<HEAD><TITLE>1890s WNG Action Geometry</TITLE> <META content="MSHTML 6.00.2900.2912" name=GENERATOR></HEAD> <BODY> <DIV>I agree with Jon.</DIV> <DIV>Kip dip is a given.</DIV> <DIV>Position of the shank at the moment the hammer strikes the string is a given.</DIV> <DIV>Everything else has to work in between as best as possible, starting from the jack tip down.</DIV> <DIV> </DIV> <DIV>Consider that for a given arrangement of balance rail pins, there is only one possible capstan line that can give equal rise of capstans and equal key ratios for both naturals and sharps.</DIV> <DIV>In a situation like this the solution may include different capstan lines for sharps and naturals, unless you're will to replace the keys for a new balance rail configuration.</DIV> <DIV>(A situation like this would occur if a factory had modified an action to fit a smaller piano without redesigning the key layout.)</DIV> <DIV> </DIV> <DIV>You will save lots of stack pulling if you mount your trial capstan on the end of a thin stick. You can move it in and out, tape it onto the front of the key for trials, make little index marks on the key to indicate the trial locations that work.  A short screw with its head filed flat can make a vertically adjustable trial capstan.</DIV> <DIV> </DIV> <DIV>Ed Sutton<BR><BR><BR></DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 0px; BORDER-LEFT: #0000ff 2px solid">-----Original Message----- <BR>From: Jon Page <JONPAGE@COMCAST.NET><BR>Sent: Jul 19, 2006 7:16 AM <BR>To: pianotech@ptg.org <BR>Subject: 1890s WNG Action Geometry <BR><BR><ZZZHTML><ZZZHEAD> <STYLE type=text/css><ZZZ!-- blockquote, dl, ul, ol, li { padding-top: 0 ; padding-bottom: 0 } --></STYLE> </ZZZHEAD><ZZZBODY> <DIV>><FONT face=Arial color=#000000>Move the dowel/capstan around until you achieve the balance weight you want.</FONT></DIV> <DIV><BR></DIV> <DIV>I have to disagree with this statement.  KR is optimally derived by regulation parameters</DIV> <DIV>not weight.  With a given knuckle radius, hammer bore, hammer blow and key dip;</DIV> <DIV>there is a KR which lifts the wippen through optimal distance.  That is, to have the jack</DIV> <DIV>in close proximity to the knuckle at full dip and not pressed into the rep. stop felt or</DIV> <DIV>bobbling on the knuckle.</DIV> <DIV><BR></DIV> <DIV>Once ideal regulation specs are configured, you can manipulate FW to target BW.</DIV> <DIV><BR></DIV> <DIV>One would get a really low KR if one were to establish BW via KR with a heavy SW.</DIV> <DIV><BR></DIV> <DIV>Once you get the mechanism operating properly and the BW is too high, consider</DIV> <DIV>lowering SW, increasing FW or installing wippen assist springs.</DIV> <DIV><BR></DIV> <DIV>Finessing weight is the polish, attending to the mechanics is the foundation.</DIV> <DIV><BR></DIV> <DIV>When I set up for new parts, key dip is known, hammer bore is known, blow distance</DIV> <DIV>is known. I select a knuckle radius and KR which produces the lowest friction and BW</DIV> <DIV>while producing an optimum regulation, it is a bit of a juggling act but a decision can</DIV> <DIV>be made by making regulation a priority.</DIV> <DIV><BR></DIV> <DIV>Once the parts are installed and the action regulated, it's time to fine tune the BW.</DIV> <DIV><BR></DIV> <DIV>Hammer weight selection should be more of a consideration in BW than KR.</DIV><X-SIGSEP><PRE>-- </PRE></X-SIGSEP> <DIV><BR>Regards,<BR><BR>Jon Page</DIV></ZZZBODY></ZZZHTML></BLOCKQUOTE></BODY>