S-91251A128 5-40 x 1/2" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating, extending service life in demanding industrial environments
• Exceptional tensile strength of 170,000 psi prevents stripping and failure under high-load applications
• Precision Class 3A thread fit ensures secure fastening with minimal backlash in critical assemblies
• Rockwell C37 hardness provides excellent wear resistance for repeated installation cycles
• Standard hex socket drive allows for high-torque installation with common industrial tools
• Coarse UNC threading enables rapid assembly while maintaining strong holding power
• Full compliance with ASTM A574, RoHS 3, and REACH regulations for quality assurance

Professional Applications & Engineering Value

Engineered for precision industrial applications, these black-oxide alloy steel socket head cap screws deliver reliable performance where vibration resistance and structural integrity are critical. The 5-40 UNC coarse thread configuration provides excellent engagement in various materials while the Class 3A thread fit maintains tight tolerances for precision machinery, automotive components, and heavy equipment assemblies. The fully threaded design ensures maximum grip length while the hex socket drive accommodates high torque applications without cam-out. Ideal for CNC machinery, industrial automation, and aerospace applications requiring 170,000 psi tensile strength and consistent performance under extreme conditions.

Specification Summary & Compliance

Manufactured to exacting Class 3A thread fit standards with UNC coarse threading (5-40) and 1/2" length in inch system measurements. Complies with ASTM A574 specification for socket head cap screws and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Features 3/32" hex drive compatibility and right-hand thread direction for standard industrial applications.