Touch weight

[Jon Page]

At 11:36 PM 3/3/99 -0500, you wrote: 
>
> Hi Rogerio, 
> <snip>
> One thing you'll have in your favor is the way the action geometry will
> affect how much felt you'll need to remove.  If the hammer travels 1 7/8 in,
> while the key travels 3/8 in., that's a ratio of 5 to 1.  If you remove
> aprox. 2 oz. of weight from the hammer, you'll remove aprox. 10 oz. of
> touchweight.  Depending upon how well the action is weighted now, and upon
> how even you file those hammers, you may need to do some work with the key
> weights to even out the touchweight. 


The travel distance ratio has no bearing on weight ratio. The weight ratio
is determined by weight and Key Ratio (capstan to b/r pin / key front to b/r
pin)
which may be closer to 7 now.  Removing 2gr from each hammer is a massive
amount. Weigh the hammers and see what strike weight zone they are in.

If the jack is being buried into the stop felt on the repetition lever then
perhaps moving the capstan forwards will be a step in the right direction.
There are many options but proper regulation should be the primary
consideration. Depending on the amount of lead in the fronts and the
friction coefficient, wippens with assist springs may be the route to go. 
Proceed cautiously.

What are some figures, Upweight & Downweight are a good start.
There are other measurements which require a gram scale.

Regards,

Jon Page
Harwich Port, Cape Cod, Mass. (jpage@capecod.net)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



>
> Rogerio Cunha wrote: 
>>
>>  To the listI am just working on a grand ( Bösendorfer ) and on it I
applied
>> new hammers ( original ) , new center pins, and others items as knuckles,
>> etc, etc,All the material applied is original and all the work was made
with
>> care and the final product was very, very good except the touch weight.I
did
>> all that I learned and read but wasn't possible to obtain 52 g on the 1st
>> section, 50 g on the 2nd section and 48 g on the 3rd and 4th section and
>> this is the problem that I want to know. ( these are manufacturer
>> measurements)The difference is about +10 g on each section.What to do?I
>> think that the only way would be to put leads on the keys. Is this
>> correct?To use the piano with + 10g of touch weight is good?If isn't
>> possible to obtain the manufacturer measurements what are the good touch
>> weight?I thanks to allROGERIO CUNHA - IC MEMBER OF THE GUILD 
>
>