Minimum LO, WAS: Hammer assist spring ?

[Delwin D Fandrich]

----- Original Message -----
From: "Bill Ballard" <yardbird@vermontel.net>
To: "Pianotech" <pianotech@ptg.org>
Sent: June 08, 2003 11:35 AM
Subject: Minimum LO, WAS: Hammer assist spring ?


> At 9:45 AM -0700 6/7/03, Delwin D Fandrich wrote:
> >This is the part that intrigues me. The ability to set very close
> >letoff and the ability to control the action at pianissimo levels.
>
> At 7:46 AM -0700 6/8/03, Delwin D Fandrich wrote:
> >So, when I hear some say some grand action design can be regulated
> >with let-off right up to within 1 mm of the string line I at least
> >want to give the thing some thought. And one of those thought is, "I
> >wonder how this thing would work with a nice graphite-filled ABS or
> >Nylon jack?"
>

> Escapement friction is a turnstile. You can reduce the hiccuping by
> fattening the LO. But the size of this friction determines the
> quietist sound one can get out of a piano. So Del, would the
> lubricity of the jack top make a big difference here?

In the Herz/Erard action I think you are analyzing--none at all. Or at
least very little.

But, in the Herrburger/Schwander Inverted-center Linked action (as
illustrated in the post I was responding to) I think quite a great deal.
This action has a sliding let-off and a sliding return mechanism. I should
think providing a precise and low friction surface for these two functions
would be important.

Del