<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: String vibrations (was Re: Stuart)</title></head><body> <blockquote type="cite" cite>At 7:23 AM -0400 24/9/03, Farrell wrote:</blockquote> <blockquote type="cite" cite><br></blockquote> <blockquote type="cite" cite>Is anyone aware of the shape of these agraffes where the string contacts the</blockquote> <blockquote type="cite" cite>agraffe?</blockquote> <div><br></div> <div>The early Stuart agraffes had small-radius ceramic inserts on the speaking length side, which I considered to be somewhat of an overkill. The recent versions have a steel pin, but I don't know if they are hardened or in an annealed condition.</div> <div><br></div> <div>At 10:59 AM -0400 23/9/03, Erwinspiano@aol.com wrote:</div> <blockquote type="cite" cite><font face="Times New Roman" color="#000040">     <font size="+1">  Hi  Ron O</font></font><font face="Arial"><br> </font><font face="Times New Roman" size="+1" color="#000040">   I have a (1950s I think) 6ft Sohmer I posted about earlier that has brass bridge aggraffes in the tenor  and first capo section but not in the bass.  Since Phil Ford was in the shop the other day we looked at the bottom of it and it has a what looks like a 1/4" maple piece running under the bridge on the bottom of the board. He said it might be there to keep the bridge from rolling backwards because of the way the pressures are applied to the bridge.</font></blockquote> <div><br></div> <div>It may have been of sufficient dimensions so as to enhance the rigidity of the bridge system. How high was nominal height of the Sohmer bridge wood, and what were the sectional sizes of the 1/4" maple under the panel?</div> <div><br></div> <blockquote type="cite" cite><font face="Times New Roman" size="+1" color="#000040">   In this config. the strings come thru the agraffe and then up over a sligthly rounded hump then on to the hitch.</font></blockquote> <div><br></div> <div>In this configuration at least it would reduce the tendency of the agraffe's vector forces to pull the bridge off the panel. The early Stuart agraffes had only one string deflection also, but they ran the opposite way. In the latest design the deflection is similar to the agraffe image Ron N. posted earlier today. That was a very neat and cheap-to-build design uncle Ron, since it could be manufactured in two press strokes only.</div> <div><br></div> <blockquote type="cite" cite><font face="Times New Roman" size="+1" color="#000040"> This piano has a reverse crown board as well & sings like a soprano. In a previous Sohmer (also with reverse crown) I rebuilt ,the aggraffes screwed into the bridge with very fine machine threads.  Can you imagine how time consumning that was. Well at least possible if they was turned into the bridge with a drill etc. My point is they were still solid in the bridge and worked well after 70 yrs.</font></blockquote> <blockquote type="cite" cite><font face="Times New Roman" size="+1" color="#000040">    Why wouldn't this system be a candidate for some one like you?</font></blockquote> <div><br></div> <div>May be it would, but I really haven't gotten around to addressing a bridge agraffe design yet, since I am still grappling with our new sound board design (the first version is going into piano no. 4 - should be glued into the case in the next few days). Just today I finalised the rib feathering after clamping the board into the case a couple of times and being dissatisfied with the deflection of the board under test loads. Fortunately, I chose initially to make the feathering shorter, paring it gradually longer until I was satisfied (for now) with the panel deflection.</div> <div><br></div> <div>I'm looking forward doing something about conventional bridge pins and falseness, which is endemic.</div> <div><br></div> <div>Ron O.</div> <x-sigsep><pre>-- </pre></x-sigsep> <div><font face="Times New Roman" size="+1" color="#0000FF"><b>OVERS PIANOS - SYDNEY</b></font></div> <div><font color="#000000"><i>   </i></font><font color="#0000FF"><i>Grand Piano Manufacturers</i></font><font color="#000000"><br> _______________________</font></div> <div><font size="-2" color="#000000"><br> </font><font color="#000000">Web http://overspianos.com.au</font></div> <div><font color="#000000">mailto:info@overspianos.com.au<br> _______________________</font></div> </body> </html>