A K Lock Nut, also known as a Keps or K nut, is a type of lock nut with an integrated, free-spinning washer that has serrations along its outer edge. These serrations dig into the mating surface when tightened, creating friction that helps prevent the nut from loosening due to vibration or motion. Unlike a standard lock nut, which typically relies on friction alone (such as nylon inserts in Nylock nuts), the K Lock Nut's washer provides both friction and a biting effect for extra grip. This makes K Lock Nuts ideal for applications with dynamic loads or vibrations, such as machinery and automotive systems.

K Lock Nuts offer several advantages, including ease of installation, vibration resistance, and secure fastening. The serrated washer on the K Lock Nut eliminates the need for a separate lock washer, which reduces the assembly time and simplifies the design. Additionally, the locking mechanism provided by the washer prevents loosening due to vibrations, making these nuts especially useful in high-vibration environments. Their self-locking design also makes them reusable under certain conditions, unlike some locking nuts that lose effectiveness after multiple uses.

K Lock Nuts are commonly made from materials like steel, stainless steel, and brass, often with coatings such as zinc or chrome for additional corrosion resistance. The material used impacts the nut’s strength, durability, and suitability for different environments. For example, stainless steel K Lock Nuts are ideal for high-corrosion environments, such as marine applications, while brass nuts are more suited for electronics due to their non-magnetic properties. The choice of material should consider the environmental conditions and specific requirements of the application.