---------- Forwarded Message ---------- From: Bill Spurlock, RPT, 74077,3053 TO: INTERNET:stanwood@tiac.net, INTERNET:stanwood@tiac.net DATE: 2/11/95 10:47 PM RE: Copy of: Scanning Electron Microscope David: How about inspecting some centerpins and bushing cloth from action centers that mysteriously tighten up? Pratt-win, Renner, some Japanese, and especially Korean centers can all have the problem of siezing up soon after brand new parts are put into service. This often occurs when the parts are put into heavy use, even though they had the correct friction initially. Typically, I'll get a call back and notice only one or two slugggish hammers when looking through the strings. But then removing the action and raising up all the shanks (past their normal range of movement) will mysteriously cause many more to sieze up entirely, to the point where they need reaming and repinning. Looking at these pins under a 30 power microscope usually reveals scoring of the pin, like an engine shaft that's been run without oil. Often small bits of cloth appear to be adhering to the pins. It is surprising that as long as wool cloth bushings have been around, manufacturers still have all kinds of problems with them. Problems with corrosion and general busning tightness after sitting idle in a humid climate are understandable, but I'd really like to know what causes this mysterious siezing up of new parts. I can provide a couple of sample pins if you're interested in giving them a close look. Bill Spurlock
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