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Nylon Insert | Serrations |
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Distorted Thread | Flex-Top |
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Cotter Pin | Steel Insert |
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RoHS (Restriction of Hazardous Substances) RoHS (Restriction ofHazardous Substances) |
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REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) REACH (Registration,Evaluation, Authorization and Restriction of Chemicals) |
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DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense AcquisitionRegulations Supplement) |
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About Nuts, Materials, and Finishes
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About Shaft Collars
Shaft collars are useful for holding and positioning components on a shaft. They can also serve as mechanical stops and stroke limiters.
More
Metric High-Strength Steel Nylon-Insert Locknuts—Class 10

A nylon insert keeps metric bolt threads from coming loose due to vibration, wear, and temperature swings. About 25% stronger than medium-strength steel locknuts, these nuts are made of high-strength, Class 10 steel. They're used in valves, pumps, suspension systems, and other high-stress parts. Combine with Class 10.9 metric bolts, which have similar strength. All are reusable but lose holding power after each use.
Zinc-plated steel locknuts are corrosion resistant in wet environments.
Some of these locknuts meet ISO 10511 (formerly DIN 985) or ISO 7040 (formerly DIN 982), which are international standards for dimensions. The ISO standards are functionally equivalent to the DIN standards with slight differences in width, height, or tolerances.
For technical drawings and 3-D models, click on a part number.
Metric Fine-Thread High-Strength Steel Nylon-Insert Locknuts—Class 10

These locknuts have a nylon insert that grips the bolt to resist loosening without damaging threads. They're reusable, but their holding power lessens with each use. They're about 25% stronger than medium-strength steel locknuts and comparable in strength to Class 10.9 bolts. A zinc plating provides corrosion resistance in wet environments.
For technical drawings and 3-D models, click on a part number.
Metric Medium-Strength Steel Nylon-Insert Locknuts—Class 8

Made from medium-strength steel with a nylon insert, these Class 8 metric locknuts are strong enough to use on most machinery and equipment that’s prone to vibration and temperature changes. The nylon insert also won’t damage the threads on your bolt. All are reusable, but their holding power lessens with each use. Pair them with compatible Class 8.8 metric bolts.
Most of these locknuts meet ISO 7040 or ISO 10511 (formerly DIN 982 or DIN 985), which are international standards for dimensions. The ISO standards are functionally equivalent to the DIN standards with slight differences in width, height, or tolerances.
Zinc- and zinc yellow-chromate plated steel locknuts are a good option in dry environments. The zinc plating prevents the steel from corroding until the plating wears away.
For technical drawings and 3-D models, click on a part number.
Thread | ||||||||
---|---|---|---|---|---|---|---|---|
Size | Pitch, mm | Wd., mm | Ht., mm | Insert Max. Temp., °F | Specifications Met | Pkg. Qty. | Pkg. | |
Zinc-Plated Steel—Class 8 | ||||||||
M20 | 2.5 | 30 | 20 | 220° | DIN 985, ISO 10511 | 10 | 000000000 | 000000 |
M20 | 2.5 | 30 | 22 | 220° | DIN 982, ISO 7040 | 1 | 000000000 | 0000 |
Zinc Yellow-Chromate Plated Steel—Class 8 | ||||||||
M20 | 2.5 | 30 | 20 | 220° | DIN 985, ISO 10511 | 5 | 000000000 | 00000 |
M20 | 2.5 | 32 | 22 | 220° | DIN 982, ISO 7040 | 5 | 000000000 | 00000 |
Metric Fine-Thread Medium-Strength Steel Nylon-Insert Locknuts—Class 8

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.
For technical drawings and 3-D models, click on a part number.
Low-Strength Steel Nylon-Insert Locknuts

These locknuts have a nylon insert that grips the bolt to resist loosening without damaging threads. They're reusable, but their holding power lessens with each use. About half the strength of medium-strength steel locknuts, they're for light duty fastening applications, such as securing access panels.
Zinc-plated steel locknuts are corrosion resistant in wet environments.
For technical drawings and 3-D models, click on a part number.
Thread | |||||||
---|---|---|---|---|---|---|---|
Size | Pitch, mm | Wd., mm | Ht., mm | Insert Max. Temp., °F | Pkg. Qty. | Pkg. | |
Zinc-Plated Steel | |||||||
M20 | 2.5 | 30 | 22 | 220° | 10 | 000000000 | 000000 |
Metric 18-8 Stainless Steel Nylon-Insert Locknuts

