Threaded Carriage Bolts

In complex engineering scenarios such as heavy timber construction, multi-layer panel connections, and mining equipment fastening, Threaded Carriage Bolts often encounter difficulties due to insufficient thread length. These bolts typically only have partial threading, leading to insufficient engagement and insecure connections when joining thick panels or multi-layer composite materials. This can even cause stripping and loosening, posing serious safety hazards and severely impacting project stability.

We are a source factory with over 15 years of experience in fastener research, development, and manufacturing. For many years, we have specialized in complex engineering connection solutions, serving global construction contractors, mining equipment manufacturers, and other clients. Based on our deep understanding of real-world engineering challenges, we know that fasteners in complex structures require strong adaptability and high reliability.

Core Technological Advantages

1. Innovative Full-Thread Design for More Stable and Flexible Connections

Stronger Connection Force: Unlike traditional carriage bolts with a smooth shank design, our Threaded Carriage Bolts have threads extending almost to the head. The nut can be screwed in deeper, significantly increasing the effective connection length. This significantly improves tensile strength and shear performance, providing more reliable safety protection for complex structural connections.

Suitable for Thick Section Connections: When connecting heavy timber beams, multi-layer steel plates, or composite materials, the full-thread design ensures that the threads are always fully engaged with the nut, completely avoiding problems such as loose connections and stripping caused by insufficient thread length. It adapts to the connection needs of various material thicknesses.

Flexible Installation and Adjustment: The full-thread structure allows for flexible adjustment of the nut tightening position according to material thickness.  Especially in scenarios where the thickness of the connecting parts varies or fine-tuning is required, there is no need to replace bolts of different lengths, greatly improving construction convenience and efficiency.

2. Classic Square Neck Anti-Loosening Mechanism for Efficient and Worry-Free Installation

Built-in Self-Locking and Anti-Rotation Function: Inheriting the core advantages of Threaded Carriage Bolts, the square neck below the head firmly locks into the workpiece hole. When tightening the nut, the bolt body does not rotate with the nut, fundamentally preventing loosening caused by vibration, making it suitable for high-vibration and high-impact working conditions.

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 feature is particularly advantageous in high-altitude operations, confined spaces, or scenarios where only one-sided access is possible, significantly reducing labor costs and improving construction efficiency.

3. Supported by High-Quality Materials and Strict Standards

Diverse Material Selection:  Utilizing high-quality medium-carbon steel such as Q235 and 35# steel, as well as SUS 304/316 stainless steel as raw materials. Through rigorous cold heading and heat treatment processes, the toughness of the bolt core and the surface hardness are precisely balanced, ensuring that the bolts possess both impact resistance and wear resistance, adapting to different working conditions.

Strict Adherence to International Standards: The products are manufactured in strict accordance with DIN 603 (German standard) and GB/T 14 (Chinese national standard). Dimensional accuracy and interchangeability are controlled at every stage, ensuring perfect compatibility with accessories of the same specifications and meeting the standardized assembly needs of different regions and industries.

Core Technical Parameters

Typical Application Scenarios

With years of industry service experience, our Threaded Carriage Bolts have been successfully applied in numerous demanding engineering scenarios, becoming a trusted choice for many customers:

1. Heavy Timber Structures: Used for connecting multi-layered glued laminated timber, heavy timber beams, and column bases. The full-thread design provides better grip on the wood, evenly distributing stress, preventing wood splitting, and offering superior shear and tensile strength, ensuring the stability of timber structures.

2. Mining and Heavy Machinery: Suitable for fixing liner plates and protective plates on equipment such as crushers, screening machines, and conveyor belt supports. Under high vibration and high impact conditions, the full-thread design provides a more reliable connection than half-threaded bolts, effectively preventing nuts from loosening due to vibration and ensuring the normal operation of the equipment.

3. Industrial Molds and Equipment: Used for connecting large mold templates and fixing factory equipment bases. When the thickness of the connecting parts varies or fine-tuning is required, the full-thread design allows for flexible adjustment of the fastening position, greatly improving the convenience of installation and maintenance.

4. Infrastructure Construction: Used for fixing railway sleepers, bridge maintenance, and large-scale scaffolding construction. The dual advantages of full threading and square neck anti-loosening ensure the long-term stability and safety of infrastructure in complex environments.

Company Strength and Quality Assurance

We are Ningbo Gangtong Zheli Fasteners 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.  Our 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. We specialize in the production of various fasteners and can provide integrated MRO procurement and distribution services for metal fasteners, comprehensively meeting the diverse procurement needs of our customers.

In the fastener industry, quality is life. We ensure the reliability and durability of every Threaded Carriage Bolts through rigorous control throughout the entire process:  During raw material warehousing, each batch of raw materials undergoes spectral analysis to precisely control chemical composition, eliminating material defects from the source; during production, the dimensional accuracy and thread quality of the bolts are fully inspected, preventing unqualified semi-finished products from entering the next process; in the finished product stage, we conduct rigorous salt spray tests (hot-dip galvanized products can withstand over 72 hours without red rust), tensile strength tests, and other tests to comprehensively verify corrosion resistance and mechanical strength. The company fully implements the ISO 9001 quality management system standard and can provide material certificates (MTC) according to customer requirements, ensuring that the product's chemical composition and mechanical properties fully meet the standards. At the same time, the products comply with the RoHS environmental directive, containing no harmful substances and being harmless to the environment and human body.

Our product range is extensive, covering heavy-duty hexagonal bolts, heavy-duty hexagonal nuts, threaded rods, studs, washers, screws, etc., with materials including 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, superior quality and price: As a physical manufacturer located in Ningbo, the fastener capital of China, we have advanced cold heading, heat treatment, and surface treatment production lines, achieving independent production throughout the entire process from raw materials to finished products. Without intermediaries, we can provide customers with highly competitive factory prices. Standard specifications are readily available in stock, allowing for quick response and delivery.

2. Technology-driven, rapid response: Our engineering team has extensive experience in the research and development and production of full-threaded fasteners, and is familiar with the standard requirements of different regions worldwide. We can provide professional non-standard customization (OEM/ODM) services based on drawings or samples provided by customers; we can quickly respond to and provide targeted solutions for technical problems encountered by customers during use. 3. Global Service Experience, Hassle-Free Cooperation: Our products have been exported to North America, Europe, Australia, and Southeast Asia, and we have a comprehensive logistics and after-sales service system. We can accurately match the procurement needs of global customers and are committed to establishing long-term and stable cooperative relationships with our clients.