Locknuts
1608 ProductsNylon-Insert Locknuts
High-Strength Steel Nylon-Insert Locknuts—Grade 8
High-strength steel with a Grade 8 rating, which indicates high tensile strength.
Metric High-Strength SteelNylon-Insert Locknuts—Class 10
Metric High-Strength Steel Nylon-Insert Locknuts—Class 10 offer robust performance with a nylon insert to prevent loosening, designed for high-strength applications and meeting Class 10 specifications.
Metric Fine-Thread High-StrengthSteel Nylon-Insert Locknuts—Class 10
Metric Fine-Thread High-Strength Steel Nylon-Insert Locknuts—Class 10 provide a secure and stable fastening solution with fine threads and a nylon insert to prevent loosening, designed for high-strength applications and adhering to Class 10 standards.
Medium-Strength Steel Nylon-Insert Locknuts—Grade 5
Medium-Strength Steel Nylon-Insert Locknuts—Grade 5 offer reliable performance with a nylon insert to prevent loosening, designed for medium-strength applications and meeting Grade 5 standards.
Metric Medium-Strength SteelNylon-Insert Locknuts—Class 8
Metric Medium-Strength Steel Nylon-Insert Locknuts—Class 8 provide secure fastening with a nylon insert to prevent loosening, designed for medium-strength applications and conforming to Class 8 standards.
Metric Fine-Thread Medium-StrengthSteel Nylon-Insert Locknuts—Class 8
Metric Fine-Thread Medium-Strength Steel Nylon-Insert Locknuts—Class 8 offer a secure fastening solution with fine threads and a nylon insert to prevent loosening, designed for medium-strength applications and meeting Class 8 standards.
Low-Strength Steel Nylon-Insert Locknuts
Low-Strength Steel Nylon-Insert Locknuts provide reliable fastening with a nylon insert to prevent loosening, designed for applications requiring lower tensile strength and reduced load-bearing capacity.
Mil. Spec. Low-Strength Steel Nylon-Insert Locknuts
Mil. Spec. Low-Strength Steel Nylon-Insert Locknuts are designed to meet military specifications, offering reliable performance with a nylon insert that prevents loosening under vibrations, while being suitable for applications requiring lower tensile strength.
18-8 Stainless Steel Nylon-Insert Locknuts
18-8 Stainless Steel Nylon-Insert Locknuts provide durable corrosion resistance and a secure fit with a nylon insert that prevents loosening under vibration and thermal changes.
Metric 18-8 Stainless Steel Nylon-Insert Locknuts
Metric 18-8 Stainless Steel Nylon-Insert Locknuts offer reliable corrosion resistance and secure fastening in metric sizes, featuring a nylon insert that helps prevent loosening due to vibrations and thermal changes.
Mil. Spec. 18-8 Stainless Steel Nylon-Insert Locknuts
Mil. Spec. 18-8 Stainless Steel Nylon-Insert Locknuts offer exceptional corrosion resistance and secure fastening through a nylon insert, meeting stringent military standards for reliability and performance.
Super-Corrosion-Resistant 316Stainless Steel Nylon-Insert Locknuts
Super-Corrosion-Resistant 316 Stainless Steel Nylon-Insert Locknuts provide superior corrosion resistance and secure fastening in harsh environments, featuring a nylon insert to prevent loosening due to vibration and thermal fluctuations.
Metric Super-Corrosion-Resistant 316Stainless Steel Nylon-Insert Locknuts
Metric super-corrosion-resistant 316 stainless steel nylon-insert locknuts provide exceptional durability and protection against severe corrosive environments, featuring a metric size for precise fit and a nylon insert that ensures a secure, vibration-resistant connection, ideal for high-performance applications in marine, chemical, and other extreme conditions.
Aluminum Nylon-Insert Locknuts
Aluminum nylon-insert locknuts offer a lightweight fastening solution with a nylon insert that ensures a secure, vibration-resistant connection, making them suitable for applications where reducing weight is important while still providing reliable fastening and moderate strength.
