<HTML>In a message dated 11/24/2002 9:12:34 AM Pacific= Standard Time, RNossaman@cox.net writes: <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Subj:Re: Belly rail crown - = Why??? Date:11/24/2002 9:12:34 AM Pacific Standard Time From:<A HREF="mailto:RNossaman@cox.net">RNossaman@cox.net</A> Reply-to:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A> To:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A> Sent from the Internet            Dale writes >     I see nothing wrong with the beveled rim person= ally, if my boards are > retaining a good amount crown even when strung I see no reason to induc= e > another unnecessary possible strain at the edge of the board by changin= g > all the beveled rastens that come through the shop to a flat edge. No, = > I'm not saying you were advocating that either. Hi Dale, There's nothing wrong with beveled rims, but if you find no performance advantage to beveling rims and are building a piano, you wouldn't be too <BR= > eager to spend the time to cut the bevel.</BLOCKQUOTE>    I agree but the= re has to be some surface cut anyway flat or beveled and As we've discovered= through lengthy discussions some things are easier than others to determine= as to there actual performance benefit. Stwy's diaphragmatic sound board de= sign is a case in point. Murky water perhaps but as I recall the treble edge= rasten was raised to meet the edge of the board so as to eliminate a bendin= g strain by so doing. The idea was that it freed up the board. What's the pr= oof?  Probably subjective ears but hey we all do a good deal of our aut= henticating that way I.e. improvements in raw hammers by voicing, tonal impr= ovements from new strings. In the case of the stwy experiment the same type = of subjectivity was used. Even if they used same action in 2 different piano= s the sound board wood is different, possibly e.m.c.s'. I believe there conc= essus was it tonally better. I couldn't say. You, Del or Ron O might have A = different slant on these findings. I Bet you Do.      At any rate the best judge of that kind of subject = determination in my mind woud be the guys in the factory who were so familia= r with the old design compared to the new one that there opinion would carry= some real weight     &nbs= p;          In rebuilding, if the bevel is <BLOCKQUOTE TYPE=CITE st= yle="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; = PADDING-LEFT: 5px">there, you leave it. The point being to not go to &n= bsp;            unnec= essary trouble to incorporate or eliminate any "feature" that has no clear e= ffect either way.</BLOCKQUOT= E>   <FO= NT COLOR="#0000ff" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY= ="SERIF" FACE="Times New Roman" LANG="0">   Uh huh. I'm with= you      <BL= OCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5= px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Also the board is often thinned do= wn to as little as .250 at the edges > so undue stress once again not desired. Why would you thin the board edges in the first place (except maybe in the <= BR> bass if you don't float it), and why would it be less desirable to unduly <B= R> stress these edges than it would a thicker edge. Tail thinning from the corn= er,around behind the bass bridge and  clear up through the curve but le= aving the top treble end thicker as you well know is fairly common practice = in boards where tails aren't floated which  is the majority of pianos t= hat get restored in America.  My personal experience is that thinning i= n these areas does provide a significant performance gain in sustain and cla= rity in conventionally reproduced  belly systems. Meaning In my case ri= b crowned boards at 5 &1/2 to 6% emc</BLOCKQUOTE>         I think it an important distincti= on to the readers on the list that particularly You and Del are using techni= ques that are, at least in some cases, a radical departure from conventional= belly replacement. Your focus is completly on belly redesign which is great= and many will hopefully incorporate your ideas and find out if this a desir= able direction they wish to go.For some the tonal difference may not be what= satisfys them compared to what is considered good to them. Also every one h= as to start somewhere. The redesign cost could be a significant impediment a= dding cost to an already pricey project.       It would be good for us who have heard much a= bout the superior design traits in these hybrid board systems to actually ex= perience it for ourselves. As yet I've not heard anyone weigh in on this ill= usive experience. Being a sustain freak myself I'd love to hear the improved= sustain and color you both speak of. <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">  As to the stress questio= n the answer is, thick or thin, any unneeded bending strain should be minimi= zed or eliminated. Isn't Floating a tail simply a removal bending strains an= d stiffnesses caused by panel restrictions due to a clamped edge system?</FO= NT></BLOCKQUOTE>     &nbs= p; And what constitutes undue <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: = #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">s= tress?     &nbs= p; again Any</BLOCKQUOTE> un= warranted bending strain <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">How is a board stressed more by= a rim beveled 1° less than the angle at which the rim meets the panel under load, than it is by a rim beveled 1° more? Doesn't compute.        Ron N</BLOCKQUOTE>   <FO= NT COLOR="#0000ff" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY= ="SERIF" FACE="Times New Roman" LANG="0">   I think you misu= nderstood my thought. = Or maybe I did.= The rim bevels on stwys roughly equating  1 &= amp; 1/2 degrees will mate with a board in the 60ft. crown range with no&nbs= p; load. What I was trying to say was  that a lesser board angle due to= string load might more closely match the crown of the board under load. Yes= I see your point though.      It is however interesting as to how much faux crown= can be exhibited in an old board only to have it disappear completly upon i= t's removal from the case. A condition or anomaly I attribute soley to the r= im bevel  capturing the rib ends and panel edge. It does have some ,alb= eit, small influence. Any way I don't dismiss it completly.     Regards      Dale Erwin <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> </BLOCKQUOTE> </HTML>