Kawai heavy action (long)

[Jim Harvey]

Hi Fred,

Responses interspersed, otherwise a typical Horace/Harvey type
response...

Thursday, March 18, 2004, 9:16:15 AM, you wrote:

FS> 	I have a customer with a small Kawai grand from the early 80's which has a
FS> very heavy touch weight. In my experience, this is very common among Kawai
FS> grands of that era (especially the ones sold as Howards), and I expect
FS> downweights in the area of 65 gm, upweights around 40 gm. I have serviced
FS> several, but never has a customer wanted me to do anything about the
FS> weight. They've all either liked the heavy weight, or been too cheap to
FS> spend a dime. Until now.

I'll try to provide the entire story, including my best guess and
punch line.

I realize that you're speaking in age-relative terms, but to clarify,
the Baldwin (Howard) agreement was long over by the 80's.

Side bar. Situations involving stencil models are handled through normal
channels. IOW, if it's distributed by Baldwin/other, issues and
reports are handled as:

owner - tech - dealer - [representing mfr.] - Kawai Japan.

Note that Kawai America is bypassed in the above path. The same
applies today with Boston products.

Best guess: During the 70's there were some incidences involving
knuckles. Again in the early 80's, there were a few instances (just
enough to be aggravating) of touch weight issues DUE to knuckles. More
below.

FS> 	This particular customer has developed "wrist problems" (incipient carpel
FS> tunnel?), and is wondering whether to trade pianos or have this one worked
FS> on. So I need to be able to speak with authority and say
FS> a) I can take care of this problem. It will cost $X. Or,
FS> b) You are better advised to trade in and get a different piano.

Shouldn't be necessary to trade pianos, and shouldn't cost mega-bucks.
If this turns out to be knuckle-related, the typical feedback to a
player can be equated to driving a bus that has lost its power
steering.

There are two supporting stories behind both the earlier and the 80's
knuckles. If you'll excuse the word "batches", it fits here. Some of
the earlier products had raw material supply problems with buckskin.
If you recall, this condition was pretty common in the industry during
the 70's, and some manufacturers resorted to other materials. 'Nuff
said.

Kawai must have had a stash of buckskin for knuckles, but apparently
some of it, with time and use, would allow the leather to continue to
stretch around the core. Whether this was due to the source (animal),
curing, or skiving process I don't know. The results were that the
initial part of the energy expended to play the key was wasted in
simply rolling the (loose) knuckle leather around the core. This
phenomenon seemed more prevalent in night clubs, teaching, and other
daily high-use areas.

In the 80's vintages, at least the few that were documented, the
results were the same, but the blame was placed on caul work while
actually making the knuckles. (I'd speculate it would be the
equivalent of how many knuckle strips a substitute or rookie worker
could make in a day -- and having those strips end up in production).

What doesn't work (at least for the long haul):
- bolstering
- knuckle lubrication

Never tried:
- shrinking (too many negative ramifications to consider)

What does work:
1. replacing knuckles
2. repairing existing knuckles

Method #1 is faster but more costly, but involves the potential of
size, noise, and even the remote possibility of duplicating the same
thing you're trying to eliminate.

Method #2 is my personal preference, because it has worked for me, and
I'm just deranged enough to enjoy the process! For brevity (yeah
right) I won't go into the procedure here, since I may not be on the
right troubleshooting track. Advise if you want my two cents worth.

FS> 	My sense is that $X needs to be in the "up to $500" range. IOW, action
FS> geometry changes are probably out of the picture.

FS> 	So I wonder if any of you have experience in addressing weight issues in
FS> small Kawai's of this vintage, and would be willing to share. Specifically,
FS> I'm wondering if a combination of wipp spring adjustment, adding a bit of
FS> lead to keys, and tapering hammers is likely to produce acceptable results.
FS> And whether just springs, just lead, or springs and lead would be enough.

Summary:

- this situation, where it existed, was particular to certain
production runs, although due to the cause and sporadic nature of the
problem, I'm not sure it can be isolated to certain serial numbers;

- where it existed, it was global, not model specific;

- you're right that many owners LIKE this phenomenon, therefore...

- there could be more incidences than were ever reported;

- you're correct that changing action geometry is more of a moot
subject with Kawai (however, since this was a period of several design
changes, need to know model and suffix -- not "small", 5 ft, etc.)

- unless already done, easing balance holes alone will drop 3~5 grams;

- considering the vintage and the problem, it's likely that you'll
drop more real or perceived touch weight in the process of regulation
(damper timing due to key end felt compression, shaping hammers, etc.)

- would consider mass (lead) a LAST resort, if at all.

Any touch weight changes via the auxiliary springs are not
only minimal, but coincidental. IOW, they were not intended to provide
adjustable touch weight. There are two schools of thought on
regulating these springs:
1. Sidecutters
2. Assuming wippen flange centers are free, adjust auxiliary springs
so that wippen -just- follows, not pushes, the knuckle when a hammer
is manually lifted from rest position.

The punch line. I'd be inclined to do a field repair on one or three
of the worst offending notes (likely the heavy-traffic area). This is
certainly within the "professional" diagnostics umbrella, and one that
I'd like to see observed more often in other areas (auto mechanics
being my latest reference). Would suggest going through ALL the
motions on these samples (shaping, regulating, and yes... even
tightening screws). Would also make before/after comparisons to other
keys, both measured (gram weights) and by using tactile senses.

There are very few elusive or magic areas on a Kawai. Even -I- can
work on 'em with confidence! You should be able to bring the down
weight specs into the 57 gram range without a lot of fuss. However,
whether you can do repairs (by either method) -and- do the requisite
regulation steps (regardless of repair method) within a $500 budget
may be somewhat optimistic.


-- 
Regards,
 Jim                            mailto:harvey@greenwood.net