[pianotech] capstain/wippen angle

[Richard Brekne]

Hi Mike !

THIS was the clue I needed...  Yes I understand the roller capstan then 
would move closer to the whippen center if it started below the magic 
line, then get farther away as it passes. Now I just have to think a bit 
on how the whippen heel is moving through this.  Any given point on the 
heel is not going to change distance from the whippen center through the 
key stroke. So as the key raises towards the magic line, the roller 
capstan would roll towards the whippen center as its distance from the 
center decreased. Then at the magic line it would cease rolling and be 
as close to the whippen center as possible, continuing upwards it would 
reverse direction and begin to roll the opposite direction... away from 
the whippen center... Almost like a pendulum motion if the starting 
point was just as below the magic line as the ending point is above. 

So..... how does an angled capstan that does'nt roll at all counter this 
tendency... I can see I am going to have to re-read these posts and do 
some thinking on it :)

Sorry bout the misquote... I'm sure Dale is ok with it.
Cheers and Thanks
RicB


    Ric,
    I wish I had reasoned out the quote you attribute to me - but it
    belongs  to Dale Erwin.  I hope he won't mind if I attempt to answer
    your  question.  Whether it ends up closer or further away depends
    on where,  in relation to the magic line, the motion occurs.  For
    example, if you start below the magic line and end an equal distance
    above it, the roller will move towards the wippen center until you
    reach the magic line, then move away, ending up right where it
    started.  The "best a tilted capstain could achieve" would depend on
    how wide the capstain is.

    Mike

        Richard Brekne wrote:
        Been trying to visualize this a bit and have the following to
        ask you  all about.

        Consider a capstan that was a brass roller instead of what we
        have  today. So that as the key move and the capstan raises the
        whippen this  brass roller simply rolls along the underside of
        the heal.  Wouldn't  this result in the roller-capstan starting
        off further back on the  heal (closer to the whippen flange)
        then it ends up ? I.e. the  opposite of this increasing leverage
        concept ?  And if that is the  case.... then wouldn't it be more
        likely that the best a tilted  standard capstan could achieve is
        to more or less compensate for that ?
        Cheers
         RicB