Metric Locknuts
RC Fasteners supplies a complete range of metric locknuts and hex nuts, including DIN 934 hex nuts, DIN 985 nylon insert locknuts, DIN 980 all-metal locknuts, and DIN 6923 flange locknuts. Our metric locknuts are available across multiple grades and finishes for virtually any industrial application. Whether you're sourcing in small quantities or need industrial volumes, RC Fasteners has the inventory and the expertise to get you the right metric fasteners with fast turnaround.
Request a Quote or call us at 623-516-1551 to learn how RC Fasteners can be your metric locknut supplier.
What Are Metric Locknuts?
A metric locknut is a nut designed to resist loosening under vibration, while meeting metric sizing standards. While regular non-locking nuts can back off over time under dynamic loads, locknuts are designed to remain secure. There are several styles of locknuts, available in a wide range of materials and coatings.There are three primary locknut mechanisms:
- A nylon insert that creates friction on the bolt thread
- A deformed or prevailing torque profile that increases resistance throughout the engagement
- Serrations on a flange face that grip into the mating surface.
Types of Metric Locknuts and Hex Nuts
Metric Hex Nuts (DIN 934)
The standard non-locking metric hex nut for general fastening applications. Available in Class 6, 8, and 10, plain and zinc-plated, with stainless options in A2 and A4. A reliable fastener for most assemblies that do not require a locking mechanism.Nylon Insert Locknuts (DIN 985)
A nylon collar at the top of the nut compresses against the bolt thread, creating friction that resists loosening. Nylon insert locknuts are great for vibration-prone assemblies but cannot be used at temperatures above roughly 120°C, or the nylon will melt. Available in Class 8 and 10, zinc CR+3, and stainless A2/A4.All-Metal Locknuts (DIN 980)
As their name implies, All-Metal Locknuts do not use nylon to create a locking mechanism. Instead, they use a distorted thread form to generate torque throughout engagement. All-metal locknuts are made for higher temperatures and heavy-duty applications where nylon inserts would fail. Available in Class 8 and 10, zinc CR+3.Hex Flange Locknuts (DIN 6923 / DIN 6927)
The integrated flange acts like a built-in washer that distributes load over a larger bearing surface. Serrated flange versions (DIN 6923) bite into the mating surface for additional resistance. The DIN 6927 prevailing torque version adds all-metal locking to the flange design. Great for applications where separate washers aren't practical.Keps / External Tooth Nuts
A hex nut with a captive external tooth washer. The teeth engage the mating surface when the nut is driven, locking against loosening through surface grip.Locking Mechanisms for Metric Locknuts Explained
- Friction-Based (Nylon Insert Locknuts): As the bolt is fastened, the nylon deforms around the thread flanks, generating friction that prevents the nut from backing off. Reliable and cost-effective, but can’t be used in high-temperature applications. Applies to DIN 985 nylon insert locknuts.
- Prevailing Torque (All-Metal Locknuts): Locking is achieved through a deformed thread profile built into the nut itself. This deformation creates resistance throughout the entire engagement. Because no plastic components are involved, all-metal prevailing-torque nuts are used in high-temperature environments. Covered types: DIN 980 all-metal locknuts and DIN 6927 flange locknuts.
- Surface Grip (Serrated Flange): Serrations on the underside of the flange dig into the bearing surface as the nut is tightened. No modification to the thread form needed. Applies to DIN 6923 serrated flange locknuts and Keps nuts.
Materials and Strength Grades
Selecting the right grade and finish comes down to load requirements and the operating environment.- Class 8: The standard strength grade for most industrial fastening applications. Covers the majority of general assembly and mechanical use cases.
- Class 10: Higher strength for more demanding structural or mechanical assemblies.
- Zinc Plated (CR+3): RoHS-compliant zinc plating suitable for indoor and some protected outdoor environments. The most common specification in industrial assembly.
- A2 Stainless (304): Good general corrosion resistance for outdoor and moderate-exposure environments.
- A4 Stainless (316): Better chloride and chemical resistance than A2. Recommended for marine, food processing, and chemically aggressive environments.
Common Applications for Metric Locknuts
- Automotive Assemblies: Drivetrain components, suspension systems, and engine mounts deal with sustained vibration. Nylon insert and all-metal locknuts are widely used in automotive components.
- Machinery and Equipment: Any equipment that generates vibration through normal operation needs fasteners that won't back off between maintenance intervals.
- Structural Fastening: Flange locknuts are often specified in structural applications that need bearing surface load distribution.
- Industrial Maintenance: Keps nuts and flange locknuts are ideal for high-volume applications where separate washers would slow down production efficiency.
Learn How RC Fasteners Can Be Your Metric Locknut Supplier
At RC Fasteners, we stock metric locknuts across every major DIN standard, from nylon insert and all-metal locknuts to hex flange nuts and beyond. Not sure which type fits your application? Our team can help you narrow it down fast.We also stock related metric hardware, including hex coupling nuts, standard hex nuts, and flange fasteners, so you can consolidate sourcing in one place.
Request a Quote or contact our team to get started today.
