Grand touch

[Richard Brekne]

Hi Stan..

I understand your concerns. What I mean by "on the strong side" is as strong as
you can get away with without creating an obnoxious "bump" as hammers are
released. Some of this "bump" is also related to the position of the jack under
the knuckle, and how high the repetition lever is in relation to the jack, and
how far the jack actually travels. So you have several angles to work from when
it concerns this "bump". The other limiting factor is the speed of the rise. I
like it to rise very firmly, almost what I would call quickly, but by no means
shall it hop upwards. Checking heigth also comes into play here. Play around
with how much repetition spring strength you need to acheive the same rise when
check is set to 10 mm (very close) as opposed to the more standard distance of
15 mm.

If I have checking problems after setting repetition as I like to (a bit
strong), I always check for loose centers, badly shaped tails, and the condition
of the checks themselves. Often you find that the factory has installed checks
to low. I find that the top of the check should be the same height as the bottom
of the tail when the hammer is at lettoff/drop position. I also find that checks
that are square to the keyline (requireing tails that are shaped such as well)
rather then angled to meet a tail angle equaling the angle that the hammer is
glued to the shank at, is more likely to have checking problems along the road.
Also hammer centers are under more stress under this later condition, which
again can lead to poor checking.

I rarely experience any checking problems if I have all these things in order.
As for speed. It goes without saying that the faster and sooner the jack gets
back into "firing" position, the faster repetition you will get.

Richard Brekne
I.C.P.T.G.  N.P.T.F.
Bergen, Norway

Stan Kroeker wrote:

> > In addition I find that ... insuring a repetition spring strength on the
> >"strong" side does wonders for
> > speed, and can contribute to the illusion of lightness of touch.
> >
> > Richard Brekne
> > I.C.P.T.G. N.P.T.F.
> > Bergen, Norway
>
> Hi Richard,
>
> If you don't mind, I'd like your views on why 'strong' repetition springs
> improve speed (of repetition?).  My experience has been that the stronger
> the reps springs are adjusted, the more difficult reliable backckecking
> becomes and the more noticeable the 'bump' becomes when hammers are released
> from check.
>
> Regards,
>
> Stan Kroeker
> Registered Piano Technician