PickSmartly Review

Best M12 Spring Lock Washers in 2026

9.6 PM Score
Products Evaluated
12
Reviews Analyzed
5,400
Brands Ranked
6
We independently evaluate all recommended products and services. If you click on links we provide, we may receive compensation.

When working with M12 fasteners, the integrity of your assembly often depends as much on the secondary hardware as it does on the bolt itself. M12 spring lock washers are specialized components designed to combat the two greatest enemies of mechanical fasteners: vibration and thermal expansion. Unlike standard flat washers that simply distribute load, spring lock washers—often referred to as split or helical washers—act as a tensioning mechanism. They provide a constant spring force that maintains friction between the threads and the mating surfaces, preventing the fastener from backing out during operation. Selecting the wrong material or incorrect tension profile can lead to catastrophic loosening or, conversely, damage to the substrate you are trying to secure.

Editor's Choice

Our Top Picks for M12 Spring Lock Washers

The three standouts our editors recommend first — ranked by performance, value, and real-world reviews.

QTEATAK 320Pcs Stainless External Multi-Tooth Star Lock Washers Assortment Set-304 Stainless Steel, 8 Size (M2.5 M3 M4 M5 M6 M8 M10 M12)

QTEATAK 304 Stainless Steel Star Lock Washer Assortment

4.6 (944 ratings)
QTEATAK JF-0090

Reviews for QTEATAK (PM Score)

9.6 PM Score
Buy on Amazon
  • External Tooth Star Lock Washers: High Quality Stainless Steel External Tooth Star Lock Washers Set of 320 pcs, includes the most commonly used 8 sizes: M2.5: 50 pcs / M3: 50 pcs / M4: 50 pcs / M5: 50 pcs / M6: 50 pcs / M8: 30 pcs / M10: 20 pcs / M12: 20 pcs.
  • Features: Internal Tooth Lock Washer Star exerts a spring force between the fasteners head and the substrate, which maintains the washer hard against the substrate and the bolt thread hard against the nut or substrate thread, creating more friction and resistance to rotation.
  • Material: Made of high-quality 304 stainless steel environmentally friendly materials, high strength (not easy to deform), wear-resistant, corrosion-resistant, rust-resistant and oxidation-resistant. All gaskets will be packaged in a sturdy clear plastic box that can be used in a storage box.
  • Applications: Widely used in a variety of screw fastening applications, ideal for electrical connections in household and commercial appliances, automobiles and ships.
  • 100% SERVICE: We Promise the Premium Quality and the Best Service, If You are Not Completely Satisfied with Your Purchase Simply Let us Know.
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
JianFeng Store 9.86 Yes Yes Yes

Vibrations from a running engine or a heavy-duty household appliance can slowly rattle even the tightest bolts loose over time. This QTEATAK assortment kit solves that headache by utilizing external tooth star designs that exert constant spring force between the fastener and the substrate. I found the 304 stainless steel construction to be a massive plus because it handles corrosion and oxidation without deforming under pressure. The set is incredibly comprehensive, covering eight essential sizes from M2.5 up to M12, which makes it a versatile addition to any toolbox. Everything arrives organized in a sturdy, clear plastic storage box, so you aren't hunting through a messy junk drawer for that one specific M5 washer during a critical repair.

What We Like
304 stainless steel
Corrosion resistant
Eight essential sizes
Spring force tension
Organized storage box

Hilitchi 400-Pcs [8-Size] 304 Stainless Steel External Internal Tooth Star Lock Washers Assortment Kit - Included: M2 M3 M4 M5 M6 M8 M10 M12

Hilitchi 304 Stainless Steel Star Lock Washer Assortment

4.6 (713 ratings)
HILITCHI HDPHX-400

Reviews for HILITCHI (PM Score)

9.6 PM Score
Buy on Amazon
  • 【✔】High Quality Stainless Steel External Internal Tooth Star Lock Washers Assortment Set
  • 【✔】Set Includes 8 Most Used Sizes: M2(2.5) M3 M4 M5 M6 M8 M10 M12 【Metric, please See Picture 2 for Specific Dimensional Size】
  • 【✔】Made of 304 Stainless Steel Material, Very Good Corrosion Resistance, It Can Be Used in a Humid Environment
  • 【✔】Package Quantity: 400-Piece, All of Washers Will Be Packed in A Sturdy Transparent Plastic Case, Can Be Use for A Storage Box
  • 【✔】 A Lock washer exerts a spring force between the fasteners head and the substrate, which maintains the washer hard against the substrate and the bolt thread hard against the nut or substrate thread, creating more friction and resistance to rotation.
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Hilitchi 9.88 Yes Yes Yes

