fast puzzle,answer

[A440A@AOL.COM]

>     A new Steinway D. a knocking sound when
>the pedal is used in rapid repetition.   This noise was the result of a
>factory defect, and I fixed it with a screwdriver and  my cordless drill with
>a #9 bit.

Ok,,  so maybe the puzzle interest is gone, but here was the problem.  The 
treble damper tray support block was moving with pedal action, and the screw 
would not tighten it anymore. 
      Steinway has changed the way the damper tray is mounted.  Formerly, the 
tray anchor blocks were cut so that they fit snugly between the keybed and 
the bottom of the shelf. With the block trapped between top and bottom 
thusly, a single screw would hold it in place with no fear of twisting or 
movement. 
    Today, these blocks are cut so that they don't come close to the 
underside of the shelf, which means that the screw is the only thing holding 
it in place.  In and of itself, this avoidance of closely fit parts allows 
weakness in the system, since the tray pivot is located above the screw and 
the forces at work want to move the block away from the tray(creating 
instability in the damper regulation).  It may have looked like a way to 
speed up the back-action assembly process but it is a step away from 
functional durability and simple craftsmanship. That they must use heavy 
paper shims on two sides of this block also indicates that somebody in the 
action department is cutting undersize and shimming to fit. That isn't the 
way it used to be!
    What I found on this particualr D, and several others, is that the 
anchoring screw is threaded through the block as well as into the case. This 
means that if you try to turn the screw to tighten the block, the block 
doesn't tighten because the screw is trapped by its own threads.  Screws are 
supposed to act like clamps, with the threads pulling the head and the part 
that it is bearing against, together.  For this to happen, the hole in the 
block must be drilled larger than the threads. ergo, a #9 bit. 
   Once that was remedied,  I found that the pivot pin had already enlarged 
the block's hole enough to make noise. This is on a Steinway D that has been 
in use for three weeks!  I plugged the hole with a 1/2" plug and redrilled 
it.  All is now quiet on this piano, but anybody that services new Steinways 
will want to look for this.  
Regards, 
Ed Foote RPT