[CAUT] Boston design... was: Grease/Oil on upright pressure bar

[David Skolnik]

David -
I read through the responses rather quickly, but I think most or all of 
them addressed the issue of the contamination, and not the inherent tuning 
instability you noticed.

At 07:24 PM 10/6/2005 -0500, you wrote:
>Hi,
>
>They have a bunch of Boston uprights (UP-125 II)  that are proving quite 
>annoying.  There is very little discernable friction between the tuning 
>pin and the speaking portion of the wire.
>When I say low-friction, I mean I can put my little hammer vertical on a 
>pin and walk a unison above and below tune without stressing my pinky.
>Is this normal?  Making unisons stable is a bit of a chore.  No wonder 
>they were warbling & howling.  Do they come from the factory this way? or 
>did one of the past piana toonas oil everything up?

My experience with Boston uprights was exactly thus, and, while not 
following through with either measurements or contact with Boston technical 
support (?), I attributed the problem to the combination of  tight pins, 
excessive flag-poling,(due possibly to some combination of tuning pin 
steel, distance of coil from block, or softness of pinblock wood),  and, 
especially, insufficient friction at the pressure bar.  Your pinky tuning 
sounds about right.  I suppose if you are refining a previously well tuned 
piano, without having to turn pins, you can do a decent job.   Since I 
never tuned very many Steinway 1098's, I can't say from my own experience, 
but I seem to recall reading or hearing that the problem there was 
excessive friction at that point.  If true, perhaps this current problem is 
the result of over-compensating in the design.

The following is a quote from Paul Legrand from some Boston thread back in 
January of 2004:

>Part of the tuning stability problem arises from the very 'rubbery' feel 
>of the pin/plank area. There is very little indication of when one has 
>'set' the pin because there is a sense that both the steel of the pin and 
>the plank are 'soft', even though the pins are 'tight' in the plank. This 
>sounds like contradiction, but I can't find another way of describing it.

Of course, I must point out that Wim Blees has no problem tuning these, and 
I think he does about 12 to 15 of them a day ;)


David Skolnik
As always, I could be wrong.