Jon & All I don't subsrcibe to this often stated hammer bore theory below but my mind is still open to convincing. I believe there is one right optimum hammer bore spec & that's when it's hitting at right angles to the string. Lengthening the bore distance in grands simply scews the geometry up & to often misses the magic line & creating friction& heavy touch. AMHIK. WHen the hammers are worn & subsequently over strike due to filing they simply need to be replaced. No, they often do not but that's my story & I'm stickin to it. I observe that most american grand actions over strike the string from the git go. They are Designed that way IMO. Due to geometry the action achieves its full power when the shank is perpendicular to the keybed however in order to allow for this the hammers are bored a bit short to allow for let-off. Make sense or not? I see where you are coming from on the upright. It shouldn't be any different. SO why is it? It seems to me that the better angle for the hammer would be an initial slight under strike so that as the hammer wears the strike angle approaches perpendicular (playing in) and gradually over striking as it wears further. Instead of hitting perpendicularly initially and playing out from the beginning. On this piano, 75% of the string cut is on the top shoulder. How can this be beneficial. And why is there a difference in theory for strike angle between verticals and grands. I see many verticals with this over strike. -- Regards, Jon Page -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20061124/e0735346/attachment.html
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