This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Re: Short Treble (sustain?)Hello Ron Overs Why not see what response your observations get from Grotrian-Steinweg = themselves? Do you mean Model 220? Or should it be Model 225? I have a = superb 225 on my rounds and have been corresponding with Grotrian on the = subject of a 10 year service/regulation. They have been most helpful. = Write to: Burkhard Kaemmerling at: kaemmerling@grotrian.de=20 Regards Michael G (UK) ----- Original Message -----=20 From: Overs Pianos=20 To: Pianotech=20 Cc: Alf Reichardt=20 Sent: Monday, November 03, 2003 10:21 PM Subject: Re: Short Treble (sustain?) Del, Ron N. and all, The string buzzing on the side of the agraffe slot is most certainly the = problem. Earlier in my career I recapped the failed bridges on a = Grotrian 220. Since the owner was travelling to Germany on business, = when he visited the factory they sold him a replacement treble bridge = cap. Unfortunately, the new bridge cap was afflicted with the same = 'disease' which was common to '70s era Grotrians (I have no idea if it = remains a problem with their contemporary instruments). However, the = bridge pin spacing was so close that there was virtually no free space = between the string and the adjacent bridge pin. Consequently, there = remain several notes on my client's Grotrian 220 which have string noise = at the bridge pins (which varies in intensity according to the relative = humidity at the time). A gentle side pressure on an offending bridge pin = will stop the noise. These Grotrian bridges from the '70s are prone to failure on account of = the close bridge pin spacing. There is simply insufficient bridge wood = around the pins to provide adequate support for the side thrust on the = pins. On Grotrians from earlier periods they have used a wider bridge = pin spacing and they do not have the same problem. Isn't it amazing how = corporate knowledge often fails to be passed down from one generation to = another? The 'Johnny come latelys' turn up with new thinking but fail = give appropriate consideration to lessons learned long ago by an older = generation of thinkers. I'm all for innovative technologies, but one = should come to it after stepping off from the knowledge which has gone = before. Clearly, the idea of placing a damping material on a noisy string = segment (wether it be new-age silicon as in the case of the Stuart = agraffe, a piece of felt or a lump of fat from under the barbecue), its = still is just a case of fixing the symptom instead of addressing the = cause of the disease. The bridge agraffe we have been discussing is a case in point. It simply = wasn't thought through prior to execution. I concur with your views Ron = N. and Del, with regard to widening the slots and using rolled pins as a = solution. Less overall height would be a plus as well. As you and I have = both mentioned previously Ron N., it would allow for the retention of a = more sensible bridge height and stiffness. Ron O. ----- Original Message ----- From: "Ron Nossaman" <RNossaman@cox.net> To: "Pianotech" <pianotech@ptg.org> Sent: November 01, 2003 8:23 PM Subject: Re: Short Treble (sustain?) I suspect the problem is with the string buzzing against the side of = the slot. Del Perhaps, though I have a hard time imagining much vibration excursion = in that short segment. At that, how difficult or more expensive is a = wider slot, as long as you're cutting one anyway? It's not like it will = cost anything important in rigidity. A grooved center rod would help too, though it would cost a bit more to produce. Ron N ------------- As do I. I did think it a possibility, though, as I worked with = similar devices at Baldwin. The easiest way to solve the problem (if it = exists) (and, other than putting some damping material between the leading termination and the center deflector rod) is, as you suggest, to = groove the center rod. This could be rolled and, in quantity, is not as expensive = as you might think. In limited quantities, however, it might well be a = factor. This can be used to solve another problem as well -- the varying = string deflection angles as the wire size changes. I played around with = several groove depths, deeper in the low tenor and bass, more shallow in the tenor/treble. Del --=20 OVERS PIANOS - SYDNEY Grand Piano Manufacturers _______________________ Web http://overspianos.com.au mailto:info@overspianos.com.au _______________________ ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/95/c9/17/b4/attachment.htm ---------------------- multipart/alternative attachment--
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