3/8 in x 3-1/2 in Galvanized Carriage Bolt Kit (50 Pack)

In this review the 3/8 in x 3-1/2 in Galvanized Carriage Bolt Kit is evaluated for outdoor and heavy-duty woodworking projects; the bottom line is that this kit is a practical choice for builders who need corrosion-resistant fasteners in bulk. The kit includes 50 carriage bolts, 50 USS flat washers, and 50 hex nuts with a hot dip galvanized coating and Grade 307A bolts, and that combination makes it particularly suited to exterior applications where rust resistance and consistent hardware sizes matter.

Key Features

• Hot dip galvanized coating: Provides superior corrosion resistance for long-lasting outdoor use on decks, pergolas, and fences.
• Complete 50-piece kit: Includes 50 carriage bolts, 50 USS thick washers, and 50 hex nuts so projects can be completed without hunting for matching parts.
• Consistent dimensions: The 3/8 in diameter and 3-1/2 in length give dependable holding strength and predictable fit for standard timber connections.
• Flat head design: The carriage bolt flat head offers a semi-flush finish that looks cleaner on visible surfaces and reduces snagging.
• Practical hardware grades: Grade 307A carriage bolts and grade 2 hex nuts provide adequate strength for general heavy-duty exterior use.

Who It's For

This kit is well-suited to DIY homeowners, deck builders, and landscapers who need a reliable, corrosion-resistant set of carriage bolts and matching hardware for outdoor timber work. Anyone installing pergolas, gazebos, fence rails, or heavy lumber connections will appreciate the uniform sizing and bulk quantity.

Those who need stainless steel or higher-strength structural fasteners for critical load-bearing engineered structures should look elsewhere; this kit is aimed at general heavy-duty exterior applications rather than specialized marine or high-tensile requirements.

Pros & Cons

Pros

• Durable hot dip galvanized finish that extends service life in exterior environments.
• Good value for money thanks to a full set of 50 matching bolts, washers, and nuts.
• Flat head carriage bolts give a semi-flush, neat appearance on visible installations.
• Clear wrench sizing (9/16 in) makes installation straightforward for common tool sets.

Cons

• Washers received mixed feedback from customers, so some projects may need different washer thickness or type.
• Grade 2 hex nuts are adequate for many uses but not intended for high-tensile structural applications.

Specifications

Diameter	3/8 in
Length	3-1/2 in
Head diameter	0.813 in
Washer outside diameter	1 in
Nut wrench size	9/16 in
Contents	50 carriage bolts, 50 USS thick washers, 50 hex nuts
Coating and grades	Hot dip galvanized; Grade 307A bolts, Grade 2 nuts

Our Verdict

The 3/8 in x 3-1/2 in Galvanized Carriage Bolt Kit is a solid, cost-effective choice for exterior woodworking and general heavy-duty fastenings. It pairs the protection of a hot dip galvanized finish with a full complement of matching hardware, making it a practical buy for builders who need uniform, rust-resistant bolts in larger quantities.

Frequently Asked Questions

Are these bolts suitable for outdoor use?
Yes; the hot dip galvanized coating provides superior corrosion resistance for exterior applications.

Do the nuts and washers come in matching sizes?
Yes; the kit includes 50 USS thick washers and 50 hex nuts sized to match the 3/8 in carriage bolts.

What tools are needed for installation?
A 9/16 in wrench is required for the hex nuts; common hand tools are sufficient for installation.