Dave Renaud here. I've been silent on the list as being very busy, and building a house this year. I've saved a few outstanding queries for
vacation time.
I have observed disturbing happenings with some new Kawai action
parts and am curious if this is an anomaly or others have the same experience. To be very clear, I am not beating on Kawi, I like their pianos, they are clean to tune and have a characteristic tone
I prefer to some other well know brands. Their actions are a pleasure
to regulate. Never less the following observations and the implications
for future service disturb me.
A client has a brand new Kawi upright with the lastest greatest action
parts. The issue is with many "sticking" notes that will not repeat. Upon inspection I see sluggish jacks. Proteck improved jacks function, but temporarily, a follow up call and return visit
finds the jacks as sluggish as before.
So I pull myself together to make a real investigation.
Upon removing a couple jacks I discover that the pin was supper
locked tight in the bushing and so loose in the Birdseye it can rattle.
The jacks should swing freely in the birds eye but the bushing cloth
had swollen with summer humidity and having nowhere to go had swollen out the bushing cloth hole towards the side of the jack. The sluggishness was a result of friction between protruding cloth and side of the jack. This motivated me to check some hammer flange and wippen flange
bushings as well............
The first call was a big pitch raise, first tuning on a new piano,
pedal work, and lubricate the jacks, in 1 hour. This second time, digging
deeper I noticed subtle clicks on some notes and upon checking these
flanges first found loose birds eyes and very tight cloth once again.
NOTE: the birdeyes were so loose I was going up to #22- 22.5 pins in some
cases so the bird eye would not have a free rotating pin. This suggests
that very soon these parts will be finished for I can not go much larger
and I can not size these plastic holes without getting quite creative.
These leaves me with a standing hypothesis on which I would very
much like feedback. It is as follows:...........
The cloth will seasonally expand and contract. The Plastic will
not expand and contract. They will not breath together. The cloth
has nowhere to go when in expands so the pin tightens up profoundly,
and when it expands in a very humid summer has nowhere to go except sideways. The friction of the pin exceeds the friction in the birdseye
and the pin begins to rotate in this birds eye. Plastic creeps and the
birds eye becomes enlarged. We can end up with loose birds eyes, clicks,
and sluggish flanges all on the same flange.
The result was that I repined a dozen parts that were sluggish, or
had audible clicks and promised to investigate further. The whole action
remains the same, only a dozen parts had reached a level to make noise
or fail, others will follow.
So here I am several months later looking for more feedback. The client has not called back so I assume the outstanding notes function for now. I am concerned as this is a long term client that just purchased a new piano and I expect to be doing repair like this at every service call from now on. The implications for Kawai parts in a place like the Ottawa Valley where we get very humid summers, but also 6 months of snow an 20-30 below zero as the daytime highs for the coldest couple weeks means 30% humidity
in some heated buildings when furnaces are working overtime. If the
expansion-contraction hypothesis is true it would be tested best in this
type of climate.
So what do you think?
22.5 pins in a brand new piano within 6 months of delivery?
Have others had similar experiences?
What to do......hmmmm.
Cheers
Dave Renaud
From the Great White North
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