<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD><TITLE>Korean Dip</TITLE> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <STYLE>P { MARGIN: 0px } </STYLE> <META content="MSHTML 6.00.6000.16587" name=GENERATOR></HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2>Interesting topic.  Key dip, after touch , and what I call the sponge zone. Is very interactice collection.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Now 10mm dip is a very common parameter for grand dip. After touch, can vary greatly depending what is going on in the sponge zone.</FONT></DIV> <DIV><FONT face=Arial size=2>Many Korean grand's have a balance rail hole that is in the 5-7mm range of height.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>My research has shown that a spruce, or basswood key needs to be 4mm max for height.  Maple shoed keys need only be 3mm.</FONT></DIV> <DIV><FONT face=Arial size=2>These heights give an adequate safety factor, with regards to wear, and eventual pulley keys.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>With a tall balance rail hole, the key starts to bind before escapement occurs, after touch will appear to vary from a very soft to a firm touch. A little under 4mm BR hole ht. .015" after touch is usually attainable. A 7mm hole you will need .050 to .060" of after touch to get the piano to feel right.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Some of the older Samick key boards reaming the mortise from 7mm down to 4mm will result in dip going from 11mm to 10mm.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Moral of the story. Measure and correct the balance rail holes before refining dip and after touch.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Now I'll crawl back under my rock.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Regards Roger.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>PS  37 steps should be 1 37 steps in some cases.</FONT></DIV> <DIV><FONT face=Arial size=2>  </FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <BLOCKQUOTE 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=pianotuner@embarqmail.com href="mailto:pianotuner@embarqmail.com">Alan Barnard</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> Wednesday, January 30, 2008 4:30 PM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Korean Dip</DIV> <DIV><BR></DIV>The subject line does NOT refer to any recipe made with kimchi and sour cream; nor does it refer, at least not directly, to any geeky little man from South <A title=Uijeongbu href="http://en.wikipedia.org/wiki/Uijeongbu"><FONT color=#000000>Uijeongbu</FONT></A>.<BR><BR>Rather it is this: I'm working on a Hyundai grand. Anyone have a key dip measurement for these? It seems to be about 10 mm which is a littler deeper than 3/8"<BR><BR>Who actually makes these pianos? I assume it's from China.<BR><BR>Alan Barnard<BR>Salem, MO<BR></BLOCKQUOTE></BODY></HTML>