Buzz problem

[jolly roger]

Hi Bill,
           Had a similar problem that I was called in to help with.
Sounded just like a board bridge type noise. One loose nose bolt in the
action bracket cup.
The other teaser some time ago. Shims under the plate were flapping against
the board.  The piano has to be on it's back to see them.  I went searching
for separation of board and liner, and got lucky spotting it.
On these spinets, the bar that supports the action is screwed to the case
and plate.  The plate bolt and washer can also cause this kind of buzz.
Hope this helps.
Roger  



At 11:15 PM 6/27/01 -0400, you wrote:
>I ran into a problem today that I could not correct despite an hour of
trying 
>before tuning the piano.  I was stymied despite my nearly 50 years' 
>experience tuning pianos.  Has anyone on the list experienced the same and 
>found the answer?
>
>The piano:  a Baldwin Howard spinet, S/N 1,095,157 (1976).  A rattling buzz 
>with hollow, false tone in the first octave or so of the bass indicated a 
>loose bass bridge.  Not so.  Bridge was tight to the shelf, the shelf tight 
>to the sound board.  Yet pressure against the bridge would restore the tone 
>just as with a loose bridge.  Seating strings made no change.
>
>Pulled the piano out from the wall.  No junk lying there, no loose ribs, no 
>separation of the sound board from the liner.  I scraped the sound 
>board-to-liner joint for loose glue.  I got a bit but there was no change in 
>the tone.  I checked the sound board button screws, all except one were 
>tight.  Anchored that one and still no change.
>
>I noted one curious fact:  from the front, I could stop the buzz by pressing 
>elsewhere, such as on the tenor bridge above the "loose" area and on the 
>board in the same area.  Checked the area between plate and board with a 
>flexible steel, but found nothing.  Checked with a mirror to see if the
plate 
>was coming loose bottom, but its "nubs" were right up against the board.
>
>From the back, with the customer banging low C, I was able again to silence 
>the buzz by pressing in the general area of the bass bridge.  Then I became 
>aware that there was a scraping, grating sound as I pressed in on the board, 
>and again as I released it.  (I recall a similar experience with a new 
>Baldwin grand in the early '70's; I never did hear how the dealer handled 
>it.)  There is a hole in the sound board (plate bolt) in this area, but
there 
>is plenty of clearance with the bolt.  
>
>The board gives the impression of solid spruce, but the joints visible in
the 
>front do not correspond with the joints visible from the rear. Am I dealing 
>with a laminated board and could it be delaminating?  If so, what can be
done 
>about it?  The cutouts around plate bolts show no separation, yet the area 
>around the plate bolt between bass and tenor bridges is the area where 
>pressure silences the buzz.
>
>Since I am on a trip, the customer is over 100 miles from my home and I will 
>be passing by their home on my way back in two days (Friday), I would 
>appreciate any input from the group.
>
>Bill Maxim, RPT
>Columbia, SC
> 
>