<html> <body> Robin, I have a rebuilder friend who ALWAYS, ALWAYS replaces the bridge pins. Even on the rare occasion when the bridge or bridge cap is NOT being replaced! Avery At 02:57 PM 8/19/2006, you wrote: <blockquote type=cite class=cite cite="">Ron, Interesting point you raise about the bridge pin contact area increasing over time.....are you suggesting that it is or could be a good idea to very closely look for this when doing restringing and possibly replace the bridge pins in toto??? I had not heard this before but it surely sounds very reasonable. Thanks. Robin Blankenship ----- Original Message ----- From: "Ron Nossaman" <rnossaman@cox.net> To: "Pianotech List" <pianotech@ptg.org> Sent: Saturday, August 19, 2006 2:25 PM Subject: Re: Rolling to Pitch <blockquote type=cite class=cite cite=""> <blockquote type=cite class=cite cite="">Where is the movement in the string going when it can be lowered without tuning any pins?</blockquote> It's coming from the back scale as you pull the strings through the bridge pins with your roller. Contrary to popular belief, strings do render across bridges, it can happen quickly with big tension differences between front and back scales, or slowly over time. I expect you're adding at least 50 pounds to the string tensions in front of the bridge as you roll them, which is enough differential between tensions in the back scale, to pull the strings through. You've also put a heck of a load at an unnaturally high angle on the bridge notch edge during the rolling process, which didn't do the bridge cap any favors. After tuning, you left the piano in a far worse state of equilibrium than if you had just tuned it as you found it, because back scale tensions are still likely higher than they were when you got there, and will slowly more nearly equalize as the string creeps across the bridge with minor temperature and humidity changes breaking friction in small increments and letting it move. That will pull the front scale sharp again. It's getting less stable as it ages, I think, because the wearing bridge pins are presenting a larger contact area to the string, increasing friction, and making rendering through the bridge less likely with each passing year. So you're leaving a less stable tuning, on average, each time it's tuned. This isn't an uncommon thing in pianos living in rotten climate control conditions, where big pitch changes are necessary with each tuning. Go back and check it in a couple of weeks and see how it sounds. I expect you've got an unpleasant surprise waiting. Meanwhile, throw that roller away. <G> Ron N </blockquote></blockquote></body> </html>