Best Flat Head Lag Bolts of 2026

Name: Valorada 20Pcs M6 x 50mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 50mm Wood Screws, Hex Head Partial Thread Black Oxide
Brand: Valorada

Corey Phillips

Last Updated: 5 Feb 2026

* We independently evaluate all recommended products and services. If you click on links we provide, we may receive compensation.

Flat Head Lag Bolts are a type of heavy-duty fastener commonly used in construction and woodworking projects. These bolts are designed to securely attach large pieces of lumber or other materials together, and are known for their exceptional strength and durability. With their flat heads and coarse threads, Flat Head Lag Bolts can provide a strong and stable connection that can help stabilise structures and prevent them from shifting or collapsing over time. These bolts are available in a variety of sizes and materials, making them a versatile and reliable choice for a wide range of applications.

At a Glance: Our Top Picks

#TOP 1

Valorada 20Pcs M6 x 50mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 50mm Wood Screws, Hex Head Partial Thread Black Oxide

9.9

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Valorada 20Pcs M6 x 50mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 50mm Wood Screws, Hex Head Partial Thread Black Oxide

#TOP1

9.9

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#TOP 2

3/8 x 1-1/4" Hex Head Lag Screws Bolts with Flat Washers

9.8

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3/8 x 1-1/4" Hex Head Lag Screws Bolts with Flat Washers

#TOP2

9.8

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#TOP 3

Valorada 12Pcs M8 x 90mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 90mm Wood Screws, Hex Head Partial Thread Black Oxide

9.6

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Valorada 12Pcs M8 x 90mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 90mm Wood Screws, Hex Head Partial Thread Black Oxide

#TOP3

9.6

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Top 10 Flat Head Lag Bolts

#TOP 1

Valorada 20Pcs M6 x 50mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 50mm Wood Screws, Hex Head Partial Thread Black Oxide

Valorada

Hex Lag Bolts

Black

M6 x 50

Valorada 20Pcs M6 x 50mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 50mm Wood Screws, Hex Head Partial Thread Black Oxide, with Washers and Hex Socket Drill Bit

9.9

FTB Score

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Features

[Rugged And Durable] 304 Stainless Steel. Valorad Lag Bolts Offer Durability And Reliability. Lag Screws Have Undergone Stringent Testing To Ensure Superior Resistance To Corrosion And Rust, Even In Harsh And Extreme Environments. With A Robust And Stable Structure, They Provide Enhanced Strength And An Extended Service Life. Please Be Aware That 304 Stainless Steel May Exhibit Slight Magnetic Properties Due To Structural Changes That Occur During Processing

[Product Size] Coach Screws: Thread Diameter: 6mm; Screw Length: 50mm; Thread Pitch: 2.5mm; Head Diameter: 10mm, Head Height: 3.7mm. Ideal For Outdoor Woodworking, Home And Industrial Applications. Package Includes: 20 Pcs m6 X 50mm Coach Screws + 20 Pcs Flat Washers + 1 Hex Socket Drill Bit

[Wide Range Of Applications] This 20 Piece Lag Bolt Kit Features Stainless Steel Hex Head Screws, Ideal For A Variety Of Furniture Assembly Tasks Such As Beds, Tables, Cabinets, Chairs, Woodworking Projects (join Wooden Boards, Build Workbenches, And Install Kitchen Countertops). The Lag Bolts Can Be Used As Furniture Fasteners In Timber Framing, Deck Construction, And Mounting Outdoor Fixtures

[Reliable Fastening Solution] Elevate Your Construction And Woodworking Projects With Our Premium 50mm Hexagonal Head Coach Screws. These Lag Bolts Are Engineered For Efficiency And Strength, Making Them Essential For Your Hardware Collection. With Easy Installation And Robust Design, They Are Perfect For Professionals And DIYers. Don't Compromise On Quality; Choose Our Black Plated 304 Stainless Steel Hex Head Lag Bolts For A Secure And Reliable Fastening Solution That Meets The Highest Standards Of Performance And Durability In All Your Projects

