Capstan angle

[A440A@aol.com]

Greetings, 
   There seems to be one thing missing about the angled capstan discussion, 
(or, I missed it!).    That is, the angled capstan on the Steinways compensates 
for wear in the action.  As the hammers age and are filed, as the parts dry 
out, as the pinning gets looser, capstan felts and knuckles pack down, etc. , 
the capstan is continually unscrewed to take all this slack up.  As the angled 
capstan is screwed out, it changes the action geometry to a higher ratio, (or 
a lower leverage, however you want to describe it).  
     The major change is to the moment arm of the whippen flange pin to the 
capstan contact point, rather than the actual key ratio.  In effect, the angled 
capstan will keep the touch weight more nearly constant thoughout the 
action's life than the straight action.  This is a minor effect, but sensitivity is 
composed of many minor things.  
   A straight up capstan doesn't change the action geometry much at all, and 
the older action gets lighter and lighter.  The angled capstan works to keep 
this change at bay. 
Regards,

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