Wow, Dale! Strike line and sound production is really a very interesting subject and one worth researching, documenting everyone's experience and trying to define. No wonder why I was struggling, with the soundboard involved and all. I can't do anything about soundboards because I don't do them. I have noticed and thought about the string height in that section. I'll have to go back and measure. I just did a hammer job on a Steinway L 1929. Turned out good but not great in that area. When I measure the string height there is a difference by section and I believe ( memory) the killer octave height is greater. I am so grateful for t his group. There is no place else we can share piano stuff like this with you all. Thanks. Randy Ellen Chastain San Francisco Bay On Feb 8, 2010, at 7:57 PM, Erwinspiano at aol.com wrote: > Hi Ed > What do you find the average amount of over centering to be ie. > no. of MM s the center of the hammer shank rises above the center > pin height? > Also I am most curious as to your subjective opoinion about what > discernable differences in sound..if any? > uhhh...and the shank is parallel to what zzzzactly? > Thanks Pal > Dale > > > > -----Original Message----- > From: Ed Foote <a440a at aol.com> > To: pianotech at ptg.org > Sent: Mon, Feb 8, 2010 7:51 pm > Subject: Re: [pianotech] boring, (was Hammer strike line) > > Dale writes: > Perhaps the idea Ed was getting at was that whatever degree the > string slope is that there should be a corresponding amount of over > centering and rake so the string and hammer are at right angles to > each other ant the keybed. However this means calculating the slope > on each piano or just checking it and averaging the bore. I think I > just devised an A B Expereiment. I'll work on it > > I do calculate the bore distance to the slope. I do this by using a > set of graduated "hammers" glued up to shanks and flanges. > Actually, the "hammers" are various lengths of the Renner slats, > glued to the shanks at exactly 90 degrees. By putting, say, a 49 mm > "hammer" in the piano, I can simply lift it to the string, drop a > square down along its edge, and instantly see if it is at right > angles to the string. When I find the correct length, I know that > upon contact, the hammer is at 90 degrees to the string, and the > shank is parallel. It is quick, accurate, and easy. > Regards, > Ed Foote RPT > http://www.uk-piano.org/edfoote/index.html > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100209/0a2cc498/attachment.htm>
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