At 15:56 -0500 13/03/2011, David Doremus wrote: >Hi Jack and John, you have really piqued my curiosity. I have worked >on many viennese style actions and have never regulated them so that >the hammer blocks and slides on the string. What is the rational for >this? I've been puzzling this over since I saw Jacks post and just >can't grasp the concept. Thanks! Hello David, the geometry of the action is such that the shank has gone several degrees past the horizontal (hence the casting out of the hammer head) when the hammer touches the string. The "tail" of the shank is therefore sloping down and tending to push the jack away and escape; the jack is, as it were, hanging on by its fingernails. The moment the hammer touches the string the jack must fly away even under very soft blow, but the momentum of the hammer-head holds it against the string for a tiny fraction of a second, just as happens in a regular action and during that time the nose of the hammer moves just a fraction along the string towards the player. Both the "blocking" and the "stroking" (or "sliding" as Jack calls it) are momentary events, little more than tendencies in practice, but they exist. Of course it is necessary to regulate the fly in such a way as to prevent actual blocking, but if you set the escapement at 1 or 2 millimetres as you would on the French action, then quiet playing will be hit and miss. JD -------------- next part -------------- A non-text attachment was scrubbed... Name: vienna-action.jpg Type: application/octet-stream Size: 58763 bytes Desc: not available URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20110313/da7dd770/attachment-0001.obj>
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