Bore lengths

[David Ilvedson]

It seems to me that bedding problems/differences with bench etc, at the extremes of the piano would be nil or close enough for piano work.   

David I.



----- Original message ---------------------------------------->
From: Richard Brekne <Richard.Brekne@grieg.uib.no>
To: Newtonburg <pianotech@ptg.org>
Received: Thu, 23 Dec 2004 00:36:25 +0100
Subject: Bore lengths

>Hi folks..


>just got through double checking a measurement for borelengths on a 
>Petrof grand and noticed a rather large discrepancy between on bench 
>measurements and in piano measurements... and ended up with the 
>following observation resulting in the accompanying question.

>Measuring the distance between strings and keybed, then hammer centers 
>and keybed yeilded a near 2 mm difference when done on the bench visa vi 
>done in the piano. At first I thought that well..... its a bit clumsy to 
>measure in the piano.... so....  But then I got to thinking about 
>bedding issues and decided to double check very closely in the piano and 
>came up with very close to the same results.  Obviously in this 
>particular example, the bedding screws accounted for a quite significant 
>difference in the height of  hammer centers. This of course is directly 
>reflected in the bore length one decides on, so its kind of important to 
>get the darned thing right.

>I ususally go about deciding bore length in a different fashion, but 
>have lately wanted to try out this <<formula based>> method and stumped 
>on this right off.

>So what do you folks do here ?  Go with a bench figure, compensate for 
>the bedding on the bench, or simply measure in the piano ?  If the 
>bedding screws are taken into account... do you always make sure of 
>optimal bedding first ?..

>I'd like a bit more detailed description of what you all do in 
>conjunction with this on the surface simple measurement.

>Cheers
>RicB
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