Lock Nuts
Vibration Resist, Zero Loose Fastening.
Precision Thread, Stable Long-Term Locking.
Full Specs, Industrial Grade Lock Nuts.
Sinsun Lock Nuts | Nylon Insert, Self Locking & Hex Lock Nut Wholesale Supplier
Sinsun manufactures premium lock nuts, including nylon insert lock nuts, self locking nuts, hex lock nuts and flange lock nuts. Shop metric M3-M20 lock nuts with washers for automotive, machinery and industrial anti-loose fastening. Factory bulk price available.
Get a Quick QouteSinsun Lock Nuts – Self-Locking Solutions for Vibration-Intensive Applications
Premium lock nuts from Sinsun – Nylock, all-metal prevailing torque, flange lock nuts, bearing lock nuts, and castle nuts. ISO & ASTM certified. Custom sizes from M3 to M64. Request a quote.
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Sinsun Lock Nuts | Product Overview & Core Brand Advantages
Lock nuts are special industrial fastener accessories to avoid threaded connection loosening caused by vibration, impact and thermal expansion. International markets use a variety of professional names. European industrial buyers call them écrous autobloquants , Spanish buyers know them as tuercas de bloqueo. Mainstream English hardware circles commonly use nylon lock nut , self locking nut and nylon insert lock nut . Unlike conventional hex nuts, these functional fasteners have a physical locking structure that provides continuous fastening tension in high vibration working environments.
As a professional lock nut manufacturer and global supplier, Sinsun creates exclusive product differentiation beyond generic hardware factories. In most cases, most suppliers offer only one type of lock nut with an anti-loose structure and one type with an unstable tolerance. The lock nut series are divided into locking mechanism, structural type and application scenario, including nylon insert, all-metal stover, flange, cam and bearing lock nuts. All products meet DIN, ISO and ANSI industrial standards to ensure accurate thread matching and consistent locking torque.
Global engineering and manufacturing customers often face critical pain points such as nut loosening under long-term equipment vibration, thread slipping, insufficient locking force and poor durability of low-grade locking nuts. We eliminate these defects through precision cold forging, integral forming and rigorous torque testing. Our full range of Sinsun lock nuts, including metric M6/M8/M10/M12 Lock nuts, Lock nut and washer assembly and top lock nuts, are stable with anti-loose performance under dynamic operating scenarios in automotive, mechanical and marine. And we offer customized sizes and structural optimization for specific industrial project needs.
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As a professional lock nut manufacturer and global supplier, Sinsun creates exclusive product differentiation beyond generic hardware factories. In most cases, most suppliers offer only one type of lock nut with an anti-loose structure and one type with an unstable tolerance. The lock nut series are divided into locking mechanism, structural type and application scenario, including nylon insert, all-metal stover, flange, cam and bearing lock nuts. All products meet DIN, ISO and ANSI industrial standards to ensure accurate thread matching and consistent locking torque.
Global engineering and manufacturing customers often face critical pain points such as nut loosening under long-term equipment vibration, thread slipping, insufficient locking force and poor durability of low-grade locking nuts. We eliminate these defects through precision cold forging, integral forming and rigorous torque testing. Our full range of Sinsun lock nuts, including metric M6/M8/M10/M12 Lock nuts, Lock nut and washer assembly and top lock nuts, are stable with anti-loose performance under dynamic operating scenarios in automotive, mechanical and marine. And we offer customized sizes and structural optimization for specific industrial project needs.
