<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=us-ascii"> <META content="MSHTML 6.00.2900.3354" name=GENERATOR></HEAD> <BODY> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>Cy~</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>Thanks for your kind words, and your observations on tuning pins.</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>Yes I often wondered if the reverse threads weren't just a side-effect of the way they cut the threads, that some salesman who happened to have a silk handkerchief discovered by accident. Apparently the ratcheting effect is quite apparent in silk; more dubious is the effect in laminated maple or beech.</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>I'm presently unstringing a Yamaha C3 from around 1977 and noticed that Yamaha used plated pins with plated threads. (i.e.The middle pin in the picture I enclosed in my initial post on this thread about Tuning Pins). David Porritt responded to my inquiry (on the pianotech archives) and revealed that a new set of Genuine Yamaha pins he had gotten within the last year or so was the same type as I just pulled out of the '77 C3: Plated pins with plated threads.</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>I decided to do a little experiment. I took the old pins I had pulled from the '77 C3 I am restringing and tried turning them in a handkerchief. I'm not sure the handkerchief was silk, as a matter of fact I'm pretty sure it wasn't, just cotton or linen, but it had very fine threads, just like silk. Here's what I discovered:</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>The threads on the plated pins I had pulled form the C3, (with the plated threads) turned just as easily one way or the other in the handkerchief. I also had a new plated thread pin I had gotten as part of a demo kit from a piano company. I tried this pin as well. Same result as above. </FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>However~</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>A new Denro pin (Blued) showed the reverse thread effect. It would turn in the clockwise (winding up, tightening the string) direction, but not the other. The effect was very pronounced. It literally would not turn in the reverse direction, but grabbed the handkerchief</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>A new Denro (nickel/blued) pin showed the same effect. It also would turn in the clockwise direction, but not the other. (In the handkerchief, that is)</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>I decided to try some used pins in the handkerchief, pins I had pulled out of pianos I was restringing. From what I could tell, pins that had been in a pinblock and in service for years demonstrated little or none of the "reverse thread" effect. I then pulled some newer Denro pins out of some pinblock samples I did a few years ago. (They had been driven in, and turned several times each way to try and duplicate what I could expect in the way of torque after driving and chipping and tuning the piano.) They too, demonstrated little or none of the effect when placed in the handkerchief. I did notice, however, that rusty pins were much harder to turn in the handkerchief, either way!</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>Okay, this is all fine for handkerchiefs. But as we all know, tuning pins are not driven into handkerchiefs.</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>I have some pinblock samples in the shop into which I had driven many test pins. These are relatively new Denro pins, and relatively new pinblock material (it hasn't been more than a few years since I did the tests. Since there is no string under tension on these pins to muck up the readings, I figured it should be fairly objective. Using a torque wrench on a sample of the standard garden variety Wisconsin rock maple medium laminate (rotary cut) pinblock material you can get from Schaff or Pianotek, I noted no differences in torque in either direction (these were the blued Denro pins.) This seemed to indicate that the reverse thread effect may work well in handkerchiefs, but not in rock maple. I also had a chunk of Bolduc quarter sawn 5 ply pinblock into which I had driven Denro nickel-blued pins. Perhaps because this material actually presents much more consistent end grain to the pin, (unlike the somewhat amorphous rotary cut material) I noted a slight differential in the torque, it was maybe 5 to 10 lbs higher in the reverse direction (or say maybe 100 inch lbs in the clockwise direction and 105 to 110 in the counterclockwise (on some pins) but I couldn't get it to consistently do this on all the pins, so I concluded that if there is a reverse torque effect, it is very slight by the time you get the pins into the pinblock and have turned them a few times.</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>Someone of course will no doubt have to submit this to much more rigorous and controlled testing to conclusively be able to say that the reverse thread claim is just so much marketing hot air, but I am convinced that, outside of brand new pins with virgin, freshly cut threads pins in handkerchiefs, there isn't much, if any, substance to it. It seems, as Fred Sturm stated, there is some byproduct of the thread cutting process where some fine burrs or projections are created on the surface of the threads that have some kind of rachet-like or velcro-like bias to it (perhaps like the hooked or burnished edge on a cabinet scraper), but it also seems the process of pounding the pin into a hard rock maple block and turning it a few times removes most, if not all, of this surface condition.</FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>Also, if there really were anything to it, why would Yamaha plate the threads on the pins they use in their pianos, effectively neutralizing any reverse thread effect? (I have also noticed that pins I removed from a Kawai grand a few years ago for restringing also had plated threads, -they looked just like the Yamaha pins.) </FONT></SPAN></DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=019352621-08072008><FONT face=Arial size=2>~Kendall Ross Bean</FONT></SPAN></DIV> <DIV> </DIV> <DIV align=left> <DIV><FONT face=Arial size=2><SPAN class=533361603-16112007>PianoFinders</SPAN></FONT></DIV> <DIV><FONT face=Arial size=2><SPAN class=533361603-16112007><A title=http://www.pianofinders.com href="http://www.pianofinders.com/">www.pianofinders.com</A></SPAN></FONT></DIV> <DIV><FONT face=Arial size=2><SPAN class=533361603-16112007>e-mail: <A title=mailto:kenbean@pianofinders.com href="mailto:kenbean@pianofinders.com">kenbean@pianofinders.com</A></SPAN></FONT></DIV> <DIV><FONT face=Arial size=2><SPAN class=533361603-16112007>phone: (925) 676-3355</SPAN></FONT></DIV> <DIV><FONT face=Arial size=2><SPAN class=533361603-16112007></SPAN></FONT> </DIV> <DIV><FONT face=Arial color=#0000ff size=2><SPAN class=533361603-16112007><EM>Connecting Pianos and People</EM></SPAN></FONT></DIV></DIV> <DIV> </DIV></BODY></HTML>