[CAUT] Thumping Baldwin SF and Bechstein C

[Fred Sturm]

Hi Shelley,
	That's an odd thing to say, "kerf the back rail with a wedge of  
veneer." Hard to interpret just exactly what she means. Saw a kerf  
where, and in what direction? If the rail is somewhat warped, high in  
the middle, you can saw a kerf or a few on the bottom of the rail  
(Yamaha and Kawai do this on the bottom of the front rail, the kerf  
extending not quite to the front edge of the rail) which will allow  
the rail to "relax" into position. And you could wedge material into  
such kerfs. If what is high is the treble and/or bass ends, you would  
kerf the top of the rail, same sort of thing. An exacto saw is good  
for this. Cut maybe halfway through the rail.
	 If it is a matter of the whole back rail slightly high, and bouncing  
against the keybed, you could glue a strip of very thin veneer to the  
bottom of the back rail. The kind of veneer you get with a very thin  
paper backing, maybe 1 mm thick. But you want to think hard and  
examine things before doing something like that, experiment with  
something like masking tape first. And look at the balance rail and  
how it interacts.
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu



On Dec 23, 2008, at 8:34 AM, Shelley wrote:

> You can even needle the knuckles a bit.  But, definitely check the  
> bedding.
> Most thumping/knocking problems are there.
> Related:
> I just spoke with Sally Phillips about a Bechstein C thumping noise  
> that is
> in the back rail. (there are no dags) She has advised to 'kerf' the  
> back
> rail with a wedge of veneer.  Sounds like a cabinet makers job.   
> I've never
> done such a thing.  Any help?
>
> Shelley Byrd Anderson
>
>
> On 12/23/08 7:38 AM, "Tim Coates" <tcoates1 at sio.midco.net> wrote:
>
>> Check the front rail felt punchings.  I have had problems with hard
>> Baldwin felts causing a thumping sound.  Also the knuckles can be
>> hard and the return thumps.  Rough them up with a brush.
>>
>> Tim Coates
>>
>> On Dec 23, 2008, at 7:33 AM, Andrew Anderson wrote:
>>
>>> I was called to tune a Baldwin SF yesterday.  It tuned up
>>> beautifully with a nice really clean treble.
>>>
>>> What bothered me was excessive action noise, thumping on every
>>> key.  It started to stand out in the midrange
>>> so I pulled the action thinking there must be foreign objects or
>>> bedding issues.  No FOs but bedding might be an
>>> issue, no glides.
>>>
>>> Is this a typical feature of Baldwins or is this likely a bedding
>>> issue?
>>>
>>> Andrew Anderson.
>>>
>>> On Dec 23, 2008, at 5:40 AM, Conrad Hoffsommer wrote:
>>>
>>>> CAUTerized folks,
>>>>
>>>> For those of you who are curious about where I work, "Christmas at
>>>> Luther" is being broadcast several times this week on public TV.
>>>> (check your local listings)  I watched the first airing last night.
>>>>
>>>> The old piano is only featured in one number, and the organ not at
>>>> all, but there is a lot of singing.
>>>>
>>>> Wim -  two kids in the bell choir are or were in my church bell
>>>> choir,
>>>> including my current stand partner.
>>>>
>>>> -- 
>>>> Conrad Hoffsommer, RPT
>>>> Luther College
>>>> Decorah, IA
>>>>
>>>
>>>
>>>
>>
>>
>
>
>