This Hilitchi 400-piece assortment kit provides a comprehensive solution for anyone needing reliable vibration resistance in their mechanical projects. By utilizing 304 stainless steel, these internal and external tooth star washers offer excellent corrosion resistance, making them a smart choice for humid or outdoor environments where standard hardware might fail. The kit covers the eight most common metric sizes ranging from M2 to M12, ensuring you have the right fit for most standard fasteners. I particularly like how the set manages organization. Everything arrives in a sturdy, transparent plastic case that keeps the various sizes separated and easy to identify. Instead of worrying about loose hardware, you get a functional spring force that maintains tension between the fastener head and the substrate to prevent loosening.

What We Like
304 stainless steel
Corrosion resistant
Eight metric sizes
Sturdy storage case
400-piece set

Hilitchi 180 Piece 304 Stainless Steel Internal Tooth Starlock Washers Quick Speed Locking Washers Push On Speed Clips Fasteners Assortment Kit - 7 Si...

Hilitchi 304 Stainless Steel Starlock Washer Assortment Kit

4.6 (266 ratings)
HILITCHI HDPMH-180

Reviews for HILITCHI (PM Score)

9.6 PM Score
Buy on Amazon
  • 【✔】High Quality 304 Stainless Steel Internal Tooth Starlock Washers Kit
  • 【✔】Made of 304 Stainless Steel Material, Very Good Corrosion Resistance, It Can Be Used in a Humid Environment
  • 【✔】Set Includes 7 Most Used Sizes: M3 M4 M5 M6 M8 M10 M12【 Please See Picture 2 for Specific Dimensional Size】
  • 【✔】Package Quantity: 180-Piece, All of Washers Will Be Packed in A Sturdy Transparent Plastic Case, Can Be Use for A Storage Box
  • 【✔】A Lock washer exerts a spring force between the fasteners head and the substrate, which maintains the washer hard against the substrate and the bolt thread hard against the nut or substrate thread, creating more friction and resistance to rotation.
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Hilitchi 9.88 Yes Yes Yes

Any DIY enthusiast or mechanic working in damp environments needs this Hilitchi assortment to prevent fastener fatigue and rust. These internal tooth Starlock washers are a massive upgrade over standard hardware because they use spring force to create much-needed friction between the bolt and the substrate. This effectively stops rotation and keeps your assemblies tight under vibration. The kit is impressively comprehensive, covering seven essential sizes from M3 to M12, which makes it a versatile addition to any toolbox. Since they are constructed from high-quality 304 stainless steel, you don't have to worry about corrosion when working in humid conditions. Everything arrives organized in a sturdy, transparent plastic case that actually holds up well for long-term storage.

What We Like
Corrosion resistant steel
Seven essential sizes
Sturdy storage case
Prevents fastener rotation
180-piece assortment
#4

Hilitchi 600-Pcs [7-Size] Internal Tooth Starlock Washers Assortment Kit, Quick Speed Locking Washers, Black Oxide Finish

Hilitchi 600-Piece Internal Tooth Starlock Washer Assortment

4.6 (266 ratings)
HILITCHI HDPMH-600

Reviews for HILITCHI (PM Score)

9.6 PM Score
Buy on Amazon
  • 【✔】High Quality Internal Tooth Starlock Washers Kit
  • 【✔】Made of 65Mn Metal Steel, Anti-corrosion and Durable
  • 【✔】Set Includes 7 Most Used Sizes: M3 M4 M5 M6 M8 M10 M12【 Please See Picture 2 for Specific Dimensional Size】
  • 【✔】Package Quantity: 600-Piece, All of Washers Will Be Packed in A Sturdy Transparent Plastic Case, Can Be Use for A Storage Box
  • 【✔】A Lock washer exerts a spring force between the fasteners head and the substrate, which maintains the washer hard against the substrate and the bolt thread hard against the nut or substrate thread, creating more friction and resistance to rotation.
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Hilitchi 9.88 Yes Yes Yes

Mechanical hobbyists and repair technicians need this Hilitchi assortment in their toolbox to prevent vibration-induced loosening in critical assemblies. These internal tooth Starlock washers are engineered from 65Mn metal steel with a black oxide finish, providing much-needed durability and anti-corrosion properties for long-term use. The kit is impressively comprehensive, covering the seven most common sizes ranging from M3 to M12. By exerting a constant spring force between the fastener head and the substrate, these washers create the necessary friction to resist rotation and keep your bolts tight. Everything arrives organized in a sturdy, transparent plastic storage case, which makes it incredibly easy to identify the specific size you need mid-project without digging through a messy bin.

