hammer acceleration

[Newton Hunt]

It is called static friction and it is the reason that you knock on the action
to break static friction.  In weighing an action the rate of rise or fall of the
hammer is as important as the actual measurements.  Even consistent velocity is
an absolute requirement from note to note AND up and down.

Static friction is the force required to overcome the distance to movement of an
object with no movement at all.

		Newton

> David Love wrote:
> 
> I notice, when I am doing a weigh-off on a key board, that on some actions as the hammer rises the acceleration is relatively slow and steady.  Other times, once the hammer starts to rise, the acceleration is quite rapid.   What is responsible for that difference?  Friction would seem to be the logical answer, but friction where?  I heavily lubricate actions before I do a weigh-off.  There seems to be something else at work in the geometry/leverage.  Among other things, with the rapidly accelerating hammer, it is more difficult to determine the measured downweight.  I there any way around that problem?
> 
> David Love