RAW MATERIAL: 1010 1035 1045
FINISH: BLACK/ZP/HDG
STANDARD: DIN935
SIZE: M4-M100
GRADE: ISO898-2 DIN267-4
Our Castellated Nuts, also known as Slotted Nuts, are designed for fastening applications where a positive mechanical locking method is preferred over friction-based locking alone. Featuring precisely formed slots around the top of the nut, Castellated Nuts are designed to work together with a cross-drilled bolt or threaded stud and a cotter pin, allowing the pin to pass through the bolt and engage with the nut slots to physically prevent the nut from rotating. This mechanical locking principle provides a visible and reliable method of securing a bolted connection, making Castellated Nuts particularly suitable for automotive assemblies, machinery, shafts, steering and linkage components, mechanical equipment, and other applications where accidental loosening must be effectively controlled.
The key advantage of a Castellated Nut is its positive locking mechanism. Unlike conventional nuts that rely primarily on thread friction or specialized prevailing torque to resist loosening, the castellated design allows the nut to be mechanically retained after installation when used with the appropriate cotter pin. Once the nut has been tightened to the required position and the slot is aligned with the cross-hole in the bolt, the cotter pin provides a physical barrier against rotational movement. This makes the locking condition easy to visually inspect during installation and maintenance, which is especially valuable in applications where fastening security is an important maintenance consideration.
Our Castellated Nuts are manufactured from 1010, 1035, and 1045 carbon steel, providing customers with multiple material options for different mechanical and production requirements. These steel grades offer a practical balance of machinability, durability, strength, and cost efficiency for standardized fastening applications. Available specifications include ISO 898-2 and DIN 267-4, allowing customers to select the appropriate mechanical grade according to the requirements of the complete bolted joint. For best performance, the nut should be matched with a compatible bolt, thread system, and cotter pin according to the actual application.
Our Castellated Nuts are manufactured according to DIN 935, a recognized European standard for slotted and castellated nuts. This broad size coverage is particularly valuable for distributors and industrial buyers who need to source multiple castellated nut sizes from a consistent product range.
DIN 935
Metric: M4–M100
Castellated Nuts are specifically designed as part of a nut–bolt–cotter pin locking system rather than as a standalone anti-loosening component. The bolt or stud normally requires a suitable cross-drilled hole, and after tightening, the hole is aligned with one of the nut slots so that the cotter pin can be inserted. This arrangement provides a straightforward mechanical retention method and is particularly useful in assemblies subject to vibration, oscillation, shock, or repeated mechanical movement. The locking system also allows maintenance personnel to quickly identify whether the cotter pin is correctly installed.
To accommodate different service environments, Castellated Nuts are available in Black, Zinc Plated (ZP), and Hot-Dip Galvanized (HDG) finishes. Finish selection can be coordinated with the environmental requirements of the complete fastening assembly.
A practical choice for general industrial applications.
Enhanced corrosion protection for common indoor and moderately corrosive environments.
A more robust protective zinc coating for outdoor construction, infrastructure, and moisture-exposed applications.
Because the locking function depends on a physical cotter pin rather than solely on thread friction, Castellated Nuts have long been used in applications where the consequences of unintended loosening can be significant. Typical applications include automotive and trailer components, axle and hub assemblies, steering and suspension linkages, mechanical shafts, agricultural machinery, industrial equipment, and other moving or vibration-prone assemblies. They are particularly useful where engineers require a locking method that is mechanically positive and can be readily inspected during maintenance.
Another important advantage of the castellated design is its compatibility with inspection and maintenance procedures. The presence of the cotter pin provides an easily recognizable locking feature, allowing technicians to confirm that the nut has been mechanically secured. When properly specified and installed, this system provides a straightforward approach to preventing unintended nut rotation while retaining the serviceability expected from conventional threaded fasteners. For applications where repeated disassembly is required, the cotter pin can also be replaced as part of routine maintenance rather than requiring a specialized locking nut.
With 1010, 1035, and 1045 carbon steel materials, ISO 898-2 and DIN 267-4 specifications, DIN 935 dimensions, M4–M100 sizes, and Black/ZP/HDG finishes, our Castellated Nuts provide a versatile solution for customers requiring a standardized mechanical locking system.
Their combination of precisely formed slots, positive cotter-pin retention, broad metric size coverage, recognized DIN standards, and multiple corrosion protection options makes them suitable for manufacturers, distributors, automotive suppliers, machinery producers, and industrial maintenance teams — a proven and practical choice where friction alone isn't enough and a physical, visible, serviceable locking method is preferred.
