Lost motion: (was puzzler on M & H BB

[A440A at aol.com]

<< David Ilvedson wrote:

> Yamaha teaches another way which  
> I'm using.   Lay a piece of paper on a table and run you finger  
> against the edge.    That is the feel you are looking for between  
> the jack and the rep window.    In other words a hair below  
> level.   >>

Greetings, 
    This will only give good results if the knuckles are in like new 
condition, and the top of the jack is perfect.  I have tried this way, and I couldn't 
get a consistant result when the hammershank was at rest.  The variables of 
knuckle texture, condition of the top of the jack, condition of the proximal 
side of the knuckle, spring strength, friction at the interface, etc.  make 
setting the jack by its relation to the balancier less dependable than knowing that 
the jack and the knuckle are in contact.  
   I have several actions in my experience that didn't allow the jack to 
return under the knuckle, regardless of how much difference there was between jack 
and mortise window and regardless of how much spring I had.  I suspected that 
it was a too weak spring working on the jack, but in any case, I set them so 
that I could barely feel the contact and they have been performing well for 
years.  
regards, 


Ed Foote RPT 
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html