<HTML><HEAD> <META content="MSHTML 6.00.2900.2995" name=GENERATOR></HEAD> <BODY> <DIV> <DIV><FONT face="MS Sans Serif" size=2>It's been a while since I have seen the slow-motion photographic study, but to the best of my recollection, the shank flexing due to impact with the strings seems to overpower other considerations.  Uprights could certainly benefit from more substantial shanks.  I said that my drawing was exaggerated, but not by much.  It is amazing how an upright hammer flops around before coming to rest.  </FONT></DIV> <DIV> </DIV> <DIV> <DIV>Frank Emerson</DIV> <DIV><A href="mailto:pianoguru@earthlink.net">pianoguru@earthlink.net</A></DIV> <DIV> </DIV></DIV></DIV> <DIV> </DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid"> <DIV style="FONT: 10pt Arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B> <A title=sjfujan@gmail.com href="mailto:sjfujan@gmail.com">Steve Fujan</A> </DIV> <DIV style="FONT: 10pt arial"><B>To: </B><A title=pianotech@ptg.org href="mailto:pianotech@ptg.org">Pianotech List</A></DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> 11/25/2006 12:02:22 AM </DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Scruffing -was - Over-Strike vs Under-Strike</DIV> <DIV><BR></DIV><FONT size=2>Wow Frank, great sketch!  <BR><BR>Hmm......<BR>So, if the shank flex causes upward scruff, and the offset axis causes downward scruff, then could they be "tuned' to cancel each other out?<BR><BR>Intuitively, it seems like scruffing and flex are both power and clarity robbers.  Could super stiff shanks help minimize both? <BR><BR>Steve Fujan<BR><BR><BR><BR> <DIV><SPAN class=gmail_quote>On 11/24/06, <B class=gmail_sendername>Frank Emerson</B> <<A onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:pianoguru@earthlink.net" target=_blank> pianoguru@earthlink.net</A>> wrote:</SPAN> <BLOCKQUOTE class=gmail_quote style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid"> <DIV> <DIV> <DIV><FONT face="MS Sans Serif" size=2>How can scruffing occur unless the hammer shank flexes?  It does flex, and it does scruff, but always upward.  As the flagpoling of the shank reverses, the hammer begins to scruff downward just as it is rebounding from the string.  The proximity of the axis of rotation to the string is less significant than the length of the hammer bore from the strike point.    This can be seen in slow-motion photograph of action movement.  It is amazing how much an upright shank flexes.  You would think it would break before flexing as much as it actually does.  A grand shank flexes also, but not nearly so much.  The drawing below is simplistic and exaggerated, but illustrates the point. </FONT><IMG alt="" hspace=0 src="http://mail/?realattid=0.1&attid=0.1&disp=emb&view=att&th=10f1d442323368aa" align=bottom border=0></DIV> <DIV> <DIV>Frank Emerson</DIV> <DIV><A onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:pianoguru@earthlink.net" target=_blank>pianoguru@earthlink.net</A></DIV> <DIV> </DIV></DIV></DIV> <DIV> </DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: rgb(0,0,0) 2px solid"> <DIV style="FONT: 10pt Arial; font-size-adjust: none; font-stretch: normal">----- Original Message ----- </DIV> <DIV style="BACKGROUND: rgb(228,228,228) 0% 50%; FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; moz-background-clip: -moz-initial; moz-background-origin: -moz-initial; moz-background-inline-policy: -moz-initial"><B>From:</B> <A title=sjfujan@gmail.com onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:sjfujan@gmail.com" target=_blank>Steve Fujan</A> </DIV> <DIV style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal"><B>To: </B><A title=joegarrett@earthlink.net onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:joegarrett@earthlink.net" target=_blank>joegarrett@earthlink.net</A>;<A title=pianotech@ptg.org onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:pianotech@ptg.org" target=_blank>Pianotech List</A></DIV> <DIV style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal"><B>Sent:</B> 11/24/2006 12:47:45 PM </DIV> <DIV style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal"><B>Subject:</B> Re: Over-Strike vs Under-Strike </DIV> <DIV><BR></DIV><FONT size=2>Shifting slightly to the concept of scruffing...    The hammer contact will always "scruff" towards the hammer pivot axis (unless the pivot axis could somehow lie in the plane of the string).   The closer the pivot axis is to the string, the less "scruffing" will occur. <BR>Steve Fujan <BR><BR></FONT> <DIV><SPAN class=gmail_quote><FONT size=2>On 11/24/06, <B class=gmail_sendername>Joseph Garrett</B> <<A onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:joegarrett@earthlink.net" target=_blank> joegarrett@earthlink.net</A>> wrote:</FONT></SPAN> <BLOCKQUOTE class=gmail_quote style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid"><FONT size=2>Upon reading the follow-ups of Jons query, I'd like to wonder which is<BR>which. I've always considered "Over-Strike" as the Downward angle of the <BR>hammer, which would put the hammer Beyond Perpendicular. ??? Am I correct <BR>on that? If so, then, "Under-Strike" would be, where the hammer does not<BR>achieve Perpendicular, on contact?? The "Over-Strike" hammer, (on an <BR>Upright), would "scruff", (for lack of a better word), downward, at impact. <BR>The "Under-Stike" hammer would therefore "scruff" upwards.<BR>Do I have all of this backwards? Confused minds need to know what the <BR>consensus is.<G><BR><BR><BR>Joseph Garrett, R.P.T.<BR>Captain, Tool Police <BR>Squares R I<BR><BR><BR></FONT></BLOCKQUOTE></DIV><FONT size=2><BR></FONT></BLOCKQUOTE></DIV></BLOCKQUOTE></DIV><BR></FONT></BLOCKQUOTE></BODY></HTML>