Lock nuts are hex nuts with a nylon insert. This design minimizes vibration, corrosion, and helps to prevent loosening. The flat side of the lock nut should sit flush with the material once tightened. Our variety of fasteners are great for many applications around the home, farm, business, auto-motives, and in industry. We have many grades of fasteners ranging from low carbon steel on up to hardened, heat treated steel. Please be certain to test thoroughly or get the opinion of a licensed builder or engineer before relying on the fasteners because not all fasteners are applicable for all applications.