overcentering justified?

[A440A@aol.com]

Greetings, 
 Bob writes: 
<< Here's the background for the question(s): 
In determining the bore distance for a new set of hammers on a Hamburg D, I 
have done the usual math to determine a perfectly level shank when the hammer 
meets the string.<< 

    Level with what?  It is often the case that the strings are not level, so 
if you want the hammer to be at 90 degrees to the string AND shank, you will 
need to measure the hammer against the string.  Steinways often have a rise 
from capo to bridge.  If the hammer is at 90 degrees to the shank, the 
"overcentering" you found on the original might have allowed the hammer to meet the 
string at 90 degrees,also. 

>> After boring at the longer distance I thought would be better than their 
old short bore distance,  I see that of course I have to lower the capstan to 
have a blow distance like the old and of course the let off.  The result is 
that 1. The shank is only 1/8 or less of the cushion << 

   This should not be a problem.  If too far off the cushion, you will suffer 
catastrophic repetition failure when the hammer goes below the jack's ability 
to reset
 
>>2. The repetition speed is very mediocre.  (I can improve the repetition 
speed on the long  bore distance hammer by decreasing blow distance to about 1 
5/8".)
The old hammers repeated very easily and as fast as you could want.  (The old 
blow distance is about 1 3/4". 

   Repetition speed is usually more dependant on checking distance than 
anything else.  How far away from the string are these new hammers checking?  
 
Ed Foote RPT 
www.uk-piano.org/edfoote/
www.uk-piano.org/edfoote/well_tempered_piano.html
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