<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD><TITLE>Re: [CAUT] Keydip--how deep</TITLE> <META http-equiv=Content-Type content="text/html; = charset=iso-8859-1"> <STYLE type=text/css>BLOCKQUOTE { PADDING-BOTTOM: 0px; PADDING-TOP: 0px } DL { PADDING-BOTTOM: 0px; PADDING-TOP: 0px } UL { PADDING-BOTTOM: 0px; PADDING-TOP: 0px } OL { PADDING-BOTTOM: 0px; PADDING-TOP: 0px } LI { PADDING-BOTTOM: 0px; PADDING-TOP: 0px } </STYLE> <META content="MSHTML 6.00.2800.1515" name=GENERATOR></HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2>Ron, if this is a reference to my post = regarding ratio, I should have been more clear, the relationship is the = successful marriage of the overall Action Ratio (or StrikeWeight Ratio ala = Stanwood) to the Hammerweight (again StrikeWeight ala Stanwood). Hope this helps. BTW I = agree with what you say in general here regarding key ratio. I just want to be = sure everybody has got apples to apples.  Chris = Solliday </FONT></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=sec@overspianos.com.au = href="mailto:sec@overspianos.com.au">Overs Pianos</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A title=caut@ptg.org href="mailto:caut@ptg.org">College and University Technicians</A> = </DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, October 12, = 2005 4:46 PM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [CAUT] Keydip--how = deep</DIV> <DIV><BR></DIV> <DIV>Hi Mike and all,</DIV> <DIV><BR></DIV> <DIV>There have been some good posts on this thread.</DIV> <DIV><BR></DIV> <BLOCKQUOTE cite="" type="cite"><FONT face=Verdana>. . .  I = don't think any hard-fast rule is going to suffice.</FONT></BLOCKQUOTE> <BLOCKQUOTE cite="" type="cite"><FONT face=Verdana>-Mike Jorgensen</FONT></BLOCKQUOTE> <DIV><BR></DIV> <DIV>With the exception of the final jack position relative to the = roller, I agree.</DIV> <DIV><BR></DIV> <DIV>The jack position (relative to the roller) at full key dip (with = the hammer in check) is probably the only hard-fast rule when it comes to = key dip/hammer blow considerations. Since the hammer/key ratio varies so = widely, as others have also mentioned, even within the one brand/model of = instrument, there will need to be an adjustment from the standard spec of dip = and/or blow in many situations. Increasing the blow distance on a high-ratio = action will tend to place the already ordinary-relationship of the jack roller = contact even further away from its line of centers. Reducing the blow distance = in the case of a low ratio action will tend to improve it.</DIV> <DIV><BR></DIV> <DIV>If the dip is insufficient for a given action ratio, the lack of jack/roller clearance at check may cause the action to blubber at = let-off, particular when played softly. If the dip is set so deep as to cause considerable clearance between the jack and roller at check it will = slow repetition.</DIV> <DIV><BR></DIV> <DIV>The much mentioned problem of the hammer/key ratio varying so = much with the US S&S pianos got me thinking about the problem again recently = when retro-fitting one of my actions to another factory piano (the = instrument in question seemed to have a plate position problem which was = accommodated in the original action by fitting the hammers 3 mm short of 130 mm. When I = fitted my action I followed suit and hung the hammers short also, since I wanted = to keep my action stack at the correct position with respect to the keyboard = (to preserve the action ratio I wanted - 5.7:1). The shorter hammer = position will reduce the hammer/key ratio, but only by a small amount.</DIV> <DIV><BR></DIV> <DIV>In the factory situation, if the plate is not positioned = according to the standard specification, I believe it is inappropriate to shift the = action stack relative to the keyboard, in an attempt to shift the strike = position (line). If a piano is built with the plate out of position, it should = be a simple matter to tolerate a small adjustment in the hammer position = along the hammer shank. A 3 mm + or - adjustment of a hammer from say a standard = 130 mm standard distance from the hammer center pin will allow for an = out-of-position plate to be accommodated without turning the action geometry into a disaster.</DIV> <DIV><BR></DIV> <DIV>If an action stack is moved only 2 mm relative to the keyboard it = will have a major influence on the hammer/key ratio, which will cause major = headaches at regulation time (if the regulator is aiming to obtain a = workable regulation with standard specifications). The truth is we often need = to bend the specs somewhere, to get real-world actions working at their = optimum level.</DIV> <DIV><BR></DIV> <DIV>Ron O.</DIV><X-SIGSEP><PRE>-- </PRE></X-SIGSEP> <DIV><FONT face="Times New Roman" color=#0000ff size=+1><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 color=#000000 size=-2><BR></FONT><FONT = color=#000000>Web http://overspianos.com.au</FONT></DIV> <DIV><FONT = color=#000000>mailto:ron@overspianos.com.au<BR>_______________________<= /FONT></DIV></BLOCKQUOTE></BODY></HTML>