---------------------- multipart/related attachment --============_-1206780990==_ma============ At 2:48 AM +1100 11/10/01, Ron Overs wrote: >JD wrote: > >> > Well, Ron, this presumes a pretty sharp "terminating pivot" >>which is neither >>> desirable nor even attainable by makers who might think it desirable. > >It's certainly attainable JD if we want it. Bars can be hardened to >cut piano wire like cheese should one desire it. And that without as >much as marking the bar. Sure... such stuff as tuners' nightmares are made on! > >Ron N replied: > >>Not necessarily. A 2X12 plank across a 55 gallon drum will rock quite easily >>with a kid on each end. It doesn't have to be a knife edge to produce the >>effect. > >Agree entirely. Well the all the 55 gallon drums on the pianos I deal with are cemented to the frame and have the 2x12 plank firmly clamped to them by the upward pressure on the plank and I challenge any kid to use them as a see-saw. The analogy doesn't hold water! > However, to follow on from Johns comments, I suspect that smaller >radius bars produces less distortion. I would say that the smaller the radius facing the speaking length the better, just as a short vertical drop in the soundboard bridge in the line with the centre of the pins will provide the best termination there, but since I am not interested in resonant front lengths I would provide a relatively long sliding surface to the plank side at the same angle as that made by the wire as it rises to the bearing bar. >The large radius bar will actually cause the effective string length >to shorten and lengthen as the string goes through each cycle. I >haven't proven this by experiment, but it sure seems to have legs, >if the bars (either duplex or capo) have a large radius, the tone >doesn't seem to be any good. It changes radically for the better >when the bar radii are reduced. Yes. in effect the string never knows how long it is and there will be minute fluctuations in the frequency together with the risk of noise. When I am restringing pianos without duplex scaling, eg. Ibach, Bechstein, I usually replace 'soft' bearings with a 1/8" round or half-round bearing backed up with a softish felt bearing, sometimes adding a second 1/8" brass bearing before the wrestpins. JD --============_-1206780990==_ma============ An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/21/9f/70/cf/attachment.htm --============_-1206780990==_ma============-- ---------------------- multipart/related attachment A non-text attachment was scrubbed... Name: Untitled.gif Type: image/gif Size: 2861 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/20/c0/95/d6/Untitled.gif ---------------------- multipart/related attachment--
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