[pianotech] Curved cast iron plate question

[Ron Nossaman]

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


Hi Chuck,
I doubt you'll hear from many "Steinway Specialists", but a 
number of us "Generic Trench Troops" have seen this. It wasn't 
intentional, it's a random casting cooling event. Some are 
pretty flat, some aren't. You'll get plates that twist and 
curve in all sorts of directions. The block will conform to 
the plate if it's just screwed to it, but If you expect to 
have the block end up flush with the underside of the 
stretcher, you'll have to taper it like the factory did. This 
is a good excuse to look at power hand planers, if you haven't 
already.
Ron N