[Easy To Use] The Hexagonal Head Design Enhances Grip And Allows For Greater Torque Application, Making These Screws Ideal For High-Stress Environments. They Work Effectively With Nylon Plugs For Secure Fastening In Masonry Applications. Black Oxide Adds Protection, Ensuring Longevity Even Outdoors. Perfect For Deck And Dock Construction, Our 50mm Hex Head Lag Bolts Are The Ideal Choice For Reliable And Sturdy Installations, Providing Peace Of Mind For All Your Construction Projects

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#TOP 2

3/8 x 1-1/4" Hex Head Lag Screws Bolts with Flat Washers

Fayeploo

01H0302-20

3/8 x 1-1/4"

3/8 x 1-1/4" Hex Head Lag Screws Bolts with Flat Washers (20 Sets), 304 Stainless Steel 18/8, Full Thread, Deck Screws, Heavy Duty Hex Head Wood Lag Screws, Fayeploo

9.8

FTB Score

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Features

Hex Drive Size: 9/16 Inch; Quantity: 10 Sets (screws + Flat Wahsers)

Thread Size: 3/8 Inch; Thread Length: 1-1/4 Inch; Length Is Measured From Under The Head

Material: The Sets Are Made Of 304 Stainless Steel 18/8; Grade A2-70, Excellent Toughness; Good Rust And Corrosion Resistance In Both Indoor And Outdoor Use; Type 304 Is The Most Versatile And Widely Used Stainless Steel

Fastener Standard: Lag Screws Meet Standard ASME B18.2.1 Commercial/Industrial Grade A2-70; Flat Washers Meet Standard ASME B18.22.1

Applications: It's Used For A Wide Variety Of Household And Industrial Applications Like Deck Buildings, Heavy Duty Shelves Or Wood Joining. Designed With A Hexagon Head And Precise Clean Thread, It Allows For Great Force To Be Applied Without Slipping And Can Be Drilled Into Wood Quickly And Easily

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#TOP 3

Valorada 12Pcs M8 x 90mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 90mm Wood Screws, Hex Head Partial Thread Black Oxide

Valorada

Coach Bolts

Black

M8 x 90

Valorada 12Pcs M8 x 90mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 90mm Wood Screws, Hex Head Partial Thread Black Oxide, with Washers and Hex Socket Drill Bit

9.6

FTB Score

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Features

[Product Size] Coach Screws: Thread Diameter: 8mm; Screw Length: 90mm; Thread Pitch: 3mm; Head Diameter: 13mm, Head Height: 5.1mm. Ideal For Outdoor Woodworking, Home And Industrial Applications. Package Includes: 12 Pcs m8 X 90mm Coach Screws + 12 Pcs Flat Washers + 1 Hex Socket Drill Bit

[Wide Range Of Applications] This 12 Piece Lag Bolt Kit Features Stainless Steel Hex Head Screws, Ideal For A Variety Of Furniture Assembly Tasks Such As Beds, Tables, Cabinets, Chairs, Woodworking Projects (join Wooden Boards, Build Workbenches, And Install Kitchen Countertops). The Lag Bolts Can Be Used As Furniture Fasteners In Timber Framing, Deck Construction, And Mounting Outdoor Fixtures

[Reliable Fastening Solution] Elevate Your Construction And Woodworking Projects With Our Premium 90mm Hexagonal Head Coach Screws. These Lag Bolts Are Engineered For Efficiency And Strength, Making Them Essential For Your Hardware Collection. With Easy Installation And Robust Design, They Are Perfect For Professionals And DIYers. Don't Compromise On Quality; Choose Our Black Plated 304 Stainless Steel Hex Head Lag Bolts For A Secure And Reliable Fastening Solution That Meets The Highest Standards Of Performance And Durability In All Your Projects

