This topic is being discussed in another thread. Double-posting the same topic makes it difficult to keep track of what is being discussed in both threads.
Bill mentioned the magnetism involved. I could not find a simple/clear explanation on-line, but I recall someone posting information on "waning" magnetism and/or erratic magnetism (as speed increased) due to wear/dirt in a pivot-point and/or weakening magnetism? Maybe Bill will see this post and comment/explain.
