
Installing a carriage bolt is straightforward — but the right technique and quality materials make all the difference. At Old West Iron, our carriage bolts are forged for both performance and beauty, with finishes that bring rustic character to any project.
Whether you're restoring the past or building something new, carriage bolts offer the strength of iron with a look that never goes out of style.
Whether you're building a barn door, timber frame, rustic gate, or vintage-style furniture, using the right hardware is key to ensuring both durability and design integrity. Carriage bolts — with their domed heads and square necks — are a favorite among craftsmen and builders for their strength, smooth finish, and historic character.
At Old West Iron, we provide a wide range of carriage bolts in hand-forged finishes that are perfect for both structural and decorative applications. In this article, we’ll walk you through proper carriage bolt installation and explain exactly how to screw in a carriage bolt for a secure, long-lasting hold.
What Is a Carriage Bolt?
A carriage bolt is a round-head bolt with a square section just below the head. This square portion locks into the material (usually wood) to prevent the bolt from spinning when the nut is tightened. It’s ideal for applications where one side of the hardware will be visible, offering a smooth, clean look with no exposed screw heads or driver slots.
Tools & Materials You'll Need:
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Drill with wood bit (matching your bolt diameter)
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Rubber mallet or hammer
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Wrench or socket for the nut
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Your carriage bolt of choice
Step-by-Step: How to Screw in a Carriage Bolt
Step 1: Mark and Drill Your Hole
Start by measuring and marking the spot where your bolt will go. Use a drill bit that matches the bolt’s diameter, and drill all the way through the material. Make sure your hole is clean and straight — this ensures proper fit and prevents wobble.
Step 2: Insert the Carriage Bolt
Place the carriage bolt into the hole. The square neck just below the head will need to grip into the material to prevent rotation.
Tip: For hardwoods or dense materials, you may need to tap the bolt into place with a rubber mallet to seat the square neck snugly into the wood.
Step 3: Add a Washer and Nut
On the opposite side, slide on a washer (standard or decorative) and thread on your nut or cap nut. Tighten slowly using a wrench or socket.
Step 4: Tighten Securely
As you tighten the nut, the square portion of the bolt will bite into the wood and lock the bolt head in place. This is why carriage bolts don’t require a screwdriver on the head side — the material holds it for you.
Step 5: Check for Flush Finish
Make sure the domed bolt head sits flush with the wood surface. If you’ve chosen a hand-hammered or raw iron finish, that visible head becomes part of the design.
Common Questions About Carriage Bolt Installation
Q: How do I keep the bolt from spinning in hardwood?
If the square neck isn’t biting well, you can use a chisel to lightly score the edges of the hole or drill a shallow square recess to help the bolt seat fully.
Q: Can I use carriage bolts in metal?
They’re primarily designed for wood, but can be used in metal if paired with proper brackets or pre-set square holes.
Q: Do I need decorative washers or cap nuts?
While not required, adding decorative washers and cap nuts can enhance the finished look, especially on exposed doors, furniture, or beams.
Final Thoughts: Form Meets Function
Installing a carriage bolt is straightforward — but the right technique and quality materials make all the difference. At Old West Iron, our carriage bolts are forged for both performance and beauty, with finishes that bring rustic character to any project.
Whether you're restoring the past or building something new, carriage bolts offer the strength of iron with a look that never goes out of style.
Ready to bolt down your build? Explore our full line of carriage bolts and accessories to complete your project with craftsmanship and confidence.