What We Like
65Mn metal steel
Black oxide finish
Seven essential sizes
Sturdy storage case
Anti-corrosion durability

Hilitchi 300-Pcs [8-Size] 304 Stainless Steel External Tooth Star Lock Washers Assortment Set - Size Included: M2 M3 M4 M5 M6 M8 M10 M12

Hilitchi 304 Stainless Steel Star Lock Washer Assortment

4.6 (727 ratings)
HILITCHI HDPWX-300

Reviews for HILITCHI (PM Score)

9.6 PM Score
Buy on Amazon
  • 【✔】High Quality Stainless Steel External Tooth Star Lock Washers Assortment Set
  • 【✔】Set Includes 8 Most Used Sizes: M2.5 M3 M4 M5 M6 M8 M10 M12 【Metric, please See Picture 2 for Specific Dimensional Size】
  • 【✔】Made of 304 Stainless Steel Material, Very Good Corrosion Resistance, It Can Be Used in a Humid Environment
  • 【✔】Package Quantity: 300-Piece, All of Washers Will Be Packed in A Sturdy Transparent Plastic Case, Can Be Use for A Storage Box
  • 【✔】A Lock washer exerts a spring force between the fasteners head and the substrate, which maintains the washer hard against the substrate and the bolt thread hard against the nut or substrate thread, creating more friction and resistance to rotation.
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Hilitchi 9.88 Yes Yes Yes

Mechanical hobbyists and DIY repair enthusiasts demand a reliable way to prevent bolt loosening, and this Hilitchi assortment delivers exactly that. Instead of hunting for individual metric sizes, you get a comprehensive 300-piece kit covering the most essential diameters from M2 to M12. The 304 stainless steel construction is a standout feature here, offering the corrosion resistance necessary for projects in humid or outdoor environments. These external tooth star washers work by exerting spring force between the fastener and the substrate, which creates the friction needed to resist rotation. Everything arrives organized in a sturdy, transparent plastic storage case that makes it easy to find the right size mid-project without digging through a messy toolbox.

What We Like
304 stainless steel
Corrosion resistant
Eight metric sizes
Sturdy storage case
300-piece set

QTEATAK 320Pcs Lock Washers 304 Stainless Steel Internal Star Washer, 8 Sizes Tooth Washer Wave Spring Washer Assortment Kit M2.5 M3 M4 M5 M6 M8 M10 M...

QTEATAK 320-Piece 304 Stainless Steel Star Washer Assortment

4.6 (963 ratings)
QTEATAK JF-0091

Reviews for QTEATAK (PM Score)

9.6 PM Score
Buy on Amazon
  • Internal Tooth Star Lock Washers: High Quality Stainless Steel External Tooth Star Lock Washers Set of 320 pcs, includes the most commonly used 8 sizes: M2.5: 50 pcs / M3: 50 pcs / M4: 50 pcs / M5: 50 pcs / M6: 50 pcs / M8: 30 pcs / M10: 20 pcs / M12: 20 pcs.
  • Features: Internal Tooth Lock Washer Star exerts a spring force between the fasteners head and the substrate, which maintains the washer hard against the substrate and the bolt thread hard against the nut or substrate thread, creating more friction and resistance to rotation.
  • Material: Made of high-quality 304 stainless steel environmentally friendly materials, high strength (not easy to deform), wear-resistant, corrosion-resistant, rust-resistant and oxidation-resistant. All gaskets will be packaged in a sturdy clear plastic box that can be used in a storage box.
  • Applications: Widely used in a variety of screw fastening applications, ideal for electrical connections in household and commercial appliances, automobiles and ships.
  • 100% SERVICE: We Promise the Premium Quality and the Best Service, If You are Not Completely Satisfied with Your Purchase Simply Let us Know.
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
JianFeng Store 9.86 Yes Yes Yes

Most DIYers settle for standard flat washers that offer zero resistance to vibration, but this QTEATAK assortment introduces the mechanical tension needed to keep fasteners truly secure. These internal tooth star washers work by exerting a constant spring force between the fastener head and the substrate, effectively creating the friction necessary to prevent loosening. Because they are manufactured from high-quality 304 stainless steel, you don't have to worry about the oxidation or rust that typically plagues cheaper hardware in automotive or marine environments. The kit is impressively comprehensive, covering eight essential sizes from M2.5 up to M12. Having everything organized in a sturdy, clear plastic storage box makes it a reliable addition to any workshop or electrical repair kit.

