Improving Upright Dynamics & Repetition

[Newton Hunt]

Dear John, 

>Determine best relationshep of dip to hammer travel in each >section and average the results.

It usually happens that there are slight differences in blow distance
from the three main section, bass, middle and treble of the action.  If
there are major differences the hammer rail can be force into complience
be pushing one end and pulling on the other end to bend the hooks into
best compience.  The shims can be cut and glued into position for this
new setup.  This procedure can be used to get a satisfactory compromise.


I am a bit lost on your meaning "average the results" and "blow distance
should start at 1 7/8" or 48mm and should be decreased a mm at a time
until you reach 1 3/4" or about 45mm." Is it dip or blow distance that
is decreasing a mm at a time, and in which dimension is it ecreasing
(base to treble etc.)? 

If at 10mm dip you have insufficient safety factor decrease blow
distance by 1mm.  After reaching 45mm with insufficient safety factor
then increase dip.  Dip and safety factor have an inverse relationship.

You say that "Forcing the jack against a stop is counter productive. Is
this why this rail is set out of the way? Is it useful and how should it
be regulated? 

That strip of wood is a liberty rail.  I have no idea how it got it's
name, but it's function is to limit the jack _bounce_ distance.  I would
regulate it so the top of the jack moves about an 1/8" when the key is
fully depressed.  This will increase repitition by jpreventing the jack
from being too far from the butt when a repitition is demanded.

"Barely not reach parallel to the strings". Got lost here, could you
please explain? 

Think in terms of centering, under and over.  If an upright shank goes
bast vertical (over centering) it is balanced in favor of the string and
will need to be pulled past center then into position for a repitition.
If the hammer shank is under centered and balanced in favor of the keys
far less energy is required to initiate a return and will position
itself for a quicker repitition.

If this is still muddy water just wait.  It will settle to the top, my
bottom and will be clear for me.

Regards,
        Newton