Steinway style rep lever springs

[Newton Hunt]

Hi Ron,

Thanks for the note.

The flexibility of a wippen spring is a function of it's
length.  On a S&S spring the wippen portion is too short to
be usefully flexible.  I know, I just one and tried to bend
it.  Required too much force.  The longer arm of the jack
spring can be flex easily but the stress placed on this arm
is much less than the one above it.

I don't remember your wippen spring arrangement but I seem
to recall it as being fairly short.

The more coils on a spring the more easily it will bend so I
can understand two coils having more than desired
flexibility.

I _have_ bent wippen springs to get them to work the way I
wanted but I don't recommend doing so unless you know
exactly what you are looking for in terms of performance of
the spring.  Too many people think bending the arm is the
proper way to adjust the spring: it is not, hence my earlier
writing.

Take care and good to hear from you.

		Newton



Ron Overs wrote:
> 
> Newton and list,
> 
> Newtown wrote:
> 
> >Butterfly springs . . .  most
> >haven't realised the leaf of the spring is NOT the spring.
> >The spring action comes from the coil only.
> 
> I shared your view about the relationship between the leaf and the coil
> of the repetition spring until quite recently.
> 
> While developing our new grand action, I redesigned the repetition
> spring. Our spring has only one spring arm (leaf), the tension of which
> is adjustable via a grub screw. When we built the first prototype wippen,
> we found that the spring rate was too progressive, ie. the repetition
> lever spring tension actually increased too much as the repetition lever
> was depressed. The cause of this problem was found to lie with the use of
> the single spring arm - the spring was less progressive since it had only
> one arm and the usual single coil.
> 
> A second style of single arm spring was manufactured with two turns at
> the spring coil instead of the usual one. This spring had the more
> uniform spring rate that we were looking for. I therefore concluded that
> although the main 'spring effect' of the double wing spring comes from
> the spring coil, the spring arms also deflect when the spring is under
> load.
> 
> >. . . . . the only way to regulate these springs is to wind or
> >unwind the coil by loving the two arms of the spring
> >together or away from each other.
> 
> Agreed.
> 
> Ron Overs
> 
> Overs Pianos, Sydney Australia
> -------------------------------
> Email:   sec@overspianos.com.au
> Website: www.overspianos.com.au
> -------------------------------