1/2 punching

John Delacour JD at Pianomaker.co.uk
Tue Aug 8 04:57:13 MDT 2006


At 10:53 pm -0700 7/8/06, Jurgen Goering wrote:

>I believe the key balance point is an area that has often been 
>overlooked in regards action refinement...

All this discussion of 1/2 punchings etc. would not be taking place 
if piano makers such as Steinway took the trouble to design the 
balance rail properly in the first place.  My camera batteries have 
died, so the archive picture below





is not as illustrative as I'd like -- I'll draw a diagram when I have 
more time -- but the rail here is made (in 1899 or another in 1860) 
in what I consider to be a proper fashion.  The bevelling of the rail 
in front of the natural pins commences just at the front of the pin 
boring and so does the trough in front of the sharp pins.  The pins 
are angled 4 or 5 degrees backwards -- another lost detail which 
Wolfenden was already regretting in many pianos in 1920.

With such a design the balance point of the keys is properly 
determined and the front part of the washers and punchings simply 
folds round the angle exerting no pressure.

By contrast a flat-topped rail, as on a 1923 Steinway 'O' I'm looking 
at at the moment, results in an indeterminate fulcrum for the sharp 
keys, which moves further forward as the key is depressed.  At least 
the pins are angled.

Congratulations to Frederick A. Vietor <http://tinyurl.com/goft9> who 
in 1931 provided Steinway with one more patent to print on their 
products and then drop for reasons of cost.

JD

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