Symmetry Bolt is a revolutionary concept in vibration resistant self-locking fasteners. Based on a unique external thread form that includes a right hand thread and a left hand thread, the Symmetry Bolt is designed to mate with a standard right hand thread main nut and a standard left hand lock nut. The right hand thread pitch is standard coarse while the left hand thread is fine pitch. The two nuts lock against each other with opposing forces. The effect is to maintain clamp load in high vibration applications where other self-locking fasteners come loose. The Symmetry Bolt is best suited to the most severe shock and vibration conditions. Recommended applications include agriculture, construction, mining, and military equipment, truck and rail transportation, rock crushers, and chippers.