Touchweight query

[Keith Roberts]

My thought is the key bushings. Uneven wear causing the extra friction.  Try
some protec on the offensive key bushings. Just a guess.
Keith R
----- Original Message -----
From: <kam544@flash.net>
To: <pianotech@ptg.org>
Sent: Saturday, June 29, 2002 7:30 PM
Subject: Touchweight query


> List,
>
> I am reviewing some fundamental principles in downweight/upweight
> [UW/DW] concepts and have come across a minor puzzle in this older
> vintage grand piano.
>
> Two notes:
> 1) one reads 48 grams DW, 28 grams UW
> 2) one reads 56 grams DW, 28 grams UW
>
> My interest was to have the 56 gram DW number be closer to the 48
> gram UW number without adversely affecting the 28 gram UW number.
>
> However, this is where my minor puzzle begins.
>
> Some information:
> Hammer flange pinning is equal on both, wippen flange pinning is
> equal on both, capstan to wippen heel appears to be satisfactory,
> knuckle/rep lever appears to be okay. And there is freedom in the key
> bushings.
>
> Additional information:
> The weights of the hammershank assemblies of both notes respectively
> are 16.4 grams 16.1 grams.
>
> The weights of the wippens assemblies of both notes respectively are
> 20.1 grams 20.8 grams.
>
> I seem to be unable to accomplish my interest. Any ideas?
>
> At your convenience,
>
> Keith McGavern
> Registered Piano Technician
> Oklahoma Chapter 731
> Piano Technicians Guild
> USA
>