<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.6000.16481" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT size=2>Terry,</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>See p. 3 here:</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2><A href="http://www.stanwoodpiano.com/seesaw.pdf">http://www.stanwoodpiano.com/seesaw.pdf</A></FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV> <DIV><FONT size=2>D = BW + F</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>Downweight is balance weight + friction.  With a given downweight and friction, you can have only one balance weight.</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>D - F = BW</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>I like the polar rule; it's handy for calculating friction when doing appraisals.</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>--Cy--</FONT></DIV></DIV> <BLOCKQUOTE dir=ltr style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B> <A title=mfarrel2@tampabay.rr.com href="mailto:mfarrel2@tampabay.rr.com">Farrell</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A title=pianotech@ptg.org href="mailto:pianotech@ptg.org">pianotech@ptg.org</A> </DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, July 06, 2007 8:59 AM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Stanwood "Polar Rule"</DIV> <DIV><BR></DIV> <DIV><FONT face=Arial>Does anyone use David Stanwood's Polar Rule for calculating BW & FW from DW & UW? I understand well that all this thing does is save you from punching a few numbers into a calculator and writing a couple number down (or doing it in your head - ouch!) - but hey, I find it easy and fun to use and I don't have to punch my calculator (or strain my brain). I bought it many years ago when he first came out with it - I guess I really thought it was something else.</FONT></DIV> <DIV><FONT face=Arial></FONT> </DIV> <DIV><FONT face=Arial>My question follows - and I am quite perplexed on this one. When using the Polar Rule you first turn the red dial to match up with the DW. Then you turn the center dial to line up the UW on the red dial. Then you simply read off the FW and BW. </FONT></DIV> <DIV><FONT face=Arial></FONT> </DIV> <DIV><FONT face=Arial>Great. Easy. Fun. Done.</FONT></DIV> <DIV><FONT face=Arial></FONT> </DIV> <DIV><FONT face=Arial>Or maybe not...........</FONT></DIV> <DIV><FONT face=Arial></FONT> </DIV> <DIV><FONT face=Arial>Le's say you have a 50 gram DW and you know that you will regulate friction to a medium amount of let's say 11g. You are stuck with a 39g BW. It can't be anything else if you want 11g of friction (using the Polar Rule). Yet I know that I can increase pinning friction and not affect BW. BW is independent of friction. But the Polar Rule suggests it can't be. This makes no sense to me.</FONT></DIV> <DIV><FONT face=Arial></FONT> </DIV> <DIV><FONT face=Arial>My question is less about what is the nature of BW, but rather what the %$&* is the deal with this Polar Rule.</FONT></DIV> <DIV><FONT face=Arial></FONT> </DIV> <DIV><FONT face=Arial>I know someone is going to suggest something that is going to make me feel real stupid for publicly posting this question - likely should have shot it to some expert privately (or likely anyone with basic common sense) - but hey, maybe someone else uses this goofy but handy little gizmo and has wondered the same thing.</FONT></DIV> <DIV><FONT face=Arial></FONT> </DIV> <DIV><FONT face=Arial>Anyone got an answer? Go ahead, take your shot at me!   :-)</FONT></DIV> <DIV><FONT face=Arial></FONT> </DIV> <DIV><FONT face=Arial>Terry Farrell<BR>Farrell Piano</FONT></DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2><A href="http://www.farrellpiano.com">www.farrellpiano.com</A><BR><A href="mailto:terry@farrellpiano.com">terry@farrellpiano.com</A></FONT></DIV></BLOCKQUOTE></BODY></HTML>