Lock Nut Low | A2 | DIN 985

If you are looking for a lock nut capable of directly securing threaded joints in exposed environments without rusting, the low-profile lock nut DIN 985 in stainless steel is a reliable choice. It is manufactured from A2 / AISI 304 stainless steel and designed to withstand moisture, weather, and temperature fluctuations. The low-profile lock nut DIN 985 is used where high durability and corrosion resistance are required – for example, in construction, industry, and outdoor applications.

FIELD OF APPLICATION

The low-profile lock nut DIN 985 is intended for securing screw joints and bolt fastenings in environments such as wet rooms, machinery installations, facade mounting, or light industry. The integrated nylon ring provides a vibration-proof and reusable thread lock without the need for washers or chemical locking agents. The product is installed using a socket or a fixed wrench for the external hexagon and fits standard metric threads. It requires little maintenance and provides long-lasting function in corrosion-prone but not aggressive environments.

TECHNICAL SPECIFICATIONS

• Product type: Low-profile lock nut
• Standard: DIN 985
• Grade: A2 / AISI 304
• Material class: A2-70
• Thread type: Metric
• Surface treatment: Untreated (natural stainless steel)
• Head shape: Hexagonal
• Grip type: External hex

FREQUENTLY ASKED QUESTIONS (FAQ)

What characterizes the lock nut DIN 985 and how does it differ from the tall model DIN 982?

DIN 985 (which in the newer international standard corresponds to ISO 10511) is the absolute most common standard model for nylon lock nuts (nyloc nuts):

• Low profile (Standard height): It has a lower nut body than DIN 982. This makes it ideal in tight spaces where protruding thread length or installation dimensions are limited.

• Built-in nylon insert: In the upper part of the nut, there is an elastic nylon ring that creates a reliable friction lock against the threads of the screw.

• Vibration-proof: Effectively prevents the joint from unscrewing during vibrations, shocks, or dynamic movements in, for example, fences, vehicles, machinery, and outdoor furniture.

How does the locking function work and what is most important during installation?

1. Elastic friction locking: When the screw is threaded through the nut, the screw threads cut into the nylon ring. The ring encloses the thread with constant radial pressure without damaging the screw.

2. The screw must go all the way through: To achieve full locking effect, the screw shank thread must stop at least 2–3 thread turns above the nylon ring. If the screw ends inside the nylon ring, a guaranteed lock is not achieved.

3. Replace upon reassembly: Since the nylon ring is permanently deformed when the nut is unscrewed, the locking capacity is reduced if it is reused. Always switch to a new DIN 985 lock nut during maintenance or disassembly of critical joints.

Why is stainless steel A2 (AISI 304) the right choice for outdoor use, and when is A4 needed?

• Long outdoor lifespan (Corrosivity class C3): A2 steel withstands rain, snow, weather exposure, and humid outdoor environments without suffering from surface rust.

• Lubricate the thread against galling: When installing a stainless steel lock nut on a stainless screw, high friction pressure is formed against the nylon insert and the thread. Always use a drop of assembly paste or grease and do not tighten at too high a speed to avoid the thread seizing.

• When is A4 needed? For marine environments (constant saltwater), docks, pools, or chemically aggressive environments, you should instead choose acid-proof A4 steel (AISI 316) to completely prevent pitting and crevice corrosion.