Yamaha hammers

[Dave Nereson]

----- Original Message ----- 
From: <A440A@aol.com>
To: <pianotech@ptg.org>
Sent: Wednesday, November 05, 2003 9:02 AM
Subject: Re: Yamaha hammers--Glenn C.


> Dale writes: 
> <<  Interesting now days I think on some models the hammers are more pliable 
> & 
> I've heard some good things about them. I'm in the shop so much I'm kinda 
> outa 
> that loop. Anbody else know? >>
 
 
>   . . . with a single #6 needle that is almost long enough to reach the core wood.  

    What kind of needle do you use and how do you keep them from breaking?  Every time I try a length longer than about 5/16", they break on me.  
 
>   The hammers are so hard that if you begin at the upper shoulder, the 
> tension in them will tear them apart after a while. 
> Regards,  
> Ed Foote RPT 

    Yes. I found that in many 80's Yamaha grands, after filing hammers, even with no needle voicing, they would pull apart at the strike point, making the hammers pear-shaped rather than egg-shaped.  I couldn't figure out why they were doing that, but it seems to make sense that the string cuts had acted like a hatchet chopping at a rope, and the filing enabled them to pull apart even more.
    But you'd think once you filed to the bottom of the string cuts (starting a "layer" on each shoulder and pulling it around to the strike point), that the felt fibers would still be intact below the cuts.  Maybe I didn't file enough off, but I wanted to remove the least felt possible.  
    Is that indeed what's happening in a hammer with lots of tension -- like bending a rope sharply, then hacking at the top of the bend with a knife, gradually cutting the fibers and making it pull apart?  
    --David Nereson, RPT