Premium Hex Socket Head Cap Screws: Precision Fasteners for High-Stress Applications
At Handan Bolt, we are a leading manufacturer of high-strength Hex Socket Head Cap Screws, widely recognized in the industry as Allen Bolts. Produced in our advanced cold-heading facility in Yongnian, China, these fasteners are the gold standard for precision machinery, automotive assembly, and heavy equipment. Unlike standard hex bolts, our socket screws are designed to handle higher torque values and fit into compact spaces where traditional wrenches cannot reach.
What is a Socket Head Cap Screw?
A Socket Head Cap Screw (SHCS) is a cylindrical-headed screw with a hexagonal internal drive. It is tightened using a Hex Key (Allen Wrench) – Read more on Wikipedia. This internal drive design is superior for several reasons:
- Compact Assembly: The cylindrical head is smaller than a hex head, allowing it to be sunk into a counterbored hole for a flush finish.
- No Side Clearance Needed: Since the tool (Allen key) is inserted from the top, you don’t need space around the bolt head for a spanner rotation. This allows engineers to place bolts closer together.
- Safety: There are no sharp external edges on the head to catch on clothing or machinery parts.
The “Knurled Head” Advantage
As clearly shown in your product images, our premium DIN 912 bolts feature Head Knurling (a textured pattern on the side of the head).
Why does this matter? The knurling provides a grip surface, allowing assembly workers to run the screw down quickly by hand (finger tightening) before the final torque is applied with a tool. This small detail significantly speeds up manual assembly lines.
Standards and High-Tensile Grades
Socket screws are almost exclusively used in high-strength applications. We manufacture strictly to the following standards:
1. DIN 912 / ISO 4762 (Metric Standard)
This is the global standard for metric socket cap screws. We supply these in:
- Grade 8.8: High tensile steel for general industrial use.
- Grade 10.9: Heat-treated alloy steel offering higher yield strength, commonly used in automotive engines.
- Grade 12.9: The strongest standard class (1200 MPa tensile strength), offering the highest clamping force for critical heavy machinery connections.
2. ASTM A574 (Imperial/Inch Standard)
For the North American market, we produce high-strength alloy steel socket screws that exceed Grade 8 specifications. These are essential for US-spec machinery and aerospace tooling.
Surface Finishes
We offer finishes that balance performance and aesthetics:
- Black Oxide (Thermal Black): The most common finish for Grade 12.9 socket screws. It retains the lubricant oil well and reduces glare, but offers limited rust protection.
- Zinc Plated (Blue/White): Provides galvanic rust protection for Grade 8.8 and 10.9 bolts used in outdoor or damp environments.
- Dacromet / Geomet: Available for automotive clients requiring high salt-spray resistance (500-1000 hours) without hydrogen embrittlement risks.
Common Applications
Our Hex Socket Head Bolts are ubiquitous in:
- Machine Tools: CNC machines, lathes, and milling equipment.
- Automotive: Engine cylinder heads, suspension components, and transmission casings.
- Robotics: The compact head allows for lightweight, streamlined joint designs.
- Die & Mold Making: High clamping force keeps heavy molds securely closed.
Why Source from Handan Bolt?
Precision Manufacturing: Our cold headers ensure tight tolerances on the socket dimension, preventing “rounded out” heads during tightening.
Complete Range: From tiny M3 screws for electronics to massive M36 bolts for infrastructure.
Custom Packaging: We can provide small “Retail Packs” with Allen keys included, or bulk industrial cartons.
Get a Factory Direct Quote
Are you a machinery manufacturer or a fastener distributor? Upgrade your supply chain with our high-grade socket screws.
Need a price list for DIN 912 bolts?
Please click here to Contact Our Sales Team for a Free Quote. We export to Europe and the USA!
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