touch weight

[Newton Hunt]

Hello Robert Scott,

We have discussed measuring weights before and I am glad you are
considering doing so.  Static friction can be very high but reduces to
'sliding' friction upon initial contact and mirro-movement of the
key.  Removing static friction from the weight equation leaves the
friction required to keep the action in motion.  Removing friction
from the equation leaves us with the true up weight and true down
weight, which will not change even when friction does.

Think of static friction as analogous to stiction in the action.  This
being the case a movement to slow will allow static friction to
reasserts itself.  Too fast and actual weights may be difficult to
measure.

Friction will vary from point to point along the movement of the
action because of variations in friction along the various paths of
movement.  What is aimed for is a movement that is something around 1
to 2 seconds for the rise and fall of the hammer along its movement
from rest to let-off and back down again to the rest position.

I was giving thought to making an action thumper because the outside
pad of my hand would get sore pounding on the action for hours at a
time finding the friction then determining the optimum weight to
reinsert into the key to get the balance weight right.

What is aimed for now is a precision adjustment of each hammer weight
then determining the optimum weight of the front of the key.  If the
strike ratio is off then adjusting balance weight is not going to
solve all the action problems.

With friction control screws, strike ratio changes, wippen helper
springs installed, key weight and hammer weight accounted for then
action pounding comes way down although it is used to refine the final
balance weight.

Is there a way, given your considerations, to determine what key
inertia may be?  This would be helpful information in determining a
'best' approach to solving an action problem.

Hope this finds you and yours well.

		Newton