---------------------- multipart/alternative attachment joegarrett@earthlink.net writes: > Also, there > are times, for whatever reason is beyond me, the line from the butt flange > center pin is closer to the strings than Hammer bore distance dictates. The reason I have heard for this is that the center of gravity is behind the center pin, so gravity aids the hammer return. It may be properly called vertical pitch, but all the hammer makers I talk to at least recognize the term "rake." I confess that's what I use. Anyway, the center pin to string being shorter than the bore seems fairly common, so it's needed to put the hammer head perpendicular to the string, or in the case of some pianos like the older Steinways, a little overcentered. Shortening the bore in order to cut the rake (excuse me, vertical pitch) changes relationships between the jack and the butt. It might work and it might not, as it would throw the butt forward and could cause the jack to skip out. Keith's original interest was in how to deduce the correct bore distance from scratch, where the original hammers might or might not be present for evidence. I couldn't answer him right off at the meeting Monday, but upon reflection, apart from looking at the rest position of the hammer rest rail with a normal thickness of cushion, I would guess that the primary factor would be the ability of the jack to push for the best power, and return efficiently under the butt. Bob Davis ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/3c/2b/5f/51/attachment.htm ---------------------- multipart/alternative attachment--
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