Grand Touch

[Mark Bolsius]

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G'day Kristinn,

There have been some excellent posts on this but I have one last thing to
add to your heavy action problem.

I agree with Stan's suggestions regarding friction, and Jon's 3 part
approach is also worth following. Unfortunately, Samick's action geometry i=
s
not conducive to light touch as Roger has well pointed out, and that is an
expensive fix...new components, time etc

The point is to get the friction right first, then worry about mass, then i=
f
still in trouble, geometry.

Korean pianos are not renown for their consistency with action centres, and
you may find that checking and remedying the action centres creates enough
difference for your customer.

I have listed below Renner's (Stuttgart) suggested friction specifications
for various piano parts. If you can get the centres close to this, you may
find you have changed enough to get a good result for your customer.

Uprights
Butt flange 2-5 gms
Wippen flange  2-5 gms
Jack flange 2 gms +/- 1 gm
Damper flange 5-8 gms

Grands
Wippen lever flange   2+/- 1 gm
Damper flange  2-4 gms
Damper block   2-4 gms
Repetition lever flange 5 +/- 2 gms
Hammer shank flange 3+/- 1 gm
Jack flange   3+/- 1 gm
Steinway damper block fall under it=B9s own weight

The ideal friction value is between 12-15gms, if you are getting values too
much more than this you know you have a problem and can deal with it using
Stan's suggestions and the right friction values for each component.

Use Richards formula

Downweight- Upweight
               2                      =3D Friction

Renner (and most good engineering supply houses) have spring gauges that
measure
the friction in a part extremely well...like any good tool, it costs a bit,
but the quality and usefulness is remembered long after the price has been
forgotten, I bought the 0.5-6gm gauge and am now wishing I had bought the
3-30 gm gauge instead...so many centres seem to be far in excess of where
they should be.

Of course repinning is the ideal solution for tight or loose centres, I hav=
e
deep reservations about putting any product in a part that has to work for
years and years... but that said, Protek can assist with certain centre
problems.

Good luck, because if friction isn't your problem then there is geometry
stuff that need to be addressed, as I said, expensive!

Keep us posted on how things turn out

Cheers
Mark Bolsius
Bolsius Piano Services
Canberra Australia

----------
>From: owner-pianotech-digest@ptg.org (pianotech-digest)
>To: pianotech-digest@ptg.org
>Subject: pianotech-digest V1997 #2121
>Date: Thu, 4 Nov 1999 5:33 AM
>

>> I=B4m servicing a relatively new Samick grand that the owner would like to=
 be
>> a little lighter.
>>
>> I=B4m curious to know, what are your favourite methods in making a grand (=
or
>> a vertical) feel lighter to play?
>>
>>
>> Kristinn Leifsson
>> Reykjav=EDk, Iceland.
>>

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