Hi everyone.  Well now, I have to take issue with those who say that
the velocity of a hammer _cannot_ be increasing after its set-off.

The function of the set-off is of course to reposition the hammer nose
correctly in order to facilitate repetition; and to allow the hammer to
fly freely before making contact with the strings - thus preventing
blocking.

Despite the absence of direct human control at the point of impact
however, surely if you strike the key hard enough initially, you can
generate enough potential force to result in continued acceleration
beyond set-off.

In terms of speed, I would suggest that the set-off acts only as a
termination of control, not as a governor.  It does not slow the hammer
down by any positive action; it merely removes the agency (the jack)
that delivered the original energy.

The hand is the impelling force, and that alone determines the speed of
the hammer prior to contact.  There is only one thing that affects the
reducing speed of the hammer in absolute terms and that is the strings.
It seems to me to be a simple question of physics.

The relationship between the degree of force that can be impelled upon
components of given weight and known travel.  I cannot rule out the
possibility that the hammer is still accelerating after set-off,
especially in an upright.  I can accept, however, that if you strike
the key softly enough then it _is_ almost certainly decelerating prior
to impact.  A grand may be different of course due to the more
pronounced effects of gravity.  Do any of our more technically
qualified members have data to support the arguments one way or the
other?

Roger Waring

Solihull UK