Made from 316 stainless steel, these flange locknuts have excellent resistance to chemicals and salt water. They have serrations that 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. Height includes the flange. Metric 316 stainless steel is also known as A4 stainless steel. Nuts may be mildly magnetic.

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Also known as collar nuts, these metric nuts have a flange that distributes pressure across the surface, so you don't need a washer. Because of the flange, they may not fit in tight spaces. Made of high-strength Class 10 steel, they’re about 25% stronger than medium-strength steel flange nuts. Their strength is comparable to Class 10.9 bolts.

When choosing your finish, consider your environment. Steel nuts without any finish should be used in dry environments. Zinc-plated and zinc yellow-chromate plated nuts have a layer of zinc that protects the steel under it from rust, extending the life of the nuts. They resist corrosion in wet environments. A black-phosphate finish shields nuts from rusting, even in the midst of oil and grease.

ISO 4161 (formerly DIN 6923) and DIN 6331 nuts meet international standards for flange nut dimensions and materials.

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No need for a washer—these metric medium-strength steel nuts have a flange that distributes pressure across its surface the way a washer does. Skipping the washer saves assembly time. Sometimes called collar nuts, the flange gives these nuts a wider profile than standard nuts, so they may not fit in tight spaces. Made of medium-strength, Class 8 steel, they’re suitable for fastening most machinery and equipment.

All meet DIN 6923 and some meet ISO 4161 dimensional standards, which confirm their compatibility with other parts and tools. The two standards are functionally equivalent.

Unfinished steel nuts are best for dry environments, since moisture will cause them to rust. They are ready for painting and welding.

Zinc-plated steel nuts resist rust, extending their life.

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

Skip the washer—these metric stainless steel nuts have a flange that does the same job, spreading pressure across its surface for a strong hold. They're also called collar nuts. By leaving out the washer, they save assembly time, which adds up on parts that have multiple bolts. On the other hand, they may not fit into tight spots since they have a wider profile than standard nuts. All are 18-8 stainless steel, which is nearly as strong as steel and stands up to outdoor, washdown, and other corrosive environments without rusting.

These flange nuts meet ISO or DIN dimensional standards that confirm their compatibility with other parts and tools. ISO 4161 is functionally equivalent to DIN 6923, which is no longer active but still a common reference for designers and makers.

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