Nylon Lock Nuts

AIMS Industrial stocks a wide range of nylon lock nuts — also known as nyloc nuts or nylon insert lock nuts — across metric, UNC, UNF and BSW thread standards. A nyloc nut is a standard hex nut with a nylon collar moulded into the top face; as the nut runs down the bolt, the nylon deforms around the thread crest and grips it, resisting loosening from vibration without any thread-locking compound. Available in zinc-plated, zinc-yellow passivate, mechanically galvanised, 304 stainless and 316 stainless finishes from Hobson, Bremick, Inox World, Champion and GJ Works. Our Nyloc Nut Guide: DIN 985, Sizes, Temperature Limits & When to Use Self-Locking Nuts walks through the key differences if you're comparing options.

Quick Reference — Nyloc Nut Types We Stock

What Is a Nyloc Nut?

A nyloc nut is manufactured to the same hex nut body as a standard nut, but with a ring of nylon inserted into the top of the nut. As the nut is threaded onto a bolt, the bolt's crest cuts a slight interference thread into the nylon, and the nylon's elastic grip on the thread — not the metal-to-metal friction alone — is what resists loosening under vibration. The general nyloc/nylon-insert lock nut style is commonly referenced against DIN 985 in industry literature; always check the specific product listing or contact us if a certified standard is required for your application.

Temperature limit: the nylon insert is the limiting factor. Nyloc nuts are generally suited to continuous service up to somewhere in the region of 100–120°C depending on the exact nylon grade used — above that range the insert can soften and lose its grip. For hotter applications (engine bays, exhaust brackets, process equipment), step up to an all-metal lock nut — see our Lock Nuts collection.

Reuse: the nylon insert is compressed and cut a little more each time the nut is run down a thread, so locking performance reduces with each reinstall. For safety-critical or high-vibration joints, fit a new nyloc nut rather than reusing one; for light-duty or non-critical assembly work a nyloc nut can often be reinstalled a small number of times, but a new nut is the safer default.

Thread Standards Available

• Metric: hex nyloc nuts in Class 6, 8 and 10, plus metric fine-thread nyloc nuts in zinc-plated and zinc-yellow passivate finishes. Also available in 304 and 316 stainless steel for corrosion-resistant work.
• UNC (Unified National Coarse): UNC hex nyloc nuts in Grade 2, 5 and 8 zinc-plated, plus 304 and 316 stainless, and UNC nyloc thin hex nuts.
• UNF (Unified National Fine): UNF nyloc thin hex nuts to ASME B18.16, plus UNF nyloc nuts in Grade 5 and Grade 8 zinc-plated.
• BSW (British Standard Whitworth): zinc-plated BSW nyloc nuts for older imperial-thread machinery and equipment still in service across Australian industry.

Materials and Finishes

• 304 stainless steel (A2): corrosion-resistant austenitic stainless for general industrial, food-grade and sheltered outdoor use. The nylon insert still limits continuous service temperature regardless of the nut body material.
• 316 stainless steel (A4): marine grade, for coastal, chemical and high-chloride environments where 304 isn't sufficiently corrosion-resistant.
• Zinc-plated (Class 6, 8, 10): standard carbon steel body with electroplated zinc for mild corrosion protection in general engineering, construction and workshop use. Class 8 is the most commonly stocked grade.
• Zinc-yellow passivate: yellow chromate passivation over zinc plating for improved corrosion resistance over clear zinc, commonly specified in automotive and earthmoving applications.
• Mechanically galvanised: a heavier zinc coating than electroplating, suited to outdoor, structural and construction applications.

Nut Profiles

• Standard hex nyloc: the most common profile, hex flats sized for standard sockets and spanners.
• Heavy hex nyloc: wider and thicker than standard hex for greater bearing area in structural and high-load fastening.
• Thin hex nyloc: reduced height for space-constrained assemblies where a full-depth nut won't fit.

AIMS also stocks natural nylon dome (cap) nuts in this range for covering exposed thread ends and protecting against snagging or corrosion. These are blind cover nuts rather than vibration-locking nuts — for a locking function, choose one of the nyloc types above.

Assortment Kits

For workshops and service vehicles that need a spread of sizes on hand, we stock several nyloc assortment kits from Champion and GJ Works, covering metric, UNC, UNF and mixed metric/imperial ranges in single cases — useful for maintenance teams who don't want to hold full-carton stock of every individual size.

Nyloc vs. All-Metal Lock Nuts

Nyloc nuts are the right default for general workshop, automotive and machinery fastening below the nylon insert's temperature limit. Where a joint runs hotter, needs to be reused repeatedly, or sits somewhere the nylon could perish or contaminate a process (food-grade lines, some chemical plant), an all-metal lock nut is the better fit. We stock all-metal stainless hex lock nuts, cone lock nuts and high-tensile flanged/collared lock nuts in our broader Lock Nuts collection.

Companion Collections

• Lock Nuts — our broader range covering all-metal, cone and flanged lock nut types alongside nyloc.
• Hex Lock Nuts — non-nylon, all-metal hex lock nuts.
• Flanged Nuts — nuts with an integral bearing flange.
• Nuts — our full nut range hub.
• Fasteners — the complete AIMS fastener range.

Order Nyloc Nuts from AIMS Industrial

Not sure which grade, thread or finish suits your application? Our team can help you match the right nyloc nut to the bolt, load and environment. Call us on (02) 9773 0122, contact our team, or request a quote for bulk or trade pricing.

Frequently Asked Questions

What is the difference between a regular nut and a nyloc nut?
A regular hex nut relies purely on thread friction and torque to stay in place, which can back off under vibration. A nyloc nut has a nylon insert moulded into the top of the nut that grips the bolt thread, adding resistance to loosening that a plain nut doesn't have.

What is a nyloc nut used for?
Nyloc nuts are used wherever a joint is subject to vibration or repeated movement and needs to stay tight — workshop machinery, automotive assemblies, general engineering and construction, provided the operating temperature stays within the nylon insert's rated range.

How many times can you use a nyloc nut?
Locking performance reduces a little each time the nut is run down a thread, so a new nyloc nut is recommended for safety-critical or high-vibration joints. For light-duty, non-critical work they're sometimes reinstalled a small number of times, but if in doubt, fit a new one.

Can nyloc nuts be removed?
Yes — they unscrew with a standard spanner or socket like any hex nut, though you'll feel extra resistance ("running torque") from the nylon insert as it passes over the bolt thread.

What temperature can a nyloc nut handle?
Nyloc nuts are generally suited to continuous service up to somewhere around 100–120°C depending on the nylon grade — check the specific product or ask our team if you need an exact rating. For higher temperatures, use an all-metal lock nut instead.

Do you stock stainless nyloc nuts?
Yes — 304 (A2) and 316 (A4) stainless nyloc nuts are stocked in metric and UNC threads for marine, food-grade and corrosive environments.