This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Hello, Dale, Yes I agree it is not easy to write about these, without sketches. 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. 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. 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. 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. 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. 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. Best Regards. 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 -----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 In a message dated 2/2/2003 3:36:25 PM Pacific Standard Time, oleg-i@wanadoo.fr writes: Subj: RE: Bearing difference on different soundboards Date: 2/2/2003 3:36:25 PM Pacific Standard Time From: oleg-i@wanadoo.fr To: Erwinspiano@aol.com 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 ? August 1995 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. >>>The effects of Downbearing on tone by John Hartman 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) 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 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 -----Message ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/caut.php/attachments/d2/08/dc/a0/attachment.htm ---------------------- multipart/alternative attachment--
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