<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style></style></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1>And so it would seem that, in a bridge agraffe system like the phoenix, energy coupling is a function of string offset, albeit in the vertical plane.  <o:p></o:p><o:p> </o:p>Thanks, Del.  <o:p></o:p><o:p> </o:p>Will<o:p></o:p><o:p> </o:p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Delwin D Fandrich Sent: Tuesday, January 08, 2013 5:59 PM To: pianotech@ptg.org Subject: Re: [pianotech] Worst Bass/Tenor Crossover in Universe<o:p></o:p></div></div><o:p> </o:p>I think this refers back to the notion that string bearing is necessary to closely couple the strings to the bridge; i.e., it is necessary to transfer energy from the vibrating strings to the bridge. But this is not the case at all. Energy coupling from the strings to the bridge is almost entirely a function of string offset between the bridge pins. <o:p></o:p><o:p> </o:p>I started working with bridge agrafes in the mid-1980s. I've not conducted any experiments specifically to ascertain the effect of string bearing on their energy transfer efficiency but nothing led me to believe that they were affect by string bearing any differently than were standard bridge pins. <o:p></o:p><o:p> </o:p>As far as I can tell the need for—or benefits of—string bearing are dependent on the type of soundboard system being used and how, or if, it is being crowned. The method of string-to-bridge coupling has little to do with it. <o:p></o:p><o:p> </o:p>I could be wrong, of course, and I’m willing to be convinced. But it will take more than marketing gobble-d-gook to convince me.<o:p></o:p><o:p> </o:p>ddf<o:p></o:p><o:p> </o:p>Delwin D Fandrich<o:p></o:p>Piano Design & Fabrication<o:p></o:p>6939 Foothill Court SW, Olympia, Washington 98512 USA<o:p></o:p>Phone  360.515.0119 — Cell  360.388.6525<o:p></o:p><a href="mailto:del@fandrichpiano.com">del@fandrichpiano.com</a> — <a href="mailto:ddfandrich@gmail.com">ddfandrich@gmail.com</a><o:p></o:p><o:p> </o:p><o:p> </o:p>-----Original Message----- From: <a href="mailto:pianotech-bounces@ptg.org">pianotech-bounces@ptg.org</a> [<a href="mailto:pianotech-bounces@ptg.org">mailto:pianotech-bounces@ptg.org</a>] On Behalf Of Encore Pianos Sent: Tuesday, January 08, 2013 11:59 AM To: <a href="mailto:pianotech@ptg.org">pianotech@ptg.org</a> Subject: Re: [pianotech] Worst Bass/Tenor Crossover in Universe<o:p></o:p><o:p> </o:p>I have heard that agraffe bridge systems like the Stuart is designed to be used at "zero bearing" ( I believe that Stuart claims to be such, if I am not mistaken).  But I have never understood why, if all else about a soundboard assembly is equal in design and construction, that this would be the case.  It seems to me like they would have more or less the same requirements of bearing and crown to drive the board. <o:p></o:p><o:p> </o:p>Indeed, the 7' 6" Steingraeber Phoenix that I saw at Larry Buck's shop in Lowell, Massachuesetts last May appeared to be ribbed "normally" in width and height and number, although I did not take any measurements to verify this.  Additionally, there was an adjustable vertical hitch pin of Richard Dain's design, which would suggest that careful setting of downbearing was considered important (again, I took no measurements to verify this).  The Dain agraffe used by Steingraeber is very similar in design to the Stuart.  <o:p></o:p><o:p> </o:p>Del, I would be grateful if you could explain why the loading requirements for an agraffe bridge system would be different from a traditional bridge with pins and side bearing, if that is the case.<o:p></o:p><o:p> </o:p>Will Truitt<o:p></o:p><o:p> </o:p><o:p> </o:p><o:p> </o:p>-----Original Message-----<o:p></o:p>From: <a href="mailto:pianotech-bounces@ptg.org">pianotech-bounces@ptg.org</a> [<a href="mailto:pianotech-bounces@ptg.org">mailto:pianotech-bounces@ptg.org</a>] On Behalf Of Delwin D Fandrich<o:p></o:p>Sent: Tuesday, January 08, 2013 2:04 PM<o:p></o:p>To: <a href="mailto:pianotech@ptg.org">pianotech@ptg.org</a><o:p></o:p>Subject: Re: [pianotech] Worst Bass/Tenor Crossover in Universe<o:p></o:p><o:p> </o:p>1)  The only place where panel cracks are a concern are in those limited areas where the grain angle of the panel roughly parallels the inner rim. In most pianos this condition is only found on the inside curve of rim on the treble side. And sometimes along a soundboard cutoff bar. Other than these two areas there is no need to set the ends of the ribs into rim notches unless your intent is to stiffen the assembly. <o:p></o:p><o:p> </o:p>2)  No bridge termination system is "designed to be used at zero bearing."<o:p></o:p>The termination system doesn't really care whether there is string bearing or not. String bearing has to do with the physical interaction between the vibrating strings and the resulting motion of the soundboard assembly. <o:p></o:p><o:p> </o:p>Cantilevered bass bridges have long been set up with "zero bearing." Fifty years ago old-timers were warning us young whipper-snappers of the dangers of putting any string bearing on cantilevered bass bridges. Even if you were to load up a cantilevered bass bridge with a bunch of string bearing it wouldn't last long; the thing just rotates and the soundboard assembly just distorts and it all goes away.<o:p></o:p><o:p> </o:p>Delwin D Fandrich<o:p></o:p>Piano Design & Fabrication<o:p></o:p>6939 Foothill Court SW, Olympia, Washington 98512 USA Phone  360.515.0119 — Cell  360.388.6525 <a href="mailto:del@fandrichpiano.com">del@fandrichpiano.com</a> — <a href="mailto:ddfandrich@gmail.com">ddfandrich@gmail.com</a><o:p></o:p><o:p> </o:p><o:p> </o:p>-----Original Message-----<o:p></o:p>From: <a href="mailto:pianotech-bounces@ptg.org">pianotech-bounces@ptg.org</a> [<a href="mailto:pianotech-bounces@ptg.org">mailto:pianotech-bounces@ptg.org</a>] On Behalf Of Jim Ialeggio<o:p></o:p>Sent: Tuesday, January 08, 2013 9:56 AM<o:p></o:p>To: <a href="mailto:pianotech@ptg.org">pianotech@ptg.org</a><o:p></o:p>Subject: [pianotech] Worst Bass/Tenor Crossover in Universe<o:p></o:p><o:p> </o:p><o:p> </o:p>... I am also edging closer to selectively bagging rim notches in cross grain areas where stiffness is required(ribs), but freedom of movement is desirable. (but still a bit concerned about panel cracks at the rim<o:p></o:p>joint)<o:p></o:p><o:p> </o:p>Also, there might be a completely different approach. Since the Phoenix agraffes are designed to be used at zero bearing, the zero bearing could conceivably allow a high bass cantilever without the roll tendency???maybe??? Though in a sh-t box like Terry's victim, the point is largely hypothetical.<o:p></o:p><o:p> </o:p>Jim Ialeggio<o:p></o:p><o:p> </o:p><o:p> </o:p><o:p> </o:p><o:p> </o:p></div></body></html>