something about after touch and movement of the jack.

[antares]

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> ----- Original Message -----
>  From: Roger Jolly
> To: Pianotech
> Sent: 3/29/2004 7:45:00 AM
>  Subject: Re: Jack to knuckle position
>
> Hi Julie,
>
> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 1mm with out the front rail =
punching starting to become=20
> depressed,=A0 will give a generous amount of after touch.
> The front rail punching, enters into the equation big time.=A0=A0 =
After=20
> touch within limits is a personal preference.
> So no black and white answer to the question.
>
> With a smile on my face:=A0 Depends on which way the nap lies??????=A0=20=

> mmmmmmmmmmmm
>
> Regards Roger
>
>
>


After touch is a rather important issue.

I personally think a seminar of certainly 2 hours could be done about=20
this subject.

Why?

Because after touch determines touch and sound.
After touch is a safety measure.
Too much after touch is a waste. Too little after touch, a deficiency=20
and a nuisance.
Why?

When we regulate an action correctly, we have to obey certain rules,=20
like :
Regulation starts with the keyboard.
The keys usually all must have a key dip of 10 mm (except for=20
regulation rules defined by some 'idiots'  (like Steinway, Pleyel and=20
Bl=FCthner) who were of a different opinion. (smile...... (; >))  )
Key dip relates to hammer striking distance as, roughly speaking. 1: 5=20=

(usually a little less in the striking distance)

This means that with a very strict key dip of 10 mm, we may expect a=20
hammer striking distance of a little less than 50 mm.
Both Steinway and Yamaha supply us with a striking distance gauge of 46=20=

mm as an average (and thus more or less correct) striking distance.
Normally speaking, 46 mm should be in accordance with a key dip of 10=20
mm or even slightly less (9,8 mm).
Most actions will satisfy these demands and give us a general ok result.
However, sometimes, an action may have just a little trouble maybe with=20=

these measures in one or two hammer sections, caused by the iron frame=20=

or otherwise) and this will have to alter the striking distance of=20
these same hammer sections.
These alterations are mainly caused by the curvature of the soundboard=20=

and the iron frame, or a technical deficiency in the action or the key=20=

bed.
To get the utmost out of any action, we must strictly follow the=20
universal regulation instructions and then...  check the possibilities=20=

and/or limitations of these actions.
After we have regulated an action 'according to the rules we have=20
learned', we could check the amount of after touch in different=20
sections of the action.
We do this by gently depressing 'a' key and following the subsequent=20
hammer movement through let off and drop.
After the hammer has gone trough the let off and 'drop' movement, the=20
key will immediately afterwards  rest on the front rail punching.
After the key has touched the front rail punching, we should gently=20
press on the key and see if there still is a movement in the hammer.

By gently pressing the key after all the action movements, we should be=20=

able to move the hammer in an upward motion by 0,4 mm.
0,4 mm is very little, but when the front punching is too soft, an=20
after touch of 1 mm or more is no exception.
For that reason, we MUST remove a too soft front punching before we=20
start regulation.
There are several very good front punching options  available :
There is the Yamaha front punching for serial instruments and  for=20
Yamaha concert instruments, there is Steinway front punching, and there=20=

is Wurzen front punching.
These three have a thickness of 5mm basically and are excellent for any=20=

piano.

When we are certain that the front punching is of excellent quality=20
(this is of course very important)  the after touch can be measured=20
very accurately.
Any after touch of more than 0,4 mm we call a 'soft landing'.
A soft 'landing' is caused by :

a too soft front punching (the key sinks into the too soft front=20
punching too much)
A too large key dip (the key dip is too big in relationship with the=20
striking distance)
A too short striking distance (the striking distance is too little in=20
relationship with the key dip)

A perfect l'anding' is an after touch of 0,4 mm.

A hard 'landing' is almost no after touch or no after touch.

A hard 'landing' means that we move key, wippen and hammer through all=20=

the playing motions without any lost motion. There is no extra movement=20=

in the action available.

A hard 'landing' is actually the very best solution because there is no=20=

waste of time, and no waste of energy, but at the same time it causes a=20=

danger for the pianist when he/she plays ppp, because, when there is no=20=

extra movement available, it may cause the jack, in extreme=20
circumstances, to not quite go away from under the knuckle and thereby=20=

cause the hammer to bounce on the jack (especially when the repetition=20=

spring is tight, or when the combination hammer-and-backcheck is not=20
optimal).

In that case, a so called free movement of the jack after let off and=20
drop is essential.


friendly greetings
from
Andr=E9 Oorebeek

Amsterdam -
The Netherlands

0031-20-6237357
0645-492389
0031-75-6226878
www.concertpianoservice.nl
www.grandpiano.nl

"where music is, no harm can be"

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