1890s WNG Action Geometry

[John Delacour]

At 6:02 pm -0400 17/7/06, Farrell wrote:

>This strikes me as a rather drastic capstan move. Has anyone else 
>run across an action that needed such a large capstan move? As our 
>action ratio is down to 4.9 and key ratio is down around 4.8 with 
>the 10mm forward capstan migration, we may move it back just a few 
>millimeters. But still it seems large. Is there some hidden pitfall 
>I'm not seeing? Comments?




I'm not familiar with the evolution of the Knabe but I'm surprised 
that such bad geometry should have persisted as late as the 1890s. 
And I can't comment on the implications of your modification without 
seeing the whole set-up, though I wonder what your touch depth will 
end up as.

What strikes me from your pictures is that this piano must have an 
entrance height more in keeping with a tied action (illustrated above 
from an 1865 Kirkman) as used by Erard, Bechstein and countless 
others up to the 1890's.  What might have happened is that up to a 
certain point they did use a tied action and then some bright 
mechanic in the factory decided to do it the Steinway way without 
bothering with any calculations or sensitivity.  I imagine they 
corrected the error pretty quickly.

And yes, the famous London maker Collard and Collard, committed the 
same mistake in spades using a cloth-topped dolly like an upright 
contacting with a short blackleaded lever heel.  It takes very little 
time and wear for these actions to squeak like mad.

The tied action is fine but it does require a height not consistent 
with a slim piano (cf. the old Steinway A for extreme economy of 
design) and it makes a little more work and inconvenience for the 
restorer.  I guess that the capstan/heel arrangement won out in the 
end becuse it was more economical and allowed makers to design a 
piano whose proportions were more in fashion.

JD




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