Lock nut | A4 | DIN 982

Do you need a lock nut that performs reliably even in humid, salty, or chemically demanding environments? Lock nut A4 DIN 982 in A4 / AISI 316 acid-proof stainless steel with a nylon insert is built to resist corrosion and maintain strength over a long period. The nylon insert creates constant frictional resistance that prevents the nut from loosening due to vibrations and high mechanical loads. The product is easy to install using standard tools and requires minimal maintenance, even during continuous operation in aggressive environments.

AREA OF USE

Perfect for fastenings in construction, machinery, furniture, vehicles, marine applications, and other outdoor structures in harsh environments. The nylon insert provides a stable, vibration-resistant, and wear-resistant connection without the need for additional fittings.

TECHNICAL SPECIFICATIONS

Product type: Lock nut with nylon insert
Standard: DIN 982
Quality: A4 / AISI 316
Material class: A4-80
Thread type: Metric ISO thread
Surface finish: Untreated (natural stainless steel)
Head shape: Hexagon
Grip type: Not applicable

FREQUENTLY ASKED QUESTIONS (FAQ)

What distinguishes the DIN 982 lock nut from the standard DIN 985 lock nut?

Both standards describe lock nuts with a nylon locking ring, but they have key differences in geometry and thread engagement:

• High profile (DIN 982): Features a taller nut body with more load-bearing thread turns below the nylon ring. This provides greater thread engagement and better stress distribution, making it ideal for high mechanical loads.

• Increased vibration damping: The greater overall height ensures the nut is seated even more securely and provides a higher prevailing torque compared to the lower-profile DIN 985.

• Function of the nylon insert: As the screw is threaded through the nut, the thread cuts into the unique polyamide (nylon) ring. This creates constant frictional resistance that prevents the nut from backing off due to vibrations, shocks, or dynamic loads.

Why is acid-proof A4 (AISI 316) stainless steel necessary for lock nuts?

Lock nuts are often used in critical joints where spontaneous loosening could have serious consequences:

• Molybdenum alloy for marine and chemical environments: A4 steel (1.4401 / AISI 316) provides complete protection against crevice and pitting corrosion from salt water, road salt, acids, and industrial cleaning agents.

• Maintenance-free safety: In harsh outdoor and marine environments, standard steel or electro-galvanized nuts rust tight or weaken. A4 steel maintains its mechanical properties and finish over time.

• Temperature range: The nylon insert can withstand continuous operating temperatures from −40 °C to +120 °C without losing its locking capability.

How do you install an A4 lock nut without the threads seizing (galling)?

Stainless steel against stainless steel has a natural tendency to cold-weld/seize during rapid tightening. Follow these three rules for trouble-free installation:

1. Use assembly paste: Always apply a drop of stainless assembly paste or thread lubricant to the screw thread before installation.

2. Tighten at a steady and low speed: Use hand tools (fixed wrench or ratchet) instead of high-speed impact wrenches. Heat generated by an impact wrench can otherwise cause the thread to seize immediately in the nylon ring.

3. Single-use for maximum locking effect: The nylon insert deforms elastically/plastically during the first installation. If the nut is removed, it is recommended that it be replaced with a new A4 lock nut to ensure complete vibration resistance.