Steinway capstan angle

[Phillip Ford]

An interesting point Ed.  Maybe this is what they had in mind.  I find that 
explanation more plausible than the 'involute' explanation.

Phil Ford


>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