Brass Nylon-Insert Locknuts
Brass nylon-insert locknuts provide excellent corrosion resistance and durability with a nylon insert that offers a secure, vibration-resistant connection, making them ideal for applications where both moderate strength and protection against rust or corrosion are required.
Titanium Nylon-Insert Locknuts
Titanium nylon-insert locknuts combine the lightweight, high-strength properties of titanium with a nylon insert that ensures secure, vibration-resistant fastening, making them ideal for high-performance applications in aerospace, automotive, and other demanding environments where both strength and weight are critical.
Thin Nylon-Insert Locknuts
Low-Strength Steel Thin Nylon-Insert Locknuts
Low-strength steel thin nylon-insert locknuts feature a compact design with a nylon insert that prevents loosening due to vibration, offering a cost-effective and reliable fastening solution for applications with moderate load requirements and less demanding environmental conditions.
Metric Low-Strength Steel Thin Nylon-Insert Locknuts
Metric low-strength steel thin nylon-insert locknuts provide a compact, cost-effective solution with a nylon insert that ensures secure, vibration-resistant fastening, suitable for metric-sized applications requiring moderate load-bearing capacity and protection against loosening in less demanding environments.
Mil. Spec. Low-Strength Steel Thin Nylon-Insert Locknuts
Mil. Spec. low-strength steel thin nylon-insert locknuts adhere to military specifications for consistent performance and reliability, offering a compact design with a nylon insert that provides secure, vibration-resistant fastening in applications where moderate strength and adherence to rigorous standards are required.
High-Strength Steel Thin Nylon-Insert Locknuts
High-strength steel thin nylon-insert locknuts offer robust durability and load-bearing capacity with a compact design, featuring a nylon insert that ensures a secure, vibration-resistant connection, making them ideal for high-stress applications requiring reliable and strong fastening.
Medium-Strength Steel Thin Nylon-Insert Locknuts
Medium-strength steel thin nylon-insert locknuts provide a durable, space-saving solution with a nylon insert that prevents loosening from vibration, making them suitable for applications requiring moderate strength and reliable fastening in less demanding environments.
18-8 Stainless Steel Thin Nylon-Insert Locknuts
18-8 stainless steel thin nylon-insert locknuts offer a compact design with moderate corrosion resistance, featuring a nylon insert that provides secure, vibration-resistant fastening for applications where strength and reliability are needed in environments with moderate exposure to moisture and corrosion.
Mil. Spec. 18-8 Stainless Steel Thin Nylon-Insert Locknuts
Mil. Spec. 18-8 stainless steel thin nylon-insert locknuts meet military specifications for durability and performance, offering moderate corrosion resistance with a slim design and a nylon insert for secure, vibration-resistant fastening, making them ideal for demanding applications in aerospace, defense, and industrial settings.
Super-Corrosion-Resistant 316 StainlessSteel Thin Nylon-Insert Locknuts
Super-corrosion-resistant 316 stainless steel thin nylon-insert locknuts provide exceptional corrosion resistance, especially in harsh or marine environments, with a slim design and a nylon insert for secure, vibration-resistant fastening, making them ideal for applications requiring durability and protection from extreme conditions.
Thin Heavy Nylon-Insert Locknuts
High-Strength Steel Thin Heavy Nylon-Insert Locknuts
High-strength steel thin heavy nylon-insert locknuts offer superior durability and load-bearing capacity, with a space-saving design and a nylon insert that ensures a secure, vibration-resistant lock, making them ideal for high-stress applications requiring reliable fastening in demanding environments.
Low-Strength Steel Thin Heavy Nylon-Insert Locknuts
Low-strength steel thin heavy nylon-insert locknuts provide a cost-effective solution for moderate-load applications, featuring a compact design and a nylon insert that prevents loosening due to vibration, making them suitable for less demanding environments where high strength is not required.
