S&S replacing Hammer Assemblies with new

[A440A@aol.com]

Greetings, 
  Inre finding a curved hammer line resulting from optimum strike points per 
section,  Terry asks: 

<< Are you simply moving the action in and out and 
listening to the tone, or do you have some other slick techniques for 
determining 
optimal strike points in various areas along the scale?
     Perhaps my ears are just not yet refined enough (likely enough), but 
while I 
can easily hear MAJOR differences in tone in the high treble when moving the 
action in and out, well, let's just say its not as obvious to me in the lower 
registers of the piano.>> 

   There are several considerations, so I will start in order.  
    I like the hammer to be at 90 degrees to the hammershank AND the string 
at the moment of contact.   Ostensibly, that should mean boring them so that 
the bore distance equals the difference between string height and 
centerpin(hammer flange).  However, most Steinways have strings that exhibit a rise from 
capo to the bridge in the upper sections, so either the hammer must be glued on wi
th an acute angle to the shank, bored excessively short so the the shank 
overcenters, or a little bit of both.   The actions will determine how much of 
either compensation is possible before regulation problems arise, (such as a too 
short bore leaving the shank too high at rest).  
   I have a set of indexing hammers mounted on shanks at 90 degrees in 
varying lengths.  I install them in the middle of each section and check their 
relationship to the string with a small square.  The bass bore can vary between 55 
mm and 59 mm, the treble can vary from 45 to 49 mm.  Even so, there are pianos 
that simply will not allow the perfectly square alignment between shank and 
string, in which case I favor the squareness to the string, even if it means a 
slight departure from 90 degrees to the shank.  It is often the case that a 
couple of degrees of acuteness to the shank accomplishes the same as a radical 
alteration of bore distance.  
   Once I have found my bore distance, I hang the end section hammers at 130 
mm and install the action for listening.  As Dale, (I think), said, the notes 
below C5 are not much affected by hanging distance, but above that, things can 
get weird.  I find where C88 (hung at 130 mm) sounds best and lock down the 
cheek plate.  Then, I move the action in and out to find where the best 
responses for the other section ends are are, and if it deviates, I use a dial 
caliper from the front of the keybed to measure how much deviation is necessary for 
the best tone.  I then subtract or add that to the 130 mm I know is on there 
to find how much to change the hammer line at each section's end.  
   It is common to find the best sound with a shorter hanging distance at the 
top most break, and many of my hammer lines have a curve to them at this 
area.  If it is radical enough of a change to upset other parameters, (like the 
sostenuto distance, tails hitting the back of the whippen, or having the front 
rail hit the keyslip), I can shorten C88, move the entire action distally, and 
find a happy medium, (geez, sounds like a laughing fortune teller).  
   It will not do to send the factory samples , since the original factory 
hammers all seem to be hung at a common distance.  It is also common to find 
these pianos with excessive amounts of lacquer in them in what appears to be an 
attempt to produce sound from a poorly hung set of hammers.  
   It is a lot of work to do things this way, but a reputation as being able 
to really "make the pianos sing" allows a correspondingly higher price than 
the mere "parts installers" can charge.  I like spending more time and charging 
more money, because the job satisfaction is worth a lot to me.  
Regards,   
 
Ed Foote RPT 
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html