<html> <body> Dale, <x-tab>        </x-tab> Interesting observations! I have one of my own if you will indulge me. If as you pointed out that the RC&S assembly should very easily survive are we loading them enough? My thoughts go along the lines of a superior assembly still acting as an opposing (stronger) spring with the same load as before. I don't have a full grasp of all this stuff yet but it seems to me that if you change one system you have to change them both, no? The opposing string bearing load should be correspondingly more I'd think. Greg Newell  At 11:04 PM 2/18/2006, you wrote: <blockquote type=cite class=cite cite="">   Ok, now this is an interesting discussion.  Admittedly not being a math guy I'm still interested in putting some numbers on some scales of things I've seen as a bench marks for comparison.    Let's just take one case I have  first hand knowledge of.  I rebuilt & 1960 Stwy L 3 years ago that lived in a Fresno area church from the beginning of it's creation to the present so it has survived wonderfully well.   I was keenly impressed  by the balance of sound, both in power &  sustain.  I measured the bearing with a lowell gauge & though I don't have numbers any more to give you my recall is that the top capo had over 2 degrees of deflection & the 2nd capo  about 2 or more &  the middle was  1 1/2 degrees tapering down to 1/2  in the bottom & the bass had positive but minimum bearing as it should be with a cantalever.  The crown string stretched across the boards underside revealed lots of residual crown in the strung condition & more than any other C.C. board I've ever seen up to that time.  All that to say it was in my opinion a text book Steinway/belly  set up both in terms of crown & bearing.   These are IMO the kinds of observations that  are important to make when we find something that is working really well.   The Stwy L scale as I recall has an average treble tension at 160 lbs per string. It is obvious to see that the majority of the bearing pressure on the long bridge is increasing  gradually the higher up the scale we go.   So knowing all of the above, what is the equation that will calculate an approximate string bearing load under the conditions I describe?   If it's the one- 40th rule for simplicity then  40 divided into  160 strings  equals 4 pounds per string. Let's remove most of the bass strings from this equation for now, since theoretically there isn't much bearing there & we have approx. 160 strings times 4 pounds equals 720 lbs. add in say 80 lbs for the bass & it's about 800 total pounds give or take      There is a much more accurate & glamorous formula for this but I dont' have it at my finger tips.  If the scale tension averages 180 lbs per string then we're talking 4 1/2 pounds per string which bumps total bearing load up another 100 ish pounds.   My point in all this is that if we are using stronger engineering materials & principles which building better stronger rib structure, which we are, then surely our rib crowned & supported boards will survive as well & IMO longer than this example of a C.C Steinway L  I cited above    Don't you think?   Dale Erwin   <dl> <dd>Consider a basic scale of moderately high tension. Say 40,000 lbs. overall. With this string tension 1,000 lbs of string down force equals 2.5% of scale tension. That is quite a lot considering that most companies are claiming string down force more on the order of 0.5% to 1.5% of string tension (which would be 200 to 600 lbs). I thought I was setting my initial string down force pretty high at around 1.0 to 1.5%. I don't like thinking about what I'd be doing to a board loading it up to 2.5%. I can't imagine it being happy enough at that level to want to stay there. <dd>  <dd>Del </dl> </blockquote> <x-sigsep></x-sigsep> Greg Newell Greg's piano Forté <a href="mailto:gnewell@ameritech.net" eudora="autourl"> mailto:gnewell@ameritech.net</a></body> </html>