18-8 Stainless Steel Thin Heavy Nylon-Insert Locknuts
18-8 stainless steel thin heavy nylon-insert locknuts offer a compact design with moderate corrosion resistance, thanks to their 18-8 stainless steel construction, while the integrated nylon insert provides a secure, vibration-resistant locking mechanism.
Super-Corrosion-Resistant 316 StainlessSteel Thin Heavy Nylon-Insert Locknuts
Super-corrosion-resistant 316 stainless steel thin heavy nylon-insert locknuts feature a compact, space-saving design with a durable 316 stainless steel body for exceptional resistance to corrosion, especially in harsh or marine environments. The integrated nylon insert provides a secure, vibration-resistant locking mechanism.
Heavy Nylon-Insert Locknuts
18-8 Stainless Steel Heavy Nylon-Insert Locknuts
18-8 Stainless Steel Heavy Nylon-Insert Locknuts provide exceptional corrosion resistance and secure fastening with a heavy-duty nylon insert that resists loosening under high vibration and thermal stress.
Super-Corrosion-Resistant 316 StainlessSteel Heavy Nylon-Insert Locknuts
Super-Corrosion-Resistant 316 Stainless Steel Heavy Nylon-Insert Locknuts offer superior protection against corrosion with a heavy-duty nylon insert to ensure a secure fit and prevent loosening in extreme environments.
Steel Heavy Nylon-Insert Locknuts
Steel Heavy Nylon-Insert Locknuts provide a strong and secure fastening solution with a heavy-duty nylon insert that resists loosening under high vibration and stress.
High-Strength Steel HeavyNylon-Insert Locknuts—Grade 8
High-Strength Steel Heavy Nylon-Insert Locknuts—Grade 8 offer exceptional durability and secure fastening with a heavy-duty nylon insert, designed to withstand high stress and vibration in demanding applications.
Locknuts with Washer
Steel Locknuts with External-Tooth Lock Washer
Steel Locknuts with External-Tooth Lock Washer combine the locking strength of a steel nut with the added security of an external-tooth lock washer, which grips the surface and prevents loosening from vibrations and movements.
Metric Steel Locknuts with External-Tooth Lock Washer
Metric Steel Locknuts with External-Tooth Lock Washer provide reliable fastening with the added security of an external-tooth washer, designed to prevent loosening and ensure a firm grip in metric applications.
Stainless Steel Locknuts withExternal-Tooth Lock Washer
Stainless Steel Locknuts with External-Tooth Lock Washer offer enhanced corrosion resistance and secure fastening, featuring an external-tooth washer that grips the surface to prevent loosening under vibration and movement.
Metric Stainless Steel Locknutswith External-Tooth Lock Washer
Metric Stainless Steel Locknuts with External-Tooth Lock Washer offer reliable corrosion resistance and a secure fit, with an external-tooth washer that enhances grip and prevents loosening in metric applications.
Metric Steel Nonmarring Locknutswith Spring-Lock Washer
Metric Stainless Steel Locknuts with External-Tooth Lock Washer offer reliable corrosion resistance and a secure fit, with an external-tooth washer that enhances grip and prevents loosening in metric applications.
Steel Nonmarring Locknuts with Spring-Lock Washer
Steel Nonmarring Locknuts with Spring-Lock Washer are designed to secure fastenings without damaging the surface, featuring a spring-lock washer that provides additional resistance to loosening and ensures a stable connection.
Steel Narrow Locknuts with External-Tooth Lock Washer
Steel Narrow Locknuts with External-Tooth Lock Washer provide a compact and secure fastening solution, featuring an external-tooth washer that grips the surface to prevent loosening and accommodate tighter spaces.
Distorted-Thread Locknuts
High-Strength Steel Top-Lock Distorted-Thread Locknuts
High-Strength Steel Top-Lock Distorted-Thread Locknuts are designed to offer exceptional security and resistance to loosening, with distorted threads that create a tight fit and prevent rotation under high stress and vibration.
