Capo Hardening, was: Tuning problems under capo bar

[Delwin D Fandrich]

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Re: Capo Hardening, was: Tuning problems under capo ba
  ----- Original Message -----=20
  From: Ron Overs=20
  To: Pianotech=20
  Sent: January 25, 2003 4:03 PM
  Subject: Re: Capo Hardening, was: Tuning problems under capo bar




     Alternatively, does anybody ever grind the original capo off and =
overlay a hardened bar, fitted for height?=20


  We do this all the time with the front duplex bars, you can place them =
in best position for de-tuning and at the shortest possible length. The =
Steinway D we did late last year has the cleanest treble we've ever =
heard on a D. I ground the original duplex bars off and filled the plate =
topography with body filler before positioning the bars. Looks very tidy =
and I like to clarity now.
  =20

Those are the counterbearing bars. And we always grind those off and =
replace them with brass half-ovals to increase the string deflection =
angle and shorten the front duplex string length as much as is =
practical.

We've also replaced the V-bars from time to time. The process is simple =
but time-consuming: The original V-bars are ground off and new ones are =
fabricated from some suitable material.=20

I'm not looking for something quite as hard as Ron is so my material of =
choice is either silicon bronze or manganese bronze. Both are harder =
than the gray iron used in piano plates. A wood pattern is made using =
the sweep of the original V-bar as a guide (unless that is what we are =
correcting) and new bars are cast at a local brass/bronze foundry. They =
are pinned to the bottom of the capo tastro bar to hold them in place =
during stringing. Once the piano is strung the force of the strings will =
be adequate to hold them in place though we do use a steel-filled epoxy =
between the casting and the capo tastro to improve mechanical coupling.

Del

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