[Easy To Use] The Hexagonal Head Design Enhances Grip And Allows For Greater Torque Application, Making These Screws Ideal For High-Stress Environments. They Work Effectively With Nylon Plugs For Secure Fastening In Masonry Applications. Black Oxide Adds Protection, Ensuring Longevity Even Outdoors. Perfect For Deck And Dock Construction, Our 90mm Hex Head Lag Bolts Are The Ideal Choice For Reliable And Sturdy Installations, Providing Peace Of Mind For All Your Construction Projects

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#TOP 4

16-Sets M6 x 65mm Hex Head Lag Screws Bolts with Flat Washers

Fayeploo

08GH0108-16

Silver

M6 x 65mm

16-Sets M6 x 65mm Hex Head Lag Screws Bolts with Flat Washers, 304 Stainless Steel (18/8), Partial Thread, Heavy Duty Hex Head Lag Deck/Wood Screws

9.5

FTB Score

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Features

Head Thickness: 3.63-4.38mm; Drive Size: 10mm Hex

Thread Size: 6mm; Total Length: 65mm (Head Excluded); Thread Length: 39mm (min)

Versatile Applications For Home & Industry: Decks, Fences, Playsets, Marine Structures, Shelving Units, Furniture Assembly, Timber Framing, And General Wood Joining In Both Household And Industrial Settings

This Combo Features A Heavy-Duty Hex Head For High-Torque Driving Without Slippage, Paired With An Oversized Flat Washer (DIN 9021); This Larger Washer Provides A Significantly Increased Bearing Surface, Expertly Distributing Load To Prevent Wood Surface Damage, Sinkage, And Screw Pull-Through For A Secure, Long-Lasting Hold

Made From 18-8 (304) Stainless Steel, These Screws Provide Corrosion Resistance And Durability Without Coating. The Natural Finish Ensures A Clean, Metallic Appearance That Is Both Professional And Rust-Resistant, While The Smooth, Burr-Free Design Offers Easy Handling And A Polished Look

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#TOP 5

Valorada 12Pcs M8 x 60mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 60mm Wood Screws, Hex Head Partial Thread Black Oxide

Valorada

Coach Bolts

Black

M8 x 60

Valorada 12Pcs M8 x 60mm Coach Screws, Heavy Duty Lag Bolts 304 Stainless Steel, 60mm Wood Screws, Hex Head Partial Thread Black Oxide, with Washers and Hex Socket Drill Bit

9.5

FTB Score

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Features

[Product Size] Coach Screws: Thread Diameter: 8mm; Screw Length: 60mm; Thread Pitch: 3mm; Head Diameter: 13mm, Head Height: 5.1mm. Ideal For Outdoor Woodworking, Home And Industrial Applications. Package Includes: 12 Pcs m8 X 60mm Coach Screws + 12 Pcs Flat Washers + 1 Hex Socket Drill Bit

[Reliable Fastening Solution] Elevate Your Construction And Woodworking Projects With Our Premium 60mm Hexagonal Head Coach Screws. These Lag Bolts Are Engineered For Efficiency And Strength, Making Them Essential For Your Hardware Collection. With Easy Installation And Robust Design, They Are Perfect For Professionals And DIYers. Don't Compromise On Quality; Choose Our Black Plated 304 Stainless Steel Hex Head Lag Bolts For A Secure And Reliable Fastening Solution That Meets The Highest Standards Of Performance And Durability In All Your Projects

[Easy To Use] The Hexagonal Head Design Enhances Grip And Allows For Greater Torque Application, Making These Screws Ideal For High-Stress Environments. They Work Effectively With Nylon Plugs For Secure Fastening In Masonry Applications. Black Oxide Adds Protection, Ensuring Longevity Even Outdoors. Perfect For Deck And Dock Construction, Our 60mm Hex Head Lag Bolts Are The Ideal Choice For Reliable And Sturdy Installations, Providing Peace Of Mind For All Your Construction Projects

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#TOP 6

10 PCS Heavy Duty Lag Screws with Flat Washers, 1/4" x 2-1/2" Hex Head Lag Screws Bolts

Qulkws

730214_1_nl96RfWP

10 PCS Heavy Duty Lag Screws with Flat Washers, 1/4" x 2-1/2" Hex Head Lag Screws Bolts Cover

10 PCS Heavy Duty Lag Screws with Flat Washers, 1/4" x 2-1/2" Hex Head Lag Screws Bolts, Black Oxide 304 Stainless Steel Bolts for Wood Working

