Young Chang Aftertouch

[Billbrpt]

In a message dated 5/13/98 4:36:38 PM Central Daylight Time, atodd@UH.EDU
writes:

<< I, personally, prefer to keep the key dip pretty standard and then
 adjust aftertouch by raising/lowering the hammer line. Most pianists will
 object if the dip is too deep and/or the sharp dip gets too close to the
 naturals.
    All of this assumes, of course, that the bore distance on the hammers
 is correct.
  >>
<<and backed out the glide bolts????????
Guy>>
<<Sounds like you have one of the Young Changs with pot metal (Zinc Alloy)
action brackets.  You need to contact Phil Glenn  at Young Chang and he
can go over warranty procedures with you.   The action brackets are
_growing_!!!

This causes all the regulation problems you have described.  DO NOT try
regulating the action until you have replaced the brackets.  You will
cause yourself all sorts of extra work.

YOu can confirm this by measuring the action spread. It will be very
wide. 114mm+

Dale Fox>>

You are getting some very good answers on this one.   The last one is the most
important.  Although I have not seen this on a Young Chang, (I do not service
many of them and did not know about this common defect), I have seen this same
problem once before.  A Chapter member brought an action to a meeting because
she was completely perplexed at how it did not play and absolutely could not
be regulated.  Everyone but one person was stumped (including myself).  It was
the strangest thing I had ever seen.  I could see no practical solution for
it.

It turned out to be the very same problem which has been identified here.
Essentially is is an action spread problem.  The person who identified the
problem spoke of what happens to "Pot Metal Action Brackets".   To this day, I
do not understand how metal can deform itself this way and cause such a
problem but apparently it does.  I would have thought only wood could warp,
swell or shrink and cause these kinds of dimensional changes.  It is very
unusual to have such a problem, so it can easily be misdiagnosed.  Also, if
there is only a little bit of excessive (or too little) spread, it can make
you regulate some of the regulating buttons to their extreme point and still
have an action that just doesn't feel right even though everything seems to be
adjsuted correctly.

Personally, I would caution against using too much dip.  3/8" should be the
minimum and 7/16" should be the very maximum with 13/32" being about right in
most cases.  If everything else is right and you still need a little more
aftertouch, shorten your blow distance.  Conversely, if everything else is
right and you have too much aftertouch, increase your blow distance.

I never actually measure my blow distance.  It wouldn't do me much good to do
so anyway since I am blind in one eye and that makes my depth perception
deceptive.  Same goes for measuring other dimensions such as let-off.  I find
ways to do these things by touch, the way a totally blind technician would
have to do.  That way, I leave the error that might occur out of it.  It seems
to me that trying to measure the blow distance accurately that a grand action
has while it is in the piano would be very difficult to do.  One thing is
certain, your hammer shanks must not rest upon the rail or pads below them.
If they do, you don't really know what your blow distance is.  Even if they
are set at just a very small amount above the surface of the felt underneath,
that is OK, just as long as they are not resting upon it or sunk down in it.

Remember all of the things which affect aftertouch and that either too much or
too little is unacceptable but that there is also a small range of tolerance:

Key frame glide bolts too high or low
Key height too high or low
Too much or too little key dip
Too much or too little escapement (let-off)  (in a grand action, the drop and
escapement                                                                    
     are interactive. Sometimes the drop may be confused as aftertouch.)     
Too much or too little blow distance
Other action geometry incorrect (your priority in this case)

Good luck getting this action working well again.

Bill Bremmer RPT
Madison, Wisconsin