Baldwin accu-hitch pins

[David Love]

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Dale:

I believe the Baldwin instructions call for setting the bearing at zero =
degrees to begin with.   After pulling the piano to pitch you then start =
at the bottom of the tenor (no bass strings yet).  Tap down note 21 - 35 =
to 1/2 degree, 36 - 53 to 1 degree and 54 - 88 to 1 1/2 degrees--in that =
order.  Thus, the 1 1/2 degrees that you set the upper range to is on a =
semi-compressed board, at least to the degree that setting the bearing =
on the previous sections will compress it.  So notes 54 -88 are actually =
set at greater than 1 1/2 degrees if you were measuring from the point =
before the board had any downward pressure it.  Moreover, if you were to =
go string by string, the measurable bearing after you got to the top =
would be something less than your initial target.  The question seems to =
be, when the board is already set with some bearing, but perhaps the =
wrong bearing, how do you approach the problem?  Can you simply go =
through and correct the bearing to read 1/2, 1, 1 1/2 degrees =
respectively?  I often wonder whether we fret over this a bit too much.  =
I've heard good sounding boards with a variety of downbearing =
measurements.  Though I have not heard one of David Hughes' boards, the =
impression I get from him is that we sweat over this a bit more than is =
necessary.  The factors that go into a good sounding board are obviously =
greater than just the bearing measurements.  Teasing out the variables =
is difficult, to say the least. =20

David Love


  ----- Original Message -----=20
  From: Erwinspiano@AOL.COM=20
  To: pianotech@ptg.org=20
  Sent: January 19, 2002 2:07 PM
  Subject: Re: Baldwin accu-hitch pins


  In a message dated 1/19/2002 11:23:14 AM Pacific Standard Time, =
RNossaman@KSCABLE.com writes:



    Subj:Re: Baldwin accu-hitch pins=20
    Date:1/19/2002 11:23:14 AM Pacific Standard Time
    From:RNossaman@KSCABLE.com
    Reply-to:pianotech@ptg.org
    To:pianotech@ptg.org
    Sent from the Internet=20




    >
    >  Ron (somebody) tell me what I'm missing on the acujust in a way I =
can absorb
    > it. What's that you say? not possible. hmmmmmmm
    >       =20
    >        Dale Erwin


    Dale,
    I'm not sure what the question is here. Like you have adjusted plate =
height to
    fine tune bearing, you can do the same thing section by section, or =
note by
    note with the hitch pin adjustment. Your initial plate height is =
determined
    just like you would normally do it, only your back scale target =
isn't the top
    of an aliquot, but a vertical position on the hitch.


  Hi Ron
    Ok I get this sort of but the place where I'm hung up is that as you =
start driving the strings down on the hitch your bearing increases as =
does the amount the board is compressing as you go. Just like in pitch =
raising. So how do you know when enough is enough and when do you know =
that there is enough ,of the desired deflections so often discussed. =
Meaning a 1 to 11/2 degree angle of deflection depending where in the =
scale we are talking about.
  Dale
  If you shoot for somewher

    around 4mm up the hitch as a target, you have some room for final =
vertical
    positioning as you find necessary.=20

  Ron
     Once again how could a person possibly know what the final position =
is?


  Does that make sense? =20
       Ron

       Uhhh not yet Ron.  I must be coming at this from a really strange =
angle of comprehension. I took Stacy Yokums class in Reno and he =
couldn't answer my question either. I wasn't the only one asking it =
either.
    Let me try another way by explaining where I'm coming from.
    Ok Take a new board and new set of too tall bridge caps. Install =
plate and cut the tops so that without any load on the board you have a =
1 degree angle of deflection in the lower tenor rising to 1& 1/2 degrees =
thru the tenor right  up to note 88. Now install all the strings from =
the tenor /bass break to 1st capo section at. Tune these up to pitch. =
Before you string further take a bearing string and check the remaining =
deflection. Meaning once again that the soundboard is sinking under down =
bearing pressure as we go. If done this way I can guarantee an =
insuffiecnt amount of bearing to drive the treble in your shiny new =
board. The bearing string will probably touch bridge and aliqot at the =
same time or almost but that isn't enough bearing for trebles.
      In fact I you can't even read much deflection with the string at =
all. Unfortunately this is the very method Nick Gravagne outlined in the =
journal many years ago and it doesn't work unless you pre- stress the =
board some. He didn't correct or I should say amend it and I only found =
out he was using pre stressing and the 1 1/2 degree angle of deflection =
in one of my conversations with him a year or so ago.
       MY point oh yes is how in the acujust system does one approximate =
total and adequate deflection with any confidence that your not creating =
the problem I described above.=20
     My answer so far is that you can't. Its more of a guesstimate than =
I'm willing to make until somebody can give me some clarification.
    Does this help to see my angle of deflection!!!!!!!
            =20
                       Dale Erwin



    Ron N




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