Original poster: Ed Phillips <evp-at-pacbell-dot-net> "Original poster: "Jim Mitchell" <electrontube-at-sbcglobal-dot-net> Thats what I said. Steve got like 3" max from his flyback and it was under oil with a toroid! Regards - Jim Mitchell" Did the spark start at that distance or is that the length of an arc after it is started with the electrodes closer together? Ed