Asian Hammer Butt Spring String Friction

[Farrell]

"Certainly anyone who would notice that miniscule an amount of friction should be playing a grand (?)."

Yeah, but.......  These are going into a Mason & Hamlin upright that is being completely remanufactured. AND this piano is getting my first soundboard. One thing I DON'T want to happen is showing the piano to a good pianist to demonstrate that fabulous soundboard, and having them bet hung up on this slow action that I also just spent 150 hours rebuilding! I think we all know that the weakest link is what will determine the overall desirability of a piano.

I'm concerned that there will be this mushy little feel right at the end of the keystroke. Or if it lets off just prior or at the same time as the friction begins, it may steal a little power. I figure MY mistakes on this piano will be conspiring to limit some of its performance - I don't need any identifiable and controllable sources adding to it! Therein lies my concern.

Terry Farrell
  
----- Original Message ----- 
From: "Dave Nereson" <dnereson@dim.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Wednesday, April 23, 2003 11:17 PM
Subject: Re: Asian Hammer Butt Spring String Friction



  ----- Original Message ----- 
  From: Farrell 
  To: pianotech@ptg.org 
  Sent: Wednesday, April 23, 2003 3:58 PM
  Subject: Asian Hammer Butt Spring String Friction


  Asian Hammer Butt Spring String Friction - say that 3 times real fast........

  Problem: Renner Asian-type upright hammer butts with the integral spring and flange cord and steel plate that retains the flange center pin. The flange cord forms an acute angle that faces the width of the steel center pin retainer. When the butt is at rest, the flange cord is a millimeter or so away from the edges of the steel plate. As the hammer is propelled forward toward the strings, the apex of the flange cord angle gets closer to the steel flange and so the opening of the angle gets smaller. Prior to the flange being parallel to the shank (which is pretty close to the position when the hammer would hit the string), the flange cord comes into contact with the edge of the steel plate and for the short distance to the flange aligning with the hammer shank, the flange cord drags along the edge of the steel plate. 

  I can feel the resistance in the flange. I can't imagine it should be like that. I just bought these hammer butts from Renner. Has anyone ever noticed this before? Does this occur on Yamahas? Any thoughts on how this might affect performance? I'm inclined to reject these hammer butts, but I've been know to obsess over trivial matters before (good enough won't cut it here). Any thoughts?

  Terry Farrell
    
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  pianotech list info: https://www.moypiano.com/resources/#archives

  Yes, I've encountered this, but it was in a piano that was also mice-infested, and I thought the mice were chewing the spring loops, which they may have been.  I dunno, maybe the cords need to be made of nylon or kevlar or some other space-age material.  Or all the butt plates need to be rounded off and polished.  Or get butts with longer spring loops.  There are Schwander-type butts without the butt plates, also (conventional pinning).  Haven't noticed the problem on Yamahas -- maybe their loops don't rub.  Don't Kawais and other Asian pianos have the same type butt?  I doubt the friction is enough to affect performance.  Certainly anyone who would notice that miniscule an amount of friction should be playing a grand (?).    --David Nereson, RPT