Often referred to as castle nuts, secure these by inserting a cotter pin or safety wire through the slots and a drilled hole in your bolt for mild loosening resistance. They’re not recommended for use on parts exposed to high vibration because the pin is prone to shearing under prolonged stress. Height includes the slots. Cotter pins are not included.

Zinc-plated steel locknuts resist corrosion in wet environments.

Steel locknuts are best for dry environments, since moisture will cause them to rust. They are weldable and can be painted or finished.

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Strong enough for use in most machinery and equipment, these medium-strength metric nuts have serrations on the underside of the flange. The serrations prevent the nuts from loosening in applications with mild vibration.

Also known as collar nuts, they do not require a washer, which saves assembly time. Instead, the flange spreads the holding force across a wide area. Because the flange makes them wider than standard nuts, they may not fit into tight spots.

Zinc-plated steel nuts have a layer of zinc on the outside that prevents the steel from rusting in wet environments, extending the life of the nut.

To ensure compatibility with other parts and tools, some nuts meet ISO 4161 (formerly DIN 6923).

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A nylon insert firmly grips threads to resist loosening and a flange distributes the load over a large area. These nuts are reusable, but their holding power lessens with each use. Suitable for fastening most machinery and equipment, they're comparable in strength to Class 8.8 bolts. Height includes the flange.

Zinc-plated steel locknuts are corrosion resistant in wet environments.

For technical drawings and 3-D models, click on a part number.

A nylon insert firmly grips threads to resist loosening and a flange distributes the load over a large area. They’re reusable, but their holding power lessens with each use. Made from Class 10 steel, they're about 25% stronger than medium-strength steel flange nuts and comparable in strength to Class 10.9 bolts. They have a zinc-yellow chromate plating to resist corrosion in wet environments. Height includes the flange.

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Grip metric bolts more securely than nylon-insert flange locknuts—the irregularly shaped threads on these locknuts hold extra tight. They resist vibration and sudden shocks, even after multiple uses. Thanks to their flange, these nuts distribute pressure across a greater area than standard nuts, so you don’t need to add a washer. However, they may not fit in tight spaces. Made of high-strength, Class 10 steel, these nuts are about 25% stronger than medium-strength steel flange nuts. Their strength is comparable to Class 10.9 bolts. A zinc plating protects the steel under it from rust, extending the life of the nut.

These flange nuts meet DIN and ISO dimensional standards that confirm their compatibility with other parts and tools. ISO 7044 is functionally equivalent to DIN 1664 (formerly DIN 6927).

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A nylon insert on these metric nuts prevents vibration from loosening them, and a domed head protects the threads at the end of the bolt from damage and debris. These nuts are reusable, but the nylon insert’s holding power decreases with each use. Also known as acorn nuts, they create a finished appearance and can reduce snagging on wires and insulation. Nuts meet DIN 986, an international standard for domed cap nut dimensions.

These nuts are made of strong and wear-resistant Class 6 steel. A zinc plating extends the life of the nut by protecting the inner steel from rust.

For technical drawings and 3-D models, click on a part number.