[CAUT] Baldwin SD (agraffe refurbishing)

[Andrew Anderson]

Ron,
Are your interested in selling plated agraffes?

Andrew Anderson
TAMIU & LCC

At 03:44 PM 4/6/2006, you wrote:
>Hello Mark and all,
>
>>. . . How long does that nice crisp "hour-glass" profile last? IOW, 
>>does the "V"
>>shaped termination quickly become a "U" shape after a few tunings and some
>>string-lifting?
>
>With free-machining brass agraffes, the profile lasts about and 
>until the piano is first chipped to pitch. We've experimented by 
>pulling-out agraffes from a freshly chipped instrument. The profile 
>is basically mangled at the outset.
>
>This is why when using standard agraffes we'll get a couple of 
>'zingers' as soon as the piano is tuned for the first time.
>
>For some years we've been getting the agraffes plated with 
>electroless nickel (which plates with a uniform thickness even 
>inside the string holes) to a thickness of 2 thou' (0.05 mm). This 
>was certainly helping the situation. Recently we've been getting 3 
>thou' plated to prevent the string from crashing through the hard 
>plated surface into the soft brass beneath. The plating bath needs 
>to be correctly balanced and continually filtered down to 1 micron 
>with a minimum of 10 bath change-overs per hour, to ensure that a 
>quality job is achieved with such a thick plating build.
>
>EN nickel has an as plated hardness of just over 40 on the Rockwell 
>C scale. It can be heat treated to around 60 Rockwell by heating it 
>to 260 degrees C for four hours. The mid phosphorus EN seems to give 
>the best results with agraffe plating.
>
>The piano we are bringing to Rochester in June will have EN plated 
>and hardened agraffes, front duplex bars, mid section counterbearing 
>metal profile, keyboard glide bolts and key capstans. EN is 
>particularly suited to these high wear applications since it 
>provides good corrosion resistance (much better than chrome), high 
>hardness after heat treating and a friction coefficient which is 
>around 70% lower than polished steel. In all its a wonderful process 
>for piano manufacturing/rebuilding.
>
>Ron O.
>--
>OVERS PIANOS - SYDNEY
>    Grand Piano Manufacturers
>_______________________
>
>Web http://overspianos.com.au
>mailto:ron at overspianos.com.au
>_______________________
>