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Subj:Re: Baldwin accu-hitch pins
Date:1/19/2002 3:28:10 PM Pacific Standard Time
From:<A HREF="mailto:davidlovepianos@earthlink.net">davidlovepianos@earthlink.net</A>
Reply-to:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A>
To:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A>
Sent from the Internet
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.
>>>>>>>> Thanks David now this is starting to make some logical sense, to me
at least. Wow 1/2 half degree isn't much for starters on a board with real
crown values. An easy way to calculate 1&1/2 degrees of bearing is to measure
the rear string length from the front bridge pin to the aliqot i.e. measure
any tenor back scale length say of 6 inches. Multiply by.026 = .156". So 1/2
degree would only be .50. It would be easy to deflect the whole central
portion of the board by that much by just leaning on it with hand pressure.
By the way 1 degree is calculated by .017 times the length.
Thus, the 1 1/2 degrees that you set the upper teble range to is on a
semi-compressed
> board, at least to the degree that setting the bearing on the previous
> sections will compress it.
>>>>> True
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.
>>>>Yes but the net result would be less than that because of board
compression. This would be barely enough pressure to"take the slack out of
the board " as John Hartman says ,let alone utilize all the crown that was so
carefully built into it. What I want is to press the board fimly so that it
is spring loaded enough to push back against the string. When this happens
the board are in firm resistance to each other and this is when I believe
that optimum power/sustain are approached, especially in new fully crowned
boards. With respect to my method of setting bearing ,at the point the
Baldwin boards bearing is set is the point at which I would probably start
adding 1 1/2 degrees of bearing but not exeeding 1/4" on the longest string
lengths.
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?
>> I agree. A bit of a sticky wicket
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 respectfully have to say I don't think so. If you have the
chance to change one of these and improve it in the process you'd answer
your own question.
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.
>>>>Yes but is bearing where you'd have me sweat less on if it was your
board project? There are several obvious primary factors that we all consider
essential. Good construction,materials ,crown ,adequate bearing,reg. and of
course voicing.
Davie Hughes and have talked bearing at length and our methods are very
similar if not identical. His boards sound very fine. Wonderful sustain and
color. I have to say he may have been understating it a bit.
Bearing/plate set up setting in my shop takes a good long time as I
consider it a VERY primary and critical component of making the whole system
work well. I've looked at a lot of torn a part pianos over the years and
90% of those that I liked the best had significant even measurable bearing
and crown. The other 10% are anomallies. I.e Board stiffness due to mass not
crown or bearing
I"ve also had the advantage of a few less than stellar results (which is
aggravating) that I could lay at the feet of uneven or inadequate
bearing/panel compression that when remedied the tonal results were greatly
improved.
To me a new board with inadequate bearing is like a fine new car wth only a
gallon of gas in the tank. It won't take you very far.
Thanks again for enlightening me to the Baldwin method. I now have a better
grasp of there concept though I consider it misguided.
Best---Dale Erwin
>
>
> David Love
>
>
>
> >> ----- Original Message -----
>> From: <A HREF="mailto:Erwinspiano@AOL.COM">Erwinspiano@AOL.COM</A>
>> To: <A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A>
>> 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, <A HREF="mailto:RNossaman@KSCABLE.com">
>> RNossaman@KSCABLE.com</A> writes:
>>
>>
>> >>> Subj:Re: Baldwin accu-hitch pins
>>> Date:1/19/2002 11:23:14 AM Pacific Standard Time
>>> From:<A HREF="mailto:RNossaman@KSCABLE.com">RNossaman@KSCABLE.com</A>
>>> Reply-to:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A>
>>> To:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A>
>>> Sent from the Internet
>>>
>>>
>>>
>>>
>>> >
>>> > 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
>>> >
>>> > 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.
>> Ron
>> Once again how could a person possibly know what the final position is?
>>
>>
>> Does that make sense?
>> 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.
>> 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!!!!!!!
>>
>> Dale Erwin
>>
>
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