16 Inch Carriage Bolts

The 16 Inch Carriage Bolts, with a length of up to 406 mm, is an extra-long fastener developed for heavy-duty structural connection applications. In the construction and industrial sectors, when standard length fasteners cannot meet the penetration depth and connection strength requirements of thick components, this bolt becomes a critical solution, capable of penetrating giant beams and columns, multi-layer composite materials, and deep underground structural components, providing stable and reliable anchoring force.

As a source factory with over 15 years of experience in fastener research and manufacturing, we understand the core pain points of long-length bolts in production and transportation. Ordinary bolts, when lengthened, are prone to bending, thread deformation, and straightness deviations, directly affecting installation results. Our 16-inch carriage bolts are manufactured using customized special processes, with strict control over straightness throughout the entire length.  We select high-quality medium-carbon steel or alloy steel base materials, ensuring excellent mechanical properties and tensile strength even at lengths exceeding 400 mm, providing long-lasting and stable connection guarantees for heavy-duty engineering projects.

Core Product Advantages

1. Heavy-Duty Structure Exclusive Design, Suitable for High-Demand Scenarios

Outstanding Deep Penetration Capability: The 16-inch extra-long size is specifically designed for connecting giant wooden beams, railway sleepers, dock piles, and multi-layer steel structures. It can easily penetrate complex multi-layer material stacks, achieving through-connection and solving the penetration challenges of large component connections.

Strong Load-Bearing Performance: This bolt is available in large diameter specifications (such as 1/2 inch, 5/8 inch, 3/4 inch, etc.). The "thick and long" combination design gives it extremely high tensile strength and shear force, capable of stably supporting heavy static and dynamic loads, meeting the high-load usage requirements of heavy-duty structures.

2. Classic Square Neck Anti-Loosening Mechanism, Efficient and Convenient Installation

Self-Locking Function: Continuing the classic design of carriage bolts, the square neck below the bolt head, when inserted into the workpiece hole, tightly engages the hole wall, forming a reliable self-locking effect. When tightening the nut, the bolt body does not rotate, preventing misalignment and slippage. Supports single-sided operation: During installation, only one wrench is needed to tighten the nut, eliminating the need for additional fixing of the bolt on the other side. This advantage is particularly crucial in confined spaces, deep pits, high altitudes, or when installing heavy components where only one side is accessible, significantly improving construction efficiency and reducing labor costs.

3. Precise process control, ensuring both straightness and strength

Advanced manufacturing process: Utilizing high-end cold heading and thread rolling technology, the straightness of the entire bolt length is subjected to multiple rigorous inspections during the production process, ensuring that each bolt is straight and regular, without bending or deformation, allowing for smooth penetration of the workpiece during installation and preventing jamming.

High-quality materials and heat treatment:  Provides material options that meet ASTM A307 (general engineering) and Grade 5, Grade 8 (high strength) standards.  Through professional heat treatment processes, the toughness of the bolt core and the surface hardness are precisely balanced, effectively preventing fracture during the tightening process.

Core Technical Parameters

Typical Application Scenarios

With years of industry service experience, our 16 Inch Carriage Bolts have been successfully applied in various demanding environments, adapting to diverse heavy-duty engineering needs:

1. Heavy Timber Structures: Used for connecting giant timber beams, column bases, and bridge frames. In projects with extremely high structural strength requirements, such as ancient building restoration and modern heavy timber construction, they are indispensable core connectors, ensuring the stability of the building framework;

2. Railway and Transportation Engineering: Suitable for railway sleeper connection and fixing, and highway guardrail post anchoring. The long thread design allows for deeper engagement, ensuring that transportation facilities remain safe and stable during long-term use;

3. Mines and Quarries: Used for fixing liners and protective plates of heavy equipment such as crushers and screening machines. Under harsh working conditions with high vibration and impact, the square neck anti-loosening design effectively prevents bolt loosening and detachment, ensuring stable equipment operation;

4. Marine and Port Engineering: Bolts with hot-dip galvanized surface treatment can withstand long-term immersion and corrosion by seawater, and are widely used in marine-related scenarios such as dock pile foundations and breakwater timber structure connections.

Company Strength and Quality Assurance

We are Ningbo Gangtong Zheli Fastener Co., Ltd. Since our establishment in 2001, we have built a mature full-chain system for fastener research, development, production, and sales. Our factory is located in the Zhenhai Chemical Industrial Zone of Ningbo, and our headquarters and foreign trade sales department are located in the Ningbo Jiangdong Eastern Business Center. The factory covers an area of 15,000 square meters, with a stable monthly production capacity of 2,000 tons and annual sales exceeding US$15 million. The company is equipped with a professional R&D team, a full-process supply chain management system, and large-scale warehousing facilities, focusing on the production of high-strength standard fasteners. We can provide integrated MRO procurement and distribution services for metal fasteners, comprehensively meeting customers' diverse procurement needs.

In the field of heavy-duty connections, quality directly relates to engineering safety. We strictly control product quality throughout the entire process: In the raw material stage, we select high-quality medium-carbon steel and alloy steel raw materials, and each batch of raw materials undergoes chemical composition spectral analysis to ensure that the materials meet the standards; in the production stage, we use advanced cold heading and roll threading processes to ensure continuous and complete metal flow lines, improving product strength, while precisely controlling the square neck size and bolt straightness; in the finished product testing stage, we fully implement the ISO 9001 quality management system, conducting full-length straightness testing, hardness testing, and tensile testing on each batch of finished products, with galvanized products undergoing additional salt spray testing. Material certificates (Mill Test Certificates) can be provided according to customer requirements, enabling full traceability of quality.

Our product range is extensive, covering heavy-duty hexagonal bolts, heavy-duty hexagonal nuts, threaded rods, studs, washers, screws, etc., made of carbon steel, alloy steel, and stainless steel. We strictly adhere to international standards such as DIN, ISO, EN, JIS, ASTM/ANSI/ASME/SAE, BS, and AS. Our products are exported to North America, Europe, Australia, Southeast Asia, the Middle East, Latin America, and many other regions, and are suitable for various fields such as building steel structures, bridges, oil pipelines, mechanical equipment, ships, and railways.

Reasons to Choose Us

1. Direct supply from the source factory, outstanding cost-effectiveness: As a physical manufacturer in Ningbo, Zhejiang, a core fastener production area in China, we have a complete production line from raw material procurement to finished product delivery, eliminating all intermediate links and directly providing customers with highly competitive ex-factory prices. We have sufficient stock of standard specifications and can quickly respond to delivery needs;

2. Professional technology and efficient response: Our company's engineering team has rich experience in the research and development and production of 16 Inch Carriage Bolts, and can accurately complete non-standard customization (OEM/ODM) services based on drawings or samples provided by customers; we can quickly respond to and provide targeted solutions to technical problems encountered by customers during use;

3. Global service experience, worry-free cooperation: With many years of experience in the international market, we have established a complete logistics and distribution system and after-sales service system. We are familiar with the standard requirements and market demands of different regions, and can accurately match the procurement needs of global customers. We are committed to establishing long-term and stable cooperative relationships with our customers, ensuring a smooth process from procurement to delivery and after-sales service.