back action replacement questions

Gene Nelson nelsong at pbic.net
Mon Jul 31 21:21:36 MDT 2006


Thank you Ron,

Its also worth noting that an alteration of the pivot height will
make very little difference to the length of the damper wire
required. The height of the damper lever end will remain the same,
since the back of the key height remains unchanged. Therefore, unless
the damper wires were cut so short that the grub screw is clamping
right at the end of the wire, it will be possible to change the pivot
height without changing the damper wires. Sometimes you'll need to
make a new damper up-stop rail, since the slot adjustment may not be
adequate if you have to lower the pivot point.

In this regard there is one thing that I neglected to account for and that 
is the original pivot device that the damper wire goes into is drilled all 
the way down to just above the center pin and this is done because the 
original tabs are not spring loaded like the new Renner parts - where the 
hole ends just above this tab - as the piano is at the clients home I will 
soon learn if I must shorten the damper wires.


> Gene  and all,
>
>>Gene----consider changing the pivot point of the back action to comply 
>>with
>>the "pivot points" of the keyframe and stack.  The protocols are fairly
>>simple; call Dale Erwin or Stephen Bellieu; they've both done it for me a
>>number of times.

I did go back and look at this magic line and it really needed to be 
adjusted - thank you.

What I have also done to the pivot point is something that Brett Dearing 
designed and that is to move it so that it is on the same plane as the 
damper lift lever flange center pin. This required building  new pivot pin 
support blocks extending farther into the keybed and adding excess material 
to the ends of the tray.
Now the tray and levers pivot on one plane rather than two.

Gene 




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