Re. Bobbling hammers on Yamaha upright

[Jim Busby]

So Jim, others,

What's the real fix? File the buckskin, iron it, reglue it, water shink
it (with distilled water)? I've had that "hump" and never found a quick
way other than what Vinny said, or by tweaking the regulation. If only a
few are bad ones, were they defective from the beginning, or did too
much lost motion cause the jack to pound the hump there? 

With 337 uprights (203 of them Yamahas) you can see how this might
interest me. Thanks.

Jim Busby BYU

-----Original Message-----
From: caut-bounces@ptg.org [mailto:caut-bounces@ptg.org] On Behalf Of
James Ellis
Sent: Monday, April 19, 2004 1:53 PM
To: caut@ptg.org
Subject: Re. Bobbling hammers on Yamaha upright

Yes Vince, changing to a thicker butt felt, and then re-regulating,
might
stop the bobbling, but it's not the fix I would like to see.  That would
also change the leverage ratio a little bit.  The ratio is just fine the
way it is.  The problem is too much of a hump at the very front of the
butt
leather, making the jack have to move too far out before it will clear.

This is the only Yamaha upright that I tune regularly that does this.
It's
about two years old, in a church chapel, and does not get used a lot, so
it's not a matter of wear.  As I said, the funny thing is, a few hammers
do
it badly unless I pound hard and really knock the jacks way back at
let-off.  The others don't, no matter how I play.  Everything is lined
up
right on the money.  At full key-stroke and let-off, neighboring jacks
line
up perfectly - same distance out.  One bumps the butt leather, but the
other does not.

The other funny thing is, no one has complained about it.  I don't think
they even notice it.  Next time I tune it, I expect to find a few more
bobbling, at which time I will fix it.

I'm glad I read all your various posts on the subject before it came
time
to tune this piano again.  This is the first time it has started doing
this.  Having read your posts, I looked closely to see what was going
on,
and that's what I found.

Thanks, Guys,

Jim Ellis


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