plywood keys???

[Overs Pianos]

>Why would it do away with the flex?
>
>Terry Farrell
>
>----- Original Message -----
>From: "Horace Greeley" <hgreeley@stanford.edu>
>To: "Pianotech" <pianotech@ptg.org>
>Sent: Wednesday, September 15, 2004 2:54 PM
>Subject: Re: plywood keys???

Hi Terry, Horace et all.

The Grotrian 275 that we rebuilt in 1995 had the keys that Horace is 
referring to. They have a hardwood laminate (about 3 mm thick) on the 
top and bottom layer of the key stick. This is indeed a very good 
idea. Because the maximum stress in any loaded beam is at the top and 
bottom edge of a beam, the key stiffness can be improved considerably 
with a minimum mass penalty if this layered approach is taken to the 
manufacture of keyboards. Indeed, keys could be made using a very 
light wood in the core of the key with hardwood (eg. rock maple) 
outer layers to achieve a key set with a very high stiffness per unit 
mass. I manufactured the key stick for the action model I took to 
Reno in 2001 in this way, using Australian King Billy Pine for the 
core and Rock Maple for the top and bottom. The depth was only 24 mm 
but the stiffness was/is impressive. I like the idea. It hasn't found 
its way into our pianos yet, but it has been on the 'ideals' list for 
some time. Thank you Grotrian for contributing to the evolutionary 
knowledge pool.

As an added bonus, the upper hardwood layer provides a very stable 
substrate for the white key tops, while the bottom layer helps to 
reduce balance pin hole wear/deformation.

Best,
Ron O.

>
>>
>>  Sarah,
>>
>>  At 11:04 AM 9/15/2004, you wrote:
>>  >Hi Don,
>>  >
>>  >If it were a grand, I'd see some utility to having laminates oriented
>>  >obliquely in a largely longitudinal direction, making dog-legged
>keysticks
>>  >more rigid.  But of course these keysticks would be pretty straight,
>>  >wouldn't they...
>>
>>  They weren't when Grotrian used this system...which I think they still
>>  do...very stable, pretty much does away with "flex" in the keystick, much
>>  more solid height and dip with less work.
>>
>>  Best.
>>
>  > Horace


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