1/2 punching

[Ric Brekne]

I'll tell you what I'd try there David.  Instead of starting right off 
by repositioning capstans,  I'd simply take strips of flange paper, say 
0.2 to 0.3 mm thick and place them under all punchings tight up to the 
back side of the balance rail pins. One strip should be good for most of 
each section on a grand.  See if this does it for you. Essentially its 
the same thing as what David Stanwood describes with his <<ratio shim>> 
except that you are simply installing for the entire piano.  Should drop 
the Balance Weight Ratio... or Strike Weight ratio if you prefer by 
around 0.5 +/- a hair.  As David states, the problem of chucking doesnt 
turn up.

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.  Looks quite doable really.  
The standard punching actually does this to some degree... tho key to 
key variance in this performance is quite large.  Defining front and 
back fulcrum points more precisely lets you have all the weight 
advantage benifits of the back half punchings and at the same time all 
the travel (distance) benifits of front half punchings.

Cheers
RicB
------------
Well, that's what I have on this Bechstein E...strikeweight of 6.0...the 
veneer shim sounds better...so the problem is the key leverage?   The KR 
averages .52...I would have to move the capstans to improve it otherwise?

David Ilvedson, RPT
Pacifica, CA  94044