<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD><TITLE>shank strike weights</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 6.00.2900.2769" name=GENERATOR></HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2>Jon,</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>I slept on it.  So you would put = the lighter weight shanks with the larger knuckles on the most overweight hammers.</FONT></DIV> <DIV><FONT face=Arial size=2>Do I have that right?</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Barbara Richmond, RPT</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2></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=jonpage@comcast.net href="mailto:jonpage@comcast.net">Jon = Page</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> Tuesday, November 15, = 2005 6:58 AM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> shank strike = weights</DIV> <DIV><BR></DIV> <DIV>><FONT face=Arial color=#000000 size=-4> What is the = benefit or what <is> the noticeable difference of measuring</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>>the knuckle, = besides making the let off buttons nice and even and look good?</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4><BR></FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>I first started = measuring knuckle and shank thickness because of what I would</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>call a poorly = installed set of knuckles and was surprised to find such a wide disparity. Measuring = the thickness of many shanks proved to have negligible differences so the differences were in the exactness of pressing the knuckle in. I = measure from the top</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>of the shank to the = bottom of the knuckle.</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>Last year I posted = about a knuckle caul press for this concern.</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4><BR></FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>Subsequent sets = measured to have differences between .5 and 1 mm (.020 - .040")</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>within the set. I = maintain a window of .25 mm (.010"), that's +/- .005" (.125 mm) from</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>the average overall = shank/knuckle height. I place the bulk (average) of the shanks</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>in the center and = the +/-'s at the extremes. A more level let off button line was just an interesting result.</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4><BR></FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>Action geometry is = affected by the size of the knuckle so anything one can do to</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>bring uniformity = benefits the action.  Priority for shank selection is matching shank = SW</FONT></DIV> <DIV><FONT face=Arial color=#000000 size=-4>to hammer weight = with knuckle height second.</FONT></DIV> <DIV><BR></DIV> <DIV>Ultimately the best scenario, inertially speaking, would be to = graduate the weight of the hammer heads themselves and group = same-weight/knuckle height shanks. But most hammer sets are</DIV> <DIV>so erratic in individual weights that it takes invasive = procedures to have them comply.</DIV> <DIV><BR></DIV> <DIV>Matching shank SW to hammer weight has proven to require minimal intervention for</DIV> <DIV>a smooth SW curve.</DIV> <DIV><BR></DIV> <DIV>First, I bore and taper the hammers.</DIV> <DIV>Weight them and plot them on a graph.</DIV> <DIV>Select shanks accordingly and install them on the rail. (# on = underside next to knuckle)</DIV> <DIV>Hang hammers.</DIV> <DIV>Remove h/s/f from the rail.</DIV> <DIV>Cut the protruding shank off with a band saw and rough cut an = arc.</DIV> <DIV>Set up fence to trim tails on disk sander to even length.</DIV> <DIV>Arc tails.</DIV> <DIV>Weigh SW and plot on chart</DIV> <DIV>Adjust SW</DIV> <DIV>Install h/s/f on rail.</DIV> <DIV><BR></DIV> <DIV>I sounds like a lot of work but it goes fast. I like to arc the = tails after hanging the hammers</DIV> <DIV>to produce a nice finished edge. I also ease the edges (sides and = bottom) of the tail molding</DIV> <DIV>to remove the sharp corners with a file.</DIV> <DIV><BR></DIV><X-SIGSEP><PRE>-- </PRE></X-SIGSEP> <DIV><BR>Regards,<BR><BR>Jon Page</DIV></BLOCKQUOTE></BODY></HTML>