---------------------- multipart/mixed attachment --part1_94.33a7daa7.2b6f4fff_alt_boundary In a message dated 2/2/2003 8:37:36 PM Pacific Standard Time, Erwinspiano writes: > Subj: Re: Bearing difference on different soundboards > Date: 2/2/2003 8:37:36 PM Pacific Standard Time > From: <A HREF="mailto:Erwinspiano">Erwinspiano</A> > To: <A HREF="mailto:oleg-i@wanadoo.fr">oleg-i@wanadoo.fr</A> > > > > In a message dated 2/2/2003 3:50:34 PM Pacific Standard Time, > oleg-i@wanadoo.fr writes: > > >> Subj: RE: Bearing difference on different soundboards >> Date: 2/2/2003 3:50:34 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 >> >> >> >> I understand that if we see, for instance 1/4 inch crown from below the >> board, that does not really mean that having 1/4 distance bearing at the >> string rest will absorb the whole crown, it depends of the back string >> length vs. the speaking length. >> >> >>> Isaac--Even with 1/4 inch crown The board could actually be pushed down >>> to flat under the situation you describe, if the board is really weak. >>> With the strings off try pushing down on a board with your hands and >>> watch how much it moves so that you can get a feel for how stiff it will >>> be. If it has some strength it will have resistence that will not >>> permit the 1/4 inch distance bearing to push it flat. >>> . >>> Dale, I mean : >>> >>> If you have 1/4' crown , and you have 1/4" height difference at the rear >>> string rest, even if the string became straight under tension, (defluxion >>> absorbed) the board will not deflect 1/4", but less, because the 1/4" >>> 'leverage' is divided by the string's length, anyway that was my idea and >>> that make sense. >> > > > >>If the string actually became straight the board would be flat but if > the board has resistence it won't allow the string to become completly > flat. Does that make sense. The problem is old CC boards most often do not > have much resistence or crown. > > >> >>> So the static method explained by Nick Gravagne is OK, showing how to >>> compute a maximum amount of down bearing , or distance bearing, in regard >>> of the existing crown (taken rib by rib) and still having some security >>> in regard of the possible collapse of the board. >> > > > >> Once again No it doesn't work exactly. His method takes the rear > string length and multiplies by .026. For example 4 inches times .026 > equals .104 distance bearing. This gives a 1 &1/2 degree angle of > deflection on a 60ft crowned board. And These figures only work on a new > fully crowned board. > Now here is the part I'm having trouble making clear to you. First I've > done it his way and it doesn't work. He himself has modified his procedure > but hasn't revised the article. What will happen if you do it as Nick has > written is that as the tenor is strung first the board is compressing so > that when you reach the beginning of the first capo section the nice > distance bearing you thought you had calculated is disappeared as the > sounbboard sunk under load . You can check it with a bearing string. So pre > stressing compensates for this. Read the article I suggested you'll be > enlightened. > Pre-stressing makes so much sense you'll be amazed > regards Dale > > >> >>> >> > --part1_94.33a7daa7.2b6f4fff_alt_boundary An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/caut.php/attachments/81/1f/be/99/attachment.htm --part1_94.33a7daa7.2b6f4fff_alt_boundary-- ---------------------- multipart/mixed attachment An embedded message was scrubbed... From: Erwinspiano@aol.com Subject: Re: Bearing difference on different soundboards Date: Sun, 2 Feb 2003 23:37:36 EST Size: 10481 Url: https://www.moypiano.com/ptg/caut.php/attachments/66/ff/55/b7/attachment.eml ---------------------- multipart/mixed attachment--
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