Metric Medium-Strength Steel Top-LockDistorted-Thread Locknuts—Class 8
Metric Medium-Strength Steel Top-Lock Distorted-Thread Locknuts—Class 8 provide reliable fastening with distorted threads that enhance grip and prevent loosening, designed for medium-strength applications and adhering to Class 8 standards.
Medium-Strength Steel Top-LockDistorted-Thread Locknuts—Grade 5
Medium-Strength Steel Top-Lock Distorted-Thread Locknuts—Grade 5 offer secure fastening with distorted threads that prevent loosening, designed for medium-strength applications and meeting Grade 5 specifications.
Low-Strength Steel Top-Lock Distorted-Thread Locknuts
Low-Strength Steel Top-Lock Distorted-Thread Locknuts provide a secure connection with distorted threads that prevent loosening, designed for applications requiring lower tensile strength.
Extreme-Strength Steel Top-LockDistorted-Thread Locknuts
Extreme-Strength Steel Top-Lock Distorted-Thread Locknuts offer maximum security and resistance to loosening with distorted threads, designed for high-stress applications requiring extreme strength.
18-8 Stainless Steel Top-Lock Distorted-Thread Locknuts
18-8 Stainless Steel Top-Lock Distorted-Thread Locknuts provide reliable corrosion resistance and a secure fit with distorted threads that prevent loosening, ideal for applications where durability and resistance to environmental factors are crucial.
Super-Corrosion-Resistant 316 StainlessSteel Top-Lock Distorted-Thread Locknuts
Super-Corrosion-Resistant 316 Stainless Steel Top-Lock Distorted-Thread Locknuts offer exceptional protection against corrosion and a secure fastening solution with distorted threads that prevent loosening in harsh environments.
High-Strength Steel Center-LockDistorted-Thread Locknuts—Grade 8
High-Strength Steel Center-Lock Distorted-Thread Locknuts—Grade 8 provide superior strength and security with distorted threads that prevent loosening, designed for high-stress applications and meeting Grade 8 specifications.
Left-Hand Threaded High-Strength SteelCenter-Lock Distorted-Thread Locknuts—Grade 8
Left-Hand Threaded High-Strength Steel Center-Lock Distorted-Thread Locknuts—Grade 8 offer robust performance with left-hand threading and distorted threads to prevent loosening, designed for high-stress applications and adhering to Grade 8 standards.
Metric Medium-Strength Steel Center-LockDistorted-Thread Locknuts—Class 8
Metric Medium-Strength Steel Center-Lock Distorted-Thread Locknuts—Class 8 provide secure fastening with distorted threads that enhance grip and prevent loosening, designed for medium-strength applications and meeting Class 8 specifications.
Low-Strength Steel Center-LockDistorted-Thread Locknuts
Low-Strength Steel Center-Lock Distorted-Thread Locknuts offer secure fastening with distorted threads to prevent loosening, designed for applications requiring lower tensile strength.
18-8 Stainless Steel Center-LockDistorted-Thread Locknuts
18-8 Stainless Steel Center-Lock Distorted-Thread Locknuts provide reliable corrosion resistance and a secure fit with distorted threads that prevent loosening, suitable for applications where durability and environmental resistance are important.
Super-Corrosion-Resistant 316 StainlessSteel Center-Lock Distorted-Thread Locknuts
Super-Corrosion-Resistant 316 Stainless Steel Center-Lock Distorted-Thread Locknuts deliver exceptional durability and corrosion resistance with distorted threads that prevent loosening, ideal for harsh environments and demanding applications.
Flex-Top Locknuts for Heavy Vibration
Steel Flex-Top Locknuts for Heavy Vibration
Steel Flex-Top Locknuts for Heavy Vibration are designed to provide secure fastening under conditions of intense vibration, featuring a flexible top that adapts to dynamic loads and helps prevent loosening.
