3/8 x 5 in Lag Screw Kit 50 Pack - Hot Dip Galvanized for Outdoor Use

In this review of the 3/8 x 5 in Lag Screw Kit, the bottom line is simple: this kit is aimed at builders and DIYers who need a reliable, corrosion-resistant fastener supply for outdoor or treated-wood projects. The reviewer found the biggest reason to buy it is the Hot-Dip Galvanized finish combined with a complete kit of washers, which removes the need to source matching hardware separately and offers long-term rust resistance for deck and structural work.

Key Features

• Complete kit: Fifty Grade 307A lag bolts and fifty USS flat washers are supplied so a single purchase covers multiple fastenings without hunting for parts.
• Corrosion resistance: Hot-Dip Galvanized coating provides superior rust protection for outdoor use and for projects with ACQ treated lumber.
• Standard sizing: At 3/8 in diameter and 5 in length with a 9/16 in head width, these lag screws fit common structural connections and match standard driver sockets.
• Industry compliance: Meets ASTM A307 and ASME B18.2.1 and related standards, giving confidence for commercial and residential applications where standard materials are required.
• Washer matched: The included USS flat washers (1 in OD) distribute load and help protect wood surfaces during tightening.

Who It's For

This kit is best for contractors, deck builders, fence installers, and homeowners doing outdoor framing who want a ready supply of durable lag screws and washers. The Hot-Dip Galvanized finish makes it particularly suitable for projects exposed to weather or when using ACQ treated lumber.

Those who need specialty grades, tapered or structural lag with engineered bolt specifications, or shorter single-piece quantities for light indoor work may prefer other options. Also, users who expect to drive without pilot holes should be aware a pilot hole is recommended for proper installation.

Pros & Cons

Pros

• Includes 50 screws and 50 washers so projects can proceed without sourcing additional hardware.
• Hot-Dip Galvanized finish improves longevity in outdoor or treated-wood installations.
• Meets common industry standards, which helps with code compliance and material traceability.
• Washers help distribute load and protect wood during tightening, improving joint performance.

Cons

• Some customers report mixed experiences with hold capacity and occasional breakage under extreme loads, so use appropriate pilot holes and avoid over-torquing.

Specifications

Diameter	3/8 in
Length	5 in
Head width	9/16 in
Quantity	50 lag screws and 50 washers
Washer OD	1 in
Finish	Hot-Dip Galvanized
Standards	Meets ASTM A307, ASME B18.2.1, ASME B18.21.1, ASTM F2329

Our Verdict

The 3/8 x 5 in Lag Screw Kit is a sensible, cost-effective choice for anyone doing outdoor woodwork who wants a ready supply of durable fasteners and washers. It is good value for routine deck, fence, and structural tasks where a Hot-Dip Galvanized finish and industry-standard material compliance matter; installers should follow the recommendation to drill pilot holes and avoid excessive torque to prevent breakage.

Frequently Asked Questions

Are these suitable for ACQ treated lumber?
Yes, the Hot-Dip Galvanized finish is specified as suitable for use with ACQ treated lumber.

Does the kit include washers?
Yes, the kit contains 50 USS flat washers with an outside diameter of 1 in, one per lag screw.

Is a pilot hole needed?
A pilot hole is recommended for installation to reduce splitting and to prevent excessive installation torque that can lead to breakage.