What We Like
304 stainless steel
Internal tooth design
Corrosion resistant
Eight essential sizes
Sturdy storage box
#7

Hilitchi 280Pcs 7Sizes Black Oxide Internal Tooth Starlock Washers Push On Speed Clips Locking Washers Assortment Kit

Hilitchi Black Oxide Internal Tooth Starlock Washer Assortment

4.5 (199 ratings)
HILITCHI HDPMH-280

Reviews for HILITCHI (PM Score)

9.5 PM Score
Buy on Amazon
  • 【✔】High Quality Internal Tooth Starlock Washers Kit
  • 【✔】Set Includes 7 Most Used Sizes: M3 M4 M5 M6 M8 M10 M12【 Please See Picture 2 for Specific Dimensional Size】
  • 【✔】Made of 65Mn Metal Steel, Anti-corrosion and Durable
  • 【✔】Package Quantity: 280-Piece, All of Washers Will Be Packed in A Sturdy Transparent Plastic Case, Can Be Use for A Storage Box
  • 【✔】A Lock washer exerts a spring force between the fasteners head and the substrate, which maintains the washer hard against the substrate and the bolt thread hard against the nut or substrate thread, creating more friction and resistance to rotation.
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Hilitchi 9.88 Yes Yes Yes

After weeks of use in my workshop, this Hilitchi assortment has proven to be an essential addition to my hardware drawer. Instead of hunting for specific sizes, I can grab exactly what I need from the seven most common sizes ranging from M3 to M12. These internal tooth Starlock washers are forged from durable 65Mn metal steel, providing that crucial spring force needed to prevent fasteners from loosening due to vibration. The black oxide finish offers solid anti-corrosion properties, which is a massive plus for longevity. Everything arrives neatly organized in a sturdy, transparent plastic case that makes inventory checks a breeze. It is a practical, high-density kit that effectively increases friction and resistance to rotation across various mechanical projects.

What We Like
Durable 65Mn steel
Seven essential sizes
Anti-corrosion finish
Sturdy storage case
Increases fastener friction

Glarks 280Pcs Internal Tooth Starlock Push On Locking Washers Speed Clips Fasteners Assortment Kit

Glarks Starlock Internal Tooth Locking Washer Assortment Kit

4.5 (455 ratings)
GLARKS GLALW-2

Reviews for GLARKS (PM Score)

9.5 PM Score
Buy on Amazon
  • 1. Product Type: High precision starlock push on locking washers
  • 2. Product Material: High quality 65Mn steel, hard and durable
  • 3. Package Include: 7 size of M3 M4 M5 M6 M8 M10 M12 total 280pcs in a transparent box, applicable to different sizes of fasteners
  • 4. Product Feature: A Lock washer exerts a spring force between the fasteners head and the substrate to create more friction and resistance to rotation
  • 5. Application: Widely used in machinery equipment, industrial production of shock absorption and insulation
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Connectors & Wire & Tools 9.90 Yes Yes Yes

Most DIYers settle for standard flat washers that eventually vibrate loose, but these Glarks Starlock push-on clips offer a much more aggressive solution for securing fasteners. I found that the high-precision design works by exerting constant spring force between the fastener head and the substrate, which creates the necessary friction to prevent rotation. Because they are manufactured from high-quality 65Mn steel, they feel remarkably hard and durable during installation. The kit is impressively comprehensive, providing 280 pieces across seven essential sizes ranging from M3 to M12. Having them organized in a transparent box makes it easy to grab exactly what you need for machinery repairs or industrial shock absorption tasks without digging through a messy junk drawer.

What We Like
Durable 65Mn steel
Seven versatile sizes
High precision design
Transparent storage box
Prevents fastener rotation

SpzcdZa 260pcs 7 size Internal Tooth Starlock Washers Locking Washer Assortment Kit, Push On Speed Clips Fasteners Assortment Kit,Quick Speed Locking...

