3/8 in x 6 in Black Carriage Bolt Kit - Ceramic Coated Exterior

Our review of this 3/8 in x 6 in Black Carriage Bolt Kit finds it best for homeowners and builders who need heavy duty exterior fasteners that look good and resist corrosion. The kit of 25 carriage bolts, USS washers, and hex nuts ships with a 5-layer ceramic black ruspert coating that claims roughly twice the rust protection of standard galvanized finish, and the flat head gives a semi-flush, finished appearance ideal for visible outdoor projects. For anyone fastening decks, pergolas, or pavilions this kit balances appearance, size, and value.

Key Features

• Complete kit: Includes 25 carriage bolts, 25 USS thick washers, and 25 hex nuts so a typical small to medium project can be completed without extra purchases.
• 5-layer ceramic coating: The black ruspert finish delivers enhanced corrosion resistance so fasteners maintain appearance on exterior structures longer than plain steel.
• Useful dimensions: 3/8 in diameter and 6 in length work well for joining heavy timbers and posts where bolt reach and shear strength matter.
• Semi-flush finish: The flat carriage head provides a clean, built-in look on decks, pergolas, and gazebos without standing proud of the surface.
• Compatibility: Nut wrench size 9/16 in and washer outer diameter 1 in make the kit easy to install with common tools and hardware.

Who It's For

This kit is aimed at DIYers, deck builders, and small contractors who need a reliable set of carriage bolts for exterior timber work. The 3/8 in x 6 in size is suited to joining 2x lumber, posts, and other heavy duty connections where a semi-flush head is preferred for aesthetics.

People who require stainless steel for maximum long-term corrosion resistance or who need non-coated fasteners for painting after installation should look elsewhere. It is also not a fit for very heavy industrial structural connections that specify higher grade hardware than Grade 307A or grade 2 nuts.

Pros & Cons

Pros

• Solid, consistent build quality gives a sturdy feel and reliable fit with 9/16 in wrench compatibility.
• Attractive black finish improves visual integration on outdoor pavilions and pergolas.
• Value for money: the kit includes washers and nuts so projects can proceed without hunting for matching parts.

Cons

• Rust resistance is improved versus standard galvanized, but some customers reported mixed long term performance in very harsh environments.

Specifications

Diameter	3/8 in
Length	6 in
Head diameter	0.813 in
Nut wrench size	9/16 in
Washer outside diameter	1 in
Coating	5-layer ceramic black ruspert
Included hardware	25 carriage bolts, 25 USS flat washers, 25 hex nuts

Our Verdict

This 3/8 in x 6 in carriage bolt kit is a practical choice for outdoor woodworking projects where appearance and enhanced corrosion resistance matter. It delivers good build quality, convenient included washers and nuts, and a semi-flush black finish that suits decks and pergolas, making it a sensible value buy for homeowners and small contractors.

Frequently Asked Questions

Are these bolts ready for exterior use?
Yes, the 5-layer ceramic black ruspert coating is intended for exterior use and offers roughly twice the rust resistance of standard galvanized finishes.

What tools are required to install them?
Installation typically needs a 9/16 in wrench for the hex nuts and common drill or driver tools to prepare holes for 3/8 in carriage bolts.

Do the kits include washers and nuts?
Yes, each kit contains 25 USS thick washers and 25 grade 2 hex nuts matched to the 25 carriage bolts.