Lock Nut

Lock nuts, also known as self-locking nuts, prevailing torque nuts, or stiff nuts, are designed to resist loosening under vibration, torque, and dynamic loads. Unlike standard nuts, they incorporate a locking mechanism that creates friction between the nut and mating threads, ensuring a secure connection that remains tight even in demanding applications.

Available Types

Type	Description	Locking Mechanism
Nylon Insert Lock Nut (Nyloc Nut)	Threaded hex nut with a polyamide insert at the top that deforms during installation, creating a tight, prevailing torque grip without cutting into threads	Non-metallic insert (nylon/polyamide)
Stover Lock Nut (Top Lock Nut)	All-metal prevailing torque nut featuring a distorted thread at the top that creates friction against bolt threads; suitable for high-temperature applications	All-metal clamping part
K-Lock Nut	Flanged lock nut with built-in serrated washer	Integrated locking flange
Reverse Lock Nut	Left-hand thread configuration for specialized applications	Left-hand thread
Flange Lock Nut	Integrated flange distributes load while providing locking function	Flange with serrations or all-metal design

Nylon Insert Lock Nuts (DIN 985 / DIN 982 / ISO 10511 / ISO 7040 / ASME B18.16.6)

Nylon insert lock nuts feature a polyamide ring firmly attached to one end face. When tightened, the plastic insert compresses around the bolt threads, creating a reliable clamping effect that prevents loosening. Unlike all-metal designs, the nylon insert does not damage bolt threads and can be reused multiple times, though reuse may gradually reduce locking effectiveness.

Stover Lock Nuts (All-Metal) – DIN 980 / ISO 7042

Stover lock nuts are all-metal prevailing torque nuts featuring a specially designed clamping part integrated into the nut body. A metal clamping piece fixed in the inner groove provides consistent clamping effect on the full circumference of the thread. These nuts can withstand higher temperatures than nylon insert nuts (up to 300°C) and are suitable for applications where plastic materials cannot be used.

Flange Lock Nut

Flanged design with integrated bearing surface eliminates need for separate washer while providing locking function. Available in both nylon insert and all-metal configurations.

Applicable Standards

Standard	Status	Description
DIN 985	Withdrawn	Nylon insert lock nuts – thin pattern; replaced by ISO 10511
DIN 982	Withdrawn	Nylon insert lock nuts – standard height; replaced by ISO 7040
DIN 980	Withdrawn	All-metal lock nuts (Stover); replaced by ISO 7042
ISO 10511	Current	Thin nylon insert lock nuts – metric series
ISO 7040	Current	Standard height nylon insert lock nuts – metric series
ISO 7042	Current	All-metal lock nuts – metric series
ASME B18.16.6	Current	Nylon insert lock nuts – inch series

Materials

Stainless Steel 304 (A2) – General corrosion resistance
Stainless Steel 316 (A4) – Superior corrosion resistance for marine environments
Steel with Zinc Plating – Cost-effective, moderate corrosion resistance
Brass – Decorative, non-magnetic, corrosion resistant

Surface Finishes