[CAUT] pedal squeal

[Jim Harvey]

Don wrote:

>Hi David,
>
>It is a Kawai UST-7 with humidity control system that is in very nice
>shape. This is the only problem it exhibits.
>  
>
Don, now that you've provided the name, I'll add a couple thoughts to 
the mix. It's not unheard of for Kawai verticals to have this situation. 
Fortunately, it is (or was) not an everyday thing either. While I don't 
remember an instance on a UST-7, there was a moment during the 80's 
where there were infrequent reports of the occurence on other vertical 
models.

On those pianos that I was made aware of, the damper lever material was, 
as best I could determine, a synthetic blend and not wool. 
Coincidentally, in every reported case, there was water involved... not 
humidity, but as in bodies of water... oceans, lakes, that kind of 
thing. In one case the seat of the pants "statistics" were skewed 
because the plate was also getting a green tint to it, as if briny air 
were setting up a reaction with the bronzing (ironically no vertigris 
was reported). And, in every case, the reports were from "up north" -- 
Wisconsin/Minnesota areas, as well as the states bordering the Great 
Lakes. Make what you will of this information -- it left me in 
head-scratching mode.

As Roger mention, glue leach is a candidate for the condition, but I 
don't think you'll find that on the UST-7. Instead, the effect is more 
on the order of the metal-to-cloth squeak of some Yamaha's at the 
balance rail/balance pin interface, and I seem to recall some, um, 
unorthadox remedies for that condition as well.

To my knowledge, there's no document trail on what serial numbers have 
which felt, but in this case, I would echo the sentiment of trying a 
smear -- make that a light film -- of the grease du'jour (MPL-1, etc.) 
on the damper rod. I don't think you'll have any "stiction" between the 
damper rod and damper levers. If this doesn't work, and if budget 
permits, -then- go with replacements of a 'known' woven cloth (not felt) 
on the levers.

Oh yeah, try one of the best and easiest Harveyism's I've ever shared. 
When you "think" you've completed the repair, cycle the pedal a minimum 
of twenty (20) times. Down and up count as one cycle, not two. Count out 
loud, otherwise you'll cheat and do it eighteen times. This is for 
"normal" visits. You might double the count in this case. The point is 
to exercise the pedal the equivalent times as someone would do after 
playing the piano for a while (and after you've long since gone home) .

Jim Harvey