Get a grip on metric bolts exposed to vibration, wear, and changes in temperature. These metric locknuts have a nylon insert that holds onto bolts without damaging their threads. They have fine-pitch threads, which are closer together than coarse-pitch threads and less likely to loosen from vibration. Fine threads and coarse threads are not compatible. These locknuts are reusable but lose holding power with each use.

Made of Class 8 steel, these nuts are strong enough for use with most machinery and equipment. A zinc plating prevents rust in wet and damp areas. Combine them with Class 8.8 metric bolts, which are comparable in strength.

These locknuts meet the dimensional and material standards of DIN and ISO that make sure they're compatible with other parts and tools. Although DIN 982 and 985 are no longer active standards, they’re still a common reference point for designers. With only slight differences in tolerance, ISO 7040 and 10511 have replaced the inactive DIN standards.

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Also known as Keps and K-lock nuts, these locknuts have a free-spinning tooth lock washer that grips the material surface instead of threads for easy installation and mild vibration resistance. Height includes the thickness of the washer. A zinc plating provides corrosion resistance in wet environments.

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A conical washer acts as a spring to add tension between the nut and the material surface for easy installation and mild vibration resistance. They have a smooth rim to resist scratching materials when tightened. Also known as Keps and K-lock nuts. Height includes the thickness of the washer.

Zinc-plated locknuts have an outer layer of zinc that provides corrosion resistance in wet environments.

Black oxide locknuts are mildly corrosion resistant and have a dark surface color.

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An irregularly shaped thread at the top of the nut grips the bolt for a stronger hold than nylon-insert locknuts. They thread on from the bottom of the nut, allowing more threads to engage the bolt before tightening for easier installation than center-lock distorted thread locknuts. The strength of the bolt should match the strength of the nut to prevent damaging threads. They're not reusable. Comparable in strength to Class 8.8 bolts, they're suitable for fastening most machinery and equipment. A zinc or zinc yellow-chromate plating provides corrosion resistance in wet environments.

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Strong enough for use with most machinery and equipment, these Class 8 metric locknuts have an irregularly shaped thread in the middle of the nut that grips bolts tighter than nylon-insert locknuts. Also known as reversible locknuts, they can be threaded on from either end. All are zinc-plated steel, so they won’t rust in wet and damp areas.

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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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The steel insert grips the threads and lifts away from the nut body when installed, isolating the insert from the nut’s load to resist spinoff caused by vibration. These locknuts are often used in shakers and vibrating equipment. The strength of the bolt should match the strength of the nut to prevent damaging threads. Comparable in strength to Class 8.8 bolts, they're suitable for fastening most machinery and equipment.

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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).

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