cylindrical head bolts
Cylindrical Head Bolts — also known as Socket Head Cap Screws or Allen Bolts — feature a cylindrical head and an internal hexagon drive (Allen key type), providing a clean and compact fastening solution. These bolts are designed for applications where high strength, limited space, and flush installation are required.They are widely used in machinery, automation, automotive assemblies, die tooling, robotics, and structural frameworks, offering excellent clamping force and easy assembly with tools even in tight or recessed spaces.
Functions and Benefits
Cylindrical Head Design
Slim profile allows for space-saving installation in compact or countersunk components.
Internal Hex Drive (Allen Key)
Enables torque application without needing side clearance — ideal for machinery and tool assemblies.

Typical Product Variants
Material | Description |
---|---|
Carbon Steel | Cost-effective; available in Grades 8.8, 10.9, 12.9 |
Stainless Steel (A2-70, A4-80) | Corrosion-resistant for outdoor or chemical environments |
Alloy Steel | High strength; suitable for heavy-load or vibration-prone assemblies |
Titanium / Brass / Special Alloys | For aerospace, medical, or customized needs |

Increased Load Distribution:
High Mechanical Strength
Available in Class 8.8, 10.9, and 12.9 grades (or equivalent), providing excellent tensile and shear strength.Precision Threading
Cold-rolled or cut threads with high dimensional accuracy and smooth surface finish.
Typical products

DIN 912 / ISO 4762 / ANSI B18.3

DIN 7984 / ISO 7379
Applications and Use Cases

Industry: Precision Machinery Location: Stuttgart, Germany Client: CNC machining center manufacturer Application: Mounting linear guide rails and servo motor brackets inside the main machine frameChallenge: The client's high-speed CNC milling machines required fasteners that could withstand high vibration, tight space constraints, and ensure perfect alignment of linear motion components. Traditional hex-head bolts were too bulky and risked misalignment during high-speed travel.Solution: We supplied Socket Head Cap Screws (DIN 912, Grade 12.9) with a black oxide finish. Their cylindrical head and internal hex drive allowed them to be installed deeply inside the equipment body using Allen keys, even in recessed or blind spots. The high tensile strength (12.9 grade) provided excellent clamping force and vibration resistance.Outcome:Assembly time reduced by 20% due to easy access with Allen toolsPerfect alignment of guide rails maintained after 1,000+ hours of operationNo bolt loosening or fatigue observed after vibration testsBecame the standard fastening choice in their next product series

