buzzing on piano

[Dean May]

I'd bet the rim. 

Turn the piano on the side. 
Fill a hypo oiler with thin CA. 
Mist accelerator all around the rim and down each rib. Wait for one minute. 
Starting at top, squirt glue all around rim (the capillary action of the
glue will actually pull it vertically into the joint). Then run it down each
rib for good measure. 

I don't know how you checked the rim joint, but the CA glue will find voids
that aren't there with a feeler gauge. 


Dean

Dean May             cell 812.239.3359 

PianoRebuilders.com   812.235.5272 

Terre Haute IN  47802


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Tom & Sharla Zasadny
Sent: Sunday, February 04, 2007 12:13 AM
To: pianotech at ptg.org
Subject: buzzing on piano

Greetings,
What would be the origin of a buzz on this 1930's Steinway Model "M"  that
seems to be soundboard related and acts like lthis:  It has been present for
a couple of years; less in the summer and more in the winter and at F5only.
It is more wooden than metallilc in quality and is more pronounced with a
harder key blow.  E5 was pitched up to the F5 pitch and caused the same
buzz.  F#5 was tuned down to
F5
and also caused the buzz.  Pressure over the bridge, movement of the duplex,
movement of the strings under the capo, pressure over all ribs and over the
soundboard top and bottom, tapping the bridge pin down and increasing its
angle availed nothing. The soundboard has no cracks and bearing is good with
good sustain.  Visual examination with light and mirror under the plate
showed nothing.
High air pressure through every opening was not productive as well.     
Muting two
strings at the F5  quieted the buzz.  When only one was muted, it returned
though less than with three singing strings.  If I struck two singing
strings, the buzz equalled that of three strings with a less forceful blow.
Now here is the only diagnostic clue I can give.  When the plate bolts were
tigtened the buzz disappeared though for only 15 minutes.  (It came back as
I was doing some regulation testing.)  I tightened the bolts again and it
was quieted for a short time. Tightening again (I put overly heavy torque
on this last time) lessened the buzz at F5 but it turned up at C6.   Soon 
the buzz
became strong at C6 and remained small at F5.  I checked for glue along the
entire inner rim at the soundboard junction and I eliminated all action and
environmental sympathetic vibration questions. What is this?  How do I fix
it?  The customer is piano professor and accomplished performer.  He is
ready for this to be history.

Thank you friends,

Thomas N Zasadny
(home)1(319)-934-3552

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