[pianotech] strike line

[John Delacour]

At 08:23 -0500 17/2/10, Russell Gordon wrote:

>John, could you please go into a little more detail / rationale 
>about your method? I've always gone off of a set of dimensions for 
>note #1 that I got many years ago from Steinway, but of course 
>neither the A or the C is listed.
>
>>If you measure from the front of the front rail to a point 3.5 mm 
>>into the speaking length of note A-85 and then measure that 
>>distance at a right angle from the rail to a point on string A-1, 
>>that should touch the strike line, I think.
>>
>>JD


The rationale is as follows:

1.  The strike line (bird's eye view) is straight (see my posting 
with subject "Hammer strike line" of Mon, 8 Feb 2010 23:41:56 +0000) 
and, on most grand pianos, parallel to the line of the key-fronts and 
hence to the front of the front rail (Am. stretcher?).

2.  The speaking length of note 85 is roughly 60 mm and the strike 
point, say, 1/16 of this, which is 3.75 mm.  The precise length of 
the string or the strike point makes hardly any difference - you'd be 
doing well to get the measurement to the nearest millimeter.

3.  Since the strike line is parallel to the front rail, the distance 
from the front rail to the strike point will be the same for all 
notes.


I'd be interested to see the dimensions you got from Steinway for 
other models.  Only today I was chatting with a local colleague about 
this question and how Steinway, unlike Yamaha, do not publish action 
dimensions etc.  Just as well for them, otherwise they might have to 
stick to them!

JD



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