Stainless Steel Nylock Nut

Environment & corrosion

Indoors / general outdoor → A2 (304) Nylock nut DIN 985

Marine / chemical / chloride exposure → A4 (316) Nylock nut DIN 985

Use A2 for standard machinery, structures, panels, and general outdoor use.

Use A4 near the sea, coastal areas, cooling towers, RO plants, chemical plants, or where pitting corrosion is a risk.

DIN 982 vs DIN 985 – which Nylock should I choose?

DIN 982 → High type Nylock nut

Taller nut, more thread engagement

Better suited for higher loads / structural joints

DIN 985 → Low type Nylock nut

Reduced height, more compact

Best where space is limited or for medium-duty applications

If the joint is highly loaded or safety-critical, prefer DIN 982.

If space is tight and loading is moderate → DIN 985 is ideal.

Strength & matching with bolt grade

General purpose joints, panels, brackets, covers →

→ With A2-70 / A4-70 bolts → use A2-70 / A4-70 Nylock nuts DIN 985

Higher clamp load / critical joints →

→ Prefer DIN 982 or all-metal lock nuts, especially at high temperatures.

Rule of thumb:

For DIN 985 Nylock:

Use it mainly for light to medium-duty joints.

The nut grade should match the bolt class (A2-70 with A2-70, A4-70 with A4-70) in the same material family.

Temperature & chemical limits (nylon insert)

Nylock nuts work because of the nylon insert:

Suitable for normal ambient to moderately elevated temperatures only.

At high temperatures, nylon softens → locking effect drops.

Certain solvents / chemicals can also attack nylon and reduce performance.

For high temperature or aggressive chemicals, use all-metal lock nuts, not DIN 985 Nylock.

Vibration level & typical applications

DIN 985 Nylock nuts are best for:

Low to medium vibration

Sheet metal, covers, guards, control panels, light machinery, automotive body parts

Places where compact height is needed but some anti-loosening function is required

For very high vibration or shock (heavy equipment, structural connections):

Prefer DIN 982 Nylock or an all-metal prevailing torque nut.

Thread form & compatibility

Default → Metric coarse (e.g., M6×1, M8×1.25, M10×1.5)

Use metric fine / UNC / UNF only when:

Matching existing bolts, studs, or tapped holes

Design specifically calls for fine pitch

Always match diameter + pitch + standard between bolt and Nylock nut

(e.g., M10×1.5 Nylock DIN 985 with M10×1.5 bolt).

Reusability of Nylock nuts (DIN 985)

DIN 985 Nylock nuts are limited-reuse:

Each tightening/loosening cycle wears the nylon insert.

Replace the nut if:

Nylon ring is flattened, cut, burnt, or damaged

Nut spins too freely and no longer gives noticeable prevailing torque

For safety-critical joints, consider DIN 985 as single-use or very limited use.

DIN 985 Nylock nuts use the same property class system as standard stainless hex nuts.

The nut’s proof load is matched to the bolt’s tensile class, within the limits of its lower height.

A2-70 / A4-70 Nylock nuts (DIN 985)

Designed to be used with A2-70 / A4-70 bolts (700 MPa tensile class).

Provide sufficient proof load for light to medium-duty clamping, plus prevailing torque from the nylon insert.

Ideal for general stainless applications, covers, brackets, panels, and non-structural connections.

Use guidelines:

Keep within recommended torque levels for the bolt size and class.

Do not treat DIN 985 like a full-height structural nut (DIN 982/ISO 4032) on very high-load joints.

Simple selection guide

General stainless joints, normal environment →

→ A2-70 Nylock nut DIN 985 with A2-70 bolt (light–medium duty).

Corrosive / marine / chemical environments →

→ A4-70 Nylock nut DIN 985 with A4-70 bolt where loads are moderate.

High strength or very critical structural joints →

→ Upgrade to DIN 982 Nylock or all-metal lock nut instead of DIN 985.