How can scruffing occur unless the hammer shank flexes? It does flex, and it does scruff, but always upward. As the flagpoling of the shank reverses, the hammer begins to scruff downward just as it is rebounding from the string. The proximity of the axis of rotation to the string is less significant than the length of the hammer bore from the strike point. This can be seen in slow-motion photograph of action movement. It is amazing how much an upright shank flexes. You would think it would break before flexing as much as it actually does. A grand shank flexes also, but not nearly so much. The drawing below is simplistic and exaggerated, but illustrates the point. Frank Emerson pianoguru at earthlink.net ----- Original Message ----- From: Steve Fujan To: joegarrett at earthlink.net;Pianotech List Sent: 11/24/2006 12:47:45 PM Subject: Re: Over-Strike vs Under-Strike Shifting slightly to the concept of scruffing... The hammer contact will always "scruff" towards the hammer pivot axis (unless the pivot axis could somehow lie in the plane of the string). The closer the pivot axis is to the string, the less "scruffing" will occur. Steve Fujan On 11/24/06, Joseph Garrett <joegarrett at earthlink.net> wrote: Upon reading the follow-ups of Jons query, I'd like to wonder which is which. I've always considered "Over-Strike" as the Downward angle of the hammer, which would put the hammer Beyond Perpendicular. ??? Am I correct on that? If so, then, "Under-Strike" would be, where the hammer does not achieve Perpendicular, on contact?? The "Over-Strike" hammer, (on an Upright), would "scruff", (for lack of a better word), downward, at impact. The "Under-Stike" hammer would therefore "scruff" upwards. Do I have all of this backwards? Confused minds need to know what the consensus is.<G> Joseph Garrett, R.P.T. Captain, Tool Police Squares R I -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20061124/4b6c3461/attachment.html -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/jpeg Size: 25392 bytes Desc: uprightactionflagpole.jpg Url : https://www.moypiano.com/ptg/pianotech.php/attachments/20061124/4b6c3461/attachment.jpe
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