Flat Head Carriage Bolt

We are a source factory with over 15 years of experience in fastener research, development, and manufacturing, and we understand the high demands customers place on balancing "aesthetics" and "functionality" in different application scenarios. Therefore, we specialize in the research and production of Flat Head Carriage Bolts, cleverly combining the concealed characteristics of countersunk screws with the anti-loosening function of carriage bolts. This precisely addresses the industry pain point of needing both aesthetics and security, making them the preferred fasteners for high-end assembly applications.

Core Product Advantages

1. Unique Countersunk Design, Balancing Aesthetics and Practicality

Flush Installation, No Protrusion: Unlike traditional round-headed carriage bolts, flat-head carriage bolts feature a countersunk design. During installation, the head is completely embedded within the material, keeping the connection surface flat and smooth without any unsightly protrusions, resulting in a more comfortable feel.

Invisible Effect for High-End Applications: This design is particularly suitable for applications requiring high surface flatness, such as solid wood dining tables, high-end bookcases, and floor joists. After installation, the bolt is almost invisible, ensuring both structural connection strength and overall visual appeal, perfectly meeting the assembly needs of high-end projects.

Suitable for Various Materials: Whether it's hard solid wood materials like mahogany and oak, or thin decorative panels, the countersunk design prevents damage to the material surface while ensuring a tight connection, making it widely applicable.

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

Self-Locking and More Secure: Inheriting the core advantage of carriage bolts, a square neck is located below the head. When the nut is tightened, the square neck firmly locks into the hole wall of the connected part, generating strong friction and preventing the bolt shaft from rotating with the nut, avoiding loosening and stripping problems, and ensuring long-term connection stability.

Single-Sided Operation Saves Time: 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 is a significant advantage in areas such as the bottom of furniture, confined spaces, or situations where only one side is accessible, greatly improving construction efficiency and reducing labor costs, especially suitable for mass assembly production scenarios. 3. High-Quality Materials and Stringent Standards for Reliable Performance

Selected high-quality raw materials:  Using high-quality medium-carbon steel such as Q235 and 35# steel, or 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 both impact resistance and wear resistance during use, preventing breakage or deformation.

Strict adherence to international standards: The products are manufactured in strict accordance with ISO 7085 (International Standard), DIN 603 (German Standard), and GB/T 14 (National Standard, in part). Dimensional accuracy and interchangeability are strictly controlled, ensuring perfect compatibility with accessories of the same specifications and meeting the standardized assembly needs of different industries.

Core Technical Parameters

Typical Application Scenarios

With years of industry service experience, our Flat Head Carriage Bolts have been successfully adapted to multiple high-end applications, becoming the preferred fastener for many customers:

1. High-end Solid Wood Furniture: Used for connecting the legs of mahogany furniture, solid wood dining tables, and bookshelves. The countersunk design ensures a smooth surface feel, and the square neck design provides stronger tensile strength than ordinary wood screws, preventing loosening during use and extending the furniture's lifespan.

2. Interior Decoration and Flooring: Suitable for fixing solid wood floor joists, installing baseboards, and connecting stair railings. After installation, the bolt head is flush with the wood, which is not only aesthetically pleasing but also prevents dust accumulation, facilitating daily cleaning and maintenance.

3. Precision Machinery and Electrical Appliances: Used for fixing machine tool guards, distribution box casings, and side panels of automated equipment. In applications requiring frequent disassembly and maintenance, and where surface flatness is critical, it offers a better balance of practicality and aesthetics compared to ordinary hexagonal bolts.

4. Doors, Windows, and Cabinets: Used for fixing heavy-duty wooden door hinges and connecting custom cabinet frames. It provides invisible and stable support, without affecting the appearance and texture of doors, windows, and cabinets, while ensuring connection strength to withstand the opening and closing impacts of daily use.

Company Strength and Quality Assurance

We are Ningbo Gangtong Zheli Fasteners Co., Ltd. Since our establishment in 2001, we have built a mature R&D, production, and sales system for fasteners. 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, specializing in the production of various fasteners. We 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 paramount. Through rigorous control throughout the entire process, we ensure that every bolt is reliable and durable:  During raw material warehousing, each batch of raw materials undergoes spectral analysis to precisely control chemical composition; during production, dimensional accuracy and thread quality are fully inspected to prevent unqualified semi-finished products from entering the next process; in the finished product stage, we conduct rigorous salt spray tests (over 72 hours for hot-dip galvanized products), tensile strength tests, and other tests to 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 protection directive, containing no harmful substances, ensuring both environmental and human safety.

Our product range is extensive, covering heavy-duty hexagonal bolts, heavy-duty hexagonal nuts, threaded rods, studs, washers, screws, etc., made from 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 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 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 ex-factory prices. Standard specifications are readily available in stock, allowing for quick response and delivery.

2. Professional technology, efficient response: Our engineering team has extensive industry experience 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 for technical problems encountered by customers during use.

3. Global service experience, worry-free cooperation: Our products have been exported to North America, Europe, Australia, and Southeast Asia, and we have a complete logistics and after-sales service system. We are familiar with the standard requirements and market demands of different regions and are committed to establishing long-term and stable cooperative relationships with our customers.