Abstract: A positive lock for a drive assembly joint. In a top driven drilling machine, the motor for rotating the drill string is threadably connected to a drill pipe by the drive assembly. The lock eliminates the need for overtorquing and prevents loosening of the drive assembly joint when using the motor to break the connection between the drive assembly and the drill pipe. The lock also prevents tightening or damage to the joint during drilling. Costs and maintenance associated with an upper wrench are eliminated since the upper wrench is no longer required for making and breaking pipe connections.