Ron Nossaman wrote:with MC%1 being the lower MC and MC%2 the higher. > > We see that a panel that is 36" wide at 4.5%MC will expand by 0.359" when > taken to 11%MC. It's proportional, so any width will produce the same > percentage size change (1% with these MC ranges). That will happen at 70° > @ 60% relative humidity. Constraining this panel to a flat rib will bring > it under compression beyond the fiber stress proportional limit, indicated > in this same reference at 580psi radially perpendicular to the long grain, Please refer me to the proper table proper column. I see on page 79 for Sitka Spruce FSPL perpendicular to the grain at 710 psi. > > Incidentally, I had always heard 4%MC quoted as the preferred dry down > level for this type of construction. When did it become 4.5%, and why? John Patton writes 5 % for Steinway panels. I can copy to the list his reply to me if you wish. > > > Ron N > > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html http://www.hf.uib.no/grieg/personer/cv_RB.html
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