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Complete Lock Nut Types | Sinsun’s Full Range of
Self-Locking Nuts
Explore all lock nut types from Sinsun — Nylock / nylon insert lock nuts, all-metal prevailing torque lock nuts, flange lock nuts, stover lock nuts, and bearing lock nuts. ISO & ASTM certified.
| Thread Size | Threads per Inch | Width Across Flats (in) | Nut Height (in) | Grade |
| #4-40 | 40 | 1/4″ | 3/32″ | N2 / N5 |
| #6-32 | 32 | 5/16″ | 7/64″ | N2 / N5 |
| #8-32 | 32 | 11/32″ | 1/8″ | N2 / N5 |
| #10-24 | 24 | 3/8″ | 5/32″ | N2 / N5 |
| 1/4″-20 | 20 | 7/16″ | 7/32″ | N2 / N5 / N8 |
| 5/16″-18 | 18 | 1/2″ | 17/64″ | N2 / N5 / N8 |
| 3/8″-16 | 16 | 9/16″ | 21/64″ | N2 / N5 / N8 |
| 7/16″-14 | 14 | 5/8″ | 3/8″ | N5 / N8 |
| 1/2″-13 | 13 | 3/4″ | 7/16″ | N5 / N8 |
| 9/16″-12 | 12 | 7/8″ | 31/64″ | N5 / N8 |
| 5/8″-11 | 11 | 15/16″ | 35/64″ | N5 / N8 |
| 3/4″-10 | 10 | 1-1/8″ | 41/64″ | N5 / N8 |
| 1″-8 | 8 | 1-1/2″ | 55/64″ | N5 / N8 |
| Thread Size | Pitch (mm) | Width Across Flats (mm) | Nut Height (mm) | Material / Grade Availability |
| M3 | 0.5 | 5.5 | 4 | 8 / A2-70 |
| M4 | 0.7 | 7 | 5 | 8 / 10 / A2-70 |
| M5 | 0.8 | 8 | 5 | 8 / 10 / A4-80 |
| M6 | 1 | 10 | 6 | 8 / 10 / A2-70 |
| M8 | 1.25 | 13 | 8 | 8 / 10 / A4-80 |
| M10 | 1.5 | 16.0 or 17.0 | 10 | 8 / 10 / A2-70 |
| M12 | 1.75 | 18.0 or 19.0 | 12 | 8 / 10 / A4-80 |
| M14 | 2 | 21.0 or 22.0 | 14 | 8 / 10 / A4-80 |
| M16 | 2 | 24 | 16 | 8 / 10 / A2-70 |
| M20 | 2.5 | 30 | 20 | 8 / 10 / A4-80 |
| M24 | 3 | 36 | 24 | 8 / 10 / A4-80 |
| M30 | 3.5 | 46 | 30 | 8 / 10 / A4-80 |
| M36 | 4 | 55 | 36 | 8 |
Product Aliases:
Nylock nut, self locking nut, nylon lock nuts, top lock nut, locking hex nut, lock nut washer assembly.
Main Materials:
Carbon steel, alloy steel, 304/316 stainless steel, PA66 high-toughness nylon.
Hot-Selling Specs:
Metric M3, M5, M6, M8, M10, M12, M16, M20; Imperial 1/4, 3/8, 1/2, 5/8, 3/4.
Surface Treatment:
Zinc plating, hot-dip galvanized, black oxide, passivation, polishing.
Compliant Standards:
DIN 985, DIN 982, ISO 7040, ISO 10512 industrial locking fastener standards.
Core Performance:
Vibration resistance, high locking torque, reusable, high temperature resistant.
Matching Accessories:
Matched bolts, flat washers, spring washers for complete lock nuts and bolts sets.
Custom Service:
Support fine thread, special locking structure and custom surface treatment.
1. Automotive & Transportation Equipment
Nylon insert lock nuts and flange lock nuts are essential anti-loose fasteners for automotive chassis, engines and suspension systems. These self locking nuts counteract constant vibrations and road shocks while the vehicle is operated to prevent connection loosening. The high strength material has a constant locking torque in varying temperature environments. They are an effective means of reducing automotive equipment failure rates due to loose fasteners.
2. Precision Mechanical Equipment
Cam lock nuts and bearing lock nuts allow precise positioning in automated production lines and transmission components. Assembly gaps and operational jitter are eliminated thanks to ultra-precise thread tolerance. Stable locking performance adapts to long-term low frequency cyclic movement. Professional lock nuts of these equipment assure repetitive motion accuracy and stability of equipment operation.
