Over-Strike vs Under-Strike

[Jon Page]

Joe,
You are correct, over strike is the hammer hitting the strings
beyond perpendicular, under striking is short of perpendicular.

It seems to me that the better angle for the hammer would be
an initial slight under strike so that as the hammer wears the strike
angle approaches perpendicular (playing in) and gradually over
striking as it wears further.  Instead of hitting perpendicularly
initially and playing out from the beginning.

On this piano, 75% of the string cut is on the top shoulder. How
can this be beneficial.  And why is there a difference in theory
for strike angle between verticals and grands.  I see many
verticals with this over strike.
-- 

Regards,

Jon Page