можете здесь почитать
http://www.abbeyclock.com/Broach5.html
фото цапф с износившимся покрытием
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Once the lubricant fails, if the torque acting on the pivot exceeds the yield pressure of the alloy on the pivot, then the alloy will begin to "flake off" to leave small pits in the surface, which becomes very abrasive and causes the brass bushing to wear at an accelerated rate. This problem with the alloy is common is very common among mass-produced German clocks made since about 1970. "