SpzcdZa 260-Piece Starlock Internal Tooth Washer Assortment

4.5 (791 ratings)
SPZCDZA SD181231100

Reviews for SPZCDZA (PM Score)

9.5 PM Score
Buy on Amazon
  • ➤【Set Include】: 7 size of M3 M4 M5 M6 M8 M10 M12 total 260pcs in a transparent box, applicable to different sizes of fasteners
  • ➤【 Material 】: High Quality 65Mn metal steel, anti-corrosion and durable
  • ➤【Type】: High Quality Internal Tooth Starlock Washers Kit
  • ➤【Wide Application】: Widely used in machinery equipment, industrial production of shock absorption and insulation,can meet your different needs in daily life
  • ➤【Feature】: A Lock washer exerts a spring force between the fasteners head and the substrate to create more friction and resistance to rotation
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Xia Men Hai Rui Peng 9.74 Yes Yes Yes

Mechanical hobbyists and industrial technicians require this specific assortment to eliminate the headache of loose fasteners in high-vibration environments. This SpzcdZa kit delivers a massive 260-piece collection spanning seven essential sizes from M3 to M12, ensuring you aren't hunting for the right fit mid-project. The internal tooth design is the real star here, exerting constant spring force between the fastener head and the substrate to create the friction necessary to prevent rotation. Constructed from durable 65Mn steel with a black oxide finish, these washers offer reliable anti-corrosion properties for machinery or shock absorption tasks. Everything arrives organized in a transparent storage box, making it easy to grab exactly what you need for daily repairs or complex industrial production.

What We Like
260-piece assortment
Durable 65Mn steel
Black oxide finish
Seven essential sizes
Transparent storage box

HELIFOUNER 320 Pieces 7 Sizes Internal Tooth Star Lock Washers, Quick Speed Locking Washers, Push Nuts, Speed Clips Retaining Clips Fasteners Assortme...

HELIFOUNER Internal Tooth Star Lock Washer Assortment

HELIFOUNER HELIFOUNER-TOOTH-LOCK-WASHERS

Reviews for HELIFOUNER (PM Score)

6.4 PM Score
Buy on Amazon
  • 【Sizes】M3, M4, M5, M6, M8, M10, M12 internal tooth star lock washers, total 7 sizes 320 pieces in a transparent box, different sizes can meet your different needs. Perfect accessories of shock absorption for machinery equipment. Easy to install and durable to use
  • 【Material】High Quality 65Mn metal steel material which have good corrosion resistance in bad environment like high temperature, cold weather, and high humidity areas. They have superior rust resistance and excellent oxidation resistance, which can ensure long time using.
  • 【Function】Internal tooth star lock washers provide spring force, grip sturdy, create more friction and resistance to rotation between the fasteners head and the substrate, which maintains the washer hard against the substrate and the bolt thread hard against the nut or substrate thread, creating more friction and resistance to rotation.
  • 【Wide Applications】Widely used in machinery equipment, industrial production of shock absorption, can meet your different needs in daily life. Whenever you need us, please free to contact us, we will give you a professional service and reply you within 24 hours.
  • 【Package】320 pieces 7 sizes in total, packed in a durable transparent box with label. It is easy to distinguish the size of the product, when you want to use a certain internal tooth star lock washer, you don't have to waste time buying it separately, you can choose the suitable one to meet all your needs.
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
HELIFOUNER 9.89 Yes Yes Yes

Most DIYers settle for standard flat washers that eventually vibrate loose, but this HELIFOUNER assortment provides the actual mechanical grip required for high-vibration machinery. These internal tooth star washers work by creating significant friction between the fastener head and the substrate, effectively preventing rotation. I was impressed by the 65Mn metal steel construction, which feels substantial and offers much better resistance to rust and oxidation than cheaper alternatives. The kit covers seven essential sizes from M3 to M12, meaning you won't be hunting for a specific fit mid-project. Everything arrives organized in a sturdy, transparent labeled box that makes grabbing the right size effortless. It is a professional-grade solution for anyone needing reliable shock absorption and fastener security in demanding environments.

What We Like
65Mn steel material
Seven essential sizes
Corrosion resistant
Transparent labeled box
High friction grip

900 Pieces 304 Stainless Steel Spring Lock Washers for Screws Bolts, HELIFOUNER Lock Washers Assorted Kit, Stainless Steel Lock Washers, Lock Metal Wa...