Metric Steel Flex-Top Locknuts for Heavy Vibration
Metric Steel Flex-Top Locknuts for Heavy Vibration offer reliable fastening in metric sizes, with a flexible top designed to withstand intense vibration and prevent loosening in dynamic applications.
Mil. Spec. Steel Flex-Top Locknuts for Heavy Vibration
Mil. Spec. Steel Flex-Top Locknuts for Heavy Vibration are engineered to meet military specifications, providing exceptional performance and security under heavy vibration conditions with a flexible top that helps prevent loosening.
Stainless Steel Flex-Top Locknuts for Heavy Vibration
Stainless Steel Flex-Top Locknuts for Heavy Vibration deliver robust performance and resistance to corrosion, featuring a flexible top designed to maintain a secure fit and prevent loosening in high-vibration environments.
Metric Stainless Steel Flex-TopLocknuts for Heavy Vibration
Metric Stainless Steel Flex-Top Locknuts for Heavy Vibration provide reliable fastening in metric sizes, featuring a flexible top that adapts to high-vibration conditions and prevents loosening, while offering excellent corrosion resistance.
Mil. Spec. Stainless Steel Flex-TopLocknuts for Heavy Vibration
Mil. Spec. Stainless Steel Flex-Top Locknuts for Heavy Vibration are designed to meet military specifications, offering superior corrosion resistance and a flexible top that ensures secure fastening and prevents loosening under heavy vibration conditions.
Steel Thin Flex-Top Locknuts for Heavy Vibration
Steel Thin Flex-Top Locknuts for Heavy Vibration provide a secure fastening solution with a thin profile and flexible top, designed to withstand intense vibration and prevent loosening in space-constrained applications.
Stainless Steel Thin Flex-TopLocknuts for Heavy Vibration
Stainless Steel Thin Flex-Top Locknuts for Heavy Vibration offer a secure and corrosion-resistant fastening solution with a thin profile and flexible top, designed to endure heavy vibration and prevent loosening in tight spaces.
Steel Heavy Flex-Top Locknuts for Heavy Vibration
Steel Heavy Flex-Top Locknuts for Heavy Vibration are built for robust performance, featuring a heavy-duty design and a flexible top that ensures secure fastening and resists loosening in high-vibration environments.
Stainless Steel Heavy Flex-TopLocknuts for Heavy Vibration
Stainless Steel Heavy Flex-Top Locknuts for Heavy Vibration provide exceptional durability and corrosion resistance with a heavy-duty design and a flexible top, engineered to maintain a secure fit and prevent loosening under intense vibration conditions.
Thin Heavy Flex-Top Locknuts for Heavy Vibration
Thin Heavy Flex-Top Locknuts for Heavy Vibration combine a thin profile with a heavy-duty design and flexible top, offering secure fastening and resistance to loosening in high-vibration applications while fitting into space-constrained areas.
Locknuts for use with Cotter Pins
Medium-Strength Steel Locknutsfor use with Cotter Pins—Grade 5
Medium-Strength Steel Locknuts for Use with Cotter Pins—Grade 5 are designed for reliable fastening in medium-strength applications, featuring a design compatible with cotter pins to prevent loosening, and meeting Grade 5 standards for tensile strength and durability.
Metric Medium-Strength Steel Locknutsfor use with Cotter Pins—Class 8
Metric Medium-Strength Steel Locknuts for use with Cotter Pins—Class 8 are durable fasteners designed for moderate to high-load applications, featuring a hole for a cotter pin to prevent loosening under vibration or torque
Low-Strength Steel Locknuts for use with Cotter Pins
Low-Strength Steel Locknuts for use with Cotter Pins are designed for light-duty applications, featuring a hole for a cotter pin to secure the nut and prevent loosening in low-torque or low-stress environments.
Stainless Steel Locknuts for use with Cotter Pins
Stainless Steel Locknuts for use with Cotter Pins are corrosion-resistant fasteners designed for environments requiring durability and security, with a hole for a cotter pin to ensure the nut remains securely fastened under vibration or rotational forces.
