Bridge Pins, was Bridge Capping Materials: Ebony?

[Mark Ultsch]

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A potential problem with (austenitic) Stainless is that there is a =
galvanic reaction with the carbon steel music wire.  The stainless =
eventually will corrode to some degree especially at/near the string =
termination point..

Mark Ultsch
Madison
  ----- Original Message -----=20
  From: Steve Fujan=20
  To: deanmay@pianorebuilders.com ; Pianotech=20
  Sent: Friday, December 02, 2005 11:25 PM
  Subject: Re: Bridge Pins, was Bridge Capping Materials: Ebony?


  Hardened stainless steel gets my vote.  Not only is it harder (hence =
more wear resistant), it is also considerably stiffer than titanium.  =
The more flexible titanium would bend more right where the pin enters =
the wood causing higher stress right where you don't want it.  The =
stainless steel would spread the force over greater depth into the =
bridge.=20

  Plus hardened stainless in these small diameters should be relatively =
easy to make, hence cheaper, er..  less expensive than titanium.

  Steve Fujan (BSME, MSME, PE)
  www.fujanproducts.com

  =20
  On 12/2/05, Dean May <deanmay@pianorebuilders.com> wrote:=20
    >>In other words, the smaller the hardness number the harder the =
steel.

    Ooops. That's backwards. A softer material will have a bigger =
diameter=20
    dent and a smaller hardness number. A harder material will have a
    smaller dent and a bigger hardness number.

    I am suspect of the numbers you are quoting, Ron. The little =
research
    I'm doing shows Vickers hardness of mild steel at 140, Hardened =
steel at=20
    900, and titanium at 970.

    Then on an ask the experts site someone asked the hardness ranking =
of
    various metals. Here is the answer:

    In General- and I have to qualify that by saying I'm considering the =

    metals to be in the annealed condition, the aluminum is 1100 alloy, =
the
    T6 (not annealed, but age hardened) aluminum is a 2000 or 7000 =
series
    alloy, and the titanium is 6Al-4V alloy rather than the commercially
    pure stuff (6-4 is a lot more common than CP)- the order would be
    aluminum, brass, bronze, T6 aluminum, mild steel, stainless steel, =
and
    titanium. If the metals are in their hardest conditions, from heat
    treating or cold work, the order would be aluminum, brass, T6 =
aluminum,=20
    bronze, titanium, mild steel, and stainless steel (cutlery grades).
    (http://experts.about.com/q/2280/1021526.htm)






    Dean
    Dean May             cell 812.239.3359
    PianoRebuilders.com   812.235.5272
    Terre Haute IN  47802


    -----Original Message-----
    From: Dean May [mailto:deanmay@pianorebuilders.com]
    Sent: Friday, December 02, 2005 8:29 PM
    To: 'Pianotech'
    Subject: RE: Bridge Pins, was Bridge Capping Materials: Ebony?

    Hardness in steel is tested by machines that try to put a dent in =
it.
    The bigger the dent, the softer the steel. The hardness number given =
is=20
    inversely proportional to the diameter of the dent left in the =
steel.

    Check out http://www.gordonengland.co.uk/hardness/vickers.htm

    Dean
    Dean May             cell 812.239.3359
    PianoRebuilders.com   812.235.5272
    Terre Haute IN  47802


    -----Original Message-----
    From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] =
On
    Behalf Of Ron Nossaman
    Sent: Friday, December 02, 2005 5:41 PM
    To: Pianotech
    Subject: Re: Bridge Pins, was Bridge Capping Materials: Ebony?=20


    > Titanium probably does resist grooving better that what is
    > usually used for bridge pins.

    I find a Vickers hardness of 60 for titanium, and 98 for mild steel.
    Why would titanium "probably" resist grooving better when it's a=20
    softer material?


    > I've thought about stainless, is it
    > harder than what we usually use?  Any other improvements to =
consider?

    Go here.
    http://www.matweb.com/search/search.asp=20
    Prospect to your heart's content.

    Ron N
    _______________________________________________
    pianotech list info: https://www.moypiano.com/resources/#archives=20



    _______________________________________________
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