Industry: Mold & Die Manufacturing Location: Incheon, South Korea Client: Tier-1 injection mold maker Application: Securing mold plates, guide bushings, and ejector housingsChallenge: Plastic injection molds require extremely tight tolerances and must withstand cyclic clamping forces during molding operations. The customer needed bolts that provided strong clamping force while also fitting flush into counterbored holes to avoid contact with plastic flow paths or moving parts.Solution: We supplied Low Head Socket Cap Screws (DIN 7984) in Stainless Steel A2-70. The low-profile head ensured flush installation inside mold bases, while the internal hex drive allowed maintenance staff to easily access and retighten bolts without disassembling the entire mold.Outcome:Improved mold service life due to consistent plate pressureFaster maintenance during mold cleaning cyclesCorrosion resistance in humid environments (from cooling channels)Strong word-of-mouth led to referrals to three other mold suppliers
Top Uses and Benefits of Cylindrical Head Bolts in Various Industries
Introduction to High Strength Fastening Systems
High strength fastening systems are essential for secure fastening in various industries, including aerospace and automotive.
Cylindrical head bolts are a type of high strength fastening system designed for secure fastening in critical applications.
These bolts are made from high strength steel and are available in various grades, including tempered steel. Many cylindrical head bolts are manufactured in countries with advanced industrial bases, such as China, which is known for its large-scale production and export of high-quality bolts.
The use of cylindrical head bolts ensures reliable contact with materials and prevents loosening over time.
Characteristics of Head Bolts
Head bolts are precision-machined components designed for secure fastening in various assemblies.
They are manufactured from high strength alloy steel and brass, ensuring durability and reliable performance.
The cylindrical head design provides a secure fastening system, preventing loosen over time.
Head bolts are available in various sizes, including M4, M5, and M6, to suit different applications.
Head bolts are offered in different models to meet specific requirements, and each item is carefully inspected to ensure quality and reliability.
Types of Special Bolts
Special bolts, including blind rivet bolts and locking bolts, are designed for specific applications.
Clamping bolts are used for secure fastening in high-stress environments.
Cylindrical head bolts are a type of special bolt designed for high strength fastening.
These bolts are suitable for various industries, including aerospace, automotive, and medical.
These special bolts are often used in combination with other fastening parts and nuts to provide comprehensive assembly solutions.
Materials Used for Head Bolts
Cylindrical head bolts are manufactured from a diverse selection of materials to meet the demands of various industries and applications. High-strength steel is a popular choice for head bolts, offering exceptional durability and the ability to withstand significant stress, making it ideal for secure fastening in environments such as aerospace and heavy machinery. Stainless steel is another widely used material, valued for its superior resistance to corrosion and suitability for applications where exposure to moisture or chemicals is common, such as in medical devices and aerospace components. For specialized uses where weight reduction is critical without compromising strength, titanium head bolts are selected due to their lightweight nature and outstanding corrosion resistance. The choice of material for cylindrical head bolts is determined by the specific requirements of the application, including the need for high strength, resistance to environmental factors, and compatibility with other components. By selecting the right material, manufacturers ensure that bolts deliver reliable performance and long-lasting secure fastening in any setting.
Sizes and Finishes of Cylindrical Head Bolt
Cylindrical head bolts are available in an extensive range of sizes and finishes to accommodate the diverse needs of different industries. The size of these bolts can range from small diameters like M2.5, suitable for precision electronics, to larger sizes such as M20, commonly used in heavy-duty aerospace and construction applications. Lengths also vary, allowing for flexibility in assembly and compatibility with a wide range of components. In addition to size, the finish of a cylindrical head bolt plays a crucial role in its performance and longevity. Common finishes include zinc plating, which provides a protective barrier against corrosion; chrome plating, which enhances both appearance and durability; and hot dip galvanizing, which offers robust protection in harsh environments. For unique requirements, bolts can be manufactured with custom sizes and specialized finishes, ensuring the right fit and protection for any application. This broad range of sizes and finishes makes cylindrical head bolts a versatile choice for secure fastening across multiple industries.
Threads and Heads of Special Bolts
Special bolts, including cylindrical head bolts, are designed with a variety of thread types and head styles to ensure secure fastening in a wide range of applications. The threads on these bolts can be coarse or fine, with coarse threads allowing for quick assembly and disassembly, and fine threads providing greater holding power and precision, especially in high-stress or vibration-prone environments. The head of the bolt is also an important consideration, with options such as hexagonal, square, and slotted heads available to suit different tools and installation methods. Some cylindrical head bolts feature a hex socket drive, making installation easy and ensuring a tight, secure fit even in confined spaces. These design variations allow special bolts to be tailored to specific tasks, whether it’s for aerospace, automotive, or industrial machinery. By choosing the right combination of thread type and head style, users can ensure efficient, reliable, and easy fastening, enhancing the overall performance and safety of their assemblies.
