--- On Thu, 6/23/11, John Delacour <JD at Pianomaker.co.uk> wrote: ...except that bows aren't made of cast iron and don't need to stay in tune. Piano makers use two main approaches to the design of the structure to make sure that this cannot happen. JD *************** Bows also don't have forty thousand pounds of tension on them. Even with nosebolts in place the forces which are of sufficient magnitude to bow the plate struts upward are able also to pull up the backposts with them. I don't know if Ted Sambell is watching this thread or not, but I believe he took some measurements of this phenomenon some years ago. He placed a rail across the piano resting on the rims and suspended a gauge from the rail to measure plate height before and after tension was released. Ted, if you're there, do you recall how much vertical movement you measured in the plate? Cheers, Bert -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20110624/754c9184/attachment.htm>
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