---------------------- multipart/alternative attachment Based on recent experiences which have me viewing older soundboards with a degree of suspicion, the question I have is whether or not crown necessarily equates to stiffness. If the issue with soundboards is whether or not they have adequate stiffness to create that opposing spring, is measured crown enough of an indicator? In other words, is it possible that a soundboard may show adequate crown but not have adequate stiffness to perform properly when loaded? David Love davidlovepianos@earthlink.net ----- Original Message ----- From: To: pianotech@ptg.org Sent: 11/12/2003 7:15:26 PM Subject: Making a soundboard-S&S L board List In the spirit of "make a soundboard" I continue to observe things that work (or not) I currently have a 1960 L in shop for finish stringing & some action sprucing. The piano has always lived in a Church sanctuary in Fresno, Ca. These people love this piano & were concerned about changing the sound so.... When a piano sounds really, really good I'm always asking, I wonder why. The piano had nicely set bearing & with the strings on as evidenced again with the strings off. The amazing thing for me is this sound board has more crown thru out its entire rib scale than most S&S I've encountered. I don't work on many this young. I stretched a string across the bottom and starting between the top two ribs. It had 2 mm of nice hemispherical crown. That equates to approx. 30ft radius. Continuing on down & measuring between each rib it had 3.4 , 4 , 5 , 6 , 6, 5, 4, 3 mm of crown. after doing a mock up pre-stressing check of the bearing it had roughly 2 degrees of bearing in the top 2 sections tapering down to 1&1/2 degrees in the tenor starting in at the treble tenor break The bass was set almost to zero. It was really fairly text book S&S bearing set up. Also there is only the faintest sign of any compression ridging & that only on 1 joint. Modest annular ring spacing (10-12 grains an inch). I've rarely measured any crown in the top end of S&S's let alone such tight radii for a CC crowned board. I was wondering if it was rib crowned but I don't think so. Looks to be about . 330 thick in the middle. It has significant crown along the bridge as well, but of course the crown hasn't sunk. It's true that it's survived well because of our moderate Ca. climate but also something was right when the board was made. This the easiest rebulding I do & this kind of thing makes it fun & interesting. Dale ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/79/86/0a/ba/attachment.htm ---------------------- multipart/alternative attachment--
This PTG archive page provided courtesy of Moy Piano Service, LLC