Hex Flange Nut w/ Nylon Insert

Our hex flange nuts with nylon insert combine a wide load-spreading flange with a polyamide locking ring crimped into the top of the nut. The nylon collar grips the bolt thread to prevent vibration loosening without marking the mating surface, making these DIN 6926 lock nuts ideal for automotive, machinery, and finished assemblies.

Hex Flange Nut With Nylon Insert — Metric Sizes

What Is a Hex Flange Nut with Nylon Insert?

A hex flange nut with nylon insert is a prevailing-torque lock nut that pairs an integral washer flange with an unthreaded polyamide (nylon) ring retained in the nut crown. As the bolt passes through, it cuts into the nylon, which grips the thread elastically and prevents the nut from backing off under vibration and shock loads. Unlike serrated flange nuts, the locking action is entirely inside the nut, so the smooth flange face will not damage painted, coated, or soft mating surfaces. Manufactured to DIN 6926 and EN 1663, these nuts are standard in automotive assembly, machinery, trailers, playground equipment, and consumer products.

Key Features and Benefits

• Nylon Locking Ring: The polyamide insert grips the bolt thread with prevailing torque, resisting loosening from vibration, shock, and thermal cycling.
• Surface-Friendly Flange: The smooth, wide flange spreads clamping load like a built-in washer without marking painted or coated surfaces.
• All-Position Locking: The lock engages anywhere along the thread, so the nut stays put even when not fully seated — ideal for pivot and adjustment joints.
• No Washer Required: The integrated flange covers oversized and slotted holes and eliminates a separate washer from the bill of materials.
• Sealing Effect: The nylon collar also impedes moisture ingress along the thread, adding corrosion protection inside the joint.

Materials and Finishes

• Carbon Steel Class 8 (Zinc Plated): Standard grade for general machinery, trailers, and equipment assembly.
• Carbon Steel Class 10 (Zinc Flake): High-strength option for automotive chassis and suspension fastening.
• Stainless Steel (A2 / A4): For outdoor, food processing, and marine environments where corrosion resistance is essential.

Standards Compliance

• DIN 6926 — Prevailing torque type hexagon nuts with flange and non-metallic insert
• EN 1663 / ISO 7043 — Hexagon flange nuts with non-metallic insert

Size Range and Availability

Available in M5 through M16 in metric coarse thread, with fine thread options on selected sizes.

Frequently Asked Questions (FAQs)

1. What is a hex flange nut with nylon insert used for?

These lock nuts secure bolted joints subject to vibration where the mating surface must not be damaged — automotive body and chassis parts, trailers, machinery guards, playground equipment, and finished consumer products.

2. How does the nylon insert lock the nut?

The bolt cuts a thread into the unthreaded nylon ring as it passes through. The nylon’s elastic grip creates prevailing torque — constant friction on the thread — that stops the nut rotating loose under vibration.

3. What is the difference between a serrated flange nut and a nylon insert flange nut?

A serrated flange nut locks by biting teeth into the mating surface, which marks it. A nylon insert flange nut locks on the bolt thread itself, leaving the surface unmarked, and also locks at any position along the thread.

4. Can nylon insert flange nuts be reused?

They can typically be reused two to three times, but prevailing torque drops with each use. For safety-critical joints, fit a new nut every time.

5. What is the temperature limit for nylon insert lock nuts?

Standard polyamide inserts work reliably from about -50°C to +120°C. Above that, the nylon softens and locking performance falls; use an all-metal lock nut for high-temperature joints.

6. What is the DIN standard for flange nuts with nylon insert?

They are manufactured to DIN 6926, with EN 1663 and ISO 7043 covering the equivalent international specifications for flange nuts with non-metallic inserts.

7. Do I need a washer with a nylon insert flange nut?

No. The integral flange functions as a washer, spreading load over a wide bearing area and covering oversized or slotted holes.

8. Should the bolt protrude through the nylon insert?

Yes. For full locking performance, at least one to two full threads should extend past the nylon ring so the insert grips fully formed thread.

9. Can these nuts be used with coated or painted bolts?

Yes, but thick coatings increase installation torque through the insert. Check that the combined prevailing and seating torque stays within the bolt’s rated limits.

10. What sizes do you stock for hex flange nuts with nylon insert?

We stock M5 through M16 in metric coarse thread in class 8 and class 10 steel, plus A2 and A4 stainless variants, with fine thread available on popular sizes.