A Carriage Bolt, also known as a coach bolt or round head square neck bolt, is designed for fastening metal-to-metal and metal-to-wood assemblies. It is recognized by its smooth, shallow domed head and square neck located directly beneath the head.
The square neck helps prevent the bolt from rotating when installed through a matching square hole, allowing the nut to be tightened using a single wrench or spanner. The smooth head also provides a clean appearance and can make the fastener suitable for applications where access to the bolt head is limited.
Carriage bolts are widely used across construction, engineering, automotive, furniture, and general fabrication applications. Adore Industries manufactures and supplies carriage bolts in different materials, sizes, thread configurations, and surface finishes, with customized options available for specific project requirements.
Key Features
- Smooth, shallow dome-shaped head
- Square neck helps prevent bolt rotation
- Suitable for metal-to-metal and metal-to-wood fastening
- Can be tightened with a wrench or spanner
- Clean and low-profile head appearance
- Available in metric and imperial dimensions
- Suitable for security and general fastening applications
- Available in different materials and coatings
- Customized dimensions available
Applications
Carriage bolts are commonly used in:
- Construction and structural assemblies
- Engineering applications
- Automotive components
- Metal-to-wood connections
- Furniture and woodworking
- Sheet metal assemblies
- Locks and hinges
- Light-duty automotive trim
- General fabrication and maintenance
- Plastic and plywood fastening applications
How Carriage Bolts Work
The square neck positioned below the head engages with a matching square hole or suitable material surface. When the nut is tightened, the square neck helps hold the bolt in position and reduces rotation.
This design allows the installer to tighten the nut from one side without requiring a second tool to hold the bolt head in many applications.
Types of Carriage Bolts
Different carriage bolt designs are available to suit specific fastening requirements, including:
- Rib Neck Carriage Bolts
- Round Head Carriage Bolts
- Short Neck Carriage Bolts
- Flat Head Carriage Bolts
- Square Neck Carriage Bolts
- Fin Neck Carriage Bolts
Each configuration has different dimensional and physical characteristics for particular installation conditions.
Security Fastening Applications
Carriage bolts can be useful for applications where the smooth domed head is preferred and access to the head side is restricted. They are commonly used with suitable nuts in assemblies such as locks, hinges, brackets, and other fixtures.
Once installed, the smooth head and square neck arrangement can help limit easy access to the fastening mechanism from the head side.
Standards
Carriage bolts can be manufactured or supplied according to applicable standards and customer specifications, including:
- BS
- ISO
- DIN
- Customized specifications
Materials
Adore Industries offers carriage bolts in a variety of materials to suit different applications and operating environments:
- High Tensile Steel
- Carbon Steel
- Stainless Steel
- Brass
- Aluminum
Material selection can be customized according to project requirements.
Available Sizes & Threads
Carriage bolts are available in both metric and imperial sizes.
Metric Sizes: M6 to M36
Metric Threads: Coarse Thread and Fine Pitch Thread
Imperial Sizes: 1/4″ to 1-1/2″
Imperial Threads: UNC, UN, UNF
Customized dimensions can also be supplied according to customer drawings and application requirements.
Coatings & Surface Finishes
Different coatings and finishes are available to provide suitable surface protection and appearance.
Available options include:
- PTFE Coated
- Hot-Dip Galvanized
- Yellow Zinc
- Blue Zinc
- Black Zinc
- Aluminum Zinc Flake
Additional coating and finishing options can be provided according to customer requirements.
Why Choose Adore Industries for Carriage Bolts?
Adore Industries manufactures and supplies carriage bolts in different head and neck configurations, materials, sizes, thread profiles, and surface finishes. Our customized manufacturing options help meet requirements across construction, engineering, automotive, woodworking, and general fastening applications.
Contact Adore Industries for carriage bolts manufactured according to your required dimensions, materials, standards, and coating specifications.