A lock nut is designed to prevent loosening under vibrations and dynamic loads, providing a more secure fastening than standard nuts. It typically includes features like a nylon insert (in a nylon lock nut) or a deformed thread (in prevailing torque lock nuts) that creates additional friction, ensuring the nut stays in place. This makes lock nuts ideal for machinery, automotive, and construction applications where movement and vibration are common.

The material of a nut significantly impacts its durability, strength, and corrosion resistance. For example, stainless steel nuts are highly resistant to rust and are ideal for outdoor and marine environments, while carbon steel nuts offer high strength for heavy-duty applications but may require coatings to prevent rust. Brass and nylon nuts are often used in environments needing non-magnetic or non-corrosive properties, with each material choice tailored to meet specific environmental and mechanical demands.

Nuts are typically hexagonal in shape to allow for easy installation with standard wrenches and tools, as the six-sided design provides a good balance between grip and accessibility in tight spaces. The hex shape allows for easier torque application, enabling the nut to be tightened or loosened with fewer turns compared to other shapes. This design also maximizes contact surface area with the tool, reducing the risk of slipping and ensuring a secure fit during fastening.