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 >_______________________ >
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