1/2 punching

[David C. Stanwood]

Ric Wrote:

>Since all this is up, I might as well reveal (since I am an open source
>kind of guy) that I'm working on a scheme useing center pin wire along
>these lines to cause a clear and distinct dual ratio characteristic to
>key travel.  Since the initial part of the key stroke benifits greatly
>by reductions in dynamic weight, yet the last 3 mm of key travel could
>well benifit by an increase in stack action travel for key travel, if
>the key could be made to act as a low ratio key for the first half of
>its travel and then act as a higher ratio key for the last half of
>travel then both these benifits are served.

Another blast from the historic past: Chris Robinson has a set of slides 
showing the capstan position with the magic line overlaid on the image at 
rest, half, and full stroke with a long ago Steinway factory installed 22 
degree angled capstan and angled heel for what he calls the Involute gear 
effect.  With this set up the capstan/heel contact point stays on the line 
rather than moving up through it as with the capstan at present day 90 
degrees with straight heels.   What's interesting in relation to the 
present discussion is that the point of contact, while staying on the magic 
line, actually moves front to back along the magic line.  So the ratio is 
low to start with and higher to end with giving a sort of "wip" effect.  I 
was very impressed when I saw this in his class.

David Stanwood