Made from 18-8 stainless steel, these locknuts have good chemical resistance and may be mildly magnetic. The nylon insert grips the bolt to resist loosening without damaging threads. They're reusable, but their holding power lessens with each use. Metric 18-8 stainless steel is also known as A2 stainless steel. These locknuts meet either DIN 982 or DIN 985, which are no longer active standards, but are still a common reference point for designers.
For technical drawings and 3-D models, click on a part number.
Metric Super-Corrosion-Resistant 316 Stainless Steel Nylon-Insert Locknuts

Made from 316 stainless steel, these locknuts have excellent resistance to chemicals and salt water. The nylon insert grips the bolt to resist loosening without damaging threads. They're reusable, but their holding power lessens with each use. Metric 316 stainless steel is also known as A4 stainless steel. Nuts may be mildly magnetic. All meet DIN 982 or DIN 985, which are no longer active standards, but are still a common reference point for designers.
For technical drawings and 3-D models, click on a part number.
Metric Low-Profile Low-Strength Steel Nylon-Insert Locknuts

With a shorter hex height than standard DIN 985 locknuts, these nylon-insert locknuts meet international ISO 10511 dimensional standards and are easy to install in tight spaces. The nylon insert grips the bolt thread to keep them from loosening without damaging the threads, so they're good for use on machinery and equipment that's prone to vibration. These locknuts can be removed and reinstalled; however, their holding power weakens with each use. Use them for light duty fastening applications, such as securing access panels. Made of zinc-plated steel, they won't corrode in wet environments.
For technical drawings and 3-D models, click on a part number.
Thread | ||||||||
---|---|---|---|---|---|---|---|---|
Size | Pitch, mm | Width, mm | Height, mm | Insert Maximum Temperature, °F | Specifications Met | Pkg. Qty. | Pkg. | |
Zinc-Plated Steel | ||||||||
M20 | 2.5 | 30 | 14.9 | 245° | ISO 10511 | 1 | 000000000 | 00000 |
High-Strength Steel Top-Lock Distorted-Thread Locknuts

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 Grade 8 bolts, they're about 25% stronger than medium-strength steel locknuts.
Black-phosphate, zinc-plated, and zinc yellow-chromate-plated locknuts resist corrosion in wet environments.
For technical drawings and 3-D models, click on a part number.
Metric Medium-Strength Steel Top-Lock Distorted-Thread Locknuts—Class 8

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.
For technical drawings and 3-D models, click on a part number.
Metric Stainless Steel Flex-Top Locknuts for Heavy Vibration

Made from stainless steel, these locknuts resist chemicals and may be mildly magnetic. Threads at the top of the nut expand to grip the bolt on all sides for a stronger hold than distorted-thread locknuts. The strength of the bolt should match the strength of the nut to prevent damaging threads.
18-8 stainless steel locknuts have good chemical resistance.
316 stainless steel locknuts have excellent resistance to chemicals and salt water.
For technical drawings and 3-D models, click on a part number.
Metric Medium-Strength Steel Locknuts for use with Cotter Pins—Class 8



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.
For technical drawings and 3-D models, click on a part number.
Metric Steel-Insert Locknuts for Extreme Vibration—Class 8

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.
For technical drawings and 3-D models, click on a part number.
Thread | |||||
---|---|---|---|---|---|
Size | Pitch, mm | Wd., mm | Ht., mm | Each | |
Steel—Class 8 | |||||
M20 | 2.5 | 30 | 17.8 | 000000000 | 00000 |
Metric Medium-Strength Steel Serrated Flange Locknuts—Class 8

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.
Thread | Flange | ||||||||
---|---|---|---|---|---|---|---|---|---|
Size | Pitch, mm | Wd., mm | Ht., mm | Dia., mm | Thick., mm | Specifications Met | Pkg. Qty. | Pkg. | |
Zinc-Plated Steel—Class 8 | |||||||||
M20 | 2.5 | 30 | 20 | 42.8 | 3 | DIN 6923, ISO 4161 | 1 | 000000000 | 00000 |
Metric High-Strength Steel Serrated Flange Locknuts—Class 10

Serrations grip the material surface instead of the threads for easy installation and mild vibration resistance. The flange distributes pressure where the nut meets the material surface, eliminating the need for a separate washer. They're about 25% stronger than medium-strength steel flange locknuts and comparable in strength to Class 10.9 bolts. Height includes the flange.
Zinc-plated steel flange locknuts resist corrosion in wet environments.
For technical drawings and 3-D models, click on a part number.
Metric Medium-Strength Steel Nylon-Insert Flange Locknuts—Class 8