Advantages of Cylindrical Head
The cylindrical head design provides a secure fastening system, preventing loosen over time.
High strength bolts, including cylindrical head bolts, offer heat resistance, abrasion reduction, and electrical insulation.
Simple construction ensures good force performance in connections, making cylindrical head bolts a reliable choice.
These bolts are removable, replaceable, and fatigue-resistant, reducing maintenance costs.
Customers are often happy with the reliability and ease of use of cylindrical head bolts, as reflected in positive reviews.
Applications of Head Bolt
Cylindrical head bolts are widely used in aerospace, automotive, medical, and machine tool industries.
Applications include rocket engine nozzles, space shuttle components, and thermal protection systems.
These bolts are also used in aircraft brake discs and various machine tool accessories.
High strength fastening systems, including cylindrical head bolts, are essential for secure fastening in critical applications.
Users can easily find the appropriate cylindrical head bolt for their specific application by consulting detailed product catalogs or supplier websites.
Industries that Use Special Bolts
Aerospace industry uses cylindrical head bolts for secure fastening in critical applications.
Automotive industry uses special bolts, including cylindrical head bolts, for high strength fastening.
Medical industry uses cylindrical head bolts for secure fastening in medical equipment.
Machine tool industry uses high strength fastening systems, including cylindrical head bolts, for secure fastening.
Industries often specify the required order or series of cylindrical head bolts, such as the EH 1555.500 series or 5SH series, to ensure compatibility with their assembly processes.
How to Choose the Right Bolt
Choose the right bolt based on the application, including the type of material and the required strength.
Consider the grade of the bolt, including tempered steel, to ensure high strength fastening.
Select a bolt with the correct size and thread pitch to ensure secure fastening.
Consult with a manufacturer or supplier to ensure the correct bolt is chosen for the application.
Customers can shop with confidence when selecting cylindrical head bolts from reputable suppliers.
Installation and Maintenance
Installation of cylindrical head bolts requires careful consideration to ensure secure fastening.
Cylindrical head bolts are often supplied in a package containing multiple items, making it convenient for bulk installations.
Maintenance of these bolts is essential to prevent loosening over time.
Regular inspection and tightening of the bolts can help prevent maintenance costs.
Use of original packaging and accessories can help ensure the bolts are installed correctly.
The best way to maintain cylindrical head bolts is to follow the recommended inspection and tightening procedures.
Common Uses
Cylindrical head bolts are commonly used in aerospace, automotive, and medical industries.
These bolts are used for secure fastening in critical applications, including rocket engine nozzles and space shuttle components.
High strength fastening systems, including cylindrical head bolts, are essential for secure fastening in various industries.
Cylindrical head bolts are available in various sizes and grades to suit different applications.
Customers can benefit from competitive price options and occasional discount offers, and a clear return policy ensures peace of mind when purchasing cylindrical head bolts.
DingLong Solution
DingLong Solution is a trusted company specializing in the manufacturing and supply of high-quality cylindrical head bolts. Known for their commitment to precision and durability, DingLong Solution offers a wide range of bolts made from premium materials such as high-strength steel and tempered alloys. Their products are designed to meet the stringent requirements of industries including aerospace, automotive, medical, and machinery. With competitive pricing, reliable delivery, and excellent customer support, DingLong Solution ensures customer satisfaction through quality products and professional service.
As a reputable seller, DingLong Solution provides a straightforward refund process for returns initiated within 30 days of delivery.
Why Choose DingLong Solution?
Experienced Manufacturer: With over 20 years of expertise, DingLong Solution is a reliable supplier of high-strength cylindrical head bolts.
Competitive Pricing: Offering factory-direct prices that help reduce your procurement costs by up to 20%, ensuring great value for money.
Customization Services: Capable of producing custom bolts based on your drawings or samples, meeting non-standard requirements with precision.
Quality Assurance: Committed to delivering bolts made from premium materials with strict quality control to guarantee durability and performance.
Fast Delivery: Partnering with multiple logistics providers to ensure your orders reach your hands quickly and safely.
Excellent Customer Support: Dedicated to addressing your questions and providing professional service to ensure your satisfaction throughout the purchasing process.
For more information, to discuss specific terms and conditions, or to request a quotation, please contact DingLong Solution via email.
Contact DingLong
Frequently Asked Questions (FAQ)
Can I order non-standard lengths or threads?
A: Yes, we support custom manufacturing based on technical drawings or specs.
What is the minimum order quantity (MOQ)?
A: For standard sizes, MOQ is flexible (as low as 100 pcs). For custom bolts, MOQ may vary by material and process.
Can you supply with 3.1 or 3.2 material certificates?
A: Yes, we provide MTCs and third-party inspections (TÜV, SGS, BV) upon request.
Q:How are the bolts packaged?
A: Typically in 25kg cartons + pallets. Custom packaging options available for OEM clients.
Q: What is the lead time?
A: Stock sizes: 3–5 days. Custom sizes: 7–15 working days depending on complexity.