9.3

FTB Score

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Features

Reliable Material: These 1/4" X 2-1/2" Hex Head Lag Screws Bolts Are Made Of High-Quality Stainless Steel, Which Is Hard And Not Easy To Deform Or Break, And Has Strong Rust And Corrosion Resistance, Durable And Long Service Life

Product Specifications: These Black Square Head Screws Are 1/4" X 2-1/2" In Size, With A Washer Diameter Of 0.74 Inches, Which Is A Moderate Size For Home And Industrial Applications

Wide Range Of Uses: These Stainless Steel Heavy Duty Hex Head Lag Screws Are Widely Used And Suitable For Repairing And Fixing Various Household Items, Such As Desks, Chairs, Door Frames, Closets, Bed Boards, Bookshelves, Cabinets, And Can Also Be Used For Office Desks And Chairs, Stage Construction, Deck Construction, Etc.

Packing List: Each Bag Contains 10 Screws And 10 Washers For Use Together. The Quantity Is Sufficient To Meet Your Daily Needs. The Combination Of Screws And Washers Is Sturdy, Stable And Highly Durable

Easy To Use: These Wood Lag Bolt With Washer Are Easy And Convenient To Use. Just Put The Washers And Screws In The Position Where The Items Need To Be Connected, And Tighten Them With Tools. The Operation Is Simple And Convenient

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#TOP 7

BNUOK 2 Sets 1/2" x 5" Hex Head Lag Screws Bolts with Flat Washers 304 Stainless Steel 18-8 Heavy Duty Lag Screw

BNUOK

BNC08020

Silver

1/2x5 (2sets)

BNUOK 2 Sets 1/2" x 5" Hex Head Lag Screws Bolts with Flat Washers 304 Stainless Steel 18-8 Heavy Duty Lag Screw Cover

BNUOK 2 Sets 1/2" x 5" Hex Head Lag Screws Bolts with Flat Washers 304 Stainless Steel 18-8 Heavy Duty Lag Screw for Wood, Driver Bit Included

9.3

FTB Score

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Features

Stainless Steel Lag Bolts: Our 1/2 Lag Bolts, Washers Are Made Of 304 Stainless Steel For Superior Corrosion Resistance, Longer Service Life. Anti-Rust Lag Bolt For Indoor And Outdoor Use

Quantity & Size: You Will Get 2pcs 1/2 X 5 Inch Hex Lag Screws, 2pcs Flat Washers, A 3/4" Hex Socket Driver Bit. Handy Screw Bolt Kit For Your Wooden Projects

Hex Head Screws: The Hex Head Lag Screws 5 Can Handle High Torque, Sharp Points, Clean Threads, Sturdy Build, Easy Installation With The Included Hex Driver. The Flat Washers Add Stability

Heavy Duty Lag Screw: Lag Screws, Also Called Lag Bolts, Firmly Fasten Wood Together, Stronger And Thicker Than Typical Wood Screws

Application: The Lag Screw Wood Screw With Thick Shafts And Coarse Threads, Designed To Securely Join Wood Pieces Together In Heavy Load Applications. Used For Decks, Framing, Fence Post, And Wooden Playground Equipment. Screwing Pressure Treated Lumber, Landscape Lumber, Log, Timber, Soft And Hard Wood

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#TOP 8

RADSO M8 Hex Head Coach Screws Pack

RADSO

3152054102708

Black

RADSO M8 Hex Head Coach Screws Pack Cover

RADSO M8 Hex Head Coach Screws Wood Lag Bolt-Black Passivated-For Wood, Masonry/Brick, Concrete, Shelving, Wall Mounting, Fastening, Installation & other Indoor Projects (8mm x 40mm)-Pack of 10

9.1

FTB Score

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The RADSO M8 Screws feature a black passivated surface treatment, ensuring durability and reliable performance for all your projects. With dimensions of 8mm thickness and 40mm length, these screws are compatible with a 13mm spanner, making installation straightforward. Made from high-quality steel, they are perfect for a variety of applications, from shelving to furniture assembly. The hexagon head design allows for easy gripping, giving you enhanced control and precision during installation, resulting in a professional finish for your DIY tasks.

