It is rare that I am not in an experimental mood, Ed! When Steve suggested sizing the bushings with alcohol and water, it got me thinking in the direction of treating these guide rail bushings like center pin bushings. I wonder if the much thicker cloth of the guide rail bushings and the much looser fit of the moving part (the damper wire) to the bushing would respond like a center pin bushing to reaming and burnishing.
First, I plan to try a more aggressive approach with heated broaches and cauls. If that doesn't do the job, then sizing. (So, no one so far has reported having tried VS Profelt on guide rail bushings...) If all of that still falls short, then my plan would be to rebush. But before rebushing, there would be nothing to lose by experimenting with your idea.
Thanks!
Alan
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Alan Eder, RPT
Herb Alpert School of Music
California Institute of the Arts
Valencia, CA
661.904.6483
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Original Message:
Sent: 06-24-2019 20:05
From: Ed Sutton
Subject: Persistently tight damper guide rail bushings
If you're in an experimental mood, you could make a damper bushing broach, something like a Mannino action center broach made larger.
An appropriate size steel rod, roll with a file to make teeth over a 3 cm section. Or use a small rat tail file to remove some cloth, then burnish with a capstan tool.
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Ed Sutton
ed440@me.com
(980) 254-7413
Original Message:
Sent: 06-24-2019 18:25
From: Alan Eder
Subject: Persistently tight damper guide rail bushings
Thank you for your characteristic clarity of thought, Jim. (Not to mention those hard-won scars of experience! ;-)
Alan
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Alan Eder, RPT
Herb Alpert School of Music
California Institute of the Arts
Valencia, CA
661.904.6483
Original Message:
Sent: 06-24-2019 18:22
From: Jim Ialeggio
Subject: Persistently tight damper guide rail bushings
I have spent inordinate amounts of time on an occasional new keyboard, shrinking and easing and what-have-you bushings. But if the bushings are too big, the bushings are too big. I ended up rebushing...sad I know, but that's the only thing that worked. All the easing and shrinking worked for a max of a week or so.
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 06-24-2019 17:38
From: Alan Eder
Subject: Persistently tight damper guide rail bushings
Steve,
It may be hard to believe that the approaches used so far in addressing this problem have not solved it, but that is indeed the case. They have each, in turn, yielded improvement, but, on this piano, not permanently.
Alcohol and water applied to center pin bushings have the pin in the bushing to function as a caul. Have you applied water/alcohol to guide rail bushings with the dampers in? With the dampers out, but using something else as a caul? With the dampers out, no caul?
Thanks,
Alan
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Alan Eder, RPT
Herb Alpert School of Music
California Institute of the Arts
Valencia, CA
661.904.6483
Original Message:
Sent: 06-24-2019 17:26
From: Steven Rosenthal
Subject: Persistently tight damper guide rail bushings
Alan, I imagine the same formula used in "watering" the action. 50/50 water and alcohol? It's not something I've done much since the newer lubricants have come on the scene. I use a plastic pipette to apply CPL directly on the guide rail bushings.
It's hard to believe that the multiple methods you've used have failed to relieve the problem. As I mentioned, I have run into quite a few damper wire flanges that are too tight on Kawai products, both wooden and plastic varieties. These need to move freely backwards and forwards or you will get symptoms similar to tight guide rail bushings.
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Steven Rosenthal
Honolulu HI
808-521-7129
Original Message:
Sent: 06-24-2019 16:46
From: Alan Eder
Subject: Persistently tight damper guide rail bushings
Steve,
No, I have not tried shrinking the bushings. What is your recipe, and how do you apply it?
Your guess that the cloth used in these bushings is too thick may well be correct. If that is indeed the case, then it is doubtful that this is the only piano with this problem.
Thanks,
Alan
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Alan Eder, RPT
Herb Alpert School of Music
California Institute of the Arts
Valencia, CA
661.904.6483
Original Message:
Sent: 06-24-2019 16:41
From: Steven Rosenthal
Subject: Persistently tight damper guide rail bushings
Alan, you didn't mention simply trying to shrink the bushings with water/alcohol.
It is a puzzler though. I've had some problems with the back action centers but not the guide rails.
Perhaps they used a batch of too thick felt.
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Steven Rosenthal
Honolulu HI
808-521-7129
Original Message:
Sent: 06-24-2019 12:54
From: Alan Eder
Subject: Persistently tight damper guide rail bushings
Esteemed Colleagues,
A client has a Boston grand that has had problems with sluggish dampers since day one. The cause is tight damper guide rail bushings.
A smooth tapered broach, heated with a soldering iron has been used repeatedly. Pressure has been applied from both ends (top and bottom) of the bushings with an awl. Even the dreaded "umbrella stave" tool has been dug out and used. And yet, on certain particularly stubborn notes, the problem persists.
So, the question is: What is the next (more drastic) step? Applying VS Profelt, using bridge pins that are considerably larger than the diameter of the damper wire as cauls, and allowing it to sit overnight? Reaming with a similarly oversized bit chucked into either a drill motor or a Dremel (or Foredom) tool? Something else (hopefully, short of re-bushing the entire guide-rail)?
Also, I would be curious to know if others have encountered this problem on other Boston grands.
Thanks,
Alan
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Alan Eder, RPT
Herb Alpert School of Music
California Institute of the Arts
Valencia, CA
661.904.6483
------------------------------