5/16" x 3-1/2" Carriage Bolts - Heavy-Duty Rust-Resistant Fasteners for Construction & Woodworking

Did you know 42% of construction delays stem from fastener failures? While you're searching for reliable 3/8 x 9 carriage bolts or 3.5 inch carriage bolts, your competitors are already using military-grade solutions. Discover how premium carriage bolts can slash your maintenance costs by up to 37%.

(5 16 x 3 1 2 carriage bolt)

FAQS on 5 16 x 3 1 2 carriage bolt

Q: What are the dimensions of a 5/16 x 3 1/2 inch carriage bolt?

A: A 5/16 x 3 1/2 inch carriage bolt has a 5/16-inch diameter shank and a 3.5-inch length under the head. It typically features a rounded dome head and a square neck to prevent spinning during installation. Common uses include woodworking and structural assemblies.

Q: How does a 3/8 x 9 inch carriage bolt differ from standard sizes?

A: A 3/8 x 9 inch carriage bolt is thicker (3/8-inch diameter) and longer (9 inches), designed for heavy-duty applications like securing large timber or metal frames. Its extended length provides deeper penetration in thick materials. The square neck ensures stability under high stress.

Q: What materials are 3-inch carriage bolts made from?

A: Most 3-inch carriage bolts are made from carbon steel, often zinc-plated for corrosion resistance. Stainless steel variants are available for outdoor or high-moisture environments. The material choice depends on load requirements and environmental conditions.

Q: When should I use a 3.5-inch carriage bolt?

A: Use a 3.5-inch carriage bolt for projects requiring moderate length and strength, such as attaching brackets to wooden beams or assembling machinery. The extra 0.5 inches compared to a 3-inch bolt allows for thicker material connections.

Q: Can I substitute a 3/8 x 9 carriage bolt with a 5/16 x 3.5 inch bolt?

A: Substitution depends on load requirements: a 5/16 x 3.5-inch bolt is thinner and shorter, suitable for lighter loads. For heavy-duty applications, stick with the 3/8 x 9-inch bolt to ensure structural integrity. Always verify load ratings before swapping.

Q: How do I measure the length of a carriage bolt?

A: Measure from the base of the head to the tip of the threaded end. For example, a 3.5-inch carriage bolt’s length excludes the head height. Accurate measurement ensures proper fit and load distribution in assemblies.

Q: Are carriage bolts with a 3-inch length suitable for outdoor furniture?

A: Yes, 3-inch carriage bolts work for outdoor furniture if paired with corrosion-resistant coatings like galvanization or stainless steel. Ensure the length matches material thickness, leaving enough thread for a secure nut fit. Regularly inspect for rust in harsh climates.