> From: CapAAVSO@....... > Date: Thu, 14 Jun 2001 10:01:42 EDT > > A low friction pivot is still a friction pivot!!! A friction-free pivot has > been described consisting of a ring going around the lower pivot post with a > spring wire under tension in back of the post. The spring stores energy and > gives it back to provide a completely friction-free pivot. It is not clear to me why a "real" spring is more "friction-free" than a ball bearing rolling on a glass plate. Any real spring will generate heat as it bends (from internal friction). Without test data I do not see that either pivot design has inherently lower friction. However, the ball bearing technique seems to be simpler to build since it does not require a machine shop. Ciao, Dave __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>