY sur SEINE FRANCE tel : 033 01 47 18 06 98 fax : 033 01 47 18 06 = 90 cell: 06 60 42 58 77 <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff = 2px solid; MARGIN-RIGHT: 0px" TYPE="CITE">-----Message </BLOCKQUOTE> </BLOCKQUOTE> </BLOCKQUOTE></BODY></HTML>