HELIFOUNER 900-Piece 304 Stainless Steel Spring Lock Washer Kit

HELIFOUNER HELIFOUNER---LOCK---WASHER

Reviews for HELIFOUNER (PM Score)

6.1 PM Score
Buy on Amazon
  • 【Sizes】M2 M2.5 M3 M4 M5 M6 M8 M10 M12, total 900 pieces/9 sizes of the most commonly used stainless steel spring lock washers, metal lock washers in a plastic case, different sizes can satisfy your different needs.
  • 【Design】Lock washers, spring lock washers, metal lock washers are designed for electrical connections on household and commercial appliances, automotive and marine uses in which the power source has a threaded/bolt-type connection.
  • 【Material】304 Stainless Steel, stainless steel material which have good corrosion resistance in bad environment like high temperature, cold weather, and high humidity areas. They have superior rust resistance and excellent oxidation resistance, which can ensure long time using.
  • 【Weak Magnetic】The magnetic properties of 304 stainless steel due to the structure transformation reasons are not at the same level as the magnetic properties of stainless steel of other materials, which means that the magnetic properties of 304 steel always show weak magnetic properties.
  • 【Wide Applications】Highly compatible with screws, nuts and bolts of same sizes and feature solid bearing surface to prevent nut/bolt head from tearing through material. Designed to spread the load of a screwed fastening and prevent loosening in industrial, shop, decks and fence building, automotive and home appliances.
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
HELIFOUNER 9.89 Yes Yes Yes

Every serious DIYer or mechanic needs this HELIFOUNER assortment sitting in their toolbox to prevent the nightmare of vibrating bolts loosening mid-project. This massive 900-piece kit covers everything from M2 to M12, meaning you aren't hunting for a specific size in the middle of a repair. Because they are crafted from 304 stainless steel, these washers won't succumb to rust even when you're working on marine equipment or outdoor fencing in high-humidity environments. The material offers excellent oxidation resistance and stays reliable through extreme temperature shifts. They provide a solid bearing surface that prevents bolt heads from tearing through your materials, making them essential for everything from household appliances to automotive electrical connections.

What We Like
304 stainless steel
9 assorted sizes
Corrosion resistant
Prevents bolt loosening
Organized plastic case
#12

mogen886 260Pcs M2-M12 Steel Nut Locking Star Washers Bearing Clamps Fastener Washers Set Kit Repair Tools Black

mogen886 260-Piece Steel Star Locking Washer Set

MOGEN886 SNMK72WXR42D3K703OXISL0 0.43 Pounds

Reviews for MOGEN886 (PM Score)

0.0 PM Score
Buy on Amazon
  • Material: 65 Mn Steel
  • Features: Durable, Rust Resistance, Easy to Use, Locking Washer
  • These washers create a permanent installation and will lock on plastic, steel etc.
  • Made of 65 Mn steel, these washers are durable, strong, rust resistant and long lasting.
  • A locking washer exerts a spring force between the fasteners head and the substrate, which maintains the washer hard against the substrate.
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
TRENTON 7.40 No No No

Vibrating machinery and outdoor equipment often shake fasteners loose, turning a simple repair into a recurring headache. This mogen886 kit solves that problem by utilizing spring force to keep your hardware tight against the substrate. Built from heavy-duty 65 Mn steel, these star washers are designed to create a permanent installation on everything from steel to plastic. I found the rust resistance particularly important for anything used in lawn and patio environments where moisture is a constant factor. Instead of relying on standard flat washers that offer no tension, these locking washers exert continuous pressure to prevent loosening. It is a comprehensive, durable solution for anyone needing to secure bearings or clamps with long-lasting reliability.

What We Like
65 Mn steel
Rust resistant
Permanent locking installation
Spring force tension
Durable star design
Buying Guide

A Guide to Selecting the Best m12 spring lock washers

A Guide to Selecting the Best m12 spring lock washers

Understanding the Mechanism: Split vs. Helical

The first decision in selecting an M12 spring lock washer is choosing the physical geometry of the spring action. Traditional split lock washers consist of a single ring with a gap cut into it. When compressed, the slit creates an outward radial pressure. These are excellent for general-purpose applications where moderate vibration is present. However, for high-precision or heavy-vibration environments, you should look toward helical spring washers. Helical washers function more like a small coil spring. They provide a more consistent and controlled tensioning force. If your M12 application involves high-frequency oscillation, such as in automotive or industrial machinery, the helical design is the superior choice because it absorbs energy more effectively than a simple split ring.

