Hi Stephane Every body has there own take on this & ...I have mine. I'll answer your queries one at a time Hello John. When boring hammers, should we favor strictly the string height minus shank center height at the cost of no straight hammer height at rest (reflecting I measure the string height & subtract the center pin height from that & then substract 1mm more & that is my bore distance. Which means the hammer shanks will all over center a small amount. But that is the way so many actions are set up & it is I believe for the following reason... The idea is that maximum power is achieved from the hammer at rest to the point of let off which occurs before the hammer ever hits the string .Now Freeze frame.... the shank is in the straight out position. Action The shank/hammer now travel freely 1 or 2 mm past that point and hit the string. the not straight strike line height at strings) ? Since the string planes on most pianos I work on are not all the same height off the key bed, I favor boring the hammers to match the curve of the string plane. This method allows for the shanks from bass to treble to all be at the same position at let off & at rest. Yes the hammer line ot tops of the hammers may travel up hill or down hill a samll amount but the important thing is the action will have a very uniform regulation end to end. Am I making any sense? Also, when gluing hammers on shanks, should we favor the hammer crowns straight line at rest, at the cost of aural best position ? I Never do. I am giving a class on this subject at the Calif. State convention. in Feb 2006 Called finding the strike line/working with hammers. The way we bore our hammers will also have a huge bearing on where the hammer strike lines are located. I find very few straight hammer strike line in the treble are the optimal strike point. In other words, how much should we care about aesthetics when doing hammer work ? I know that a hammer job can be both beautiful & tonally accurate even without straight strike lines in the treble which is where all the futz factor comes into play. Usually when ahnging them by ear the resulatant line will be horshoe type curve or slightly curving line or lines that vary from the first treble to the top treble. Hammer Boring ,plate casting variations & erroneous original guide hammers can all contribute to a new set of hammers failing to optimize the tonal potential of the piano. Hope this helps Regards Dale Erwin Best regards. Stéphane Collin. -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20061009/fbb42d76/attachment-0001.html
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