[pianotech] capstain/wippen angle

Mike Spalding mike.spalding1 at verizon.net
Mon Mar 16 05:02:47 PDT 2009


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
>
>
>    MIKE writes:
>
>    As the capstan/wippen moves thru its rotation the capstan moves
>    upwards & rotates to the middle of the capstan & then to the rear
>    edge. SO, as it continues thru its arc, the point at which the
>    wippen is lifted moves to the rear edge of the capstan & closer to
>    the wippen pin thereby accelerating the key/action motion. Kind of
>    an automatic transmission affect.Things move faster without shifting.
>
>
>
>



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