[pianotech] Curved cast iron plate question

[Mike Spalding]

Chuck,

1/4" seems like a lot, but you can figure out how to get a good fit to 
the pinblock.  I would be more concerned with the string heights and the 
resultant effect on hammer bore distance, assuming that the agraffes and 
v-bar are similarly arched.  Steinway string heights often peak at the 
top of the agraffe section, then taper off a mm or two in the high 
treble, but this one might be extreme.  Don't know how you and Frank are 
dividing up the tasks, but you'll want to coordinate very closely when 
setting pinblock/plate height and boring hammers.

Mike

Chuck Behm wrote:
> Hi - I've got a question for those of you who specialize in Steinway 
> rebuilds. A technician in my Guild chapter brought a plate to my shop 
> asking me to fit a pinblock to it. It's from a Steinway M, and what 
> seems unusual is that the plate is bowed in the webbing area from side 
> to side. I have the plate upside down on sawhorses, and if you put a 
> straightedge from side to side across the area for the pins, there is 
> nearly a 1/4 inch gap in the center. The original pinblock had been 
> shaved down on either end for a tight fit without any filler of any 
> kind. I've got a plan for fitting the new one, but that's not the 
> question. What I'm wondering is how unusual is this? Have any of you 
> seen this type of thing before? The rebuilder who brought it in to my 
> shop has been around longer than myself (Frank Ludnak of Traer, Iowa), 
> and he said he had never seen anything of the kind before. I would 
> have guessed that a plate with that amount of deformity would have 
> been sent back to the melting pot, or was this curvature done 
> intentionally for some reason I'm not grasping?  Chuck