<HTML>In a message dated 2/2/2003 2:54:41 PM Pacific Standar= d Time, Erwinspiano writes: <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Subj: Re: Bearing difference on different soundboards </= B> Date: 2/2/2003 2:54:41 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 = 7:36:12 AM Pacific Standard Time, oleg-i@wanadoo.fr writes: <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Subj: RE: Bearing difference= on different soundboards Date: 2/2/2003 7:36:12 AM 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 Thanks much , a very good vi= ew. 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 c= rown, it depends of the back string length vs. the speaking length.</BLOCKQU= OTE>   >>That's right = it won't absorb it all if there is an strength to resist. However in a very = flexible board it could completely deflect under the load. <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> Do you use this as a "rule o= f thumb" , or do you go thru that computation about rear length to know how = much distance is allowed before the board reverse crown ? (as suggested by N= ick Gravagne in the articles he write)</BLOCKQUOTE>    Nick printed an= article about how to compute angle of deflection with no load but it doesn'= t take into account the amount of soundboard squash as the strings go on. I = use a pre-stressing of the board  method of bearing which is described = very thoroughly in the archives or read august 1995 ptj by John  Hartma= n "The effects of downbearing on tone" A must read. Actually four articles.<= /FONT> <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> The basic idea of my origina= l post is that as we aim for internal tension in the board to produce a good= tonal response, we may use the more appropriated process when bearing, and = that the bearing on cc crowned board with nod add that tension (at last in t= he bass and medium), while on rib crowned boards, internal tension is very l= ow before down bearing is applied (unless it is build when you glue the boar= d on its perimeter.</BLOCKQUOTE> >>I don't understand = the thought here. I'm sorry could you clarify. <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> I am very far from truth, or= just a little bit .>) </BLOCKQUOTE> >>You're on the right = track my friend <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> We too see bearing load appl= ied regularly but without relation to crown often, and often too I see too m= uch bearing in the killer zone, that tend to deform even more the panel.&nbs= p; The Bob Grihalva add on seem to help well, and the result is very clear (= cleaner tone and better sustain).</BLOCKQUOTE> >>>Me too. What's a= Bob Grihalva add on. Can we post our e-mails on caut for the benifit of others. It's completely = up to you .It's OK with me except delete the refrence to Stephens secret dev= ice. <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> Have a nice Sunday</BLOCKQUO= TE> ... And too you---Dale Erwin=     Finally SUNNY and warm after a month of rain and fog. Alm= ond trees in bloom and simply Glorious!!!!!!!!!!!!!!  ^68 degrees Come = visit sometime. Extra room here. 2 hours from yosemite. <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> Stephen is looking for a goo= d place where to have his eyelets made actually they are too expensive to be= sold.  his string rests are tunable on a 3mm zone (1.5 high,1.5 down) = , and are 5mm tall, but as they have to be installed on a metal support to b= e moved, the final height is more of a Steinway aliquot scale actually.</FON= T> Best Regards, form snowy Par= is ! Isaac OLEG Entretien et r�paration 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 TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">-----Message </BLOCKQUOTE> </BLOCKQUOTE> </BLOCKQUOTE> </HTML>