What We Like

Durable black passivated coating

Versatile for various materials

Easy to install with hex head

High-quality steel construction

Suitable for heavy-duty projects

#TOP 9

20-Pack 1/4 x 2-1/2" Hex Head Lag Screws Bolts with Flat Washers

Fayeploo

08HH0105-20

Black

1/4 x 2-1/2 Inches

20-Pack 1/4 x 2-1/2" Hex Head Lag Screws Bolts with Flat Washers Cover

20-Pack 1/4 x 2-1/2" Hex Head Lag Screws Bolts with Flat Washers, Heavy Duty 304 Stainless Steel (18/8), Corrosion Resistant Outdoor Wood Screws- Includes Hex Bit for Installation

8.9

FTB Score

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Features

Material: Crafted From 18/8 (304) Stainless Steel With A Black Coating, These Screws And Washers Sets Deliver Enhanced Corrosion Resistance Alongside Exceptional Toughness And Heat Tolerance. Engineered For High-Strength Durability, They Reliably Withstand Heavy Loads In Both Indoor And Outdoor Environments

Thread Size: 1/4 Inch; Thread Length: 2-1/2 Inch

Ideal For Decks, Fences, Playsets, And Marine Applications Exposed To Harsh Weather And Moisture; Each Screw Includes A Flat Washer, Distributing Load Effectively To Protect Wood Surfaces And Prevent Pull-Through. The Hex Head Design Provides Superior Grip For High-Torque Driving And Easy Installation, Even In Tight Spaces. Includes A Compatible Hex Bit, Ensuring You Have The Right Tool Ready

Hex Drive Size: 7/16 Inch; Quantity: 20 Sets (screws + Flat Wahsers)+ 1 Pcs Hex Bit

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#TOP 10 Best LLB Lag Bolt

LLB Coach Wood Screws Hex Head Zinc Plated

LLB

ART276WBD200ART40KSZ45

Grey

M8 x 100mm

LLB Coach Wood Screws Hex Head Zinc Plated Cover

LLB Coach Wood Screws Hex Head Width 13mm Zinc Plated Steel Screw Hexagon Lag Bolts Silver Long M8 (4" x 0.31") 8mm x 100mm Box of 5pcs

8.7

FTB Score

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The LLB Wood Screws are designed for connecting wooden construction elements with ease. Measuring 8mm x 100mm, these screws provide a robust solution for your projects. Made from 8.0mm thick steel, they ensure durability and strength, giving you confidence in your build. The galvanised finish offers additional protection against corrosion, making them suitable for various environments. Each pack contains five screws, providing you with enough quantity to complete your tasks efficiently.

What We Like

Durable steel construction

Galvanised for corrosion resistance

Ideal for wooden connections

Pack of five screws

Editor's Notes

During our flat head lag bolt research, we found 226 flat head lag bolt products and shortlisted 10 quality products. We collected and analyzed 2,432 customer reviews through our big data system to write the flat head lag bolts list. We found that most customers choose flat head lag bolts with an average price of £20.00.

The flat head lag bolts are available for purchase. We have researched hundreds of brands and picked the top brands of flat head lag bolts, including Valorada, Fayeploo, Qulkws, BNUOK, RADSO.

Written by

Corey Phillips

Corey Philips is an electrician and lighting expert. He graduated from the University of Birmingham in 2012 with a Bachelor's degree in electrical and electronics engineering. Corey is a specialist contractor in lights. He sells and installs and recommends lights and lamp sheds, and other lights accessories. Aside from that, Corey is vast in installing and maintaining electrical appliances like air conditioners, water heaters, and the likes.