"...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." I should have mentioned, as you might be curious how one would hold the ruler in one hand, the opposite thread end in the other and still have an appendage available to use a wedge to measure crown. The best way to do this that I have found is to have an opposing thumb surgically attached to your nose - then all you need to do is wiggle your face up there and measure! Great for itchy noses also! ;-) Terry Farrell P.S.: I'd post a picture, but it's too darn embarrassing....... ----- Original Message ----- From: "Farrell" <mfarrel2 at tampabay.rr.com> To: "Pianotech List" <pianotech at ptg.org> Sent: Saturday, August 04, 2007 1:06 PM Subject: Re: Baldwin SD-10 ruminations (long) > 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 >> >> > > -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20070804/f431ca1e/attachment.html
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