Carriage bolts are essential fasteners known for their secure, self-locking functionality. Ideal for various applications from construction to woodworking, these bolts provide stability, strength and a clean finish. Nickel Systems offers a comprehensive selection of carriage bolts and specialty fasteners, including those made from high-nickel and exotic alloys like Inconel® and Hastelloy®. Contact us to help you find the right fastener for your project.
Carriage bolts come in various sizes and specifications. Check out our dimensioning and specification data below. If your projects require unique dimensions or specialized performance, we welcome custom requests to tailor our offerings to your specific needs.
For common nominal sizes, hex head bolts are typically stocked in 1/8″ increments up to 1″ long, in 1/4″ increments from 1″ to 6″ long & in 1/2″ increments from 6″ to 10″ long.
Carriage bolts are precision-engineered fasteners designed for strength and aesthetic appeal. They are characterized by a shallow, rounded head and a square- or oval-shaped neck that prevents the bolt from turning during installation. This design enables a secure, self-locking mechanism when the nut is tightened, making them ideal for wood-to-wood or wood-to-metal applications in structural and decorative projects.
Key Characteristics
Self-locking design: The square or oval neck prevents the bolt from turning when tightening the nut, offering a self-locking feature that secures the fastener firmly in place.
Aesthetic appeal: The smooth, rounded head provides a clean finish that enhances the overall appearance.
Versatile application: Carriage bolts are suitable for numerous uses, from securing heavy materials in construction to providing a decorative yet durable connection in woodworking.
Common Types of Carriage Bolts
Square neck carriage bolts
Oval neck carriage bolts
Step bolts
Other Names
Carriage bolts are known by several other names:
Plow bolts
Coach bolts
Round head square neck bolts
Cup square bolts
Step bolts
Industries and Applications
Carriage bolts in exotic materials are critical components across various industries. They provide secure fastening solutions for demanding applications that require strength, stability and resistance to harsh conditions.
Marine and Offshore Engineering
In marine environments, fasteners are constantly exposed to saltwater, humidity and harsh weather conditions. Nickel Systems’ carriage bolts in alloys like Monel® and 2205 Duplex stainless steel offer exceptional corrosion and biofouling resistance, making them ideal for applications such as:
Ship deck construction: Carriage bolts made from Monel® or 2205 Duplex stainless steel secure wooden or composite decking to metal frames. They resist saltwater corrosion.
Dock structures: Exotic alloy bolts fasten dock planks and structural components exposed to constant water and humidity.
Offshore platforms: Durability in marine environments is critical. Carriage bolts secure handrails, gratings and equipment housings on oil rigs.
Carriage bolts in chemical plant applications must withstand exposure to acidic, caustic and high-temperature environments. Our carriage bolts in Hastelloy® or Alloy 20 (Carpenter® 20) maintain structural integrity in even the most aggressive chemical processing applications.
Chemical storage tanks: Hastelloy® or Alloy 20 bolts secure access panels and nozzles on tanks that store corrosive substances like sulfuric acid or hydrochloric acid.
Pipeline fastening: Carriage bolts are used to attach flanges and support brackets in chemical pipelines handling aggressive chemicals.
Mixers and reactors: Exotic alloy bolts fasten mixing blades and reactor components exposed to acidic or caustic solutions.
The oil and gas industry depends on high-strength fasteners to withstand high pressures, extreme temperatures and exposure to corrosive substances. Carriage bolts provide secure connections in:
Pipeline supports: 2205 Duplex stainless steel carriage bolts are often used in pipelines carrying high-pressure and corrosive fluids.
Refinery equipment:Inconel® carriage bolts fasten heat exchangers and pressure vessels that operate under high temperatures or chemical exposure.
Offshore rig assemblies: Carriage bolts in 2507 Super Duplex are used to attach platform gratings and safety barriers to resist harsh environmental conditions.
Carriage bolts in aerospace applications require high-strength, lightweight materials that endure intense heat, stress and vibration. These fasteners are ideal in applications such as:
Aircraft interiors: Titanium carriage bolts fasten interior panels and seats. They provide strength with a lightweight profile.
Engine components: Inconel® carriage bolts secure engine casings and exhaust systems exposed to high heat and pressure.
Satellite structures: High-performance alloy carriage bolts are used to mount and assemble lightweight but durable satellite components.
