S-91251A296 1/4"-28 x 1 5/8" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 PSI ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Precision Class 3A thread fit provides superior engagement and vibration resistance, minimizing loosening in critical assemblies.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance, extending service life in demanding industrial environments.
• Partially threaded design allows for precise clamping force control and secure fastening in specific joint configurations.
• Hex socket drive enables high-torque installation with standard tools, preventing cam-out and ensuring efficient assembly.
• Fine UNF thread spacing delivers improved load distribution and finer adjustment capabilities compared to coarse threads.
• Rockwell C37 hardness provides excellent wear resistance, maintaining thread integrity through repeated use.

Professional Applications & Engineering Value

These Black-Oxide Alloy Steel Socket Head Cap Screws with 1/4"-28 UNF fine threads are engineered to solve critical fastening challenges in precision machinery, automotive systems, and heavy equipment. The Class 3A thread fit ensures minimal clearance between mating parts, eliminating play in vibration-prone applications. The partially threaded configuration allows engineers to position the unthreaded shank in shear planes while concentrating threads in tensile zones, optimizing load distribution. With 170,000 PSI tensile strength and corrosion-resistant black-oxide finish, these fasteners withstand harsh operating conditions while maintaining dimensional stability. The hex socket drive accommodates high installation torque without damaging the fastener head, making them ideal for confined spaces where wrench clearance is limited.

Specification Summary & Compliance

This 1/4"-28 UNF Socket Head Cap Screw features Class 3A thread fit for precision applications with tight tolerances. Manufactured to ASTM A574 specification for socket head cap screws, it ensures consistent quality and performance. The product is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international environmental standards for industrial use. With fine thread spacing and right-hand thread direction in the inch system, it provides reliable fastening performance across various engineering applications.