<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; = charset=iso-8859-1"> <META content="MSHTML 6.00.2800.1106" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY> <DIV>I see the point about if the action center is on the string plane = and the hammer raked so that it is perpendicular to the string plane when the = hammer tip hits the strings, the hammer tip will move through a circular arc = steadily going up until it is traveling exactly horizontal at the moment it hits the string.</DIV> <DIV> </DIV> <DIV>Ahhhhhh, that's it! The hammer tip will not only contact the string = when it is perpendicular to the string plane, its motion will also be = perpendicular to the string plane at that moment!</DIV> <DIV> </DIV> <DIV>In the case where the hammer butt centers are equidistant from the = string plane as the hammer bore, and as such the hammers are bored at 90 = degrees, when that hammer hits the strings, its orientation will be perpendicular to = the strings, but its motion will be at some downward angle toward the = strings.</DIV> <DIV> </DIV> <DIV>Or am I wrong? Hard to picture in mind accurately. But at least the = raked hammer travels in the same arc as the shank tip, the right-angled hammer = travels in a converging arc to the shank tip. To what advantage/disadvantage is that?</DIV> <DIV> </DIV> <DIV>Thought I had it, but obviously still mixed up.</DIV> <DIV>Terry Farrell</DIV> <DIV> <SPAN id=__#Ath#SignaturePos__></SPAN> </DIV> <DIV>----- Original Message ----- <DIV>From: "James Ellis" <<A href="mailto:claviers@onemain.com">claviers@onemain.com</A>></DIV> <DIV>To: <<A = href="mailto:Pianotech@ptg.org">Pianotech@ptg.org</A>></DIV> <DIV>Sent: Friday, March 14, 2003 8:53 AM</DIV> <DIV>Subject: Rake Angle, and More</DIV></DIV> <DIV><BR></DIV>> I see that my comments about "rake angle" have = stirred up other comments<BR>> and arguments.  All I was trying to do was = to show you fellows that just<BR>> because the hammer is pointed straight = toward the string, it does not mean<BR>> that it is moving in that = direction.<BR>> <BR>> Someone sent a jpeg image to illustrate a point.  My = computer has jpeg as<BR>> well as psp, but that illustration came through as two = pages of jibberish.<BR>> The system either can't handle it, or else I don't = have the right version<BR>> of jpeg to read it.  It doesn't matter.  = I understood what he was talking<BR>> about.<BR>> <BR>> I was = trying to expose a fallacy, and I think it worked.  I was not<BR>> = advocating some crazy impractical design.  Theory and practicality often<BR>> = don't go hand in hand.<BR>> <BR>> A few years ago, many piano technicians = believed that a tuning hammer with<BR>> a very short head would reduce the = bending force on the tuning pin despite<BR>> the fact that the head was bored = at a very high angle, which elevated the<BR>> handle and put the tuner's = hand high up in the air.  (I'm using a grand<BR>> piano for = illustration.)  I saw that I was getting nowhere when I told them<BR>> that the very = high angle of the handle defeated the effect of the very<BR>> short head, = because it put the application of force high up above the<BR>> tuning pin.  So = finally I said, "OK, keep raising the angle of the handle<BR>> until you have = it pointing straight up.  Now, what will that do"?  PAUSE = -<BR>> PAUSE.  "OH, yeah, now I see it"!  Well, I was not advocating = a tuning<BR>> hammer with the handle pointing straight up.  I was = using an absurd<BR>> illustration to make a point, and it worked.<BR>> = <BR>> As long as we have actions where hammers are attached to shanks that = swing<BR>> in arcs, we will have hammers that do not move straight toward the strings.<BR>>  No matter what we do, that hammer is going to be = rotating about an axis as<BR>> it moves toward the string, and the crown will = hit the string a somewhat<BR>> glancing blow.  All we are trying to do = is to minimize that glancing blow.<BR>> Actions have been visualized in = people's minds that enable the hammers to<BR>> hit the strings straight on, = but they are very impractical, so we don't go<BR>> there.  We just stay = with what is practical, and try to minimize the<BR>> shortcomings.<BR>> = <BR>> Sincerely, Jim Ellis, RPT<BR>> <BR>> <BR>> _______________________________________________<BR>> pianotech list = info: <A href="https://www.moypiano.com/resources/#archives">http://www.ptg.org= /mailman/listinfo/pianotech</A></BODY></HTML>