Cracked plate

[John Delacour]

At 7:13 AM -0600 12/13/01, Todd Mapes wrote:

>This week I experienced my first cracked plate. ...  I then 
>explained the pitch raise procedure that I performed and told him 
>that to the best of my knowledge, I had exercised due professional 
>care ....
>So, that brings me to the questions - Have you or anyone you know 
>been sued because of a cracked plate?  If so, how did you defend 
>yourself in court and what was the ultimate outcome?

I'm sure your client hasn't a leg to stand on.  If a plate cracks, it 
is almost certainly the maker's fault and in this case the plate 
almost certainly had a crack 3/4 the way through the metal either 
since new or for a long time.

In Europe every technician is familiar with cracking plates in 
certain old Bechstein grands.  These plates were installed "green", 
ie. without being weathered, and besides, the pattern-maker made the 
corners far too sharp and inadequately filleted so that the plates 
have terrific internal stress from the beginning.  These plates can 
crack in four or five places.  If one of these should open up during 
a pitch raise or a move or just spontaneously, that's just the 
owner's bad luck.

Whenever I restring a piano now, I warn the customer that in the very 
unlikely event of the plate breaking, I will take no responsibility. 
I was very lucky once to notice an incipient crack in a bar of an 
Ibach grand I was about to rebuild.  I phoned the customer and warned 
her the bill would be higher, since I'd need to have the plate 
stitched.  Indeed, when I took off the tension, the crack widened and 
the bar parted.  I thanked goodness I'd covered myself.  The cause of 
the original crack was pure maker error;  the plank did not mate with 
the underside of the plate and the forcible screwing down of the 
plate to the plank when the piano was made had introduced an 
insupportable stress.

The piano you are dealing with is obviously for the scrap heap, but 
cracked plates can be stitched successfully using the Metallock 
process.  This involves a special dumbbell-shaped ( =O=O=O=O= ) 
"rivet" of high-tensile nickel which joins the two parts together. 
Metallock have centres in various places and a man comes out to the 
job. Very impressive and, in my limited (thank goodness) experience, 
quite successful.  Cast iron CANNOT be welded or brazed.

Good luck with your client.  The best thing is to get one or two 
reputable technicians to write to you explaining the situation and 
show the letters to your client.  If he's adamant, it's his own 
look-out.  You can sleep easy.

JD