What was found
SLICK MAGNETO (MODEL NR 6350 S/N 15087263) FOLLOWER ARM OF CONTACTOR POINTS BROKE AFTER 76 HOURS SINCE NEW. THE BREAK OCCURRED AT THE BEND ON THE SIDE OF THE SPRINGY METAL FOLLOW ARM. THIS CAUSED THE MAGNETO TO FAIL (DEAD MAG) DURING BEFORE TAKEOFF MAGNETO CHECKS. THE BEND IN THE SIDES OF THE FLAT METAL SPRING FORMED A CRACK THAT PROGRESSED ACROSS THE METAL WHICH FAILED AFTER ONLY 76 HOURS IN SERVICE. PREVIOUS FOLLOWER ARMS WERE SLIGHTLY THICKER MATERIAL AND NO BEND ON SIDES OF FOLLOWER ARM.