<HTML> <HEAD> <TITLE>Re: [CAUT] pre-stretching new string?</TITLE> </HEAD> <BODY> On 6/9/07 4:53 PM, "Ed  Sutton" <ed440@mindspring.com> wrote: <BLOCKQUOTE>Wegman and Wurlitzer (and perhaps other companies) made pianos with cast iron pinblocks.  Tuning records on these pianos might reveal something. ES </BLOCKQUOTE> I service a Wurlitzer with Wegman pin setup on a regular basis. Its response to humidity change is very similar to that of other pianos. There is also no difference in the way unisons go out of tune: same pattern of left to right string differences.     I have taken this, plus a lack of any observable pattern of pitch change relative to the Steinway tuning pin pattern (extreme offset of pins, unison to unison) to convince myself that swelling and shrinking of the pinblock is not a major factor in unison issues, and probably very minor in all humidity related tuning variances. I’d be happy to hear of opposing viewpoints, or contradictory data, if such things exist. Regards, Fred Sturm University of New Mexico </BODY> </HTML>