When to do it

[Ron Nossaman]

>No, I didn't notice a difference in key dip. At least not that I can 
>remember. And with as much as I had to adjust the capstans, I am sure I would 
>have noticed a difference. 
>Wim

I expect you would, if it were there, and I would think that reasonably
rules out balance rail (alone) movement. Keith verified the minimal capstan
height change with balance rail movement, so that seems reasonable enough
to me. What's that leave? If the hammer rest rail hasn't moved, that leaves
any combination of keybed warp, key frame warp, and/or back rail cloth
dimensional change, or key thickness, wippen pad,  and/or butt
leather/cloth changing with humidity. Well, now we know something it's
probably not, so what else can we look at? If the action has more than the
two end brackets and is supported in the middle of the keybed somewhere,
the middle bracket(s) wouldn't be sitting on the posts if the keybed had
sunk (capstans too low), and the action relationship to the keybed wouldn't
change much if the keybed rose (capstans won't get too high), since the
action would either keep it from rising, or go up with it. If it only has
the end brackets, that doesn't tell us anything. Some appropriate
measurements at humidity extremes should tell you either what else it's
not, or what it is. Either way, you'll eventually run out of things it's
measurably not, leaving what it most probably is. 

Sorry, that's not really an answer, but it's a start on a kit. It's the
best I can do. There's just a little  more assembly required.


Ron N