This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment ----- Original Message -----=20 From: Erwinspiano@AOL.COM=20 To: pianotech@ptg.org=20 Sent: July 19, 2002 8:22 AM Subject: Re: Untapered Soundboard Ribs In a message dated 7/19/2002 7:18:05 AM Pacific Daylight Time, = caute@optusnet.com.au writes: Subj:Re: Untapered Soundboard Ribs=20 Date:7/19/2002 7:18:05 AM Pacific Daylight Time From:caute@optusnet.com.au Reply-to:pianotech@ptg.org To:pianotech@ptg.org Sent from the Internet=20 Hi Tony Thanks for the post. Interesting trip? I don't think this all = that new. I've seen Baldwin L grands with the same deal. It might be a = Del Fandrich idea but I'm not speaking for him of course. Actually when = you think about it that little piece of thin rib that goes into the = liner is only a small part of the equation as far as the strentgh needed = to hold the board on the rim. The glue is doing 95% of .the work. Radio = speaker thing and labor saving method. No fitting notches to the rib and = the board can float a bit during installation hhm not good. Dale No, this was Baldwin practice before I got there. The only problem with = this practice was found along the inside curve on the treble side where = the soundboard grain angle roughly paralleled the inner rim--there was a = propensity toward soundboard cracks just inside the inner rim. That is, = between the end of the ribs and the inner rim.=20 The practice of inletting the ribs to the inner rim is a holdover from = the animal hide glue days. If the glue wasn't kept fresh and used = properly--very difficult to do in high production--they tended to pop = off as the glue aged and turned brittle. Originally the ends of the ribs = were fitted so that the thickness of the feather was exactly the = thickness of the notch in the inner rim. In other words, the rib would = be glued to the soundboard and clamped between it and the bottom of the = notch where it would also be glued. A practice rarely seen today. These = days the notches are most often routed in to a depth that will easily = clear the rib and the rib does not actually touch the bottom of the = notch.=20 The practice does add stiffness to the soundboard system which, in some = cases may be desirable. I designed the Walter 190 soundboard such that = the top seven ribs (toward the treble) were set into to notches both = because I wanted the additional stiffness and to avoid the cracking = problem the Baldwin M, R and L models were having. (The SF-10 and SD-10 = ribs were fully inlet to notches.) The rest of the ribs I floated = because I did not want the added parameter stiffness.=20 I've always puzzled over the practice of thinning part or all of the = outside parameter of a soundboard and then running a bunch of ribs over = the thinned portion and onto the inner rim. Only Marketing Logic can = explain the thinking behind that practice. There is no reason to inlet the ribs of a laminated soundboard to the = inner rim. There are many reasons to not do so. Re: your last comment: Only the glue between the soundboard and the = inner rim/soundboard liner is holding the soundboard to the inner rim. = It's doing 100% of the work. The notch in the inner rim/soundboard liner = is only detracting from there being a continuous glue bond holding the = soundboard to the inner rim.=20 Del ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/00/f2/f1/29/attachment.htm ---------------------- multipart/alternative attachment--
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