Premium 6 Carriage Bolts Zinc-Plated Heavy-Duty Fasteners

Picture this: Your deck wobbles dangerously after just one season. Your trailer hitch rattles like a jar of marbles. That custom furniture project starts separating at the joints. Why? 92% of structural failures trace back to substandard fasteners. Using weak carriage bolts costs contractors $1.2 billion annually in rework. Don't become another statistic!

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Technical Advantages: Why Our Carriage Bolts Dominate

Why trust your critical joints to ordinary bolts? Our 3/8 x 4 inch carriage bolts feature military-grade enhancements:

Heat-treated to Rockwell C35 hardness. Precision-rolled threads prevent cross-threading. Square necks bite into wood to prevent rotation during tightening. That's engineering peace of mind!

Head-to-Head: Why Our 3/8" Bolts Outperform

We put 7 leading brands through torture tests. See how we dominate:

Feature	Our Bolts	Brand X	Big-Box Store
Shear Strength (lbs)	4,850	3,200	2,700
Corrosion Resistance	HDG Class 55	Electroplated	Basic Zinc
Square Neck Height	0.225"	0.180"	0.150"
Warranty	Lifetime	1 year	None

Notice those numbers? Competitors cut corners where it counts. Our thicker galvanized coating on 3/8 x 3.5 carriage bolts protects against weather extremes. Don't pay for premium and get peasant quality!

Custom Solutions: Tailored for YOUR Project

Standard bolts failing you? We solve specialist headaches:

• 🔧 3/8 x 3.5 galvanized carriage bolts - Ideal for marine & high-moisture applications
• 🔧 Square-neck serrations for soft woods and composite decking
• 🔧 Reduced shank versions for structural steel connections
• 🔧 Non-magnetic stainless steel for sensitive electronics

Over 72% of orders ship same-day with custom modifications. Need 6 carriage bolts
with unique markings? We laser-etch identifiers at no extra cost!

Real-World Success Stories

Coastal Construction Co. eliminated bolt failures in their boardwalks:

✔️ Heavy-duty trailer manufacturer reduced warranty claims by 41% after switching to our bolts

✔️ Heritage barn restoration saved from collapse using our custom-length bolts

✔️ DIY inventor secured patent using our non-standard sizes

Stop Compromising. Build Fearlessly!

Why risk recalls, lawsuits, or wasted weekends? Our carriage bolts transform structural integrity from weak link to strongest asset. Thousands trust their safety to our precision engineering.

LOCK IN SECURITY NOW →

BoltPro USA® delivers American-made fasteners since 1987. ISO 9001-certified quality. Ships same-day with quantity breaks at 6 carriage bolts. Projects fail without notice. Your preparedness shouldn't.

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FAQS on 6 carriage bolts

Q: What are the standard dimensions of 6 carriage bolts?

A: Carriage bolts typically feature a rounded head with a square neck under it to prevent rotation during tightening. A set of 6 carriage bolts usually shares identical diameter and thread pitch, such as 3/8 inch shank with coarse threading. The length varies based on application needs but common options include 3.5-inch or 4-inch versions.

Q: What projects suit 3/8 x 4 inch carriage bolts?

A: These 4-inch bolts are ideal for thick material joining where extra length is needed for securing nuts. They excel in outdoor decking, heavy furniture assembly, or trailer flooring applications requiring substantial penetration. The square neck provides self-locking capability in wood or soft metals.

Q: How do 3/8 x 3.5 inch carriage bolts differ from longer versions?

A: 3.5-inch bolts offer mid-range penetration for projects like furniture legs, gate hinges, or garden equipment where 4-inch would be excessive. They share the same 3/8-inch diameter as longer bolts but provide optimized grip range for medium-thickness materials. This length avoids unnecessary protrusion while maintaining strength.

Q: Why choose 3/8 x 3.5 galvanized carriage bolts?

A: Galvanization adds zinc coating for superior rust resistance in wet or outdoor environments. These bolts withstand exposure in marine hardware, agricultural equipment, and exterior wood structures where corrosion occurs. The protection extends service life 5-10 times over uncoated steel alternatives.

Q: Can carriage bolt sizes be mixed in a single project?

A: Yes, combining lengths like 3.5-inch and 4-inch versions creates tiered security in multi-layered assemblies. Use longer bolts for primary structural joints and shorter ones for reinforcement points. Ensure all share matching diameter (e.g., 3/8-inch) to maintain consistent torque specifications and nut compatibility.