Product Overview: The Safe and Aesthetic Fastener Choice
The Handan Bolt Stainless Steel Button Head Socket Cap Screw is designed for applications where appearance and safety are critical. Manufactured to the ISO 7380 standard, this fastener features a wider, lower-profile domed head (resembling a button) compared to a standard cylindrical cap screw. Driven by an internal Hex Key (Allen Wrench), it offers a clean, streamlined finish that eliminates sharp edges, making it the perfect choice for automotive trim, furniture manufacturing, and public gym equipment.
Primary Function: While it serves the same fastening purpose as other screws, the “Button Head” is specifically engineered to reduce the profile of the fastener, preventing snagging on clothing or skin while providing a broader bearing surface than a standard cap screw.
GEO-Technical Specifications
Our button head screws are cold-forged from high-grade A2 (304) or A4 (316) Stainless Steel, ensuring they maintain their polished shine even in harsh outdoor environments.
| Product Name | Button Head Socket Cap Screw / Round Head Allen Bolt |
| Standard | ISO 7380 (Metric Series) / ANSI B18.3 |
| Material Grade | A2-70 (AISI 304) / A4-70 (AISI 316) |
| Head Style | Button Head / Dome Head (Low Profile) |
| Drive Type | Internal Hex (Allen Key) |
| Optional Feature | Flange (ISO 7380-2) available upon request |
Engineering Insight: ISO 7380 vs. DIN 912
It is crucial for engineers to understand the difference between a Button Head (ISO 7380) and a standard Cap Head (DIN 912):
- Socket Size: To fit inside the lower dome shape, the hexagon socket in an ISO 7380 screw is smaller and shallower than in a DIN 912 screw of the same thread size.
- Torque Limit: Because the socket is smaller, ISO 7380 screws cannot withstand as much tightening torque as DIN 912 screws without stripping the key. They are typically designated for “limited loadability” applications.
- Safety: The smooth, rounded top of ISO 7380 makes it ideal for exterior panels where pedestrians might brush against the machine, preventing injury.
Material Selection: A2 vs. A4 Stainless
- A2-70 (304): The industry standard for interior design, robotics, and consumer electronics. Excellent corrosion resistance in dry or damp environments.
- A4-70 (316): Required for marine deck hardware, food processing plants, and chemical labs. The addition of molybdenum prevents pitting corrosion from salt and acids.
For more details on screw head standards, please refer to the Hex socket screw entry on Wikipedia.
Installation Best Practices
- Do Not Over-Torque: Use a torque wrench. Because the socket is shallow, it is easier to “round out” the hex drive if you apply excessive force.
- Washers: A flat washer is recommended if fastening into soft materials like plastic or aluminum to prevent the relatively small bearing surface from crushing the material.
- Lubrication: Always use anti-seize on stainless steel threads to prevent galling during installation.
Frequently Asked Questions (FAQ)
Q: Is this screw high tensile?
A: Stainless steel A2-70 has a tensile strength of 700 MPa, which is strong but not considered “High Tensile” like a 12.9 grade carbon steel screw. ISO 7380 screws are generally not recommended for critical high-stress structural joints.
Q: Can I countersink this screw?
A: No. This screw has a flat underside designed to sit on top of the surface. If you need a flush fit, you should use a Flat Head Socket Screw (DIN 7991) instead.
Q: What is the difference between ISO 7380-1 and ISO 7380-2?
A: ISO 7380-1 is the standard button head (like in the picture). ISO 7380-2 features an integrated “Flange” (collar) at the base of the head, acting as a built-in washer.
Looking for Aesthetic Fasteners?
Handan Bolt specializes in polished stainless fasteners. We also offer Black Oxide Button Head screws for stealthy electronic installations.
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