<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML style="FONT-SIZE: x-small; FONT-FAMILY: MS Sans Serif"><HEAD> <META http-equiv=Content-Type content="text/html; = charset=iso-8859-1"> <META content="MSHTML 6.00.2900.2627" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial>Good point there Alan. I am sure you are right! = Which is why we use CA to tighten up those pins - to STOP them from revolving counter-clock-wise. I don't know about you, but I often find that = subsequent to replacing a pair of metals (due to breakage etc.) the new string stays = much better in tune. Though what that has to do with this subject I'm not = sure. Just food for thought.</FONT></DIV> <DIV><FONT face=Arial>Regards</FONT></DIV> <DIV><FONT face=Arial>Michael G.(UK)</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=tune4u@earthlink.net = href="mailto:tune4u@earthlink.net">alan and carolyn barnard</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A = title=pianotech@ptg.org href="mailto:pianotech@ptg.org">Pianotech</A> </DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, May 12, 2005 = 1:50 AM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Grist for the = Mill</DIV> <DIV><BR></DIV> <P> <DIV>We recently had a long dialog on here about the actual changes in = a piano that has gone flat. There was much poo-pooing (can we say that on TV?) = from some folks of the notion that tuning pins turned = counter-clockwise when pianos go flat. Their arguments were logical and some folks even = produced mathematics to demonstrated that pin reversal is unlikely.</DIV> <DIV> </DIV> <DIV>BUT ...</DIV> <DIV> </DIV> <DIV>I was thinking about this on my way home from PTG chapter meeting = (2.5 hr drive) and came up with a little point of logic which suggests that = the pins MUST move. See what you think ...</DIV> <DIV> </DIV> <DIV>Virtually all pianos go flat over longish time periods and = certainly are found flat more often than sharp if you go through a whole cycle of = season changes, i.e., an annual tuning. When we bring a flat string up = to pitch, it tends to increase the width of the coil slightly every time we turn = the pin. If the pin is turned one full revolution--360 = degrees--over years of tuning, this would add the thickness dimension of the = wire to the overall coil width and one full wire wrap to the number of = coils. </DIV> <DIV> </DIV> <DIV>You with me?</DIV> <DIV> </DIV> <DIV>So let's take a hypothetical piano string--say a very stable 1905 = Howard upright A4 middle string--that has averaged (let's be conservative...) = falling flat enough that a 7.5 degree turn of the pin = was required each year to bring it up to pitch. Now 7.5 degrees is a = fairly small annual adjustment, just a little tweak, actually. Ce n'est pas? = It's only 1/6 if a quarter turn.</DIV> <DIV> </DIV> <DIV>So, between 1905 and 2005, we have turned that string's = pin 100 X 7.5 = 750 degrees, more than two full turns.</DIV> <DIV> </DIV> <DIV>How many old pianos do we run into that have five or more coils = on the pin? I never noticed any.  In fact, most seem to have = the original 3 coils standing about as far from the plate as the day it = was strung--unless someone has hammered them in, in which case it's still = only about 3 coils!</DIV> <DIV> </DIV> <DIV> <DIV>Pause ... thinkin on that?</DIV> <DIV> </DIV> <DIV>Now strings must become ever so slightly thinner as they stretch, = especially in the earlier years. So, for the string to produce the = same pitch, the string tension required would be ever so slightly less over time. = This would have a very slight mitigating effect on the thought = puzzle proposed above. But nowhere near enough to explain 100 years of flatness, = methinks. And ven if the string is stretching, you would still be adding linear = length to the coil every time.  <DIV> <DIV> </DIV></DIV></DIV> <DIV>I believe, in fact, that about a 30 annual correction, or more, would be very common.  Think about your own = real-world, real-piano experience. Visualize pulling your tuning hammer = through a 30 degree arc, i.e., 1/3 of a quarter turn. That's still a = pretty darned small once-a-year adjustment. So, I think my estimates = here have been very, very conservative.</DIV> <DIV> </DIV> <DIV>Anyway, at 30 degrees the piano would have to have a = total of 8+ full coils on every pin if the pin never turned backward.</DIV> <DIV> </DIV> <DIV>Your turn or, as we used to say in Viet Nam .... I n c o m i n g = ! ! ! </DIV> <DIV> </DIV> <DIV>Alan Barnard</DIV></DIV> <DIV>Hunkered in the Bunker in Salem, MO</DIV> <DIV> </DIV> <P></P></BLOCKQUOTE></BODY></HTML>