Steel-Insert Locknuts for Extreme Vibration
Metric Steel-Insert Locknutsfor Extreme Vibration—Class 8
Metric Steel-Insert Locknuts for Extreme Vibration—Class 8 are high-strength fasteners designed to resist loosening in environments with extreme vibration, featuring a steel insert for additional grip and security in moderate to high-load applications.
Steel-Insert Locknuts for Extreme Vibration—Grade 5
Steel-Insert Locknuts for Extreme Vibration—Grade 5 are medium-strength fasteners designed to withstand extreme vibration, featuring a steel insert that provides extra locking strength in moderate-load applications.
High-Strength Steel Heavy Steel-InsertLocknuts for Extreme Vibration—Grade 8
High-Strength Steel Heavy Steel-Insert Locknuts for Extreme Vibration—Grade 8 are durable, high-strength fasteners designed for heavy-duty applications, equipped with a steel insert to provide superior resistance to loosening in environments with extreme vibration and high loads.
Medium-Strength Steel Heavy Steel-InsertLocknuts for Extreme Vibration—Grade 5
Medium-Strength Steel Heavy Steel-Insert Locknuts for Extreme Vibration—Grade 5 are designed for moderate to heavy-duty applications, featuring a steel insert that provides extra locking security to prevent loosening in environments with significant vibration.
Thin Steel-Insert Locknuts for Extreme Vibration
Thin Steel-Insert Locknuts for Extreme Vibration are compact fasteners designed for use in space-constrained applications, featuring a steel insert to ensure a secure lock and prevent loosening in environments subject to extreme vibration.
Spring-Stop Locknuts
Metric Low-Strength Steel Spring-Stop Locknuts—Class 6
Metric Low-Strength Steel Spring-Stop Locknuts—Class 6 are designed for light-duty applications, utilizing a spring mechanism to prevent loosening, with a focus on providing a secure lock in environments with minimal vibration or stress.
Metric Stainless Steel Spring-Stop Locknuts
Metric Stainless Steel Spring-Stop Locknuts are corrosion-resistant fasteners designed for secure locking in applications with light to moderate vibration, featuring a spring mechanism to prevent loosening and ensure stability in challenging environments.
Two-Piece Thread-Clamping Locknuts for Extreme Vibration
Two-Piece Thread-ClampingLocknuts for Extreme Vibration
Two-Piece Thread-Clamping Locknuts for Extreme Vibration are designed with a two-piece construction that clamps onto the threads for a more secure hold, providing excellent resistance to loosening in environments subject to extreme vibration and high stress.
Locknut Assortments
Nylon-Insert Locknut Assortments
Nylon-Insert Locknut Assortments are collections of locknuts that feature a nylon insert to create friction with the threads of a bolt, preventing loosening in applications prone to vibration. These assortments typically include various sizes to accommodate a range of fastening needs.
Assortments of Locknuts withExternal-Tooth Lock Washer
Assortments of Locknuts with External-Tooth Lock Washer include a variety of locknuts equipped with external-tooth washers, which bite into the surface to provide a secure hold and resist loosening, especially in environments with vibration or rotational forces. These assortments offer multiple sizes for versatile fastening applications.
LILY Bearing stocks 1,608 locknuts in Inch and Metric threads, across nine distinct locking mechanisms and dozens of material and strength options. Use the filters below, or the comparison table, to narrow down by locking type, material, or thread size.
