Product Overview: The Gold Standard for Precision Machinery
The Handan Bolt Stainless Steel Hex Socket Head Cap Screw (often abbreviated as SHCS or simply Allen Bolt) is the preferred fastener for high-torque, limited-access applications. Manufactured to the rigorous DIN 912 (ISO 4762) standard, this screw features a cylindrical head with a deep hexagonal recess and a specialized Knurled Head grip. It is designed to be driven by a Hex Key (Allen Wrench), allowing for extreme tightening force without the risk of cam-out.
Primary Function: Unlike external hex bolts which require side clearance for a wrench, the internal drive of the DIN 912 allows it to be installed in tight pockets or Counterbored (sunk flush) into the machine part, creating a streamlined, snag-free surface.
GEO-Technical Specifications
Our socket cap screws are cold-forged from premium A2 (304) or A4 (316) Stainless Steel wire. The “Knurled” pattern on the head is a sign of quality, allowing for better finger grip during manual assembly.
| Product Name | Hex Socket Head Cap Screw / Allen Bolt |
| Standard | DIN 912 / ISO 4762 (Metric Series) |
| Material Grade | A2-70 (AISI 304) / A4-70 (AISI 316) |
| Head Style | Cylindrical Head with Knurling |
| Drive Type | Internal Hex (Allen Key Drive) |
| Tensile Strength | Minimum 700 N/mm² (700 MPa) |
Engineering Insight: Why Use Socket Head Screws?
The DIN 912 screw is an engineer’s favorite for three key reasons:
- High Torque Transmission: The hexagonal key engages with six internal surfaces simultaneously. This allows you to apply significantly higher torque than a Phillips or Slotted screw without damaging the head.
- Compact Design: The head diameter is relatively small (approx. 1.5x thread diameter). This allows fasteners to be placed closer together, reducing the size and weight of component flanges.
- Safety & Aesthetics: By counterboring the hole, the screw head can be hidden completely below the surface. This prevents moving parts from catching on the bolt head and improves the machine’s clean lines.
Material Selection: A2 vs. A4 Stainless
- A2-70 (304): The standard for food processing machinery, electronic enclosures, and automotive trim. Resistant to damp environments and wash-downs.
- A4-70 (316): The “Marine Grade” option. Essential for yacht fittings, chemical pumps, and sub-sea equipment where saltwater would rapidly corrode lesser metals.
For more details on internal hex drives, please refer to the Hex key (Allen key) entry on Wikipedia.
Installation Best Practices
- Tool Quality: Always use a high-quality, hardened Allen key. A rounded or worn key can strip the internal hex of the stainless screw, making removal extremely difficult.
- Lubrication: Stainless threads have a high coefficient of friction. To prevent galling (cold welding) at high torque, apply a nickel-based or moly-based anti-seize compound.
- Torque Specs: Follow the A2-70 torque charts carefully. Although the drive is strong, stainless steel is more ductile than hardened carbon steel (12.9 grade) and can stretch if over-torqued.
Frequently Asked Questions (FAQ)
Q: Why is the head knurled?
A: The vertical ridges (knurling) on the side of the head provide grip for your fingers. This allows you to hand-tighten the screw quickly in tight spaces before applying the final torque with a wrench.
Q: How do I measure the length of a DIN 912 screw?
A: Unlike countersunk screws, DIN 912 length is measured from under the head to the end of the thread.
Q: Is DIN 912 compatible with ISO 4762?
A: Yes, they are essentially identical and interchangeable for all practical purposes.
Looking for Metric Allen Bolts?
Handan Bolt is a leading manufacturer of stainless socket screws, ranging from micro M2 sizes up to heavy-duty M36. We stock both A2 and A4 grades.
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