This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Hi Ron,,,, I'm going to defer to Arnold on this one, as he is better=20 informed and knows Udo much better then I do. One meeting at a=20 convention is hardly enough to qualify as <<establishing a relationship>>= =2E Otherwise thanks again for a very interesting post making clear again =20 many of the points youve brought up before. A few answers to direct=20 questions you ask me.... 1. The K point being the most vunerable point. To begin with it seems clear now that I have not understood this "K=20 point" thing clearly, something I've suspected all along which is why=20 I've posted about it from time to time... hopeing to flush out some more = info about it. Arnold seems to at least have heard the term, and has=20 corrected me (as you do also here) as to the location of the highest=20 point on the panel. What I can do is contact the fellow I had my=20 origional discussion about this so called K-point and see if I can get a = better picture of what he meant then. Perhaps that will put my=20 conversation with Udo into better perspectives. With this said, then I understood that the highest point was the=20 weakest, as it then was that point which would experience the greatest=20 stress downwards by the application of string bearing. Since the basic=20 understanding of this seems to be somewhat in error, I suppose this=20 point would be erroneous as well, tho it does stand to reason that the=20 highest point (in itself) would experience the brunt of the push=20 downwards... yes ??? ... no ??? Your comments would be appreciated as=20 always. 2. I have no reason to doubt the claims that CC panels can be found=20 often enough with reverse crown. Tho I must admit I am somewhat miffed=20 even now as to just how that condition comes about. Ribs that << resist=20 crown >> should equally resist reverse crown to begin with, especially=20 in the light of the fact that the nearer a panel is being compressed=20 flat, the less increased downward pressure the strings are able to bring = to bear. Given some of the string deflection angles tossed around... it = would seem that in some instances the strings would be getting close=20 to holding the panel up before it gets completely flattened to begin=20 with. Correct my figureing here.. but a... say 30 cm long string with a = 1 degree deflection angle has the potential to move about 5mm downwards=20 before it is straight. That in itself is enough to provide for reverse=20 crown I suppose.......say even as much as 2 mm... but then how much=20 pressure does it take to resist that ?? This equivilates to .38 degrees = of string deflection given that same string and the need to deflect a=20 string plane 2 mm.=20 For the SB assembly to experience this reverse crown the top flange of=20 the ribs would have to come into a state of compression from being in a=20 state of tension, and the bottom of the panel would have to have moved=20 from compression towards a tensive state. Given the assumption that=20 this reverse crown can only come about because the panel itself has=20 suffered so much compression damage as to loose its ability to stress=20 the system enough to resist down bearing, one has to wonder how it can=20 then be tensioned at all, and how the ribs which have great strength=20 against any stress along their grain can not suffice to hold the=20 downward pressure of the strings in check. Afterall... the panel itself=20 can no longer be placing any stress on the system as such because its=20 assumed that its ability to do so is already destroyed. 3: (copied from below) >/Udo was of the position that along the grain />/crowning was every bit as important as cross />/grain crown. / I would have expected this point to be a 'position', rather than a 'conclusion'. =20 I rather thought I did refer to it as a 'position' . I did not use the=20 word 'conclusion' at all... yes ??? And, as I understood him to say, he = meant that the compression along the grain helped to stablize the=20 situation cross grain. Now whether this is true or not I do not know.=20 But it certainly does not become true or false simply because some one=20 claims it to be so. If there is some clear documentation to show one way = or the other, I am sure we all would love to see it. I hadnt really=20 thought the question had been asked much as I've only run into this kind = of thing over here. As to your position relative to how much is needed=20 "to achieve an alleged worthwhile crown along the grain." again.. there seems to be an apparent dissagreement between your=20 position and that of Steingr=E6ber. Tho perhaps this is just because of=20 some misunderstanding on my part.. I can not say. Thats why I ask ...=20 yes ?? I agree that Ron N's comments relative to the bridge rolling were very=20 well put. As to the final comments relative to the claim of a different acoustical = result given the two methods. Given the significant differences in the=20 stresses the ribs and panels are subjected too, I really have difficulty = understanding how and why one should not expect a different result. I=20 just wrote a post which went more into why, so I wont repeat it here. =20 But as to the importance of along the grain crown and compression to the = end acoustical result... I cant say, and it seems you havent got more=20 then belief on the matter either. All I can do is report what my=20 understanding of Steingr=E6bers position is.=20 Arnold no doubt has a better understanding of all this, so if he chirps=20 in then so much the better. Thanks for some great reading Ron. Cheers RicB ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/c6/13/ad/8c/attachment.htm ---------------------- multipart/alternative attachment--
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