[pianotech] Grand damper wire bending

[John Delacour]

At 19:49 -0400 26/09/2010, Michael Staples wrote:

>List members: I would appreciate it if you would share your choice 
>of tools and techniques for efficient Grand damper wire bending.

Though I have both types of plier illustrated on page 67 of Schaff's 
catalogue, I don't use either of them for damper wires, but instead a 
very light old-fashioned bending tool.  This serves also to do any 
bending that may be required right at the top of the wire to 
centralize the damper head on the strings, for which the plier tools 
are no use.

The first thing to get right is the offset of the wire at the head 
and the left-to-right angle of the top section of the wire, which 
must be at 90° both to the line of the damper heads and to the line 
of the damper guide.  If the angle is right but the damper head is 
not sitting centrally on the unison then the offset of the wire from 
the head must be changed.  To do this I grip the head and the inset 
wire in a pair of duck-billed  pliers while bending the topmost angle 
of the wire in or out and then adjusting the angle of the bend above 
the guide.

Next hang the damper through the guide so that the bottom of the wire 
hangs in front of the damper drop, and hold the head so that it is 
perfectly flat on the strings. It is convenient to make a tool to 
hold the damper in this position.  The bottom of the wire must be 
perfectly in line with the centre of the damper drop (the bit that 
holds the set-screw), which means it must also be perfectly vertical 
and parallel with the part that goes through the guide.  This 
condition is achieved by changing the angle of the two opposing bends 
below the guide.

If the guides are worn and need replacing, it is not a bad idea, and 
probably saves quite a bit of time, to do all the bending work using 
the worn bushings.  There must be no pressure on the sides of the 
bushing and, if the bending has been properly done, when the wire is 
clamped by the screw in the drop, the damper wire will 'float' in the 
guide.  It is easier to get things just right if the guides are worn 
enough to allow this floating.  The dampers and guides can then be 
removed and the guides rebushed before the main regulation commences.

And above all remember the dictum of one old foreman at the Steinway 
shop in London : "Nobody likes dampers!"

JD


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