3/8 x 3 in Lag Screw Kit (50 Pack) - Hot-Dip Galvanized Hold

In this review the 3/8 x 3 in Lag Screw Kit (50 Pack) is examined for homeowners and contractors who need a mid-size, weather-resistant fastener for outdoor and structural work. The bottom line: this kit stands out for its combination of corrosion protection and completeness, arriving with 50 Grade 307A lag bolts and 50 USS flat washers so buyers can start most deck, fence or pergola jobs without hunting for parts. Our review focuses on durability, compatibility with treated lumber and real-world convenience.

Key Features

• Diameter and length: The 3/8 in diameter and 3 in length provide a balance of shear strength and embedment suitable for medium-duty structural fastening in wood.
• Complete kit: Including 50 lag bolts and 50 USS flat washers means projects can proceed without sourcing separate washers, saving time on prep and reducing hardware mismatch.
• Hot-dip galvanized finish: The hot-dip galvanization offers superior rust resistance for outdoor use, extending service life when exposed to the elements.
• Compatibility with treated lumber: Rated for use in ACQ treated lumber, the bolts are suitable for pressure-treated decks and exterior builds where corrosion is a concern.
• Standards compliance: Meeting ASTM A307, ASME B18.2.1, ASME B18.21.1 and ASTM F2329 ensures consistent dimensions and material performance for industrial or commercial applications.

Who It's For

This kit is aimed at DIYers, carpenters and small contractors who frequently build or repair outdoor wood structures such as decks, stairs, fences and pergolas and need a ready supply of mid-size lag screws with washers. The hot-dip galvanized finish and Grade 307A material make it practical for seasonal exposure and treated lumber projects.

Customers who need heavier structural fasteners, specialty head styles, or metric sizes should look elsewhere. Also, installers who prefer self-drilling anchors or one-piece coated fasteners for submerged or marine environments may want a different specification.

Pros & Cons

Pros

• Durable hot-dip galvanized coating provides reliable corrosion resistance for outdoor projects.
• Kit includes 50 screws and 50 washers so projects can start immediately without extra parts.
• Meets multiple industry standards, offering predictable dimensions and material quality.
• Suitable for ACQ treated lumber, reducing risk of accelerated corrosion common with some coatings.

Cons

• Some users report mixed hold capacity under extreme loads, so it may not replace specialized structural anchors for very high-stress connections.
• A pilot hole is recommended for installation, adding an extra step compared with self-tapping alternatives.

Specifications

Diameter	3/8 in
Length	3 in
Head width	9/16 in
Quantity	50 screws and 50 washers
Washer size (OD)	1 in
Finish	Hot-dip galvanized
Standards	ASTM A307; ASME B18.2.1; ASME B18.21.1; ASTM F2329

Our Verdict

The 3/8 x 3 in Lag Screw Kit is a practical, value-minded choice for most outdoor wood projects where corrosion resistance and ready-to-use hardware matter. Contractors and DIY builders will appreciate the included USS washers and the hot-dip galvanized finish; however, those needing extreme load capacity or faster installation with self-drilling screws should consider alternatives. Overall it represents solid value for typical deck and fence work.

Frequently Asked Questions

Are these safe for pressure-treated lumber?
Yes, the hot-dip galvanized finish and Grade 307A bolts are specified as suitable for use in ACQ treated lumber.

Do I need to pre-drill?
A pilot hole is recommended for proper seating and to reduce the risk of splitting, especially near board ends.

What size washer is included?
The kit includes USS flat washers with an outside diameter of 1 in for each lag screw.