double striking hammers

[Michael Wathen 556-9565]

Here's what I think.  On S&S....For the longest time Steinway
sent out hammers or new pianos with hammers whose tails were two
short.  If I reckon correctly they began making a longer hammers
about two or three years ago which would rectify this problem in
certain vintage Steinways.

For Yamaha, my suspicion is that the backcheck wire is too far
towards the back of the key to be effective on a lighter blow.  I
won't go into this two much except to say, ask your self: If you
were a designer how would you figure out where to put the
backcheck wire on the key?  Several considerations.....

      1). the line scribed by the outer most surface of the
hammer tail forms an arc of a certain radius.

      2). with a ruler and compass you can scribe this line on
paper.

      3). Where should you draw a tangent line on this arc so
that it corresponds to the hammer in the checked position as
indicated by some predetermined specification?


This exercise, as scantly as I have sketched it, can be performed
analytically with equations and a coordinate system, or it can be
performed with a ruler and a compass.  You must have the overall
length of the hammer, the thickness of the tail, the distance
from the hammershank center to the strike point, the bore
distance, and the height of the key surface at the back of the
key when lightly depressed to its full travel.

You can also use the same method to determine the correct length
and curvature of the hammer tail.

Michael Wathen