Hi Cy,
Nice to see you at the convention!
Over the Fourth of July weekend I visited the piano in question, loaded for bear (i. e., prepared to do everything everyone suggested, short of rebushing the rail in the customer's home). As usual, I started with the simplest, least intrusive option that did not preclude doing any of the other stuff if it didn't work. First, I confirmed that the problem was, indeed, tight DGR bushings. The first option was to apply VS Profelt to the damper guide rail bushings, withOUT removing the dampers. This was suggested by someone who has had previous experience with this particular problem on this particular brand but, like several other individuals, decided to communicate via PM only.
It is now three weeks out, and all indications are that it worked! For all of the obvious reasons, this option was far less labor intensive than anything that involved removing and replacing the dampers. I was at the client's home over a two day period (doing other work on the piano, and hiking in Joshua Tree!), so if another approach was needed, there would have been time for it. Not necessary.
In the event that the problem returns to this piano, I will let this list know.
Thanks again, to everyone who responded in a constructive way, for all of your input. Three cheers for the high-quality of collaboration at which our species excels!!!
Alan
------------------------------
Alan Eder, RPT
Herb Alpert School of Music
California Institute of the Arts
Valencia, CA
661.904.6483
------------------------------
Original Message:
Sent: 07-24-2019 10:32
From: Cy Shuster
Subject: Persistently tight damper guide rail bushings
Alan said:
"...if the damper unstop railI were too high, I could see sostenuto tabs getting stuck on the sostenuto knife when it is engaged. Do you mean that the sos. tabs could also get stuck when the knife is at rest, if the unstop rail is too high? Just curious."
It's certainly possible, depending on the size of the tabs and the adjustment of the blade (knife). Many times the blade doesn't have much clearance at rest, and the fore/aft position of the tabs can vary.
On rebushing guide rails, I was taught to refinish the wooden guide with lacquer before bushing, and then to size the bushings with alcohol/water and usually a #7 bridge pin. The alcohol will soften the lacquer and then glue the bushings in place.
-Cy-
Original Message------
Cy,
Thanks for offering a response to my question to Timothy. Following your line of explanation, if the damper unstop railI were too high, I could see sostenuto tabs getting stuck on the sostenuto knife when it is engaged. Do you mean that the sos. tabs could also get stuck when the knife is at rest, if the unstop rail is too high? Just curious.
Nevertheless, I am convinced that the damper guide rail bushings are the culprit on this piano.
Alan
------------------------------
Alan Eder, RPT
Herb Alpert School of Music
California Institute of the Arts
Valencia, CA
661.904.6483
------------------------------