Baldwin SD-10, was circle of sound

[Overs Pianos]

Hi Serge,

>I just lifted my first SD-10 (20 years old) plate last week, very heavy
>piece of material and impressive engineering set-up.
>The duplex gismos make me perplex...
>Just got the information from Baldwin, that piano should have a very
>small amount of down bearing example: for a bass string 1 pound of down
>pressure on the bridge (maybe I misinterpret the info here) seen to be
>too small. 
>
>Could you please be more specific about the improvement you made on this
>particular piano?
>
>Serge Harel

We recapped both bridges, retained the sound board but glued the back 
section to the inner rim again since it had de-laminated behind the 
bass bridge. We changed the hammers for Imadegawa walnut cores. But 
the most important change was the forged inserts in the top two 
treble sections. The original bearing radius on these was, in my 
opinion, way too large. So I ground them to a smaller radius with an 
angle grinder. The bass metal is quite hard on the forgings, so they 
remained quite effective at resisting the cutting action of the 
strings. Originally, these were electroless nickel plated. We didn't 
re-plate them, but we will when it is re-strung again.

Each forging is straight and not curved. So the hammer strike line in 
each string section must be curved to achieve the correct strike 
ratio. The new strike line was derived by testing samples of the new 
hammers and moving the action in and out while playing, until the 
optimum position was determined for each sample hammer, to determine 
the required curve.

This SD we rebuilt (in 1988) had one of the finest tonal qualities of 
any instrument we have rebuilt. But the Renner action/key board 
combination was a bit of a disaster. There is something wrong with 
the hammer/key ratio which causes it to be exceedingly heavy. At the 
time we weren't familiar with trouble shooting actions, but we'll be 
fixing it shortly.

I owned the piano until 2003, when I sold it as is. We are just about 
to redo the piano again for the new owner. This time I've designed a 
new keyboard which will allow us to fit our Overs action to the 
SD-10. Rick Wheeler is going to build a keyboard for me once I get 
our bureau to output it at the exact size required for the clear film 
template. At the same time as the SD board was drawn, I designed a 
key board for fitting our action to a Steinway D.

Ron O.
-- 
OVERS PIANOS - SYDNEY
    Grand Piano Manufacturers
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Web http://overspianos.com.au
mailto:ron@overspianos.com.au
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