Work over, just

[Tony Caught]

Hi Ron,

As I said, removed the action, moved the damper lift bar and listened for
sound. Heard a click and felt it with my fingers. Almost sounded like metal
tapping. Pressed sections of dampers back but sound is still there, noticed
that the damper rod hinges were flexing with rod movement, checked the
damper rod hooks, not loose.

Removed one DR Hinge, removed the damper rod.

In removing the damper rod I noticed a squeak as the rod came out so I
removed all the hinges to see what was happening.

All the hinges were tight, and, when you slowly moved the hinge on the rod
hook you could feel the grip between the hook and the felt bushing of the
hinge, it seemed to grip until enough pressure was applied then become free,
with a clicking sound.

Lubricate and problem solved but why did the hook show that sort of
resistance ?

My thought is that the damper bar and hooks are CHROME PLATED not cadmium,
and a very smooth surface of the chrome is gripping the felt ? fibres in
some static form. I query the felt because it may be an artificial felt with
nylon or something in it and we all know that two very smooth surfaces when
placed together seem to grip first then slide easily.

If this is the case with the chromed surface against a nylon type felt, you
are going to hear more of it as these pianos become available. Could also be
a future trend in manufacture with Yamaha.

Regards

Tony Caught

----- Original Message -----
From: Ron Nossaman <RNossaman@KSCABLE.com>
To: <pianotech@ptg.org>
Sent: Wednesday, May 09, 2001 9:01 PM
Subject: Re: Work over, just


>
> >
> > Same piano, squeaky sustain, a mechanical click when you depress the
pedal.
> >
> > Isolated the problem to the damper lift bar (in the action) you could
really
> > feel a jump as the click sounded.
> >
> > This is a new one for me, I know what the problem was, do you ?
> >
> > Regards
> >
> > Tony Caught
>
>
>
> Hi Tony,
> I've run into clicks just like in Yamahas that came from the pedal lever
pin.
> The pedal spring is stiff enough that as the pedal is depressed, the lever
> fulcrum point shifts from the pivot bolt to the spring. As that happens,
> pressure on the bolt bushings reverses direction and the bushings click.
It's
> hard to find the source of this click because it jars the whole piano when
the
> bushings shift. The easy test is to put your hand on the pedal lever with
a
> couple of fingers bridging between the brackets of the pivot. You can feel
the
> relative movement between the parts with the click. A lighter spring
helps. I
> don't think of anything likely to click like that in the action, but if
you
> find what it is, I'd sure like to know about it too.
>
> Ron N