David: I didn't see any responses to this email. Do keep us posted on how this comes out. dp David M. Porritt dporritt@smu.edu -----Original Message----- From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of David Renaud Sent: Monday, July 04, 2005 7:08 PM To: pianotech@ptg.org Subject: Stienway d-rolled bridge saga- report Esteemed list I have taken my time following this up as I ponder what attitude to take. For new readers...to review.... bridge is lower on speaking side then backscale side by as much as 20 thou. over much of this new D Steinway.. including the bass bridge. The result is strings that will not stay seated, and various buzzing off the backscale. It is severe enough in at least one place the back of the bridge is highenough that there is no pressure on the backscale plate before the hitch pin and the string will buzz on the plate unless held down to the plate or muted. From previous posts I understand bridges do not roll so much as soundboards in front of the bridges may collapse. Also it was suggested by at least one person that the piano was built this way. I have a response from Stienway, and have respectfuly taken off the name of the person writing for the moment. They are coming from NY to see this piano and in light of the response I hope for more feedback. They obviously wish to manage the problem and leave it alone. I can not see strings staying seated in its current condition. String seating and hammer mating is at present, in my opinion, a waste of time. Here it is......... ------------------------------------------------- Hello David, First, thank you for your very complete letter. Your comments are very helpful in trying to assess any possible problems with this piano. As to the excess glue, you are correct that this is simply glue squeeze-out that should have been cleaned up in the manufacturing of the piano. It is sometimes difficult to see this at the belly rail but, as you have done, should be removed to prevent possible buzzes in the future. Concerning the bridge/downbearing, let's keep an eye on this if the buzzes have been eliminated for the time being. While it presents a situation to keep an eye on, I do not want to make an immediate pronouncement that there is something wrong there. The primary thing that manufacturers look for is the total composite bearing on the front and back combined. This should, of course, be a positive bearing. Theoretically, there should be positive front and back bearing. However, pianos seldom conform to the theoretically correct. I have taken many bearing measurements - on both good sounding and not-so-good sounding pianos. Some of the best sounding pianos have exhibited the measurements you describe below while some of the lesser sounding pianos are textbook perfect. The downward forces of the strings over the bridges (anywhere from 800 - 1100 lbs of force) cause each piano to develop its own unique shape. Sometimes that "settling" can be measured to exhibit what we technicians commonly cause bridge roll. That in itself is not a great cause for concern but rather a sign that we need to monitor this in case tonal issues arise consistently with a piano. In my experience, seating and leveling the strings, hammer filing, voicing meticulously, hammer spacing, and making sure the bridge pins are seated in the bridges alleviate any tonal problems 98% of the time. You MAY have one of the "2% pianos" there but let's wait and see if problems develop again before we determine a course of action. Again, thanks for your very detailed and thoughtful note. And please call or contact me if I can be of service on any issues or questions you have. ---------------------------------------------------- Some of my Original Letter to Stienway........ ------------------------------------------------- Hello Dave Renaud here, Ottawa-Gatineau, Canada. One of my clients is the Quebec Conservatory in Gatineau Quebec. They have a new D you are likely aware of. It was in ......cut............... I have a few observations that should be investigated. Minor...... There were very large 2-3 inch long shards of glue where the soundboard meets the belly rail. Some of these thin shards from oozing glue (I saved some, could take a pic.), were lightly touching/buzzing against the board. I cleaned this up, It eliminated some buzzes and did take time to troubleshoot.........when all else was eliminated, I thought it had to be the glue joint along the rim. Major...... The bearing on the back of the bridges is high, the bearing on the front(speaking side) much lower. As much as 20 at the back and 0 at the front. This is all over, on both the treble , and bass bridge. I was motivated to measure because a buzz on the backscale could not be eliminated without pushing the string down on the backsacle plate. This string would not seat on the plate due 0 bearing over the plate, This lead be to wonder if Perhaps the back of the bridge was high. It is, and the front is low, string travelling downhill to the speaking length. These measurements were made with a Lowell gauge. I followed up by having xxxx from xxx measure with a bubble gauge. He had negative measuments on the bridge cap angle all over the piano as much as negative 18 in places. I then had xxxxx look at it and confirm the same thing. The strings should travel "uphill" to its termination point at the speaking length. They are travelling downhill to the speaking length. Marcel came down from Quebec city, and spent a day seating and mating strings, did a wonderful job, and the piano was much better. With the negative slop to the bridge nothing will stay seated for long. What believe has happened with this piano is technicians arriving for a day, with a program in mind to treat normal problems. Indeed, they find strings that need seating, and hammers that need mating....normal.....and proceed to fix it. But on this piano, the poor seating, and string mating is NOT because it was neglected, or not maintained properly, and not because needs proper concert service. We can do that. It is a recurring symptom of the negative bridge cap angle. The opinion that I am hearing suggested from techs is the soundboard at the front of the bridge may have collapsed somewhat. Hmmm...that belly rail that should supports the crown and all those oozing glue shards at that very joint. Could this mean something related. What does those shards suggest in the manufacturing process. Just too much glue? not securely glued down at the belly normally? Just not cleaned up? Just thinking out loud ...any thoughts here. If I am missing something here I am very interested in understanding how this can be. Your thoughts, observations, and suggested solutions will be of great interest to me. At this point I believe I have observe and diagnosed something everyone else has missed. Not that others were in any way delinquent, they did fine fine work, but were I think on a schedule, a program to follow, and seeing the symptoms went straight to work without sufficient "why is this." I happen to spent a great deal of time in front of this instrument tuning and pondering over recurring buzzes that motivated me to look to the bridges,and check those glue joints. I hope this has been helpful If I could make further measument charts, but I think you see what is here. If I can be of help, please ask away. David Renaud __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________________ pianotech list info: https://www.moypiano.com/resources/#archives
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