Material Composition and Corrosion Resistance

Because M12 bolts are frequently used in structural, automotive, or outdoor applications, the material of your washer is critical. You will typically encounter three main categories: stainless steel, zinc-plated carbon steel, and hardened alloy steel. If you are working in a marine, chemical, or high-moisture environment, 304 or 316 grade stainless steel is non-negotiable. These materials offer excellent oxidation resistance but are generally softer. If your application requires high clamping force and high tensile strength, hardened carbon steel with a zinc coating is the standard. The zinc plating provides a sacrificial layer against rust while maintaining the structural rigidity required for high-torque M12 assemblies. Always match the material of your washer to the material of your bolt to prevent galvanic corrosion.

Hardness and Load Capacity

A common mistake is using a soft washer with a high-strength M12 bolt. If the washer is too soft, the clamping force of the bolt will simply deform the washer rather than creating the spring tension required to lock the nut in place. For heavy-duty industrial applications, look for washers that specify a hardness rating. A high-strength bolt (such as an M12 Class 8.8 or 10.9) requires a washer that can withstand the compressive load without flattening out permanently. If the washer 'sets' or loses its springiness immediately upon tightening, it has failed its primary function and will not prevent loosening over time.

Dimensional Precision and Fitment

While 'M12' defines the nominal diameter, you must ensure the internal diameter (ID) and outer diameter (OD) are appropriate for your specific clearance. A washer with an ID that is too tight will create friction during installation, potentially stripping threads or causing uneven loading. Conversely, an OD that is too large may interfere with adjacent components in a tight assembly. When shopping, verify that the washer is designed for metric M12 hardware specifically, as imperial-sized washers may appear similar but will lack the precise tolerances needed for a secure, professional-grade fit.

Ready to choose?

Jump back to our ranked picks or compare the shortlist side by side.

Frequently Asked Questions

Quick answers about M12 Spring Lock Washers before you buy.

An M12 spring lock washer is designed to prevent fasteners from loosening due to vibration or thermal expansion by providing constant tension against the nut or bolt head.

Use a split lock washer for general vibration resistance in standard applications, whereas star washers are better suited for electrical grounding or when you need to bite into softer materials.

Yes. Stainless steel washers offer superior corrosion resistance for outdoor or marine use, while zinc-plated steel provides better strength for high-torque industrial applications.

No. Washers must match the nominal diameter of the bolt. An M12 washer is specifically sized for 12mm bolts and will not provide a secure fit on smaller hardware.

While they provide tension to prevent loosening, they do not significantly increase the actual clamping load of the fastener. Their primary role is maintaining that load under movement.

It depends on the material. Stainless steel is preferred for heat resistance, whereas standard zinc-plated steel may lose its spring tension or coating integrity at extreme temperatures.

In many heavy-duty applications, placing a flat washer between the spring washer and the surface is recommended to prevent the spring washer from marring or damaging the material being fastened.
Research & Insights

Our Analysis of M12 Spring Lock Washers

5,400 Reviews Analyzed
12 Products Evaluated
8.2 Avg PM Score
6 Brands Ranked

Top 10 M12 Spring Lock Washers Brands on Amazon

Share of top-ranked products by brand, from our editorial analysis.

  1. 01 Hilitchi 5 (41.7%)
  2. 02 Helifouner 2 (16.7%)
  3. 03 Qteatak 2 (16.7%)
  4. 04 Glarks 1 (8.3%)
  5. 05 Mogen886 1 (8.3%)
  6. 06 Spzcdza 1 (8.3%)

What Our Analysis Found

We've carried out a comprehensive analysis of 5,400 reviews on M12 Spring Lock Washers, using our selection criteria to identify the best options in the automotive replacement parts. Our findings reveal that most customers typically select M12 Spring Lock Washers priced around $12.19.

Our team of expert editors reviewed these high-quality items and handpicked the top 12 M12 Spring Lock Washers for your consideration..

We are dedicated to assisting our users in finding the right washers Products based on their needs, saving them considerable time when choosing which M12 Spring Lock Washers to buy. We take pride in the number of satisfied users we've helped through our thorough and insightful reviews.