Dan, congratulations on your success using the ball bearing pivot point.
More than a few people are using this method of suspension. I am the
person who started  people using it . My web site is
http://freeweb.pdq.net/fxc/four.htmI   I have developed what i call a
modified Lehman quad convex surface system for the lower and upper pivot
points .The lower and the upper pivot points consist of a ball bearing
resting on a convex surface instead of a flat polished bolt head. The
ball is chrome nickel steel and the static surfaces are also chrome
nickel steel polished to a mirror finish. WE have several of the new quad
detectors running at this time and they are looking good. Time will tell.
The old wire suspension is long gone on these detectors as well as the
turn buckle etc
  Dan, I believe that it can be proven theoretically, and i have
demonstrated empirically , that an increase of convexity at the pivot
point can result in increase sensitivity . This makes sense because there
is less surface contact between the static and mobile elements of the
interface , resulting in less friction  and increased isolation of the
pendulum. MY modified instruments using this technology  have shown
remarkable improvement over the standard Lehman detector.
   I intend to upgrade my site and have pictures of the quad convex
surface detector soon. Thanks to Professor Albert Hrubetz of Dallas,
Texas for suggesting the convex to convex  pivot point concept as well as
the extensive research on the new super coils..  Professor Hrubetz,  it
may be of interest to you to know that i am currently using your role    
 .                                                                       
                                                      
                                                                         
                                                     
                                                                         
                                                                         
                       JOHN W5AUH

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