Abstract: A self-locking threaded connection including an externally threaded male part having a series of projections adjacent the trailing or last-to-be-threaded threads and an internally threaded female part having a series of detents adjacent the leading or first-to-be-threaded threads. As the parts are threaded together, the snap reception of the projections into the detents produce both audio and tactile responses indicating that the connection is made and near to a destructive over tightening.