Steinway strike line

[John Delacour]

At 10:32 AM -0500 11/30/01, Erwinspiano@AOL.COM wrote:

>         Thanks for the reply. To me each  opinion is experience and 
>personal bias. That's what makes them valuable.
>
>           The other issue about stwy string scales are the floating 
>hammer strike lines....but Stwy B D and A models are particularly 
>notorious.
>        The most often fix looks like a small horseshoe shape in the 
>hammer line right at in the octave six area with note c 64 being the 
>hammer that is usually pulled in the furthest towards the front of 
>the piano. Often it's pulled in 1/8" or more.The horsehoe starts 
>about note 60 and usually ends  about note 69.

That's interesting.  I have recently had to put right quite a lot 
that was wrong with a D, which had suffered at the hands of two 
people who ought to have known better.  One of them had fitted the 
hammers and apart from not being impressed with various aspects of 
this work I noticed your 'horseshoe' in the hammer line and asked a 
fellow rebuilder who could have done that.  I got the answer straight 
away since it's apparently a fad of the man in question.  That's not 
to say he was wrong in this case or that the principle is wrong, but 
since the strike line is the first line drawn in a piano design, it's 
a very queer designer that's not going to draw it straight.  As to 
what follows and the disposition of the speaking lengths each side of 
that line, then there's all the room for error in the world, so one 
question is, did Steinway position the agraffes too far from the 
strike line in this area etc.

I don't know what happens in America but here the great majority of 
restorers buy their hammers bored, and this is asking for trouble.  I 
bore my own hammers differentially, taking account not only of the 
varying height of the strings above the key bottom (or, which is 
equivalent, the line of hammer centres) but also of the varying slope 
of the strings from agraffe/pressure-bar to soundboard bridge, in 
order that each hammer should meet the string at a right angle after 
allowance for toning and facing.  This always used to be the practice 
at the Steinway factory and consequently a set of old original 
hammers can show a variation of 5 or 6 mm in bore length in the plain 
wire range to accommodate the 'arch' or even steps in the height of 
the strike line.

If a string is 4 mm higher, and a variation of 4mm is not at all 
unusual between tenor and treble on a lot of pianos, including 
Steinways, then the hammer will strike the string over 1.5 mm closer 
to the agraffe if the hammer is not bored 4mm further from the nose, 
unless the bore angle is altered.  To bore the hammers at different 
angles to achieve the effect will affect the geometrical relationship 
between hammer and lever, so besides being awkward it is also not the 
solution.

If standard bore hammers are used and there is any variation in the 
strike height, provided the hammer rail is straight, as it always 
should be in a Steinway, then some hammers in the set are bound to 
over-centre or under-centre if they are glued on in a straight line. 
Towards the extreme treble, where the upward angle of the string 
generally increases, adjustment has also to be made to preserve all 
the right relationships.

It follows from this that a set of standard bore hammers all striking 
the strings at the proper points can never be in line when at rest 
unless the strike line and the string angles are perfectly flat.

JD