A slotted nut, also known as a castellated nut, is a type of fastener with slots cut into one end. These slots align with a hole drilled through a bolt or stud, allowing a cotter pin to be inserted. This setup prevents the nut from loosening under vibration or torque. Slotted nuts are commonly used in automotive, aerospace, and machinery applications where secure fastening is critical.

Slotted nuts are made from durable materials to withstand high stress and environmental factors. Common materials include stainless steel, carbon steel, brass, and sometimes high-strength alloys. Stainless steel slotted nuts are popular for corrosion resistance, while carbon steel nuts are used for high-strength applications. Material choice depends on the operational environment, such as exposure to moisture, chemicals, or extreme temperatures.

The primary difference lies in their design and application. A standard nut relies on friction to stay in place, often supplemented with washers or thread-locking compounds. A slotted nut, on the other hand, incorporates slots and is used with a cotter pin for mechanical locking. This makes slotted nuts ideal for applications with high vibrations or where disassembly needs to be controlled, such as in automotive axle assemblies or turbine shafts.

Yes, slotted nuts come in various sizes and conform to standards such as ANSI, DIN, or ISO. These standards ensure compatibility with specific bolts and threads. They range in diameter from small (used in electronics or small machinery) to large (for industrial or heavy-duty applications). Dimensions like thread size, slot width, and nut height vary by standard and application, so selecting the correct size for your bolt and pin is critical for safety and performance.