Mystery Noise

[Jim Coleman, Sr.]

Hi David:

Yes, it is possible to replace just one damper guide rail bushing.
remove the damper wire, push the existing bushing thru, take new
bushing cloth approx 9/16" wide with pointed tip, and with tweezers
put it in the hole from below. Pull it up until almost flush with the
bottom of the guide rail. Touch a very small amount of glue to the 
bottom outer edge of the cloth, then pull it on up till the bottom of
the cloth is flush with the bottom of the rail. With a razor blade,
slice the cloth flush with the top of the rail. If the bushing is a
little tight, it can be ironed with a hot nail or rod approx .093"
diameter, or even a heated damper wire. Reinsert the damper and adjust.

Jim Coleman, Sr.

On Tue, 14 Oct 1997, Vanderhoofven wrote:

> Dear Friends,
> 
> I have a mystery noise that is baffling me and irritating my customer.
> 
> The piano in question is a small, older Osborne grand.  The hammer shanks
> have no knuckles, instead they have leather covered "bumps" on the hammer
> shank.  Also, the wippens have brass billings flanges instead of wooden
> flanges.  This piano also does not have a una corda pedal or sostenuto
> pedal. Instead, the keyframe is screwed down to the keybed and the left
> pedal lifts a rail that raises all of the hammers closer to the strings
> (similar to the way an upright piano soft pedal functions).
> 
> The mystery noise is like a rattle, and is located in the first note past
> the bass/treble break - note A#2.  Although the overall "noise" level of
> this action is rather high, this particular noise ("rattle") is not in the
> key, wippen, hammer, shank or flange.  The noise is not from the soundboard
> or ribs or any loose case parts.  After inspection with a small mirror and
> light, there does not appear to be anything laying on the soundboard that
> would make a rattle like this.  The noise is isolated to the damper
> underlever, wire and damper head.  The damper underlever flange screw is
> tight, the screw that secures the damper wire into the underlever is tight,
> and the damper wire is tight in the damper head.
> 
> Possibilities...  The two small leads in the underlever were slightly
> loose.  Whereupon I promptly swedged them, splitting the wood of the
> underlever.  (Oops!  My mistake.  I know, I know, I can't afford to
> purchase a pair of the Renner DeadLeader pliers yet.)  Once the underlever
> was reglued with Titebond II and the leads were secured, that did not seem
> like the cause of the noise because the noise is still there. 
> 
> One other possibility:  This note right past the bass/treble break has the
> damper head offset quite a bit because of the plate strut. The damper guide
> rail bushing is worn out and the wire has a lot of loose play.  The damper
> head and wire do vibrate quite a bit when the key is played, but the rattle
> is not caused by the wire or damper head touching the plate, the adjacent
> damper head and wire, or any of the strings.  I do believe that the noise
> is coming directly from the contact of the damper wire with the worn out
> guide rail bushing.  Lubricating the damper wire has little to no effect on
> the noise.
> 
> Question:  Is it possible to rebush an individual damper guide rail bushing
> with the rail still in the piano?  Removing the guide rail and rebushing
> the entire rail is out of the question because of the quality of the
> instrument.
> 
> Suggestions are welcome, and will be forwarded to my customer who is also
> on the Internet.  If you don't want your answer forwarded to my client,
> please let me know and I will respect your privacy.
> 
> Thanks for your help!
> 
> David
> 
> 
> David A. Vanderhoofven, RPT
> Joplin, Missouri, USA        
> e-mail:  dkvander@clandjop.com
> 
> web page:  http://www.clandjop.com/~dkvander/
> #pianotech page:  http://www.clandjop.com/~dkvander/ircpiano.html
> 
>