Mysterious unsolvable Yamaha double-striking uprights

[David Nereson]

J Patrick Draine wrote:

>
> On Jul 12, 2005, at 2:48 AM, Geoff Sykes wrote:
>
>>  
>> Loose hammer flanges sounds like a real likely culprit. How many 
>> times have we checked the pinning on a brand-new hammer flange only 
>> to see eight or ten swings? Since this is dealer prep I think I was 
>> actually avoiding that as a possibility. 
>
>
> Good god, Geoff! This is Yamaha that we're talking about -- not a 
> company that wants products out in the world that are "semi 
> acceptable!" Go back, check the pinning friction, and then give Yamaha 
> tech support a phone call (better yet, call them first!). I'm sure 
> they will help you figure this one out (and make sure you're paid for 
> your efforts). Just a guess -- if the center pin/flange friction is 
> within specs, are the return springs too strong?
>
> Patrick Draine
>
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>
>
I used to work for a Yamaha dealer in the 80's and called them 
repeatedly about this problem and they refused to admit it was a common 
thing in Yamaha verticals.  They always told me to double-check the 
regulation and the pinning.   My thought was, "These are brand new 
pianos by a supposedly reputable manufacturer and dozens of jacks and 
hammer flanges shouldn't have to be re-pinned on new instruments!"  Here 
it is 20 years later and techs are still encountering the same problem.  
They've never addressed it.  I think part of it may have to do with the 
curve of the butt leather compared to other hammer butts -- maybe the 
jacks sit too far under the butt; I don't know.   And I don't have 
sophisticated enough equipment to experiment, such as high-speed 
photographic equipment to analyze the movement of the jack in relation 
to the butt, or machines to mill different curves on hammer butts.    
But you'd think a big, wealthy corporation like Yamaha could afford to 
re-tool their butt-shaping machine or research their action pinning 
torques to get rid of this ongoing botheration.
    --David Nereson, RPT