I think it's a spark plug thread, maybe 14mm? Sandy At 08:46 AM 8/18/97 -0800, you wrote: >The welder installed my O2 sensor adaptor but buggered up the >first couple of threads. I will re-tap as soon a someone can tell me >what size tape to use......Help >Bob Cuda-65 - Angels Camp, Calif. >cudabob at workmail.com >http://www.goldrush.com/~rhuish/ > >