Front Weight Problem

[David Ilvedson]

I would have thought this was Kawai built?

David I.

-----Original Message-----
From: owner-pianotech@ptg.org [mailto:owner-pianotech@ptg.org]On Behalf
Of Roger Jolly
Sent: Monday, July 17, 2000 8:56 AM
To: pianotech@ptg.org
Subject: Re: Front Weight Problem


Hi Richard,
                 Lets deal with the clacks first, before getting into the
touch weight.
The following is a common list of Samick assembled piano's of this vintage.

I. knuckles are far too hard. Ideally replace them, band aid reduction of
noise.  Work a darning needle between the leather and felt core roll the
needle from one end of the knuckle to the other to slightly stretch the
leather.

2, Drop button leather is a synthetic. Replace leather.

3. Jack spoon leather is a hard woven green felt. Replace with soft red
felt buttons.

I will now make a bold statement.  The hammer mass on these pianos is
rediculously high.
typically 13gms at #1 bass hammer and 11gms at the first tenor.

I have replaced at least a dozen hammer and shank sets on these models,
using Wally Brook's Encor's with Tokai shanks. I request 9.5gm #1 bass and
7.5 first tenor hammer.

This will cure quite a bit of your noise, and dramatically improve the tone
and touch problem,

The jack button is a given to quiet this action.

Now just a general comment or two on the touch weigh.

You will find leads both in front and to the the rear of the balance rail
holes in all kinds of random order.  Adjacent keys will sometimes have two
leads in front and the next one lead to the rear.  In short the factory
does not have a clue how to weight off an action.
So you have to address the friction problems first.  Treating all the
centre pins with alcohol and water and leaving over night is often a
partial solution.

Once these things have been attended to, you can start a touch weight
analysis and correction.

Wippen assist springs should be used for minor assistance and fine tuning
of touch weight. In this case they have been used to mask a pile of other
friction and geometry problems.

If you look at the back checks of these actions you will also find that the
bass back checks are at 15 degrees to the hammer rails with some very
agressive checkering.  Good regulation is nigh impossible untill this is
corrected.  Given the high mass of the hammer, good checking and repitition
spring adjustment is very frustrating.

Just going into weighting off,  will compound the problems.

Regards roger


At 11:06 PM 16/07/00 -0700, you wrote:
>Hi list.
>
>Piano is a Howard baby grand number 358898. Basic symptomatical type
problem
>is an unbelievably loud clacking action. Have done just about everything I
>can in terms of softening knuckles and whippen underfelt, even reduced
>hammer mass a bit, with only slight reduction in noise.
>
>Having just purchased a Stanwood kit I got the following numbers for you
all
>to work with. (I'll give you the numbers for key # 32, the basic tendencies
>hold for the whole piano)
>
>Strike Weight is 10.2 g
>Strike Weight ratio is 3.6  !!!
>Front Weight is 10.3
>Key Weight Ratio is 0.54
>Whippen Weight Ratio is 17.5
>Balance Weight is 36
>Upweight is 26
>Down Weight is 45
>
>
>Now this piano has very strong and heavy whippen assist springs adjusted to
>full strength, probably as an attempt to keep down weight and up weight in
a
>reasonable range. Seems like a classic example of the kinda problem
Stanwood
>talks about when he expounds on the weakness of useing just up and
>downweight measurements to decide leading in the keys (In this piano there
>is like almost no lead at all).
>
>My call on this is that the keys need to have about 20 grams more front
>weight, and then the whippen assist springs need to be readjusted to
>maintain about the same Balance weight as exists now. This would give a
>Strike Weight ratio of about 5.5 which seems to go well with examples in
the
>kit.
>
>But I am like very new to the Stanwood approach so I am not sure about all
>this. So anyone out there who has experience with this.... grin....
>HELP!!!..
>
>Intuitively... I would also think that increased front weight would resist
>better the top action better so as to keep the whippen from banging up and
>down on the capstan so much, thereby also better absorbing and minimizing
>the same kinda banging up and down on the repetition lever by the knuckle,
>which by the way is like kinda extreme in this case. You can see the front
>of the key just jumping back up on release.
>
>Thanks for any and all input.
>
>Richard Brekne
>RPT, NPTF
>Bergen, Norway
>
Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505