<HTML><HEAD> <META charset=UTF-8 http-equiv=Content-Type content="text/html; charse= t=utf-8"> <META content="MSHTML 6.00.2730.1700" name=GENERATOR></HEAD> <BODY style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; BACKGROUND-COLOR: #fffff= f"> <DIV>In a message dated 10/11/2003 10:18:55 AM Pacific Daylight Time, RNossa= man@cox.net writes:</DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue = 2px solid">>       As you say It d= oesn't seem the panel is going to compress > significantly with these= minor increases from downbearing. I typically > dry Sitka  pane= ls before ribbing between 5.5% to 6% EMC out here in > Calif. Many go= to the bay area with higher average moisture levels than > the centr= al valley where I am. I have followed many of these pianos over > tim= ed see no sign of compression ridges, cracks bulging etc. With other &gt= ; kinds of spruce with less strength across grain , or containing too much <= BR>> soft spring/early wood, it could be a problem. But then neith= er you nor John are building compression crowned soundboards with flat r= ibs, so the comparison isn't of much use. >>>Well , uhh, not xactly. Early O= n I dried some panels down to what was probably 4.5% to 5% with lightly crow= ned ribs with very little if any addition in height. The only one that had a= problem  with a bulge was an eastern spruce board with a huge plank of= early wood in the bass corner.  With the damp chasers on it diminished= significantly. </BLOCKQUOTE> <DIV>  <FON= T size=3>  Not only that but I do rib a= bit drier than some folks (I know my climate) and the backs of the rib= s do bow some even though they were machined straight. Primarily its the lon= gest ribs. As you well know all boards have some compression componenet. I'v= e stated it before that I prefer the sounds of a board with a bit more compr= ession based on what I hear in my own boards & in others I prefer I pref= er the sounds of.  My philosophy is that if a board sounds really good = for 50 yrs. isn't that long enough? Obviously most hybrids will persevere lo= nger than that & besides, Uhh I won't be here... probably.</FON= T></DIV> <DIV>  But no in general I crown my rib= s 60ft & more in the treble, it depends on the piano.<BR= > > >>> So then it looks like a safe level of E.M.C for panel= crowning could > range from 5.5 % to 6%emc In purely compress= ion crowned boards, the overall compression is the problem, not the star= ting MC. Similar panel compression levels can be gotten by either severe= drying, or pressing the assembly in a deeper dished caul. If the result= ing crown is the same, the panel compression is the same no matter how i= t was arrived at. >>Panel Moisture content at ribbing equals overall panel = compression. As to the latter my press caul is steeper(45 ft.)&nbs= p;than most of the rib radii I use as well but the rib backs are straight wh= en it comes out of the press so I'm not sure how much steeper it'd have to b= e to make this true.(speaking of panel compression) &= gt;    If anyone has had the idea that only a highly modified boar= d is an > exceptable and legitimate attempt at quality piano rebuildi= ng just isn't so. And as far as I'm aware, not a living soul has made= that claim, so I can't help but wonder why so many people repeatedly an= d specifically make this point against a claim that was never made. <= FONT face="Times New Roman" color=#000040 size=3>>>> = When an idea has so dominated discussion on this list it is possible to conc= lude that a thing has been said or assumned, even though unstated. People dr= aw perceptions in a variety of ways. I wasn't pointing any fingers just maki= ng clear that there are a variety of different ways to be succesful doing th= is work.-Most all are valid-Regards-Dale I also note that= my original request for an explanation still hasn't been approached. Jo= hn said that the ribs of a compression crowned soundboard supported most= of the crown, and the panel supported very little. I'd still like to kn= ow how that can be when it is panel compression that is bending the rib = in the first place, thus supporting both the rib and the bearing to reta= in crown. <STRONG= >>>> Angled rim joint has an effect though not one you'd obviously = build a whole concept around This Ron N</DIV> <DIV></DIV></BODY></HT= ML>