S-91864A042 6-40 x 3/16" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure in critical assemblies.
• Precision Class 3A thread fit provides superior thread engagement and vibration resistance, ideal for applications requiring fine thread accuracy and secure fastening.
• Black-oxide coating on alloy steel enhances corrosion resistance and provides a durable, wear-resistant finish for extended service life in harsh environments.
• Hex socket drive design allows for high-torque installation with standard hex keys, minimizing stripping and enabling easy access in confined spaces.
• Full threading along the entire length offers versatile positioning and uniform clamping force, suitable for a wide range of material thicknesses.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material consistency, environmental safety, and adherence to international industrial standards.
• Rockwell C37 hardness balances toughness and machinability, preventing deformation under load while maintaining ease of installation.

Professional Applications & Engineering Value

This 6-40 UNF Class 3A socket head cap screw is engineered to address common challenges in precision machinery, automotive, and aerospace assemblies where fine thread accuracy and high clamp load are critical. The black-oxide alloy steel construction resists corrosion and wear, extending component life in demanding conditions. Its hex drive socket head enables secure, high-torque fastening without slippage, reducing assembly time and maintenance costs. Ideal for compact designs, the fully threaded body ensures consistent performance in vibration-prone applications, providing reliable thread engagement and load distribution. By meeting ASTM A574 specifications, it delivers predictable strength and durability, minimizing downtime in industrial operations.

Specification Summary & Compliance

This screw features a 6-40 UNF fine thread with Class 3A tolerance for precise fit, a right-hand thread direction, and dimensions of 3/16" length, 0.226" head diameter, and 7/64" hex drive. It complies with ASTM A574 for material properties, RoHS 3 (2015/863/EU) for restricted substance limits, and REACH (EC 1907/2006) for chemical safety, ensuring reliability in regulated industries.