[CAUT] measuring wippen weight

[Tim Coates]

Alan,

Yes, the half punching will do that.  I think a  better choice if you  
are in the shop is a strip of veneer on the backside of the balance  
rail pin.   The half punching works well in the field.  The veneer  
should be as long as you can get it.

I don't use the Stanwood jig to measure KR when doing this.  I do it  
the old fashion way.  Balance out the key>20 grams on the  
capstan>find the correct DW>do the math=KR.  The Stanwood jig doesn't  
allow for moving the fulcrum point like a half punching or veneer  
will do.  Maybe David has a work around that I don't know about with  
his jig.

Tim Coates

On Oct 2, 2007, at 6:40 PM, Alan McCoy wrote:

> Jon, Anne, Barbara
>
> I think she does indeed mean a 0.4 change in the action ratio (not  
> a 0.04
> change in key ratio).
>
> Bob Marinelli and I were talking about this the other day and he  
> mentioned
> that using a half-punching will result in a .5 change in the action  
> ratio. I
> have not verified this independently yet, just reporting what Bob  
> said.
>
> I am currently working on a M&H BB with a 0.57 key ratio. I just  
> put half
> punchings on it and will install miracle wips to move the wip heel  
> closer to
> the balance rail. I need to get the key ratio down to about 0.52,  
> which will
> get my action ratio down from 6.5 to about 5.8. Then I'll be able  
> to weigh
> it off at a 38 BW using only a 3-2-1-0 lead pattern (and minimal  
> spring
> assist). As it was I was going to need 5-4-3-2-1 leading pattern  
> and a 42
> BW. Not acceptable for this situatio. This with a newly made set of  
> keys
> (not Pianotek)!
>
>  :-(
>
> Alan
>
>
>> From: Jon Page <jonpage at comcast.net>
>> Reply-To: "College and University Technicians <caut at ptg.org>"  
>> <caut at ptg.org>
>> Date: Tue, 02 Oct 2007 16:52:03 -0400
>> To: <caut at ptg.org>
>> Subject: [CAUT]  measuring wippen weight
>>
>>> There is a .4 change in action ratio either up or down when the half
>>> punching or balance rail veneer is used to help correct a high or  
>>> low R
>>
>>
>> I think you mean .04 change.  I have use b/r shims twice to lower KR
>> (moving the fulcrum back) and friction.  It was used because nothing
>> else worked satisfactorily.
>> -- 
>>
>> Regards,
>>
>> Jon Page
>
>