Good memory, Steve! My original Lehman (long since gone, donated to Yamato High School in Japan) used a knife-edge which required perfect adjustment in order for the entire knife edge to contact the base. this adjustment was made via the turnbuckle in the middle of the suspension wire. The other newer designs are far superior but it worked well for a long time. Regards, Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>