Thanks muchly John, for a really well worded posting.... a couple comments below. John Hartman wrote: > Richard Brekne wrote: > > > What I dont get is why the Balance Rail needs to be elevated so much. > > And how are we supposed to determine the proper balance rail height to > > begin with ? I was always told that glide bolts need to just make > > contact with the key bed... not to lift the whole darn middle of the key > > frame up. > > > > Explainations please ? > > I don't have an explanation but I think that just having the glide bolts > kiss the bed is not the best way to bed the key frame. Changes in > humidity and forceful use of the pedals can cause problems. I adjust the > glide bolts to apply a little force to the key bed. Starting with the > one over the right pedal I turn it down until it takes a little pull to > lift it. I apply my foot to the right pedal and check again. I also > check it with my left foot on the left pedal (shifting the action) at > the same time. Work your way out from the first glide checking for good > pressure with the pedals in play. The end glides don't need as much > pressure as the ones toward the middle. Just make sure you don't over do > it and end up with the front rail lifting up. Perhaps this might be a thumbs rule clue then... adjust them as much as you can as long as you avoid the front rail from lifting ?... something along those lines ? As far as the explanation for why such pressure is necessary... maybe stressing the frame thus keeps it from flexing under the pressure of hard play ? Even tho you cant see a lift in that back rail no matter how you look, the frame will tend to flex in that direction unless its already << pre flexed >> if you get my meaning ??... just guessing here. > Your balance rail must have been just barely floating above the bed if > is caused the hammers to dance. I am sure you are happy that you found > the true cause of the problem before you made a new hammer rail. It is > so easy to jump to conclusions in this business, I have done that many > times. Finding the problem is more than half the battle. Once again good > detective work and simple pianocraft win over impetuous re-engineering. Well, I've always been under the impression that glide bolts must be just down enough to cause a thin piece of paper to drag heavily when inserted between the bolt and the bed. That yeilds a pretty minimal contact. Why this works well on some pianos and not so well on others is another question. Issac has some thoughts on that I think he is going to share with us. I aggree that one has to be very carefull about jumping on the re-engineering wagon. Understanding the origional intent as clearly as one should is not always as straightforward a task as it may seem. Hesitancy to change has its up side for sure. > Congratulations and thank you, you saved us all a lot of effort. Now we > don't have to go forth and change the hammer rails on all those Yamaha > pianos! Thanks on both accounts.... especially the second ... gawd I'd hate to have on my concsious knowing that folks started just revamping those rails for no good reason. That being said... they still flex when stressed as I described origionaly... what is to be gained by eliminating that flex is another question entirely. In anycase... its not part of my present situation. > > John Hartman RPT > > John Hartman Pianos [link redacted at request of site owner - Jul 25, 2015] > Rebuilding Steinway and Mason & Hamlin > Grand Pianos Since 1979 Thanks John.... and I might suggest that this whole subject seems interesting enough for an article or series in the journal for anyone interested enough in putting out the effort necessarry to write it. Or what ? -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html http://www.hf.uib.no/grieg/personer/cv_RB.html
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