In power generation, carriage bolts provide secure fastening for critical infrastructure exposed to extreme temperatures, pressure and corrosion. These include:
Turbine casings: Inconel® carriage bolts secure turbine casings and components in steam or gas turbines exposed to high heat and pressure.
Geothermal plants: Carriage bolts made from 2507 Super Duplex stainless steel fasten equipment exposed to hot, mineral-rich fluids.
Nuclear reactors: Hastelloy® bolts are used in reactor cores and piping systems to resist radiation-induced corrosion.
Mining and Mineral Processing:
Specialized carriage bolts are used extensively in mining and mineral processing for their durability against abrasive and acidic conditions.
Crushers and grinders: Alloy 20 carriage bolts fasten wear plates and liners in crushing and grinding equipment. These resist wear due to abrasive materials.
Conveyor systems: 2205 Duplex stainless steel bolts secure frames, rollers and brackets in conveyors transporting acidic or abrasive ores.
Acid leaching equipment: Hastelloy® carriage bolts secure tanks and piping in acid leaching processes for metal extraction.
Architectural and Structural Engineering:
Exotic alloy carriage bolts provide structural stability and corrosion resistance in high-end architectural projects. These projects include bridges, outdoor sculptures and infrastructure exposed to extreme weather or pollution.
Bridge components: 2205 Duplex stainless steel carriage bolts fasten handrails, grates and other exposed structural elements for long-term corrosion resistance.
Outdoor sculptures: Exotic alloy bolts secure artistic installations that are exposed to pollution and/or weathering.
High-end construction: Inconel® or titanium carriage bolts are used in architectural projects that require strength and resistance to environmental factors.
These industries rely on exotic alloy carriage bolts to maintain performance and safety in challenging conditions, making them vital components in mission-critical applications.
Specialty Carriage Bolts for Unique Applications
A special carriage bolt is a round-head oval neck bolt. In contrast to the typical square neck, these specialty bolts have an oval neck. Below is a description and additional advantages for considering an oval neck bolt for your application.
Improved anti-rotation grip: Compared to a standard square neck, the oval neck provides a stronger and more reliable grip in softer or nonstandard materials. Its shape reduces the risk of the bolt spinning during installation or under load.
Compatibility with non-square holes: The rounded profile of the oval neck makes it suitable for use in pre-drilled or irregularly shaped holes. This offers versatility in applications where precise square holes may be impractical.
Reduced stress on material: The smoother transition of an oval neck spreads the load more evenly across the material, reducing the chance of cracking or deformation.
Enhanced aesthetic finish: The oval neck allows for a clean, low-profile finish while maintaining secure fastening. This makes oval neck carriage bolts ideal for visible or decorative applications.
Specialized applications: Oval neck carriage bolts are often used in furniture making, marine applications and lightweight structures where secure, nonintrusive fastening is essential.
Tips for Purchasing Carriage Bolts
To maximize performance and longevity, keep these best practices in mind when selecting your carriage bolts:
Accurate dimensioning specifications: Verify the nominal diameter, thread type and desired length to select the correct dimensions. Refer to our detailed dimensions table above for a perfect fit.
Suitable material selection: Select the appropriate material for your application. For example, stainless steel carriage bolts are ideal for rust resistance, while various high-performance alloys provide durability in extreme environments. Explore Nickel Systems’ materials list for more information.
Additional protection: If your application requires extra protection, inquire about available coatings that can further enhance durability.
Strict adherence to standards: To ensure compatibility, verify that your chosen part conforms to specific standards, such as ASTM, ASME, ISO, DIN or other industry specifications.
Complementary fasteners: Carriage bolts are often paired with nuts or washers for a complete fastening solution.
Contact Nickel Systems today to request a quote & find the perfect solution for your next project.
Nickel Systems provides high quality exotic grade materials that hold up in the toughest, most severe heat & corrosive environments. With our large inventory of specialty fasteners in stock, we are always ready to answer the call to serve the most challenging applications.
Contact Nickel Systems Today for Top-Tier Carriage Bolts
Nickel Systems provides high-performance carriage bolts for industries requiring strength, durability and corrosion resistance. With an extensive inventory that includes exotic materials like Inconel® and Alloy 20 and varying dimensions like 3/8- or ¼-inch stainless steel carriage bolts, we have the right solution for your application. We also offer free consultation and support services to help customers find the ideal products for their needs.
Contact us today to request a quote or speak to an expert and find the perfect solution for your next project.
