Generally, the threads of our steel hex nuts are right-hand threads, so the tightening of the screw is right-handed, and the unscrewing is left-handed, which is usually referred to as right-tightening and left-handing. If it is the opposite situation, where screw tightening is left-handed and unscrewing is right-handed, then the hexagon nut is a left-handed thread. The right thread is a positive thread, and the left thread is a reverse thread.