Adjusting Drop

[Richard Moody]

There is a time when the jack is "dragging" across the knuckle from
the time the elbow hits the let off button to the time when the jack
actually clears the knuckle. I don't know if there is a name for
this.  This does occupy a portion of the key dip.  I have found this
is influenced by the flatness of the knuckle and where the jack lines
up with the knuckle before the key is depressed. Drop has to occur
after let off. ie it can't happen while the jack is in contact with
the knuckle.  After that it is how and when the jack returns
underneath the knuckle, which depends on the balance lever spring
tension, key dip, (concerning amount of after touch), and don't
forget check heighth, and probably a couple of other things we all
over look at one time or another.  Check is also related to the
contour of the tail.. 
Of course if the key bushings are "loose" there will be enough wobble
to cause any or all of the above considerations moot especially if
there is ANY end play in the keys. And then the keys "dance" on
stacatto.  
	No wonder it sometimes takes 6 hours just to tweek if there is no
moot.  For "dirty tricks" see the technical manuals for various
brands. Baldwin and Young Chang are good. I assume the others are
just as good or better. : ) 

Richard Mooty (not any more I hope)
----------
> From: Dave Sanderson <pianobiz@juno.com>
> To: pianotech@ptg.org
> Subject: Adjusting Drop
> Date: Thursday, June 19, 1997 8:21 PM
> 
> Hello tech friends,
> 
> I have learned that drop and let-off are to occur simultaneously.  
In
> struggling to make this happen "simultaneously" I have developed a
method
> which I think works and would like to share my method and open it
up for
> discussion on the list to see if there is anyone else doing it this
way. 
> I am interested in knowing if anyone can see a reason why this
method
> wouldn't  be an accurate enough way to set the drop. 
> 
> First I adjust the let-off properly with the drop screws up enough
to be
> out of the picture.  I then lift the hammer shanks up and out of
the way,
> exposing the rep lever and the jack in the window.   Watching the
upward
> progress of the jack in the window I note the point at which the
jack
> stops traveling upward and begins to travel forward (towards the
> pianist).  This I assume to be the actual point of let-off.  I then
> adjust the drop screw to coincide the forward travel of the jack
with the
> upward limitation of the repetition lever.  Simple.
> 
> Has anyone else done it this way?  Can you see any problems with
doing it
> this way? It certainly is less nebulous than trying to guess when
the two
> occur by pushing down the key. It is possible to exactly define the
point
> at which the jack begins its' forward travel and this is what makes
the
> method so simple.
> 
> David Sanderson
> Littleton, MA
> pianobiz@juno.com
>