Young Chang Syndrome

[Delwin D Fandrich]

----- Original Message -----
From: Richard Brekne <richardb@c2i.net>
To: <pianotech@ptg.org>
Sent: January 05, 2000 10:20 PM
Subject: Re: Young Chang Syndrome


> I do not know what Young Chang used / uses... but the symptoms you
describe are very typical of graphite being used in the bushings. Graphite
is .... crystalline formed and doesn't respond well to heat generated by
repeated use.. or so the explanation goes. Tho there may be other
contributing factors to this problem when graphite is present.

This has been our experience as well.  We have also found this to be a
problem with Renner and Tokiwa action parts.  Whenever graphite is used as a
"lubricant" this problem is inevitable.



> Generally, the solution is easy enough, but time consuming. I repin, and
in the process use the bushing reamer to lightly clean out a bit of the
graphite, then work a bit of Teflon powder into the bushing with a
burnishing tool. I have been doing this for several years now and have yet
to have a repeat of the problem.

The logical question, of course, is why should we have to do all this at
great expense to somebody -- either ourselves or the customer, occasionally
the manufacturer?  Why not just leave the bloody stuff out?



> August Forster pianos used some kind of clear solution for some years as a
lubricant. This stuff, what ever it was ended up hardening to some kind of
glueish stuff. The centers would freeze up and stay that way. In such cases
I have found you just have to re-bush the flanges.. or simply buy new -
prebushed ones.
>
> Teflon powder is the only thing I have ever seen that really works (and
lasts) as a bushing lubricant.

Again, this has also been our experience.  What will it take to convince the
action parts manufacturers to either simply leave the graphite out and do
nothing at all, or brush on Teflon powder in place of the graphite.

When we complained to Renner about this -- What, ten years ago now? Renner
action parts were simply freezing up in our pianos -- we were simply told
that the German piano makers did not have problems and so there must be
something wrong with how we were installing the actions in our pianos.  No
suggestions were offered as to what we might be doing wrong.

(I should add that some of the parts we received did not exhibit this
problem.  Perhaps 10% to 20& of them exhibited problems severe enough to
require attention.  Mostly the problems only developed in the hammer butt
flanges.  Which makes sense -- the angle of rotation is fairly great and the
stress loads are high.  When compared bushings between the parts that gave
us problems with those that did not, we found that there was considerably
more graphite in the frozen parts than in the non-frozen parts.  At least
the bushing cloth in the parts we had the most trouble with was considerably
darker inside the pin hole than was the cloth in parts that did not exhibit
these problems.)

Regards,

Del