Touch Weight Too Heavy on MX100

[David C. Stanwood]

What is the difference in the meaning of Balance Weight between an upright
and a 
grand ?

In an upright it is greatly from the force exerted by the butt spring
downward through the wippen then translating though the ratio of the key to
an upward force at the front.  This force is attenuated by whatever effect
the key leads have on things.  In uprights we see keyleads in either front
or back. Tipping the key onto a scale (Front Weight) would tell us how much
effect the keystick is having on making the Balance Weight.   As we know,
gravity does not have nearly as much effect on things as in a grand.   I
admit I haven't done very much work with uprights.  It would be interesting
to have Tom's numbers with the butt springs disengaged and to know the
Front Weight of the associated keys as well.

In the grand, the Balance Weight is a function of the weight of the hammer,
shank, and wippen exerting a downward force on the capstan* then
translating through the ratio of the key to an upward force at the front of
the key.  This upward force, (I call it Top Action Balance Weight) is
reduced to whatever degree mainly by virtue of the number and location of
key leads in the key, which degree may be determined by measuring the Front
Weight of the key.... Whew!  In fact to know the Top Action Balance Weight
is to add together the Balance Weight and the Front Weight.

(*which force can be reduced by a wippen support spring and it's tension if
present)

David Stanwood

>You mind extrapolating a bit on this difference in the meaning of Balance
Weight
>between an upright and a grand ?

>Richard Brekne
>I.C.P.T.G.  N.P.T.F.
>Bergen, Norway