Baldwin SD-10 ruminations (long)

[Farrell]

Hi Rob. I don't feel qualified to fully answer your questions, but I do have 
a couple observations that can help you proceed forward.

Being that you have crown measurements in the unloaded state, I presume all 
the strings have been removed from the piano - is that correct?

It would be helpful to have more crown measurement of the soundboard. I know 
access can be difficult up in the treble, but the killer octave area and the 
high treble is where you really need good measurements - especially the 
killer octave - as when sound/tone is lacking in a piano, it is most often 
up in these areas. The belly rail underhang (is that a word?) under the 
soundboard often makes crown measuring difficult as you proceed toward the 
treble end of the soundboard. One can often get good measurements up there 
by attaching a thread around (really over) the tip of a stick - something 
like a wooden ruler - tape the thread to the bottom side of the stick - 
press the upper side of the thread end of the stick up against the 
soundboard panel between two ribs and push the stick over the belly rail 
until you hit the rim, all the while maintaining stick tip pressure on the 
soundboard panel bottom. Stretch the other end of the thread out to the 
other end of the panel and measure downbearing - best done with a wedge.

If the soundboard has no crown unloaded in the killer octave area you may 
need a new soundboard.

Some years ago when I used my first Lowell Downbearing Gauge, I initially 
got more erratic measurements than any that made any sense. I found that it 
really took quite a bit of practice to use it reliably. Your measurement do 
sound erratic - but of course, it may well be the piano that is erratic, 
rather than your downbearing measurement technique. A good check on that is 
to use a rocker gauge, or better, a digital angle gauge - the angle gauge 
really should roughly agree with your Lowell measurements.

If your Lowell measurements accurately reflect downbearing in this piano, in 
addition to perhaps adjusting plate height, you appear to be needing some 
bridge top height/angle adjustment - perhaps a new bridge cap is in order so 
downbearing can be set optimally.

If this piano does need a new soundboard, and especially if the owner is 
interested in top performance - and if so, even if the old soundboard is 
still "functional" - you might want to talk to someone like Ron Nossaman or 
Del Fandrich (Del is a lot closer to you than anyone else) about doing some 
redesign work and having a rib-crowned soundboard system installed.

A question that often bounces around in my head when contemplating replacing 
a 35 year old soundboard that has failed, is whether it is the wisest choice 
to replace it with one of the same (or nearly so) design. And yes, I am 
clearly biased toward the benefits of  rib-crowned belly systems in pianos.

Just a few things to think about.

Terry Farrell
Farrell Piano

----- Original Message ----- 
From: <atonal at telusplanet.net>
To: <pianotech at ptg.org>
Sent: Saturday, August 04, 2007 10:37 AM
Subject: Baldwin SD-10 ruminations (long)


> Greetings all,
>
> It's been quite a while since I've posted, although I sporadically check 
> the list and I'm
> pleased to see the new techs along with some old-timers (mind you, 10 
> years is
> forever for a internet listserve).
>
> Today's project is a 1972 Baldwin SD-10. We have acquired this piano from 
> a local
> church that has changed venues and traded the piano on other musical 
> equipment.
>
> Condition of the piano is beaten. Over the years, top treble restringing 
> has ocurred,
> hammers have been extensively hardened, critters have taken up residence 
> in it for
> a time mauling the damper felt, and overall tone and power are bright and 
> weak.
>
> Leaving aside action considerations for a moment, I am now in the analysis 
> phase of
> the soundboard and downbearing. The board is free from separations, and I 
> have
> found no change in crown measurements from the loaded state (4-6 mm in 
> central
> sections of the board) to unloaded. I am getting the same crown 
> measurements with
> the strings off as with them on.
>
> Bearing analysis shows some whacky results. Using my newly-acquired Lowell
> Composite Bearing Gauge (shout out to Piano Tek!) The front bearing is 
> nicely
> positive in the top two sections, zero to negative in the tenor and mid 
> sections, and
> back to decently positive in the bass. Back bearing shows the opposite, 
> negative in
> the top 2, positive in the centre and tenor, and positive in the bass. 
> Now, the Accu-
> Just pins won't be able to cure all of the back bearing problems, as they 
> are at the
> bottom of the pin on the top two sections (the re-strung ones) and the 
> rear bearing is
> still negative! Judging by feel, I can't discern any bridge roll or 
> rippling/cracking of the
> soundboard at the bridge. So now I have to decide of I can change the 
> plate height to
> correct these bearing problems, or if a new soundboard is in order.
>
> Having mulled this over for the past week, the problems boil down to this:
>
> Lowering the plate will increase front bearing in the centre where needed, 
> but also
> severely increase the front bearing in the top, which is currently nicely 
> positive.
> Lowering the plate will also allow me to increase rear bearing in the top 
> treble and
> allow the Accu-Just pins to be set properly. The tenor and bass Accu-Just 
> pins were
> near the top of the pin, and bearing was positive. If I keep the existing 
> board, I will
> have to cant the plate, lowering the front (more on the bass side) and 
> bringing down
> the rear on the treble side, if possible.
>
> As much as I'd like to pack the whole thing off to Bolduc for a new board 
> and
> bridges, I have to make my business case to the powers that be (i.e. he 
> who writes
> the cheques.)
>
> Still in the analysis phase currently, anyone with experience in resetting 
> threaded
> plate systems please chime in.
>
> Regards,
>
> Rob Kiddell RPT
> Edmonton, Canada
> atonal at telusplanet.net
>
>