[CAUT] measuring wippen weight

[Richard Brekne]

Hi Tim, and Bill.

I think its a good idea to remember the context in which the KR 
measurement is taken.  Stanwoods KR has the key in perfect level 
orientation for the measurement. When this is the case... you can get 
the exact same results by simply measuring across the top of the key in 
a straight line.  In the horizontal case.. weight vectors are vertical 
and you will get the same result no matter how high or low you place 
place your 10 gram weight on the capstan after zeroing the scale. Unless 
you have very good measuring devices however... its easier to just do it 
on the scale with the Stanwood jig.

If you DO have fine distance measuring tools tho... the opposite true.  
And doing the compensation for the half round punching is just a matter 
of re-identifying the fulcrums exact placement on that same horizontal 
line. I havent tried your way of doing the KR for beginning and end 
either... but because of the same horizontal measuring condition... I 
would suspect that any difference that occurs would be either due to 
some slight change in the jigs exact positioning under the key (despite 
its pointy profile) and/or some weight contibution  from the jigs BR pin 
which is out of its <<natural>> position. I suppose you could pivot and 
lock the roller in your position to deal somewhat with this last.  I'll 
have to give this a try tonite.

Curious tho... is David moving in the direction of redefining KR to be 
some kind of a dynamic quantity ?  I havent had the time to read through 
all the posts on this thread so I am no doubt missing a few important 
points made.

Cheers
RicB


        On Oct 6, 2007, at 5:22 PM, Tim Coates wrote:
         > One minor mistake I made in explaining the older method is I
        put 40  
         > grams on the capstan.  20 grams works also, but 20 grams
        doesn't  
         > have the ability to split hairs with the math like 40 grams.


    Effectively increasing the resolution (and sensitivity (and noise))  
    of the measuring device. (Who remember's Michael Antonionni's movie  
    "Blow Up".) Actually there's no problem, measuring the change of KR  
    as the key rock on the fulcrum. Just check with the remaining keys on  
    the keyframe to see start/finish of the balance pin's travel in the  
    BR bushing. 1.) Do your first KR with the BR pin at the start of its  
    travel, and the roller pivot held in place. 2.) Change nothing else  
    about the set-up for measuring the KR except to pivot the roller so  
    that the top end of the pin reaches the finish point in its travel.  
    You have the KR before and after the rock.

    Mind you I haven't tried this yet. I've been out raking leaves today.

    bill ballard
    wbps at vermontel.net