<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <body bgcolor="#FFFFFF"> Thanks Delwin. <p>Does this item have a specific / proper name ? And as to whether its turned to tight, I had thought about taking a quick look with a rocker gauge at string angles off the bridge in the area and compare to the area immediatly around it. My understanding is that it was snug, but the bolt could be turned with a wrench without much difficulty, and the rep decided to give it a whole turn. Given the possible negatives here with regard to bearing I thought it might be wise to back it off again if it seemed appropriate. <p>I'm not sure I understand your point about damping here. I thought you were of the opinion that the problem with internal damping was that it absorbed to much energy, tho here you are concerned about the plate actually vibrating to much, and the purpose of the device itself supports you. <p>Cheers <p>RicB <p>Delwin D Fandrich wrote: <blockquote TYPE=CITE> <blockquote dir=ltr style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px"> </blockquote> <div dir=ltr><font color="#000080">You mean the cast iron thing bolted to the inside of the inner rim? It, along with the long coupling bolt going up through the soundboard and the plate, mass-couples the plate hitchpin panel to the inner rim. It reduces the natural tendency of the plate hitchpin panel to vibrate overly much in response to the vibration of the  strings. Any vibrating in this portion of the plate will result in a substantial and noticeable energy loss--i.e., it reduces an already short sustain time through the treble region.</font></div> <div dir=ltr> </div> <div dir=ltr><font color="#000080">Remember the natural vibration damping characteristic of gray iron? This is just one portion of the plate where you can dramatically see this characteristic in action.</font></div> <div dir=ltr> </div> <div dir=ltr><font color="#000080">The bell and the coupling bolt are not structural in any way, take out the coupling bolt and you can generally hear the sustain time drop off.</font></div> <div dir=ltr> </div> <div dir=ltr><font color="#000080">Which brings up the question, "how tight is tight" on that bolt and nut? I don't know what the official answer is but I make them snug, plus one turn. It needs to be tight enough to efficiently couple the two together but not so tight as to affect bearing and/or break something.</font></div> <div dir=ltr> </div> <div dir=ltr><font color="#000080">Del</font></div> </blockquote> <br>  <br>  <p>-- <br>Richard Brekne <br>RPT, N.P.T.F. <br>UiB, Bergen, Norway <br><A HREF="mailto:rbrekne@broadpark.no">mailto:rbrekne@broadpark.no</A> <br><A HREF="http://home.broadpark.no/~rbrekne/ricmain.html">http://home.broadpark.no/~rbrekne/ricmain.html</A> <br>  </body> </html>