3. Heavy-Duty Industrial Machinery
Heavy-load mechanical equipment and high-temperature industrial use are the applications for strong all-metal lock nuts. The all-metal design eliminates high temperature aging and fatigue failure inherent in nylon lock nuts. Strong locking tension resists heavy pressure and vibration. These strong lock nuts extend mining, engineering and industrial machines' service lives.
4. Outdoor Construction & Municipal Facilities
Galvanized hex bolt nuts and lock nut washer assemblies for outdoor steel structures, guardrails and municipal facilities. Anti-corrosion surface treatment prevents rust and locking failure in humid and open-air conditions. The integrated structure of the washer improves pressure resistance and fastening firmness. They reduce outdoor engineering projects' long-term maintenance costs.
5. Electronic & Household Mechanical Devices
MINIATURE M3/M5/M6 nylon wing nuts and secure wing nuts for electronic equipment and household appliances. The soft nylon insert prevents damage to precision threads when repeatedly disassembled. Tool-free wing lock nuts for easier maintenance of adjustable equipment. These light weight fasteners meet light industrial products' assembly requirements.
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Torque to specification – Over-torquing can strip the threads or damage the locking element. The joint is not tight under torque. Ask Sinsun for the torque chart applied to your particular type of lock nut and bolt grade.
For nylon insert lock nuts it is imperative to install them with the nylon ring facing the bolt tip (away from the bearing surface). To function correctly, the nylon ring should be on the opposite side of the joint from the bolt head.
Use the latest lock nuts for safety critical joints – The prevailing torque drops with each installation cycle. - In aerospace, automotive brakes/suspension and pressure vessel flanges, replace old lock nuts and stover lock nuts with replacement nuts each time.
Check bolt thread condition – Burring, rusty or damaged bolt threads will diminish locking performance. Before installing lock nuts and bolt assemblies, clean the bolts with a thread chaser.
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Real Customer Stories | Sinsun Fasteners in Action
Engineers and procurement managers across Latin America, Southeast Asia, and the Middle East share their experience with Sinsun‘s bolts and nuts – on‑time delivery, precise threading, and consistent quality.
Q1: What are lock nuts used for to stop screws loosening from vibration?
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A: Lock nuts create friction locking force to resist vibration, seasonal wood movement and mechanical shaking, widely applied on deck frames, construction brackets and machinery to prevent fastener backing out.
Q3: Can nylon insert lock nuts be used for exterior outdoor construction projects?
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A: Yes, galvanized nylon lock nuts support outdoor use. The zinc coating prevents rust jacking, while the nylon insert maintains anti-backout performance in humid and temperature-changing environments like outdoor decks.
Q5: Why do regular hex nuts back out easily on vibrating machinery and deck boards?
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A: Without friction locking structures, standard hex nuts lose clamping force from continuous vibration and wood seasonal shrinkage; lock nuts eliminate this issue via built-in anti-loose locking design.
Q2: How do lock nuts differ from standard hex nuts in anti-loosening performance?
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A: Ordinary hex nuts only rely on basic thread fit; lock nuts add nylon inserts or deformed threads to build extra friction, effectively solving the common problem of loose fasteners under long-term vibration.
Q4: What size lock nuts match full threaded deck screws and structural bolts?
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A: We supply metric & imperial lock nut sizes compatible with full threaded deck screws, partial threaded fasteners and construction anchor bolts. Custom sizes are available for wholesale bulk orders.
Q6: Can lock nuts replace washers to reinforce outdoor fastening connections?
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A: Lock nuts alone deliver reliable anti-loose effects for most light & medium loads. For heavy structural construction, pairing lock nuts with flat washers further boosts holding power on soft wood and thin metal plates.
We manufacture, not distribute.
One supplier, all lock nut types.
Technical support that engineers actually respect.
Global compliance with local responsiveness.
Low MOQs for samples, capacity for scale.
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