304 - Stainless steel - Hexagon socket knurled heads cap screw

Why Choose Knurled Head A2 Screws?

In many assembly processes, speed and ease of handling are critical. The knurled head on our 304 socket screws solves a common problem: smooth round heads can be slippery and difficult to spin by hand. The knurling provides mechanical grip, allowing assemblers to start the thread quickly and accurately without needing to reach for a tool immediately. This feature, combined with the hygienic and rust-proof properties of A2 stainless steel, makes them a staple in electronics, medical devices, and light machinery.

Material Specifications: A2-70

Corrosion Resistance: Grade 304 (A2) is an austenitic stainless steel containing 18% Chromium and 8% Nickel. This chemistry forms a passive oxide layer that protects the screw from atmospheric corrosion and moisture. It is the ideal choice for applications that are not exposed to harsh marine salt but still require long-term visual appeal and structural integrity. Mechanical Performance: Our knurled socket screws are typically supplied as Class 70 (A2-70). This indicates a tensile strength of minimum 700 N/mm² and a yield strength of 450 N/mm². This strength level is comparable to many commercial carbon steel bolts but with the added benefit of not requiring a plated coating that could chip or wear off.

Quality Assurance

Reliability is key for precision components. We can provide an EN 10204 3.1 Material Certificate upon request, which verifies the chemical composition of the stainless steel batch. Please note that third-party inspection services are available for an additional fee.

Common Applications

The combination of grip and corrosion resistance makes these screws suitable for:

• Consumer Electronics: Assembling casings and internal components where precision is required.
• 3D Printers & Robotics: Used extensively in frames and motion systems for easy adjustment.
• Food Packaging Machinery: Non-food contact zones where cleanability and rust prevention are needed.
• Automotive Interiors: Dashboard and trim assembly where moisture might be present.

Frequently Asked Questions

Does the knurling affect the head diameter?

Yes, slightly, but it stays within the standard DIN 912 tolerances. The knurling adds a microscopic amount to the outer diameter, but the screw is designed to fit into standard counter-bored holes (holes drilled to hide the screw head) without interference.

Is A2 stainless steel magnetic?

In theory, austenitic stainless steel (304) is non-magnetic. However, the manufacturing process of cold-heading the socket and knurling the head works the metal hard. This stress can induce slight magnetism in the finished screw. This is a normal physical property of cold-worked stainless steel and does not indicate poor quality.

Can I use A2 stainless screws with aluminum profiles?

Yes, this is a very common application in robotics and frame building. However, because stainless steel and aluminum are dissimilar metals, galvanic corrosion can occur in wet environments. In dry indoor conditions, this is rarely an issue. For outdoor use, applying a jointing compound or anti-seize paste helps isolate the metals and prevent seizing.