Lock Nuts

lock nuts

Lock nuts (also called locking nuts) have a certain elasticity compared to ordinary nuts. It is a nut designed to prevent bolts or screws from loosening under vibration, impact or dynamic loads.

Locknuts enhance locking by friction locking (nylon inserts, all-metal), and material deformation, which often require higher torque for installation and removal.

51Fasteners offers locknuts in a variety of grades, materials, standard (inch) and metric sizes.

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Lock Nut Specifications

  • Diameter: M3 to M100
  • Threads: UNC thread, UNF thread, ISO thread, Metric thread, Imperial thread, Full thread, Half thread, Coarse thread, Fine thread
  • Strength grades: 04, 05, 5, 6, 8, 10, 12
  • Packing: Small Box + Carton +Pallet, Custom Packaging Service
lock nuts dimensions

Surface Treatments

  • Hot-dip galvanizing
  • Electroplating colored zinc
  • Oxidation blackening
  • Anodizing
  • Chrome plating
  • Nickel plating
  • Heat treatment
  • Passivation

Materials

  • Carbon Steel
  • Stainless Steel
  • Alloy Steel
  • Aluminum Alloy
  • Copper
  • Nylon

Standards for Lock Nuts

DIN 985DIN EN 1666UNI 8835GB 805ISO 12126ISO 12125
DIN EN 1667DIN 982DIN 6921GB/T 6185ISO 7044ISO 10511
DIN 7967DIN 6924DIN 6925IFI 100-2ISO 7041ISO 7043
DIN 6927DIN EN 4123DIN 980GB/T 6182ISO 7720ISO 7042
DIN EN 1664DIN EN ISO 10511DIN 6926GB/T 6183ISO 7040ISO 10512
DIN EN ISO 7719DIN 987DIN 2510-5GB/T 6187ISO 7719BS 4929
DIN 980VDIN 980MNF E25-409GB/T 889ASME B 18.16ASME B 18.16M
UNI 8835UNI 7474UNI 2733UNI 8835GB/T 1339JIS B 1199-2

Types of Lock Nuts

Locknuts with nylon inserts

Nylon Insert Locking Hex Nuts

The top of the nut is embedded in the nylon ring, when tightening the bolt thread extrusion nylon friction, anti-loosening effect is good, the working temperature -40 ℃ to +100 ℃.

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Locknuts with metal plates

Metal Locking Hex Nuts

The upper part of the nut generates elastic clamping force by metal deformation (notching, grooving) and operates at temperatures from -50°C to +600°C.

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Hex-flange-self-locking-nut

Hex Flange Lock Nuts

With one-piece flange with additional non-slip teeth for increased contact surface and head with nylon insert or sheet metal locking.

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Applications

  • Railway Vehicle
  • Construction Machinery Boom
  • Wind turbines
  • High Voltage Transmission Equipment
  • Aerospace Components
  • Ship and Port Facilities

Lock Nuts: FAQ

We offer free samples of locknuts, but courier charges are not included.

Choose nylon type for low-frequency vibration, metal deformation type for high-frequency vibration

For important connection parts, it is recommended to use once and not to reuse.

Nylon lock nut reuse 20 times after the nylon material extrusion of insufficient resilience, the need to increase the tightening torque; if more than 40 times the use of the internal nylon inserts may be damaged.

The effective torque and dispersion of all-metal self-locking nuts are greater than that of nylon self-locking nuts, and it is recommended to reuse them for less than 5 times.

The tightening direction of locknuts follows the thread type: standard right-hand threads need to be tightened clockwise, while left-hand threads need to be tightened counterclockwise. In special cases (e.g. rotating parts) reverse threads are used.