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.
Thread | Flange | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Size | Pitch, mm | Wd., mm | Ht., mm | Dia., mm | Thick., mm | Insert Max. Temp., °F | Specifications Met | Pkg. Qty. | Pkg. | |
Zinc-Plated Steel—Class 8 | ||||||||||
M20 | 2.5 | 30 | 24.8 | 42.8 | 3 | 250° | DIN 6926 | 1 | 000000000 | 00000 |
Metric High-Strength Steel Nylon-Insert Flange Locknuts—Class 10

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 or zinc-yellow-chromate plating to resist corrosion in wet environments. Height includes the flange.
For technical drawings and 3-D models, click on a part number.
Thread | Flange | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Size | Pitch, mm | Wd., mm | Ht., mm | Dia., mm | Thick., mm | Insert Max. Temp., °F | Specifications Met | Pkg. Qty. | Pkg. | |
Zinc Yellow-Chromate Plated Steel—Class 10 | ||||||||||
M20 | 2.5 | 30 | 24.8 | 42.8 | 3 | 250° | DIN 6926 | 1 | 000000000 | 00000 |
Metric High-Strength Steel Distorted-Thread Flange Locknuts—Class 10

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).
For technical drawings and 3-D models, click on a part number.
Thread | Flange | ||||||||
---|---|---|---|---|---|---|---|---|---|
Size | Pitch, mm | Wd., mm | Ht., mm | Dia., mm | Thick., mm | Specifications Met | Pkg. Qty. | Pkg. | |
Zinc-Plated Steel—Class 10 | |||||||||
M20 | 2.5 | 30 | 22.4 | 42.8 | 3 | DIN 1664, DIN 6927, ISO 7044 | 1 | 0000000 | 00000 |
Metric Nylon-Insert Cap Locknuts

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.
Thread | |||||||||
---|---|---|---|---|---|---|---|---|---|
Size | Pitch, mm | Dp., mm | Wd., mm | Ht., mm | Insert Max. Temp., °F | Specifications Met | Pkg. Qty. | Pkg. | |
Zinc-Plated Steel—Class 6 | |||||||||
M20 | 2.5 | 13.5 | 30 | 35 | 245° | DIN 986 | 1 | 000000000 | 00000 |
Bearing Retaining Locknuts




With a nylon insert that grips your threaded shaft or spindle without damaging its threads, these locknuts—also called shaft nuts—hold bearings, bushings, gears, and pulleys prone to vibration tightly in place. They come as one piece, so you can easily clamp them onto your shaft or spindle. But, since they aren’t made entirely of metal, they don’t stand up to heat as well as all-metal locknuts. Slots in their sides mean you can tighten and loosen them with a spanner wrench or spanner socket. Their face is also chamfered to help keep the size and weight of your assembly at a minimum. All meet international standards for bearing locknut dimensions.
When choosing your thread spacing, consider the precision of your application. The finer the threads, the more control you have when making adjustments.
All carbon steel locknuts are strong and resist wear, though they don’t stand up to corrosion as well as stainless steel locknuts. Zinc-plated steel locknuts resist rusting from some moisture, but you shouldn’t use them with salt water or chemicals.
303 stainless steel locknuts resist corrosion better than steel locknuts but aren’t as strong. They withstand washdowns and chemicals.
For technical drawings and 3-D models, click on a part number.
Locknuts | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Thread | Spanner Sockets | |||||||||
Size | Pitch, mm | Spacing | OD | Wd., mm | Insert Max. Temp., °F | Specifications Met | Each | Each | ||
Carbon Steel | ||||||||||
Chamfered Face | ||||||||||
M20 | 1 | Extra Fine | 32mm | 10 | 160° | ISO 2982-2 | 0000000 | 000000 | 00000000 | 0000000 |
Zinc-Plated Carbon Steel | ||||||||||
Chamfered Face | ||||||||||
M20 | 1 | Extra Fine | 32mm | 9.5 | 210° | __ | 0000000 | 00000 | 000000 | 00 |
M20 | 1.5 | Extra Fine | 32mm | 9.5 | 210° | __ | 0000000 | 00000 | 000000 | 00 |
303 Stainless Steel | ||||||||||
Chamfered Face | ||||||||||
M20 | 1 | Extra Fine | 32mm | 10 | 160° | ISO 2982-2 | 0000000 | 00000 | 00000000 | 000000 |