lowering inertia without voiding warranty?

[David C. Stanwood]

Mark,

you misunderstood Bob.  What he intended to convey to you was the 
technique you described below, of putting a little glue on the bottom 
of the key, putting the key down on the punching, letting it harden, 
then lifting the key out and cutting off part of the punching... 
thereby shifting the pivot point of the key...  to lower the ratio 
and lighten cut off the front part of the punching as needed and vice 
versa.

I know because to my knowledge I originated the technique and taught 
it to Bob over a decade ago.  I've taught the technique to many many 
people since then but I've never published anything written about 
it... maybe on this list or maybe someone I taught it too mentioned 
it on this list...

However if the piano is under warranty then it must have accelerated 
action so the 1/2 punching technique won't work on this piano...

I'll mention to Bob M. that he needs to be more concise when he 
describes the method, especially in his classes...  thanks for the 
feedback...

David S.

>Bob at Pianotek was helpful. He suggest adding 1/2 punching to the key
>at the balance rail. My punchings are scarlet (.055). Not having any, I
>used several layers of maksing tape to get up to about .033, in the
>shape of a regular puncing, cut in two, and stuck them on --facing the
>right way-- at the balance pin hole of the key.
>        
>This indeed did lighten the feel of the piano, but it caused it to be
>sluggish. Plus it raised the key height 1/16 and the back end, nearly
>3/8" (which makes since with the leverage as we calculated is above
>that 6.2 to 1.
>       
>      
>    
>The way I've done this (and I'm pretty sure that I learned this from
>somebody else on this list) was to use the existing punchings. Apply a
>very small amount of glue to the bottom of the key  just behind the
>balance holes, and reinstall the keys. Once the glue has set remove
>them and slice off the front half of the punching with a sharp blade.
>Done this way it shouldn't affect the key height much at all -
>certainly it won't raise it. My question would be is there really a
>difference between this and moving capstans - from a warranty-voiding
>perspective, that is. And if there is...should you really care?
>
>- Mark Dierauf
>
><snip>
>>The AR, shows the inertia.   I'm (we) are looking at
>>6.2. I would like it around 5.5, and lower the FW into the low to 
>>medium range.
>
>>We've figured out that the key geometry is in trouble. But to move 
>>the capstan or knuckle,
>>will void the piano's warranty.
><snip>