Key Leads and Inertia

[David Love]

I can't comment from real scientific data, but I have never liked the feel
of assist springs when they are tensioned above some undetermined amount
(say, 10 - 15 grams which is typically the level at which they are used),
if at all.  I am suspicious of the disconnect that they create between key
and wippen with the assist spring always pushing the wippen away from the
key.  Any bounce in the hammer off the rest rail (something that they also
contribute to) will enhance this disconnect.  My hypothesis is that an
assist spring will work best when used in conjunction with a rocker arm
capstan arrangement in which the key is directly linked to the wippen. 
With an adjustable rep spring, you could easily adjust the degree of assist
by measuring the change in downweight as you tighten the spring.  

David Love
davidlovepianos@earthlink.net


> [Original Message]
> From: Bill Ballard <yardbird@vermontel.net>
> To: Pianotech <pianotech@ptg.org>
> Date: 6/14/2003 5:21:01 AM
> Subject: Re: Key Leads and Inertia
>
> We are both paraphrasing the whispers from the great unwashed. Can 
> someone on the list comment on the performance shortcomings of 
> springs? Are these shortcomings a direct function of the amount of 
> work the springs are doing?
>