Responding to John Lillico's subject "Young Chang Syndrome" of Jan 5/00, Don Mannino wrote on Jan 6/00 <I think every manufacturer has had phases where their action centers would go tight. I know of others right now which are experiencing this problem and when I tested their procedures for fitting action centers I duplicated the problem exactly. To my knowledge Young Chang never used graphite in their centers - and neither has Yamaha or Kawai, as far as I know. There are many causes of tight centers. Some can be due to plating which cracks and grabs at the cloth, others can be caused by burrs from improper pin cutting, excess glue soaked into the cloth, bent pins from misadjusted machinery, etc, etc, etc, etc, . . . . The most common cause though, cannot be seen by inspection. If the cloth bushing is not installed in a stable fashion it will work great in the factory, then will gradually tighten up. Usually this is because the cloth is twisted or rotated when it is glued in, then the pin is fit through shrinking only, never giving the cloth a chance to settle into a stable state. As the action is played, the heat and friction cause the bushing to creep into a more relaxed (for the cloth, anyway) position, which usually causes the center to freeze up. Reaming and repinning is normally a permanent solution. If you see dark crud in the centers, don't rule out the previous technician. Nasty lubricants like WD-40 (sorry, Newton) can attack the metal of the pin (the pin will often turn green, sometimes very dark so as to be almost black) and attract other dirt that will gum up the works. Teflon powder is nice in an action center, but it won't solve or prevent tightness from arising if the bushing isn't stable. It will merely help to get a nice firm fit that is low in friction. Some manufacturers get it right, John! But all still have occasional problems. Don Mannino RPT> Hi Don, I thank you very much for your insight and quick response to my post. For a guy like me who can't see so good, all "crud" looks dark, but I do buy your explanation of the possiblilty of "twisted or rotated" (insertion) of bushing cloth, bearing in mind this is a 1981 vintage Wagner. Your contribution has assisted immensely in my preparation of an estimate of repair for my client and by the looks of the house, they can afford top dollar. Dinner's on me next time your Toronto-bound. Sincerely, John Lillico, RPT, Oakville, Ontario, Canada
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