Compare Locking Mechanisms
| Type | How It Locks | Best For | Watch Out For |
|---|---|---|---|
| Nylon-Insert Locknuts | A nylon ring inside the nut grips the bolt threads | General-purpose vibration resistance without marring the mating surface | Insert is rated to about 220°F — not for higher-temperature service |
| Serrated Locknuts | Serrations on the bearing surface dig into the mating material | Bare metal surfaces where marring is acceptable | Can mar painted, coated, or finished surfaces |
| Distorted-Thread Locknuts (Top-Lock / Center-Lock) | A deformed section of the internal thread grips the bolt — no plastic insert | Higher-temperature environments where a nylon insert would degrade | Generally needs more installation torque than a nylon-insert type |
| Flex-Top Locknuts for Heavy Vibration | Threads at the top of the nut expand to grip the bolt on all sides | Heavy vibration where a stronger hold than distorted-thread is needed | All-metal grip means higher installation torque than nylon-insert types |
| Steel-Insert Locknuts for Extreme Vibration | A separate steel insert grips the threads and lifts away from the nut body, isolating it from the load | Extreme vibration where resisting spin-off matters more than raw clamp strength | A distinct mechanism from flex-top or distorted-thread — not interchangeable by name alone |
| Locknuts with External-Tooth Lock Washer (Keps/K-Lock) | A free-spinning tooth washer grips the material surface instead of the bolt threads | Easy installation with mild vibration resistance | Weaker locking than nylon-insert or distorted-thread types |
| Nonmarring Locknuts with Spring-Lock Washer | A curved spring washer with a smooth rim grips without biting into the surface | Mild vibration resistance on surfaces that can't be scratched | Less holding power than a toothed washer or distorted-thread locknut |
| Two-Piece Thread-Clamping Locknuts (Drake-Style) | A two-piece clamp expands to grip the bolt on all sides, plus a concave jam nut that clamps threads for extra resistance | Extreme vibration and high-stress applications | More complex assembly than a single-piece locknut |
| Locknuts for Use with Cotter Pins | Slots in the nut align with a hole in the bolt so a cotter pin can mechanically lock it in place | Applications needing a positive, visually verifiable mechanical lock, such as access panels | Requires a matching drilled bolt and a cotter pin — not a drop-in replacement for a standard nut |
Matching the Mechanism to Your Vibration Level
Not every locknut resists vibration the same amount. Locknuts with an external-tooth or spring-lock washer offer mild resistance and easy installation, gripping the surface rather than the threads. Nylon-insert and serrated locknuts step up to general-purpose vibration resistance. For heavy or extreme vibration, all-metal mechanisms — flex-top, steel-insert, and two-piece thread-clamping designs — grip the bolt threads directly and hold up in higher-temperature environments where a nylon insert would degrade. If you need a mechanically verifiable lock rather than a friction-based one, locknuts for use with cotter pins provide a positive lock that can be visually inspected.
Need a Custom Locknut or a Part Cross-Reference?
Working from an existing McMaster-Carr or manufacturer part number? Our team can cross-reference it to an equivalent LILY Bearing locknut, or quote a custom material, locking type, or finish. Request a Quote or Contact Us.
Frequently Asked Questions
What's the difference between a nylon-insert locknut and a distorted-thread locknut?
A nylon-insert locknut grips the bolt with a plastic ring, which is limited to roughly 220°F. A distorted-thread locknut uses a deformed section of all-metal thread instead, so it holds up in higher temperatures but generally needs more torque to install.
What's the difference between a locknut with a lock washer and a distorted-thread or nylon-insert locknut?
Locknuts with an external-tooth or spring-lock washer grip the material surface, not the bolt threads, offering mild vibration resistance and easy installation. Nylon-insert and distorted-thread locknuts grip the bolt threads directly, giving stronger holding power for more demanding vibration.
What does a steel-insert locknut do differently from a flex-top locknut?
A steel-insert locknut has a separate insert that grips the bolt threads and lifts slightly away from the nut body, isolating the insert from the clamping load. A flex-top locknut instead uses the expanding threads at the top of the nut itself to grip the bolt on all sides. Both are all-metal, high-vibration solutions, but they're mechanically distinct.
When would I use a locknut for use with cotter pins instead of a nylon-insert or distorted-thread locknut?
Use a cotter-pin locknut when you need a positive mechanical lock that can be visually verified, rather than one that relies on friction. It requires a bolt drilled to match the nut's slots and a cotter pin, so it's not a drop-in swap for a standard locknut.
